Co-reporter:Li Wang, Hai-Long Wu, Xiao-Li Yin, Yong Hu, Hui-Wen Gu, Ru-Qin Yu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 170() pp: 104-110
Publication Date(Web):
DOI:10.1016/j.saa.2016.07.018
Co-reporter:Zhi Liu;Li-Xia Xie;Yong Hu;Huan Fang;Xiao-Dong Sun;Tong Wang;Rong Xiao;Ru-Qin Yu
Analytical Methods (2009-Present) 2017 vol. 9(Issue 22) pp:3361-3374
Publication Date(Web):2017/06/08
DOI:10.1039/C7AY00415J
In the present work, a novel chemometrics-assisted analytical strategy that combines three-way high performance liquid chromatography-diode array detection (HPLC-DAD) data with a second-order calibration method based on the alternating trilinear decomposition (ATLD) algorithm was developed for direct, accurate and simultaneous determination of thirteen phenolic compounds in complex red wine samples without an intricate clean-up step. All analytes were rapidly eluted out (7.5 min) under a simple gradient LC-separation and then detected in a multi-channel UV window. With the aid of the prominent “second-order advantage” of the ATLD algorithm, four common HPLC problems, i.e. solvent peaks, peak overlaps, unknown interferents and baseline drifts, could be mathematically calibrated, enabling “pure signals” of analytes to be extracted out from interference-heavy but information-rich HPLC-DAD profiles. The new strategy could avoid the loss of analytes of interest to significantly improve the analytical accuracy. Validation parameters, i.e. recovery (97.7–104%), precision (RSD < 7.1%), matrix effect, limits of detection (LODs, 0.02–0.27 μg mL−1) and limits of quantitation (LOQs, 0.06–0.82 μg mL−1) of thirteen analytes, were surveyed and further confirmed by the LC-MS/MS method. Based on the indexes of phenolic compositions in wines, pattern recognition methods, i.e. principal component analysis and linear discriminant analysis (PCA-LDA), were applied for distinguishing wines of different storage years, and the discriminant accuracies were higher than 90%, which proved that this chemometrics-assisted HPLC-DAD strategy was an excellent method for direct and accurate determination of phenolic compositions in complex wine samples as well as the authentication of vintage year.
Co-reporter:Yong Li, Hai-long Wu, Xiang-yang Yu
Chemometrics and Intelligent Laboratory Systems 2017 Volume 171(Volume 171) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.chemolab.2017.10.021
•W-APTLD was proposed to analyze three-way data arrays with missing values.•W-CORCONDIA was proposed to estimate the chemical ranks.•Better than other three methods, W-APTLD was insensitive to excessive factors.•Similar as INDAFAC, W-APTLD could overcome severe collinearity.Multi-way data arrays contain missing values for several reasons, such as various malfunctions of instruments, responses being outside instrument ranges, irregular measurement intervals between samples and data postprocessing. In the present study, one new method, weighted alternating penalty trilinear decomposition (W-APTLD), based on the weighted trilinear model and the idea of alternative trilinear decomposition was given to analyze three-way data arrays containing missing values. In addition, one improved core consistency diagnostic method (W-CORCONDIA) was proposed to estimate the chemical ranks of three-way data arrays containing missing values. The results of one simulation and two real data sets demonstrate that the new method W-APTLD could be used to deal with missing values and reserves the second-order advantage. When meeting excessive factors, W-APTLD could give more accurate results than weighted PARAFAC (W-PARAFAC), PARAFAC with single imputation (PARAFAC-SI) and incomplete data PARAFAC (INDAFAC). The convergence rate of W-APTLD was much faster than W-PARAFAC and PARAFAC-SI but slower than INDAFAC. Better than W-PARAFAC and PARAFAC-SI, W-APTLD could overcome the problem due to severe collinearity. In addition, this new method could be extended to analyze higher-way data arrays containing missing values.
Co-reporter:Li-Xia Xie, Hai-Long Wu, Xiao-Hua Zhang, Tong Wang, Li Zhu, Shou-Xia Xiang, Zhi Liu, Ru-Qin Yu
Chemometrics and Intelligent Laboratory Systems 2017 Volume 167(Volume 167) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.chemolab.2017.05.017
•A proper generalization of the “slicing” concept to the four-way case is made.•Multiplication of a higher-order tensor by a matrix will be newly established.•A new slicing alternating quadrilinear decomposition algorithm is proposed.•It achieves quadrilinear decomposition, preserving the inner structure.•It has a fast convergence and overcomes severe collinearity.A three-way data array in the trilinear component model can be described into sliced matrices and then decomposed into three underlying matrices by iterative procedure. In this paper, we make an in-depth study of the quadrilinear component model, generalize the “slice” to the four-way scenario, and develop a novel quadrilinear decomposition algorithm for third-order calibration, i.e., slicing alternating quadrilinear decomposition (SAQLD). The presently developed algorithm can be considered as a generalization of ATLD to four-way case. In the algorithm, updates of four underlying matrices are alternately iterated until convergence is reached. Operation of extracting diagonal elements is adopted, which makes SAQLD focus on extracting the quadrilinear part in data, leading to a significant decrease in the loss function and finally a high-performance computing strategy for SAQLD, i.e., fast convergence. Owing to its specific optimization approach, the proposed SAQLD algorithm recovers parameter matrices faster when compared with the existing quadrilinear decomposition algorithms. Both numerical simulations and experimental measurements demonstrate that third-order calibration based on the SAQLD algorithm allows one to obtain quantitative information regarding known constituents present in samples without worrying about other interferents. Moreover, quantitative results supplied by the SAQLD algorithm are still satisfying when the number of components used in calculation is excessive. Such a feature is very useful in quantitative chemical analysis since it is not easy to accurately determine the appropriate number of components due to the complex of chemical substrates.
Co-reporter:Yong Hu, Hai-Long Wu, Xiao-Li Yin, Hui-Wen Gu, Rong Xiao, Li Wang, Huan Fang, Ru-Qin Yu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 175() pp:229-238
Publication Date(Web):15 March 2017
DOI:10.1016/j.saa.2016.12.030
•A novel spectrofluorometric method was proposed for the quantification of nephrotoxic AA-I and AL-I in five herbal medicines.•A chemical derivatization that converts the non-fluorescent AA-I to high-fluorescent AL-I achieves a high sensitivity.•The coupling to second-order calibration methods renders an attractive and green strategy.•No significant difference for quantitative results between the proposed strategy and validated LC-MS/MS method.A rapid interference-free spectrofluorometric method combined with the excitation-emission matrix fluorescence and the second-order calibration methods based on the alternating penalty trilinear decomposition (APTLD) and the self-weighted alternating trilinear decomposition (SWATLD) algorithms, was proposed for the simultaneous determination of nephrotoxic aristolochic acid I (AA-I) and aristololactam I (AL-I) in five Chinese herbal medicines. The method was based on a chemical derivatization that converts the non-fluorescent AA-I to high-fluorescent AL-I, achieving a high sensitive and simultaneous quantification of the analytes. The variables of the derivatization reaction that conducted by using zinc powder in acetose methanol aqueous solution, were studied and optimized for best quantification results of AA-I and AL-I. The satisfactory results of AA-I and AL-I for the spiked recovery assay were achieved with average recoveries in the range of 100.4–103.8% and RMSEPs < 0.78 ng mL− 1, which validate the accuracy and reliability of the proposed method. The contents of AA-I and AL-I in five herbal medicines obtained from the proposed method were also in good accordance with those of the validated LC-MS/MS method. In light of high sensitive fluorescence detection, the limits of detection (LODs) of AA-I and AL-I for the proposed method compare favorably with that of the LC-MS/MS method, with the LODs < 0.35 and 0.29 ng mL− 1, respectively. The proposed strategy based on the APTLD and SWATLD algorithms by virtue of the “second-order advantage”, can be considered as an attractive and green alternative for the quantification of AA-I and AL-I in complex herbal medicine matrices without any prior separations and clear-up processes.
Co-reporter:Xiao-Li Yin, Hai-Long Wu, Hui-Wen Gu, Yong Hu, Li Wang, Hui Xia, Shou-Xia Xiang, Ru-Qin Yu
Journal of Chromatography A 2016 Volume 1435() pp:75-84
Publication Date(Web):26 February 2016
DOI:10.1016/j.chroma.2016.01.042
•A novel HPLC-DAD method assisted with second-order calibration was developed.•The method was employed to solve varying interfering patterns for beverage analysis.•The method was applied to determine six co-eluted colorants in different kinds of beverages.•The results of the proposed method were consistent with those of the HPLC-UV method.•The method proved to be accurate, economical and universal.This work reports a chemometrics-assisted high performance liquid chromatography-diode array detection (HPLC-DAD) strategy to solve varying interfering patterns from different chromatographic columns and sample matrices for the rapid simultaneous determination of six synthetic colorants in five kinds of beverages with little sample pretreatment. The investigation was performed using two types of LC columns under the same elution conditions. Although analytes using different columns have different co-elution patterns that appear more seriously in complex backgrounds, all colorants were properly resolved by alternating trilinear decomposition (ATLD) method and accurate chromatographic elution profiles, spectral profiles as well as relative concentrations were obtained. The results were confirmed by those obtained from traditional HPLC-UV method at a particular wavelength and the results of both methods were consistent with each other. All results demonstrated that the proposed chemometrics-assisted HPLC-DAD method is accurate, economical and universal, and can be promisingly applied to solve varying interfering patterns from different chromatographic columns and sample matrices for the analysis of complex food samples.
Co-reporter:Zhi Liu, Hai-Long Wu, Hui-Wen Gu, Xiao-Li Yin, Li-Xia Xie, Yong Hu, Hui Xia, Shou-Xia Xiang and Ru-Qin Yu
RSC Advances 2016 vol. 6(Issue 31) pp:25850-25863
Publication Date(Web):02 Mar 2016
DOI:10.1039/C5RA26549E
A novel ‘dilute-and-shoot’ analytical strategy coupling a self-weighted alternating normalized residue fitting (SWANRF) algorithm with two-dimensional fluorescence detection enhanced through photochemical derivatization (PD) was proposed in the present work for rapid, simultaneous and accurate quantitative analysis of aflatoxin B1 and G1 in various foodstuffs (including cereals, honey, and edible oil). By coupling the predominant second-order advantage of the SWANRF algorithm with the ultra-sensitivity of fluorescence detection enhanced through off-line photochemical derivatization, the specific quantitative information of both analytes could be successfully extracted from heavily interferential matrices without complicated multi-step purification and chromatographic separation procedures. Consequently, the whole analytical time and expense were significantly decreased, accurate recoveries (with relative standard deviations, RSDs) (93.5 ± 6.6–102.8 ± 4.0% for AFB1, and 96.4 ± 3.6–107.2 ± 6.0% for AFG1) and extremely low limits of detection (LODs) (0.12–0.21 ng mL−1 for AFB1, and 0.27–0.75 ng mL−1 for AFG1) were obtained for analytical foodstuff matrices. In addition, all quantitative results of this proposed strategy were carefully compared with the standard IAC-LC-ESI+-MS method for further confirmation, which proved that SWANRF-EEMs are promising as an alternative analytical strategy for the routine analysis of multiplex aflatoxins, and a theoretical basis for developing portable detecting devices.
Co-reporter:Li Zhu, Hai-Long Wu, Li-Xia Xie, Huan Fang, Shou-Xia Xiang, Yong Hu, Zhi Liu, Tong Wang and Ru-Qin Yu
Analytical Methods 2016 vol. 8(Issue 24) pp:4941-4948
Publication Date(Web):25 May 2016
DOI:10.1039/C6AY00821F
A fast analytical method that combines second-order calibration based on alternating trilinear decomposition (ATLD) algorithm with excitation–emission matrix (EEM) fluorescence technique is proposed to mathematically separate the overlapped spectra and simultaneously quantify arbutin (AR) and hydroquinone (HQ) in cosmetic products. This method inherits the merit of high sensitivity of traditional fluorescence and fully realizes the “second-order advantage”. For AR and HQ, the calibration ranges are 40.00–400.00 and 20.00–200.00 ng mL−1, respectively. The limits of detection for both analytes are in the range of 1.51–4.01 ng mL−1. The proposed method could be applied to diluted samples of different cosmetic products with satisfactory results. The actual concentrations of AR in the tested cosmetic products are found to be in the allowable concentration range (7%); while, the prohibited skin whitening agent HQ is detected in lotion. The contents of AR and HQ in the tested cosmetic products obtained by the proposed method are also in accordance with those of the validated high-performance liquid chromatographic method. These satisfactory results indicate that the proposed method has the potential to accurately quantify AR and HQ in complex matrices containing uncalibrated interferents, and shows promise as a reliable tool for quality monitoring of cosmetic products.
Co-reporter:Xiao-Hua Zhang, Hai-Long Wu, Xiao-Li Yin, Yong Li, Xiang-Dong Qing, Hui-Wen Gu, Chao Kang, Ru-Qin Yu
Chemometrics and Intelligent Laboratory Systems 2016 Volume 155() pp:46-53
Publication Date(Web):15 July 2016
DOI:10.1016/j.chemolab.2016.04.008
•The strategy of introducing an extra solvent mode in the three-way EEMs data was first used.•The ‘third-order advantage’ was studied by processing the EX–EM-solvent-samples data.•Third-order calibration can resist the influence of serious collinearity and high background.•The direct quantitative analysis of schizandrol A and schizandrol B in complex DMEM was achieved.In this paper, a new strategy of introducing an extra solvent mode in the three-way EEMs data to construct a four-way EX–EM-solvent-samples data set was used in order to investigate the ‘third-order advantage’ by comparing the performances of two four-way calibration algorithms with those of two three-way calibration algorithms. The results of the self-weighted alternating normalized residue fitting (SWANRF) and the parallel factor analysis (PARAFAC) algorithms were both disappointing in this work due to serious collinearity and high background interference. In contrast, the satisfactory results (average recovery, 100.0–107.4% and standard deviation, 1.0–3.0%) were obtained by the third-order calibration methods based on both four-way self-weighted alternating normalized residue fitting (four-way SWANRF) and four-way parallel factor analysis (four-way PARAFAC) algorithms. In addition, for prediction of Dulbecco's modified eagle medium (DMEM) samples, the root-mean-square error of prediction (RMSEP) values for schizandrol B obtained from two three-way calibration algorithms were 60.91 and 35.46 μg mL− 1 with 80% ethanol in the aqueous solvent, which were obviously much larger than these (0.0832 and 0.0825 μg mL− 1) obtained using two algorithms of the four-way calibration. The results demonstrated that third-order calibration can extract more inherent information from the data, and can easily solve the problems of serious collinearity and high background interference. In short, among the advantages of this method over the existing methods, low cost, non-toxic and non-destructive analysis can be cited.
Co-reporter:Hui-Wen Gu, Hai-Long Wu, Shan-Shan Li, Xiao-Li Yin, Yong Hu, Hui Xia, Huan Fang, Ru-Qin Yu, Peng-Yuan Yang, Hao-Jie Lu
Chemometrics and Intelligent Laboratory Systems 2016 Volume 155() pp:62-72
Publication Date(Web):15 July 2016
DOI:10.1016/j.chemolab.2016.04.001
•A rapid and green chemometric-enhanced full scan mode of LC–MS method was developed.•ATLD was employed to solve the overlapped peaks and uncalibrated interferences.•ATLD-LC–MS was applied to determine six SOADs in health teas and human plasma samples.•The proposed method proved to be fast, low-cost, high sensitivity and simple implementation.•This methodology conformed to the highly recommended green analytical chemistry principles.In this work, a rapid chemometrics-enhanced liquid chromatography–single stage mass spectrometry (LC–MS) was developed for the simultaneous green determination of six co-eluted sulfonylurea-type oral antidiabetic agents (SOADs) in health teas and human plasma samples. Shortening the chromatographic separation time and reducing the cost per analysis were achieved via using full scan mode of LC–MS under simple isocratic elution condition followed by an environment-friendly “mathematical separation” strategy. The problem of the complete separation of target analytes from each other and/or from the uncalibrated interferences in complex matrices was resolved by alternating trilinear decomposition (ATLD) method as a posteriori. Satisfactory qualitative and quantitative results were obtained even in the existence of unknown interferences and the “second-order advantage” was fully exploited. The average spiked recoveries for all target analytes were between 81.6% and 110.1% with standard deviations less than 7.7%. It was demonstrated that the proposed strategy could be promisingly used for green resolution and determination of co-eluted multi-analytes of interest in complex samples while avoiding elaborate sample pretreatment steps and complicated experimental conditions as well as more sophisticated high-cost instrumentations.
Co-reporter:Chao Kang, Hai-Long Wu, Chang Zhou, Shou-Xia Xiang, Xiao-Hua Zhang, Yong-Jie Yu, Ru-Qin Yu
Analytica Chimica Acta 2016 910() pp: 36-44
Publication Date(Web):3 March 2016
DOI:10.1016/j.aca.2015.12.047
•A novel three-way calibration method for the quantitative kinetic analysis of NADH and FAD in human plasma is proposed.•The method can directly monitor the concentration of each analyte in the reaction in real-time and nondestructively.•The method has the second-order advantage.•A four-way calibration procedure is developed as an alternative for highly collinear systems.The metabolic coenzymes reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are the primary electron donor and acceptor respectively, participate in almost all biological metabolic pathways. This study develops a novel method for the quantitative kinetic analysis of the degradation reaction of NADH and the formation reaction of FAD in human plasma containing an uncalibrated interferent, by using three-way calibration based on multi-way fluorescence technique. In the three-way analysis, by using the calibration set in a static manner, we directly predicted the concentrations of both analytes in the mixture at any time after the start of their reactions, even in the presence of an uncalibrated spectral interferent and a varying background interferent. The satisfactory quantitative results indicate that the proposed method allows one to directly monitor the concentration of each analyte in the mixture as the function of time in real-time and nondestructively, instead of determining the concentration after the analytical separation. Thereafter, we fitted the first-order rate law to their concentration data throughout their reactions. Additionally, a four-way calibration procedure is developed as an alternative for highly collinear systems. The results of the four-way analysis confirmed the results of the three-way analysis and revealed that both the degradation reaction of NADH and the formation reaction of FAD in human plasma fit the first-order rate law. The proposed methods could be expected to provide promising tools for simultaneous kinetic analysis of multiple reactions in complex systems in real-time and nondestructively.Download full-size image
Co-reporter:Zhi Liu, Hai-Long Wu, Yong Li, Hui-Wen Gu, Xiao-Li Yin, Li-Xia Xie, Ru-Qin Yu
Journal of Chromatography B 2016 Volume 1026() pp:114-123
Publication Date(Web):15 July 2016
DOI:10.1016/j.jchromb.2015.08.008
•A novel chemometrics-assisted HPLC–DAD coupled with ATLD method was developed.•The proposed strategy was employed to determine five vinca alkaloids in complex matrices.•Results indicated that the strategy can solve co-eluted peaks in LC analysis.•Satisfactory results were obtained in Catharanthus roseus and human serum samples.A novel chemometrics-assisted high performance liquid chromatography method coupled with diode array detector (HPLC–DAD) was proposed for the simultaneous determination of vincristine (VCR), vinblastine (VLB), vindoline (VDL), catharanthine (CAT) and yohimbine (YHB) in Catharanthus roseus (C. roseus) and human serum samples. With the second-order advantage of the alternating trilinear decomposition (ATLD) method, the resolution and rapid determination of five components of interest in complex matrices were performed, even in the present of heavy overlaps and unknown interferences. Therefore, multi-step purification was omitted and five components could be fast eluted out within 7.5 min under simple isocratic elution condition (acetonitrile/0.2% formic acid water, 37:63, v/v). Statistical parameters, such as the linear correlation coefficient (R2), root-mean-square error of prediction (RMSEP), limit of detection (LOD) and limit of quantitation (LOQ) had been calculated to investigate the accuracy and reliability of the method. The average recoveries of five vinca alkaloids ranged from 97.1% to 101.9% and 98.8% to 103.0% in C. roseus and human serum samples, respectively. The five vinca alkaloids were adequately determined with limits of detection (LODs) of 29.5–49.3 ng mL−1 in C. roseus and 12.4–27.2 ng mL−1 in human serum samples, respectively. The obtained results demonstrated that the analytical strategy provided a feasible alternative for synchronously monitoring the quality of raw herb and the concentration of blood drugs.
Co-reporter:Haiyan Fu;Hedong Li;Mei Shao;Tianming Yang;Xu Zhang
Science China Chemistry 2016 Volume 59( Issue 7) pp:816-823
Publication Date(Web):2016 July
DOI:10.1007/s11426-016-5569-0
A highly sensitive and selective 3D excitation-emission fluorescence method has been proposed to rapidly quantify the combined antidiabetics Repaglinide (Re) and Irbesartan (Ir) in rat and human plasmas with the aid of second-order calibration method based on alternating trilinear decomposition (ATLD) method. Re and Ir with weak fluorescence can be endowed with strong fluorescent property by changing the microenvironment in samples and improving the fluorescence quantum yield by using an appropriate micellar enhanced surfactant. The enhanced excitation-emission matrix fluorescence of Re and Ir can be accurately resolved and can simultaneously attain the optimal concentration even in the presence of a potentially strong intrinsic fluorescence from complex biological matrices, such as rat and human plasmas, by using the ATLD method, which completely exploits the “second-order advantage”. The average recoveries of Re and Ir obtained from ATLD with the factor number of 3 (N=3) were 101.0%±4.3% and 99.1%±4.1% for rat plasma and 100.5%±5.4% and 97.1%±3.6% for human plasma. Several statistical methods, including Student’s t-test, figures of merit, and elliptical joint confidence region, have been utilized to evaluate the accuracy of the proposed method. Results show that the developed method can maintain second-order advantage in simultaneous determinations of the weak fluorescent analytes of interest in different biological plasma matrices.
Co-reporter:Xiang-Dong Qing, Hai-Long Wu, Xi-Hua Zhang, Yong Li, Hui-Wen Gu, Ru-Qin Yu
Analytica Chimica Acta 2015 Volume 861() pp:12-24
Publication Date(Web):25 February 2015
DOI:10.1016/j.aca.2014.12.037
•Five-way HPLC–DAD–kinetic-pH data were obtained for the first time.•A new algorithm, alternating quinquelinear decomposition (AQQLD), was developed.•Simulated data and real data were analyzed to explore the performance of AQQLD.•PARAFAC and AQQLD were applied to investigate the kinetics of naptalam.•It indicates the potential for the use of fourth-order data in complex systems.Five-way high performance liquid chromatography–diode array detection (HPLC–DAD)–kinetic-pH data were obtained by recording the kinetic evolution of HPLC–DAD signals of samples at different pH values and a new fourth-order calibration method, alternating quinquelinear decomposition (AQQLD) based on pseudo-fully stretched matrix forms of the quinquelinear model, was developed. Simulated data were analyzed to investigate the performance of AQQLD in comparison with five-way parallel factor analysis (PARAFAC). The tested results demonstrated that AQQLD has the advantage of faster convergence rate and being insensitive to the excess component number adopted in the model. Then, they have been successfully applied to investigate quantitatively the kinetics of naptalam (NAP) hydrolysis in two practical systems. Additionally, the serious chromatographic peak shifts were accurately corrected by means of chromatographic peak alignment method based on abstract subspace difference. The good recoveries of NAP were obtained in these samples by selecting the time region of chromatogram. The elution time, spectral, kinetic time and pH profiles resolved by the chemometric techniques were in good agreement with experimental observations. It demonstrates the potential for the utilization of fourth-order data for some complex systems, opening up a new approach to fourth-order data generation and subsequent fourth-order calibration.
Co-reporter:Hui-Wen Gu, Hai-Long Wu, Xiao-Li Yin, Shan-Shan Li, Ya-Juan Liu, Hui Xia, Li-Xia Xie, Ru-Qin Yu, Peng-Yuan Yang, Hao-Jie Lu
Journal of Chromatography A 2015 Volume 1407() pp:157-168
Publication Date(Web):14 August 2015
DOI:10.1016/j.chroma.2015.06.049
•PDS/ATLD is firstly proposed for transferring LC–MS signals measured on different days.•ATLD method is employed to solve the overlapped peaks and potential interferences.•PDS is carried out to overcome the signal change over time once the ATLD model is established.•Results from the PDS/ATLD strategy are comparable to those from the complete recalibration.•This methodology is in accordance with the recommended green analytical chemistry principles.The application of calibration transfer methods has been successful in combination with near-infrared spectroscopy or other tools for prediction of chemical composition. One of the developed methods that can provide accurate performances is the piecewise direct standardization (PDS) method, which in this paper is firstly applied to transfer from one day to another the second-order calibration model based on alternating trilinear decomposition (ATLD) method built for the interference-free resolution and determination of multi-analytes in complex systems by liquid chromatography–mass spectrometry (LC–MS) in full scan mode. This is an example of LC–MS analysis in which interferences have been found, making necessary the use of second-order calibration because of its capacity for modeling this phenomenon, which implies analytes of interest can be resolved and quantified even in the presence of overlapped peaks and unknown interferences. Once the second-order calibration model based on ATLD method was built, the calibration transfer was conducted to compensate for the signal instability of LC–MS instrument over time. This allows one to reduce the volume of the heavy works for complete recalibration which is necessary for later accurate determinations. The root-mean-square error of prediction (RMSEP) and average recovery were used to evaluate the performances of the proposed strategy. Results showed that the number of calibration samples used on the real LC–MS data was reduced by using the PDS method from 11 to 3 while producing comparable RMSEP values and recovery values that were statistically the same (F-test, 95% confidence level) to those obtained with 11 calibration samples. This methodology is in accordance with the highly recommended green analytical chemistry principles, since it can reduce the experimental efforts and cost with regard to the use of a new calibration model built in modified conditions.
Co-reporter:Shou-Xia Xiang;Chao Kang;Li-Xia Xie;Xiao-Li Yin;Hui-Wen Gu ;Ru-Qin Yu
Journal of Separation Science 2015 Volume 38( Issue 16) pp:2781-2788
Publication Date(Web):
DOI:10.1002/jssc.201500391
A simple method has been developed by combining high-performance liquid chromatography with diode array detection with the alternating trilinear decomposition method for simultaneous determination of four tyrosine kinase inhibitors in different human plasma samples. Chromatographic separation of the analytes was performed on a reversed-phase column with methanol (65%, v/v, A) and 0.1% aqueous solution of formic acid (35%, v/v, B). Analysis time was 5.0 min per run and analytes could be completely eluted within 2.8˗−3.8 min. The calibration concentration ranges of vandetanib, pazopanib, afatinib and dasatinib were designed as 0.50–6.10, 0.50–6.10, 0.70–7.00 and 0.70–7.00 μg·mL−1, respectively. The intra- and inter-day RSDs ranged between 0.1 and 8.9%. Quantitative information could be extracted from the unsegregated interferences of different human plasma samples with the aid of the “second-order advantage” of three-way (second-order) calibration methods. All results demonstrated that the proposed method for direct quantitative analysis of four tyrosine kinase inhibitors in different complex systems possessed good characteristics of rapidity, sensitivity and efficiency, and it is expected to be an attractive choice in the fast analysis of clinical samples.
Co-reporter:Li-Xia Xie, Hai-Long Wu, Chao Kang, Shou-Xia Xiang, Xiao-Li Yin, Hui-Wen Gu, Qi Zuo and Ru-Qin Yu
Analytical Methods 2015 vol. 7(Issue 16) pp:6552-6560
Publication Date(Web):02 Jul 2015
DOI:10.1039/C5AY00790A
In fluorospectrophotometric studies on protein–drug interactions, the fluorescence intensity of proteins is often vulnerable to interference from ligands or newly produced complexes which exhibit significant fluorescence at the chosen excitation or emission wavelengths. Alternatively, this paper suggests an effective and sensitive method for quantitative determination of free human serum albumin (HSA) in a dynamic interaction system with procaine (PRO) and further investigation of their interaction mechanism using a multi-way calibration method coupled with three-dimensional fluorescence spectroscopy. A second-order calibration method realized the quantitative determination of free HSA in a dynamic system with overlapping spectra even in the presence of an uncalibrated interferent. The quantitative results were used to further calculate the binding parameters, including the binding constant, binding site number, thermodynamic parameters and nature of binding forces. Furthermore, the four-way excitation–emission–temperature–sample data were analyzed to investigate the effect of temperature on the interaction system studied.
Co-reporter:Shu-Rong Zhang;Ru-Qin Yu
Journal of Chemometrics 2015 Volume 29( Issue 3) pp:179-192
Publication Date(Web):
DOI:10.1002/cem.2690
This study presents an in-depth discussion of the differential properties of various iterative trilinear decomposition algorithms, including Parallel Factor Analysis-Alternating Least Squares (PARAFAC-ALS), Alternating Trilinear Decomposition (ATLD), Self-Weighted Alternating Trilinear Decomposition (SWATLD), and Alternating Penalty Trilinear Decomposition (APTLD). The shape of each algorithm's objective function (“convex” or “strictly convex”) is related to the algorithm's sensitivity to the estimated component number of the trilinear system. Different situations near the objective solution are analyzed both theoretically and numerically. The wall of perturbation generated by deviations in the iterative steps prevents the PARAFAC algorithm from achieving the objective solution when the component number is overestimated. This may explain, from a calculational perspective, why the PARAFAC algorithm could not obtain the objective solution or any equivalent thereto (although equivalents might still be chemically meaningful optimal solutions). The different effects of deviation and residual on the algorithms are demonstrated by numerical analysis in this paper. The convergence rate can be improved by the use of high-performance computing strategy of the specific algorithm. The concept of solution set discussed in this paper complements the theory of the uniqueness of trilinear decomposition. Copyright © 2014 John Wiley & Sons, Ltd.
Co-reporter:Hui-Wen Gu, Hai-Long Wu, Xiao-Li Yin, Yong Li, Ya-Juan Liu, Hui Xia, Shu-Rong Zhang, Yi-Feng Jin, Xiao-Dong Sun, Ru-Qin Yu, Peng-Yuan Yang, Hao-Jie Lu
Analytica Chimica Acta 2014 Volume 848() pp:10-24
Publication Date(Web):27 October 2014
DOI:10.1016/j.aca.2014.08.052
•A smart strategy that combines three-way LC–MS data with ATLD method was developed.•This strategy was employed to determine ten β-blockers in human urine and plasma samples.•The results indicated the proposed strategy can solve co-elution problems in quantitative LC–MS.•This strategy proved to be a powerful tool to enhance the selectivity and sensitivity of LC–MS.•The performances of the proposed strategy were compared with those of MRM method.β-blockers are the first-line therapeutic agents for treating cardiovascular diseases and also a class of prohibited substances in athletic competitions. In this work, a smart strategy that combines three-way liquid chromatography–mass spectrometry (LC–MS) data with second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm was developed for simultaneous determination of ten β-blockers in human urine and plasma samples. This flexible strategy proved to be a useful tool to solve the problems of overlapped peaks and uncalibrated interferences encountered in quantitative LC–MS, and made the multi-targeted interference-free qualitative and quantitative analysis of β-blockers in complex matrices possible. The limits of detection were in the range of 2.0 × 10−5–6.2 × 10−3 μg mL−1, and the average recoveries were between 90 and 110% with standard deviations and average relative prediction errors less than 10%, indicating that the strategy could provide satisfactory prediction results for ten β-blockers in human urine and plasma samples only using liquid chromatography hyphenated single–quadrupole mass spectrometer in full scan mode. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring (MRM) method. T-test demonstrated that there are no significant differences between the prediction results of the two methods. Considering the advantages of fast, low-cost, high sensitivity, and no need of complicated chromatographic and tandem mass spectrometric conditions optimization, the proposed strategy is expected to be extended as an attractive alternative method to quantify analyte(s) of interest in complex systems such as cells, biological fluids, food, environment, pharmaceuticals and other complex samples.
Co-reporter:Xiao-Li Yin, Hai-Long Wu, Hui-Wen Gu, Xiao-Hua Zhang, Yan-Mei Sun, Yong Hu, Lu Liu, Qi-Ming Rong, Ru-Qin Yu
Journal of Chromatography A 2014 Volume 1364() pp:151-162
Publication Date(Web):17 October 2014
DOI:10.1016/j.chroma.2014.08.068
•A novel chemometrics-enhanced strategy combing HPLC-DAD with ATLD algorithm was developed.•The proposed strategy was employed to determine eight co-eluted compounds in Chinese tea.•Results indicated that the strategy can solve baseline drifts and co-eluted peaks in LC analysis.•Satisfactory results could be obtained in all kinds of Chinese tea samples studied.•Tea species were successfully classified by PCA based on our quantitative results.In this work, an attractive chemometrics-enhanced high performance liquid chromatography-diode array detection (HPLC-DAD) strategy was proposed for simultaneous and fast determination of eight co-eluted compounds including gallic acid, caffeine and six catechins in ten kinds of Chinese teas by using second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm. This new strategy proved to be a useful tool for handling the co-eluted peaks, uncalibrated interferences and baseline drifts existing in the process of chromatographic separation, which benefited from the “second-order advantages”, making the determination of gallic acid, caffeine and six catechins in tea infusions within 8 min under a simple mobile phase condition. The average recoveries of the analytes on two selected tea samples ranged from 91.7 to 103.1% with standard deviations (SD) ranged from 1.9 to 11.9%. Figures of merit including sensitivity (SEN), selectivity (SEL), root-mean-square error of prediction (RMSEP) and limit of detection (LOD) have been calculated to validate the accuracy of the proposed method. To further confirm the reliability of the method, a multiple reaction monitoring (MRM) method based on LC–MS/MS was employed for comparison and the obtained results of both methods were consistent with each other. Furthermore, as a universal strategy, this new proposed analytical method was applied for the determination of gallic acid, caffeine and catechins in several other kinds of Chinese teas, including different levels and varieties. Finally, based on the quantitative results, principal component analysis (PCA) was used to conduct a cluster analysis for these Chinese teas. The green tea, Oolong tea and Pu-erh raw tea samples were classified successfully. All results demonstrated that the proposed method is accurate, sensitive, fast, universal and ideal for the rapid, routine analysis and discrimination of gallic acid, caffeine and catechins in Chinese tea samples.
Co-reporter:Yong-Jie Yu, Qiao-Ling Xia, Sheng Wang, Bing Wang, Fu-Wei Xie, Xiao-Bing Zhang, Yun-Ming Ma, Hai-Long Wu
Journal of Chromatography A 2014 Volume 1359() pp:262-270
Publication Date(Web):12 September 2014
DOI:10.1016/j.chroma.2014.07.053
•A new chemometric strategy for automatic chromatographic peak detection and background drift correction was developed in this study.•It is convenient for large-scale sample analysis.•Chromatographic peak detection and background drift correction can simultaneously be provided.Peak detection and background drift correction (BDC) are the key stages in using chemometric methods to analyze chromatographic fingerprints of complex samples. This study developed a novel chemometric strategy for simultaneous automatic chromatographic peak detection and BDC. A robust statistical method was used for intelligent estimation of instrumental noise level coupled with first-order derivative of chromatographic signal to automatically extract chromatographic peaks in the data. A local curve-fitting strategy was then employed for BDC. Simulated and real liquid chromatographic data were designed with various kinds of background drift and degree of overlapped chromatographic peaks to verify the performance of the proposed strategy. The underlying chromatographic peaks can be automatically detected and reasonably integrated by this strategy. Meanwhile, chromatograms with BDC can be precisely obtained. The proposed method was used to analyze a complex gas chromatography dataset that monitored quality changes in plant extracts during storage procedure.
Co-reporter:Shu-Rong Zhang, Hai-Long Wu, Xi-Hua Zhang, Min Zhai and Ru-Qin Yu
New Journal of Chemistry 2014 vol. 38(Issue 6) pp:2422-2427
Publication Date(Web):16 Jan 2014
DOI:10.1039/C3NJ01533E
The present investigation attempts to separate the variation in time domain from steady-state fluorescence and to discuss quantitatively the state-switching of α-chymotrypsin (CHT). The activity of CHT is pH dependent (inactive at low pH, such as 2.2, but active at physiological pH, such as 8). ANS (1-anilinonaphthalene-8-sulfonate) has two states of fluorescence corresponding to different excitation and emission processes. Though a steady-state technique, Excitation–Emission Matrix fluorescence (EEM) can record all the excitation and emission signals for the ANS–CHT complex system. The trilinear decomposition of the constructed three-way data set (using EEM data of different samples) can provide excitation and emission spectra indicating specific excitation and emission processes, respectively, and a quantitative description for the time domain processes. Besides a detailed description of the excitation–emission processes of ANS, the quantitative investigation of state-switching by CHT is also possible because the fluorescence, due to the S1,ct state of ANS, is sensitive to the solvation environment, which is one of the indicators of CHT activity. Finally, the switching output curve of the ANS–CHT system over a wide pH range is obtained. This study proposes a convenient and economical protocol for investigating state-switching in proteins.
Co-reporter:Chao Kang, Hai-Long Wu, Shou-Xia Xiang, Li-Xia Xie, Ya-Juan Liu, Yong-Jie Yu, Jing-Jing Sun and Ru-Qin Yu
Analytical Methods 2014 vol. 6(Issue 16) pp:6358-6368
Publication Date(Web):02 Jun 2014
DOI:10.1039/C4AY00943F
A practical analytical method based on intrinsic fluorescence is proposed for simultaneous determination of L-phenylalanine, L-tyrosine, and L-tryptophan in cell culture and human plasma. By using a three-way calibration method coupled with excitation–emission matrix fluorescence, the proposed method successfully achieved quantitative analysis of the three aromatic amino acids in the two different complex systems simultaneously, even in the presence of three unknown, uncalibrated serious interferents. The method needs little preparation by using “mathematical separation” instead of chemical or physical separation, which makes it efficient and environmentally friendly. Satisfactory results have been achieved for calibration, validation, and prediction sets. For phenylalanine, tyrosine, and tryptophan, the calibration ranges are 6.00 to 60.00, 0.40 to 4.00, and 0.10 to 1.00 μg mL−1 respectively. The average spike recoveries (mean ± standard deviation) are 98.5 ± 7.8%, 103.7 ± 6.9%, and 102.3 ± 7.9% respectively. The relative errors are −4.2%, 6.3%, and −0.8% for predicting real contents of phenylalanine, tyrosine, and tryptophan in cell culture respectively. Additionally, we discussed the potential of the three-way calibration method for determining analytes of interest in different systems simultaneously, to further explore the second-order advantages. The paired t-test results indicate that the predicted results between prediction in two systems simultaneously and prediction in a single system individually have no significant difference. The satisfactory results obtained in this work indicate that the use of the three-way calibration method coupled with the EEM array is a promising tool for multi-component simultaneous determination in multiple complex systems containing uncalibrated spectral interferents.
Co-reporter:Hai-Long Wu;Yong Li ;Ru-Qin Yu
Journal of Chemometrics 2014 Volume 28( Issue 5) pp:476-489
Publication Date(Web):
DOI:10.1002/cem.2570
Developments in chemical multiway calibration methodologies in chemometrics that have taken place in tune with advances in modern (hyphenated) analytical instrumentation have been reviewed in this article. These advances in the ability to predict the concentration of an analyte using information-rich data collected from such instruments are outstanding examples of the philosophy of analytical method development outlined by Bruce R. Kowalski more than three decades ago. With the increase in the complexity of analytical objects, sophistication in analytical instrumentation has also been enhanced. Chemometrics classifies analytical instruments as zeroth-order, first-order, second-order, and higher-order according to the order of data that the instrument produces. Different multiway calibration methodologies have been developed to calibrate the instrument and predict the concentration of analytes. In this review, select works of Kowalski and co-workers in the context of second-order calibrations, as well as other recent developments in multiway calibration, especially the three-way and four-way calibrations, which preserve the second-order or high-order advantages, are highlighted. Copyright © 2013 John Wiley & Sons, Ltd.
Co-reporter:Yong Li, Hai-Long Wu, Chong-Chong Nie, Hui-Wen Gu, Xiang-Dong Qing, Qi Zuo and Ru-Qin Yu
Analytical Methods 2014 vol. 6(Issue 16) pp:6322-6331
Publication Date(Web):14 Mar 2014
DOI:10.1039/C3AY42251H
In this paper, a novel algorithm, alternating coupled two-unequal residual functions (ACTUF), has been presented to deal with three-way data for second-order calibration and it is able to achieve the important second-order advantage. This new algorithm resolves the parameter matrices by minimizing the two functions of measurement residuals and parameter residuals. Compared with two widely used algorithms, i.e., PARAFAC and SWATLD, the performance of the new algorithm is evaluated by using two simulation and two real data arrays in some aspects, such as noise, collinearity, analysis speed and solution. The results reveal that ACTUF can not only retain the second-order advantage, but also be insensitive to excessive component numbers and hold strong anti-noise tolerance. Besides, compared to the other two algorithms, ACTUF can successfully deal with the problems due to severe collinearity.
Co-reporter:Jian-Yao Wang, Hai-Long Wu, Yan-Mei Sun, Hui-Wen Gu, Zhi Liu, Ya-Juan Liu, Ru-Qin Yu
Journal of Chromatography B 2014 Volumes 947–948() pp:32-40
Publication Date(Web):1 February 2014
DOI:10.1016/j.jchromb.2013.12.009
•The extraction is unnecessary and a column washing is also not required.•Different kinds of oils can be analysed with the same chromatographic conditions.•Ten synthetic phenolic antioxidants (SPAs) can be eluted within 6 min.•Baseline drift and peak overlapping were successfully resolved by our method.•Low detection limits are rapidly achieved with minimal organic reagents.A novel strategy that combines the chemometrics method with high performance liquid chromatography with fluorescence detector (HPLC–FLD) was developed for the simultaneous determination of seven phenolic antioxidants in six kinds of oil samples. After a simple dilution step, oil samples can be directly injected into the detecting system and the data were measured in a short time with a chromatographic system operating in the gradient elution mode. Since the chromatographic and spectral peaks among interesting analytes and interferences were heavily overlapped, second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm which fully exploiting the second-order advantage was adopted. Successful resolution was obtained in the presence of different matrix interferences in different oil samples, and the developed approach allows the quantification of the antioxidants at levels found in edible vegetable oils, without the necessity of applying either preconcentration or extraction steps, moreover, a column washing is also not required. Meanwhile, the effectiveness and reproducibility of the proposed method were also validated by some statistical parameters like root mean squared error of prediction (RMSEP), limits of detection (LOD) and relative standard deviation (RSD). Then the proposed method was compared with several commonly selected methods in sample preparation, elution time and LOD.
Co-reporter:Yan-Mei Sun, Hai-Long Wu, Jian-Yao Wang, Zhi Liu, Min Zhai, Ru-Qin Yu
Journal of Chromatography B 2014 Volume 962() pp:59-67
Publication Date(Web):1 July 2014
DOI:10.1016/j.jchromb.2014.05.027
•A new HPLC-DAD analysis of eight flavonoids assisted by ATLD was proposed.•The sample pretreatment was simple and the analysis time was relatively short.•Baseline drift and peak overlapping were successfully resolved by our method.•The analytical method has been applied for 3 kinds of propolis capsules analysis.•The results are satisfactory even in the presence of matrix interferences.A fast analytical strategy of second-order calibration method based on the alternating trilinear decomposition algorithm (ATLD)-assisted high performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was established for the simultaneous determination of eight flavonoids (rutin, quercetin, luteolin, kaempferol, isorhamnetin, apigenin, galangin and chrysin) in propolis capsules samples. The chromatographic separation was implemented on a Wondasil™ C18 column (250 mm × 4.6 mm, 5 μm) within 13 min with a binary mobile phase composed of water with 1% formic acid and methanol at a flow rate of 1.0 mL min−1 after flavonoids were only extracted with methanol by ultrasound extraction for 15 min. The baseline problem was overcome by considering background drift as additional compositions or factors as well as the target analytes, and ATLD was employed to handle the overlapping peaks from analytes of interest or from analytes and co-eluting matrix compounds. The linearity was good with the correlation coefficients no less than 0.9947; the limit of detections (LODs) within the range of 3.39–33.05 ng mL−1 were low enough; the accuracy was confirmed by the recoveries ranged from 91.9% to 110.2% and the root-mean-square-error of predictions (RMSEPs) less than 1.1 μg/mL. The results indicated that the chromatographic method with the aid of ATLD is efficient, sensitive and cost-effective and can realize the resolution and accurate quantification of flavonoids even in the presence of interferences, thus providing an alternative method for accurate quantification of analytes especially when the complete separation is not easily accomplished. The method was successfully applied to propolis capsules samples and the satisfactory results were obtained.
Co-reporter:Chao Kang, Hai-Long Wu, Li-Xia Xie, Shou-Xia Xiang, Ru-Qin Yu
Talanta 2014 Volume 122() pp:293-301
Publication Date(Web):May 2014
DOI:10.1016/j.talanta.2014.01.036
Co-reporter:Min Zhai;HaiLong Wu;ShuRong Zhang;XiHua Zhang;YanMei Sun
Science China Chemistry 2014 Volume 57( Issue 5) pp:748-754
Publication Date(Web):2014 May
DOI:10.1007/s11426-013-4987-5
The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix (EEM) fluorescence. The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable. The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ. The quenching was static quenching, epicatechin had a weak interaction with BSA and the binding site was one. The total concentration and the free concentration of quenchers had different effect on the system. The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions, avoiding complicated pretreatment and simplify experimental procedure.
Co-reporter:Chao Kang, Hai-Long Wu, Yong-Jie Yu, Ya-Juan Liu, Shu-Rong Zhang, Xiao-Hua Zhang, Ru-Qin Yu
Analytica Chimica Acta 2013 Volume 758() pp:45-57
Publication Date(Web):3 January 2013
DOI:10.1016/j.aca.2012.10.056
A novel quadrilinear decomposition algorithm for four-way calibration (third-order tensor calibration), which was called as regularized self-weighted alternating quadrilinear decomposition (RSWAQLD), has been developed in this work. It originates from the alternating trilinear decomposition (ATLD) algorithm, inherits the philosophy behind self-weighting operation from the self-weighted alternating trilinear decomposition (SWATLD) algorithm. The RSWAQLD algorithm is based on a nearby least-squares scheme, in which two extra terms are added to each loss function, making it more stable and flexible. Experiment shows that RSWAQLD has the features of fast convergence and being insensitive to the excess estimated factors in the model. Owing to its unique optimizing approach, RSWAQLD is much more efficient than four-way PARAFAC. Moreover, the performance of RSWAQLD is quit stable as the number of factors used in calculation varies (as long as it is no less than the true number of factors). Such a feature will simplify the analysis of four-way data arrays, since it is unnecessary to spend a lot of time and effort on accurately determining the appropriate number of factors in the matrix. In addition, the result of four-way fluorescence excitation–emission–pH data, as well as that of simulated data, illustrated that RSWAQLD can not only remain the “higher-order advantage” but also provide a satisfying result even in high collinear systems.Graphical abstractRelative true profiles (dash-dot lines) and resolved profiles (solid lines) with N = 6 for the simulated EX–EM–pH type four-way data array (ahomo = 5%).Highlights► A new quadrilinear decomposition algorithm for four-way calibration is presented. ► Simulations and experiments show RSWAQLD has the feature of fast convergence. ► The proposed algorithm can resist the influence of the excess factors. ► The analysis of real four-way fluorescence data corroborated above-mentioned features.
Co-reporter:Yong-Jie Yu, Hai-Long Wu, Jing-Fang Niu, Juan Zhao, Yuan-Na Li, Chao Kang and Ru-Qin Yu
Analyst 2013 vol. 138(Issue 2) pp:627-634
Publication Date(Web):06 Nov 2012
DOI:10.1039/C2AN35931F
The alignment of chromatographic peaks and deconvolution of overlapped peaks still remain challenges in the field of complex sample analysis. In this paper, we highlight a strategy that employs a new time shift alignment method derived from the well-known Rank Minimization method for aligning chromatographic peak shifts among samples and then uses trilinear decomposition methodology to interpret the overlapped chromatographic peaks in order to quantify analytes of interest. The performance of this novel strategy for chromatographic data analysis was evaluated using simulated chromatographic data as well as real chromatographic data. The results indicate that the new time shift alignment method can accurately correct time shifts in test samples even in the presence of unexpected interferences, and thus the low-rank trilinearity of the same analyte can be obtained, which will be helpful for trilinear decomposition to achieve the second-order advantage. Moreover, the results showed that this new alignment method is more automated in comparison with the Rank Minimization method and will be suitable for the alignment of the time shifts of analytes that are completely overlapped by coeluted interferences.
Co-reporter:Xiao-Hua Zhang, Hai-Long Wu, Jian-Yao Wang, De-Zhu Tu, Chao Kang, Juan Zhao, Yao Chen, Xiao-Xia Miu, Ru-Qin Yu
Food Chemistry 2013 Volume 138(Issue 1) pp:62-69
Publication Date(Web):1 May 2013
DOI:10.1016/j.foodchem.2012.10.033
This paper describes the use of second-order calibration for development of HPLC-DAD method to quantify nine polyphenols in five kinds of honey samples. The sample treatment procedure was simplified effectively relative to the traditional ways. Baselines drift was also overcome by means of regarding the drift as additional factor(s) as well as the analytes of interest in the mathematical model. The contents of polyphenols obtained by the alternating trilinear decomposition (ATLD) method have been successfully used to distinguish different types of honey. This method shows good linearity (r > 0.99), rapidity (t < 7.60 min) and accuracy, which may be extremely promising as an excellent routine strategy for identification and quantification of polyphenols in the complex matrices.Highlights► We use a second-order calibration method to quantify polyphenols in honeys. ► Baseline drift was overcome in this work. ► The contents of analytes have been used to discriminate different honeys. ► This method shows good linearity (r > 0.99) and rapid separation (t < 7.60 min).
Co-reporter:Yong-Jie Yu, Hai-Long Wu, Hai-Yan Fu, Juan Zhao, Yuan-Na Li, Shu-Fang Li, Chao Kang, Ru-Qin Yu
Journal of Chromatography A 2013 Volume 1302() pp:72-80
Publication Date(Web):9 August 2013
DOI:10.1016/j.chroma.2013.06.009
•Coelution problems in three-dimensional chromatographic data can be successfully resolved by the mathematical separation strategy of PARAFAC.•Significant improvement in the quantitative capability of PARAFAC can be achieved with background drift correction by orthogonal spectral space projection.•Analyte(s) of interest can be accurately quantified from overlapped chromatographic peaks by using the new strategy presented in this work.Chromatographic background drift correction has been an important field of research in chromatographic analysis. In the present work, orthogonal spectral space projection for background drift correction of three-dimensional chromatographic data was described in detail and combined with parallel factor analysis (PARAFAC) to resolve overlapped chromatographic peaks and obtain the second-order advantage. This strategy was verified by simulated chromatographic data and afforded significant improvement in quantitative results. Finally, this strategy was successfully utilized to quantify eleven antibiotics in tap water samples. Compared with the traditional methodology of introducing excessive factors for the PARAFAC model to eliminate the effect of background drift, clear improvement in the quantitative performance of PARAFAC was observed after background drift correction by orthogonal spectral space projection.
Co-reporter:Xiao-Hua Zhang, Hai-Long Wu, Xiao-Li Yin, Liang-Hong Li, Jian-Yao Wang, Yao Chen, Chao Kang and Ru-Qin Yu
Analytical Methods 2013 vol. 5(Issue 3) pp:710-717
Publication Date(Web):05 Dec 2012
DOI:10.1039/C2AY25975C
In the present study, excitation–emission matrix (EEM) fluorescence data of guest–host complexes between naproxen enantiomers and β-cyclodextrin were used to develop a second-order calibration method that was subsequently used to determine the enantiomeric composition of samples of naproxen. The chiral discrimination of naproxen enantiomers was realized via their difference in interaction with the chiral cavity of β-cyclodextrin due to their difference in stereochemical structure. The strategy combined the use of a self-weighted alternating normalized residue fitting (SWANRF) algorithm, for extraction of the pure analyte signal, with the standard addition strategy, for determination of naproxen enantiomers in the presence of a matrix effect caused by the proteins present in human urine. Feasible results were obtained in a molar fraction range from 60.0 to 85.0% of S-naproxen, providing absolute errors lowers than 7.50%. Finally, molecular modeling was performed to determine the chiral recognition on a molecular level, and the difference in the interaction energies and the patterns of molecular interactions were discussed. The results were in good agreement with experimental data.
Co-reporter:Shan-Shan Li, Hai-Long Wu, Ya-Juan Liu, Hui-Wen Gu, Ru-Qin Yu
Chinese Chemical Letters 2013 Volume 24(Issue 3) pp:239-242
Publication Date(Web):March 2013
DOI:10.1016/j.cclet.2013.01.044
A “green” and quick analytical method for complex compounds was developed for simultaneous determination of tyrosine (Tyr) and dopamine (DA) in urine samples in this paper. The three-way responsive data recorded by excitation–emission matrix fluorescence (EEM) spectrometer was analyzed using second-order calibration methods based on both parallel factor analysis (PARAFAC) and self-weighted alternating trilinear decomposition (SWATLD) algorithms. The EEM spectra of the analytes were overlapped with the background in urine samples. However the second-order advantage of both PARAFAC and SWATLD methods was exploited, even in the presence of unknown interferences and the satisfactory results can be obtained. Furthermore, the linear ranges of Tyr and DA were determined to be 0.042–6.42 μg/mL and 0.18–4.43 μg/mL, respectively, and the accuracies of both methods were validated by the analytical figures of merit (FOM).In this study, we have successfully developed a “green” and fast method for quantitative analysis of tyrosine and dopamine in human urine samples by using second-order calibration methods, for the excitation–emission matrix fluorescence (EEM) data, based on both the parallel factor analysis (PARAFAC) and the self-weighted alternating trilinear decomposition (SWATLD) algorithms.
Co-reporter:Yao Chen;HaiLong Wu;JianYao Wang;XiaoHua Zhang;Yong Li
Science China Chemistry 2013 Volume 56( Issue 5) pp:664-671
Publication Date(Web):2013 May
DOI:10.1007/s11426-012-4765-9
A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix (EEM) fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin (EQ) and tert-butylhydroquinone (TBHQ) contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error (ANWE) algorithm was used to deal with EEM data. Via the introduced “second-order advantage”, the individual concentrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows: EQ, from 4.58 to 20.6 μg mL−1 in plasma and from 6.87 to 20.6 μg mL−1 in urine; TBHQ, from 4.49 to 20.2 μg mL−1 in plasma and from 6.73 to 22.4 μg mL−1 in urine. The recoveries from spiked biological fluid samples were in the ranges of 92.8%–106.2% for EQ and 94.6%–107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.
Co-reporter:XiangDong Qing;HaiLong Wu;ChongChong Nie;Yong Li;XiuFang Yan
Science China Chemistry 2013 Volume 56( Issue 11) pp:1641-1650
Publication Date(Web):2013 November
DOI:10.1007/s11426-013-4892-y
This work presents a novel application of second-order calibration based on self-weighted alternating trilinear decomposition (SWATLD) algorithm for analyzing the HPLC-DAD data. The proposed method makes it possible to simultaneously determine teflubenzuron, hexaflumuron, flufenoxuron, chlorfluazuron, diflubenzuron and benzoylurea in different fruit samples, i.e. pear, apple and banana, in the selected time region of chromatogram. The concentration, elution time and spectral information of these benzoylurea insecticides are selectively extracted from complex matrices even in the presence of unknown interferences. The root-mean-square error of prediction (RMSEP) and figures of merit, including sensitivity (SEN), selectivity (SEL) and limit of detection (LOD) are employed to access the performance of the method. The LODs obtained for these insecticides are within the range 0.017–0.26 ppm in pears, 0.039–0.33 ppm in apples, 0.041–0.44 ppm in bananas, respectively. Such a chemometrics-based protocol holds great potential to be extended as a promising alternative for more practical applications in food safety and quality monitoring.
Co-reporter:Xiang-Dong Qing, Hai-Long Wu, Chong-Chong Nie, Xiu-Fang Yan, Yuan-Na Li, Jian-Yao Wang, Ru-Qin Yu
Talanta 2013 Volume 103() pp:86-94
Publication Date(Web):15 January 2013
DOI:10.1016/j.talanta.2012.10.012
In this work, with the purpose of developing an effective and inexpensive method, excitation–emission matrix fluorescence data and second-order calibration method based on the self-weighted alternating trilinear decomposition (SWATLD) algorithm were combined for simultaneous determination of 2-naphthoxyacetic acid (NOA) and 1-naphthaleneacetic acid methyl ester (NAAME) in environmental samples, i.e. soil and sewage samples. In order to investigate the prediction quality of the proposed method, different strategies, such as taking spectroscopic measurements in the presence of different matrix interferents and at different fluorescence spectrophotometers, were introduced to build calibration models and comparisons among them were done subsequently. The root-mean-square error of prediction and t-test were used to compare different SWATLD-based calibration models. The limits of detection obtained for NOA and NAAME were 0.36–0.95 ng mL−1 and 1.32–2.69 ng mL−1, respectively, for different models. Such a chemometrics-based protocol may possess great potential to be extended as a promising alternative for more practical applications in environment monitoring and for the design of small intelligent and field-portable analytical instruments that rely on statistical discrimination, not complete instrumental separation, of the target analytes even in the presence of unknown and uncalibrated interferences.Highlights► NOA and NAAME are important plant growth regulators by synthesis. ► Chemometrics-assisted EEMF can quantify them in complicated environmental samples. ► We took spectroscopic measurements at different experimental conditions. ► Different calibration models were built and compared subsequently. ► The LODs for NOA and NAAME were 0.36–0.95 ng mL−1 and 1.32–2.69 ng mL−1, respectively.
Co-reporter:Jian-Yao Wang, Hai-Long Wu, Yao Chen, Min Zhai, Xiang-Dong Qing, Ru-Qin Yu
Talanta 2013 Volume 116() pp:347-353
Publication Date(Web):15 November 2013
DOI:10.1016/j.talanta.2013.05.028
•The overlapping spectra were successfully resolved by our method.•The LOD were 1.2–1.3 ng/ml for BHA and 2.2–2.9 ng/ml for PG.•Compared to the AOAC official method, our method is more economical and simpler.•The runtime of one sample is 3.5 min.•The quantification of PG and BHA was accomplished using green-chemistry principles.This work presents a novel approach for simultaneous determination of butylated hydroxyanisole (BHA) and propyl gallate (PG) in a very interfering environment by combining the sensitivity of molecular fluorescence and the selectivity of the second-order calibration method. The excitation–emission fluorescence matrix data are processed by applying the second-order calibration method based on the self-weighted alternating normalized residue fitting (SWANRF) algorithm. The limits of detection (LOD) were 1.2–1.3 ng/ml for BHA and 2.2–2.9 ng/ml for PG. The recoveries from spiked cosmetics samples are in the ranges 95.7–103.9% for BHA and 95.9–105.7% for PG. The proposed method avoids preconcentration and elution procedures, so it considerably decreases the analytical time and the experimental expenses. Because the instrument involved in the measurement is nonsophisticated, the experiments could be carried out in routine laboratories. Then it is compared with the HPLC method in dosage of cosmetics and organic reagents, runtime, cost per analysis and LOD.
Co-reporter:Jian-Yao Wang, Hai-Long Wu, Yao Chen, Yan-Mei Sun, Yong-Jie Yu, Xiao-Hua Zhang, Ru-Qin Yu
Journal of Chromatography A 2012 Volume 1264() pp:63-71
Publication Date(Web):16 November 2012
DOI:10.1016/j.chroma.2012.09.070
A new chromatographic methodology is presented for fast quantitative analysis of ten synthetic phenolic antioxidants in five kinds of oil samples: propyl gallate (PG), 2,4,5-trihydroxybutyrophenone (THBP), tert-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), ethoxyquin (EQ), 3-tert-butyl-4- hydroxyanisole (BHA), octyl gallate (OG), 2,6-di-tert-butyl-4-hydroxymethyphenol (Ionox-100), dodecyl gallate (DG), 3,5-di-tert-butyl-4-hydroxytoluene (BHT). The second-order calibration, with second-order advantage, based on the alternating penalty trilinear decomposition (APTLD) algorithm has shown to be an excellent tool for modeling the three-way data, where overlapping peaks, uncalibrated inteferences, and baseline drift existed, making the fast determination and resolution of the phenolic antioxidants in oils possible. Such extraction procedure in which the antioxidants of interest would be seperated is unnecessary and the ten antioxidants can be eluted within 6 mins. For the validation of the method, linearity, root-mean-square error of prediction (RMSEP) and limit of detection (LOD) have been performed. The average recovery of antioxidants ranges from 94.9 to 106.1% and the ten analytes can be adequately determined with limits of detection of 0.18–5.72 μg ml−1.Highlights► Ten Synthetic phenolic antioxidants (SPAs) can be eluted within 6 min. ► The extraction of the SPAs in oils is unnecessary. ► Baseline drift and peak overlapping were successfully resolved by our method.
Co-reporter:Xiang-Dong Qing, Hai-Long Wu, Yuan-Na Li, Chong-Chong Nie, Jian-Yao Wang, Shao-Hua Zhu and Ru-Qin Yu
Analytical Methods 2012 vol. 4(Issue 3) pp:685-692
Publication Date(Web):23 Feb 2012
DOI:10.1039/C2AY05790E
This work presents a novel strategy for simultaneous and rapid quantitative analysis of three pre-emergence herbicides in environmental samples using HPLC-DAD combined with second-order calibration based on the self-weighted alternating trilinear decomposition (SWATLD) algorithm. The sample preparation procedure was simplified only by using water as solvent and methanol as extractant and data were measured in less than 4.2 min by applying an isocratic mode. Although the elution and spectral profiles of the analytes, prometryne (PRO), napropamide (NAP) and alachlor (ALA), are heavily overlapped with each other and with matrix constitutes, the method not only extracts the profiles of the analytes, but also simultaneously determines the concentrations of them in actual complex systems, i.e., river sediment and wastewater samples. In the analysis of river sediment and wastewater samples, the obtained average recoveries were 99 ± 6% and 98 ± 5% for PRO, 108 ± 6% and 100 ± 4% for NAP and 98 ± 5% and 97 ± 4% for ALA, respectively. Furthermore, the accuracy and precision of the proposed method was also evaluated through elliptical joint confidence region tests as well as figures of merit. Such a chemometrics-based protocol may be a very promising tool for more analytical applications in environment monitoring, due to its advantages of easy sample pretreatment, green, sufficient spectral resolution and concentration prediction even in the presence of unknown interferences.
Co-reporter:Yong Li, Hai-Long Wu, Yong-Jie Yu, Shu-Rong Zhang, Yao Chen, De-Zhu Tu, Chong-Chong Nie, Hui Xu and Ru-Qin Yu
Analytical Methods 2012 vol. 4(Issue 12) pp:3987-3996
Publication Date(Web):26 Sep 2012
DOI:10.1039/C2AY25646K
Rayleigh scattering, which is often contained in excitation-emission fluorescence data, does not conform to a trilinear structure and its existence can complicate decomposition using second-order calibration methods. In this paper, a novel method, two-direction resection PARAFAC (TDR-PARAFAC) is proposed to deal with three-way fluorescence data including Rayleigh scattering. This is a convenient method where only two parameters, i.e. the scattering regions and the number of components, are required. A simulated data set was employed to demonstrate the reasonability of the new method. It was successfully used to analyze two experimental data sets in which interferents and significant Rayleigh scattering were present. The performance of the new method was compared by inserting missing values within PARAFAC (IMV-PARAFAC). The final results suggest that TDR-PARAFAC can not only obtain more stable and satisfactory resolution than IMV-PARAFAC, but also that it speeds up the analysis. In addition, the new method can be applied to other interferences such as Rayleigh scattering, which appear in the same position in each sample matrix.
Co-reporter:De-Zhu Tu, Hai-Long Wu, Yuan-Na Li, Juan Zhang, Yong Li, Chong-Chong Nie, Xiao-Hua Zhang and Ru-Qin Yu
Analytical Methods 2012 vol. 4(Issue 1) pp:222-229
Publication Date(Web):23 Nov 2011
DOI:10.1039/C1AY05388D
This paper describes a sensitive excitation–emission matrix fluorescence (EEM) method for simultaneously measuring contents of two estrogens, estriol (E3) and estrone (E1), in liquid cosmetic samples with the aid of a second-order calibration method based on a parallel factor analysis (PARAFAC) algorithm. Before processing the obtained three-way data, a better region of the excitation and emission spectra was purposely selected. Then PARAFAC was recommended to acquire the clean spectra and predict the individual concentrations of the analytes of interest even in the presence of uncalibrated interferences. The standard curves of the two analytes are linear within a linear concentration range of 0–0.736 μg mL−1 of E3 and 0–18.000 μg mL−1 of E1 with correlation coefficients typically greater than 0.99. In the analysis of watermelon frost anti-acne toner sold on the internet web site, the limit of detection (LOD) of E3 is 4.7 ng mL−1 with an accuracy of 102.3–113.7%, and for E1, the LOD is 96.1 ng mL−1 with an accuracy of 92.3–111.0%. In the analysis of pagoda flower relaxing lotion from the commercial market in Changsha, the LOD of E3 is 8.9 ng mL−1 with an accuracy of 95.0–107.1%, and for E1, the LOD is 76.9 ng mL−1 with an accuracy of 98.6–119.3%. Generally, a new avenue has been opened up to determine estrogens quantitatively in cosmetic samples. This methodology will achieve greater development and gradually become a more routine approach in cosmetic quality control due to its advantages of high sensitivity, simple pretreatment procedure and non-destructive nature.
Co-reporter:Yajuan Liu;Hailong Wu;Shaohua Zhu;Chao Kang;Hui Xu;Zhiyi Su;Huiwen Gu;Ruqin Yu
Chinese Journal of Chemistry 2012 Volume 30( Issue 5) pp:1137-1143
Publication Date(Web):
DOI:10.1002/cjoc.201100677
Abstract
A novel methodology that combines high performance liquid chromatography with photodiode-array detector (HPLC-DAD) coupled with second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm was used in determination of the effective constituents such as costunolide and dehydrocostuslactone, in plasma sample and Chinese patent medicine Xiang Sha Yang Wei (XSYW) capsule. Complicated systems such as plasma and Chinese patent medicine which have intricate components are tedious to isolate and purify. The problem that chromatographic peaks are heavily overlapped among the analytes and interferents from the background matrices can be resolved, and the satisfactory quantification results have been gained with the help of the ATLD algorithm which utilized "mathematical separation" instead of partial "physical or chemical separation". Meanwhile, HPLC-MS/MS method was used to validate the accuracy of the proposed determination method.
Co-reporter:Juan Zhao, Hai-Long Wu, Jing-Fang Niu, Yong-Jie Yu, Li-Li Yu, Chao Kang, Quan Li, Xiao-Hua Zhang, Ru-Qin Yu
Journal of Chromatography B 2012 Volume 902() pp:96-107
Publication Date(Web):1 August 2012
DOI:10.1016/j.jchromb.2012.06.032
A novel chemometric-assisted high performance liquid chromatography method coupled with diode array detector (HPLC-DAD) was presented for the simultaneous determination of eleven antihypertensives from multiple classes in most concerned matrix systems. With the aid of second-order calibration which enables specific information of analytes to be well extracted, the heavily overlapping profiles between analytes and the coeluting interferences can be successfully separated and thus accurately quantified. A great advantage of the novel strategy lies in the fact that the analysis could be carried out with the same isocratic mobile phase (methanol/KH2PO4: 58:42, v/v, pH 2.60) in a short time regardless of the changes of matrices, such as human serum, health product and Chinese patent medicine. Both qualitative and quantitative results indicate that the hybrid strategy that using HPLC-DAD coupled with second-order chemometric method would be a high performance approach for the purpose of simultaneously quantifying multiple classes of antihypertensives in complex systems. Additionally, the analytical strategy can potentially benefit drug monitoring in both therapeutic research and pharmaceutical quality control. Moreover, the accuracy and reliability of the proposed methodology has been evaluated using several statistical parameters such as root mean squared error of prediction (RMSEP), figures of merit (FOM) and reproducibility of inter-day analysis.Highlights► Eleven antihypertensives were simultaneously assayed in isocratic mode within 10 min. ► The proposed method enables a comprehensive study in three most concerned systems. ► The method provides a more general condition for analyses in various systems.
Co-reporter:Xiao-Hua Zhang, Hai-Long Wu, Jian-Yao Wang, Yao Chen, ... Ru-Qin Yu
Journal of Pharmaceutical Analysis (August 2012) Volume 2(Issue 4) pp:241-248
Publication Date(Web):1 August 2012
DOI:10.1016/j.jpha.2012.04.002
The effectiveness of traditional Chinese medicine (TCM) against various diseases urges more low cost, speed and sensitive analytical methods for investigating the phamacology of TCM and providing a theoretical basis for clinical use. The potential of second-order calibration method was validated for the quantification of two effective ingredients of Schisandra chinensis in human plasma using spectrofluorimetry. The results obtained in the present study demonstrate the advantages of this strategy for multi-target determination in complex matrices. Although the spectra of the analytes are similar and a large number of interferences also exist, second-order calibration method could predict the accurate concentrations together with reasonable resolution of spectral profiles for analytes of interest owing to its ‘second-order advantage’. Moreover, the method presented in this work allows one to simply experimental procedure as well as reduces the use of harmful chemical solvents.
Co-reporter:Zhi Liu, Hai-Long Wu, Li-Xia Xie, Yong Hu, Huan Fang, Xiao-Dong Sun, Tong Wang, Rong Xiao, Ru-Qin Yu
Chemometrics and Intelligent Laboratory Systems (15 January 2017) Volume 160() pp:
Publication Date(Web):15 January 2017
DOI:10.1016/j.chemolab.2016.12.003
•A smart Chemometrics-assisted LC-MS strategy is explored for mycotoxin-analysis.•Cereal samples are analyzed without intricate and inefficient clean-up step.•Peak overlaps, unknown interferences and baseline drift are perfectly calibrated.•Multi-class mycotoxins are directly quantified in interferential LC-MS environment.•The accuracy of mycotoxin-analysis can be significantly improved.Mycotoxins are a class of highly carcinogenic substances often naturally occurring in the moldy foods especially cereals. In the present work, a smart chemometrics-assisted analytical strategy that combines liquid chromatography-full scan-mass spectrometry (LC-MS) detection with second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm is developed for direct, fast and interference-free determination of multi-class regulated mycotoxins in complex cereal samples with one-step ultrasound-assisted extraction. Ten mycotoxins with different property are fast eluted out (9.0 min) under a simple gradient LC-separation and detected by full scanning MS with a segmented fragment program. With the aid of prominent "second-order advantage" of the algorithm, the problems of co-eluted peaks, unknown interferences and baseline drifts occurring in the LC-MS profiles are mathematically resolved, making "pure signals" of targeted analytes can be extracted out from heavily interferential information. The new strategy avoids intricate physical/chemical clean-up steps to significantly improve the accuracy of the trace analysis of mycotoxins, average recoveries of ten analytes in both complex cereal samples (maize and rice) range from 93.8 to 109% with standard deviations (SD) lower than 9.8%, and the limits of detection (LOD) range from 0.01 to 1.17 μg kg−1. In order to further confirm the reliability of the method, the same batch of samples is analyzed using LC-MS2 method with complicated immunoaffinity column (IAC) purification step, the elliptical joint confidence region (EJCR) tests of quantitative results of ten mycotoxins show that higher precision is obtained using the proposed method. Therefore, this new strategy can be as an attractive alternative for simple, fast and accurate determination of multi-class mycotoxins in complex cereal samples.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 16) pp:
Publication Date(Web):
DOI:10.1039/C4AY00943F
A practical analytical method based on intrinsic fluorescence is proposed for simultaneous determination of L-phenylalanine, L-tyrosine, and L-tryptophan in cell culture and human plasma. By using a three-way calibration method coupled with excitation–emission matrix fluorescence, the proposed method successfully achieved quantitative analysis of the three aromatic amino acids in the two different complex systems simultaneously, even in the presence of three unknown, uncalibrated serious interferents. The method needs little preparation by using “mathematical separation” instead of chemical or physical separation, which makes it efficient and environmentally friendly. Satisfactory results have been achieved for calibration, validation, and prediction sets. For phenylalanine, tyrosine, and tryptophan, the calibration ranges are 6.00 to 60.00, 0.40 to 4.00, and 0.10 to 1.00 μg mL−1 respectively. The average spike recoveries (mean ± standard deviation) are 98.5 ± 7.8%, 103.7 ± 6.9%, and 102.3 ± 7.9% respectively. The relative errors are −4.2%, 6.3%, and −0.8% for predicting real contents of phenylalanine, tyrosine, and tryptophan in cell culture respectively. Additionally, we discussed the potential of the three-way calibration method for determining analytes of interest in different systems simultaneously, to further explore the second-order advantages. The paired t-test results indicate that the predicted results between prediction in two systems simultaneously and prediction in a single system individually have no significant difference. The satisfactory results obtained in this work indicate that the use of the three-way calibration method coupled with the EEM array is a promising tool for multi-component simultaneous determination in multiple complex systems containing uncalibrated spectral interferents.
Co-reporter:
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 1) pp:
Publication Date(Web):
DOI:10.1039/C1AY05388D
This paper describes a sensitive excitation–emission matrix fluorescence (EEM) method for simultaneously measuring contents of two estrogens, estriol (E3) and estrone (E1), in liquid cosmetic samples with the aid of a second-order calibration method based on a parallel factor analysis (PARAFAC) algorithm. Before processing the obtained three-way data, a better region of the excitation and emission spectra was purposely selected. Then PARAFAC was recommended to acquire the clean spectra and predict the individual concentrations of the analytes of interest even in the presence of uncalibrated interferences. The standard curves of the two analytes are linear within a linear concentration range of 0–0.736 μg mL−1 of E3 and 0–18.000 μg mL−1 of E1 with correlation coefficients typically greater than 0.99. In the analysis of watermelon frost anti-acne toner sold on the internet web site, the limit of detection (LOD) of E3 is 4.7 ng mL−1 with an accuracy of 102.3–113.7%, and for E1, the LOD is 96.1 ng mL−1 with an accuracy of 92.3–111.0%. In the analysis of pagoda flower relaxing lotion from the commercial market in Changsha, the LOD of E3 is 8.9 ng mL−1 with an accuracy of 95.0–107.1%, and for E1, the LOD is 76.9 ng mL−1 with an accuracy of 98.6–119.3%. Generally, a new avenue has been opened up to determine estrogens quantitatively in cosmetic samples. This methodology will achieve greater development and gradually become a more routine approach in cosmetic quality control due to its advantages of high sensitivity, simple pretreatment procedure and non-destructive nature.
Co-reporter:
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 3) pp:
Publication Date(Web):
DOI:10.1039/C2AY05790E
This work presents a novel strategy for simultaneous and rapid quantitative analysis of three pre-emergence herbicides in environmental samples using HPLC-DAD combined with second-order calibration based on the self-weighted alternating trilinear decomposition (SWATLD) algorithm. The sample preparation procedure was simplified only by using water as solvent and methanol as extractant and data were measured in less than 4.2 min by applying an isocratic mode. Although the elution and spectral profiles of the analytes, prometryne (PRO), napropamide (NAP) and alachlor (ALA), are heavily overlapped with each other and with matrix constitutes, the method not only extracts the profiles of the analytes, but also simultaneously determines the concentrations of them in actual complex systems, i.e., river sediment and wastewater samples. In the analysis of river sediment and wastewater samples, the obtained average recoveries were 99 ± 6% and 98 ± 5% for PRO, 108 ± 6% and 100 ± 4% for NAP and 98 ± 5% and 97 ± 4% for ALA, respectively. Furthermore, the accuracy and precision of the proposed method was also evaluated through elliptical joint confidence region tests as well as figures of merit. Such a chemometrics-based protocol may be a very promising tool for more analytical applications in environment monitoring, due to its advantages of easy sample pretreatment, green, sufficient spectral resolution and concentration prediction even in the presence of unknown interferences.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 16) pp:
Publication Date(Web):
DOI:10.1039/C3AY42251H
In this paper, a novel algorithm, alternating coupled two-unequal residual functions (ACTUF), has been presented to deal with three-way data for second-order calibration and it is able to achieve the important second-order advantage. This new algorithm resolves the parameter matrices by minimizing the two functions of measurement residuals and parameter residuals. Compared with two widely used algorithms, i.e., PARAFAC and SWATLD, the performance of the new algorithm is evaluated by using two simulation and two real data arrays in some aspects, such as noise, collinearity, analysis speed and solution. The results reveal that ACTUF can not only retain the second-order advantage, but also be insensitive to excessive component numbers and hold strong anti-noise tolerance. Besides, compared to the other two algorithms, ACTUF can successfully deal with the problems due to severe collinearity.
Co-reporter:Yong Li, Hai-Long Wu, Yong-Jie Yu, Shu-Rong Zhang, Yao Chen, De-Zhu Tu, Chong-Chong Nie, Hui Xu and Ru-Qin Yu
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 12) pp:NaN3996-3996
Publication Date(Web):2012/09/26
DOI:10.1039/C2AY25646K
Rayleigh scattering, which is often contained in excitation-emission fluorescence data, does not conform to a trilinear structure and its existence can complicate decomposition using second-order calibration methods. In this paper, a novel method, two-direction resection PARAFAC (TDR-PARAFAC) is proposed to deal with three-way fluorescence data including Rayleigh scattering. This is a convenient method where only two parameters, i.e. the scattering regions and the number of components, are required. A simulated data set was employed to demonstrate the reasonability of the new method. It was successfully used to analyze two experimental data sets in which interferents and significant Rayleigh scattering were present. The performance of the new method was compared by inserting missing values within PARAFAC (IMV-PARAFAC). The final results suggest that TDR-PARAFAC can not only obtain more stable and satisfactory resolution than IMV-PARAFAC, but also that it speeds up the analysis. In addition, the new method can be applied to other interferences such as Rayleigh scattering, which appear in the same position in each sample matrix.
Co-reporter:Xiao-Hua Zhang, Hai-Long Wu, Xiao-Li Yin, Liang-Hong Li, Jian-Yao Wang, Yao Chen, Chao Kang and Ru-Qin Yu
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 3) pp:NaN717-717
Publication Date(Web):2012/12/05
DOI:10.1039/C2AY25975C
In the present study, excitation–emission matrix (EEM) fluorescence data of guest–host complexes between naproxen enantiomers and β-cyclodextrin were used to develop a second-order calibration method that was subsequently used to determine the enantiomeric composition of samples of naproxen. The chiral discrimination of naproxen enantiomers was realized via their difference in interaction with the chiral cavity of β-cyclodextrin due to their difference in stereochemical structure. The strategy combined the use of a self-weighted alternating normalized residue fitting (SWANRF) algorithm, for extraction of the pure analyte signal, with the standard addition strategy, for determination of naproxen enantiomers in the presence of a matrix effect caused by the proteins present in human urine. Feasible results were obtained in a molar fraction range from 60.0 to 85.0% of S-naproxen, providing absolute errors lowers than 7.50%. Finally, molecular modeling was performed to determine the chiral recognition on a molecular level, and the difference in the interaction energies and the patterns of molecular interactions were discussed. The results were in good agreement with experimental data.
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