Co-reporter:Xiudan Hou;Xusheng Wang;Yingxin Sun
Analytical and Bioanalytical Chemistry 2017 Volume 409( Issue 14) pp:3541-3549
Publication Date(Web):11 April 2017
DOI:10.1007/s00216-017-0291-0
A solid-phase extraction (SPE) method for the efficient analysis of trace phenolic acids (PAs, caffeic acid, ferulic acid, protocatechuic acid, cinnamic acid) in urine was established. In this work, a graphene oxide (GO) coating was grafted onto pure silica to be investigated as SPE material. The prepared GO surface had a layered and wrinkled structure that was rough and well organized, which could provide more open adsorption sites. Owing to its hydrophilicity and polarity, GO showed higher extraction efficiency toward PAs than reduced GO did, in agreement with the theoretical calculation results performed by Gaussian 09 software. The adsorption mechanism of PAs on GO@Sil was also investigated through static state and kinetic state adsorption experiments, which showed a monolayer surface adsorption. Extraction capacity of the as-prepared material was optimized using the response surface methodology. Under the optimized conditions, the as-established method provided wide linearity range (2–50 μg L−1 for protocatechuic acid and 1–50 μg L−1 for caffeic acid, ferulic acid, and cinnamic acid) and low limits of detection (0.25–1 μg L−1). Finally, the established method was applied for the analysis of urine from two healthy volunteers. The results indicate that the prepared material is a practical, cost-effective medium for the extraction and determination of phenolic acids in complex matrices.
Co-reporter:Fanpeng Ran, Hongmei Liu, Xiaoqi Wang, Yong Guo
Journal of Chromatography A 2017 Volume 1507(Volume 1507) pp:
Publication Date(Web):21 July 2017
DOI:10.1016/j.chroma.2017.05.018
•A novel MoS2 nanosheet self-assembled flower-like monolithic material was successfully synthesized as SPE sorbent.•The as-prepared MoS2 sorbent possesses high extraction efficiency.•The as-prepared MoS2 sorbent shows a long service life.A novel material consisting of molybdenum disulfide (MoS2) nanosheet that self-assemble into flower-like microspheres which aggregate to form a monolithic matrix with a micro or nano-scaled mesopore structure was successfully synthesized and used as an efficient sorbent for solid-phase extraction (SPE) due to its large specific adsorption area and good stability. The extraction properties of the as-prepared sorbent were evaluated by high-performance liquid chromatography with variable wavelength detection (HPLC-VWD) by analyzing four flavonoids (apigenin, quercetin, luteolin, and kaempferol). Under optimal conditions, the LODs and LOQs were found to be in the ranges of 0.1–0.25 and 0.4–0.5 μg L−1, respectively, and wide linear ranges were obtained with correlation coefficients (R) ranging from 0.9991 to 0.9996. Compared with commercial C18 and Alumina-N sorbents, the as-prepared sorbent showed high extraction efficiency at different concentrations of flavonoids. After 100 uses, the extraction ability of the self-assembled MoS2 nanosheet monolithic sorbent had no evident decline, denoting a long service life. Finally, the SPE-HPLC-VWD method using the as-prepared sorbent was applied to flavonoid analysis in beverage samples with satisfactory results.
Co-reporter:Xiudan Hou, Shujuan Liu, Panpan Zhou, Jin Li, Xia Liu, Licheng Wang, Yong Guo
Journal of Chromatography A 2016 Volume 1456() pp:10-18
Publication Date(Web):22 July 2016
DOI:10.1016/j.chroma.2016.05.096
•PF6−-based PILs@GO@Sil was prepared by insituanion exchange.•A Box-Behnken design was used for optimization of the experiment parameters.•The excretion-dynamics of flavonoids in urine were investigated by the proposed method.•The PILs provided lower limits of detection for flavonoids coupling to the HPLC-UV.A solid-phase extraction method for the efficient analysis of the excretion-dynamics of flavonoids in urine was established and described. In this work, in situ surface radical chain-transfer polymerization and in situ anion exchange were utilized to tune the extraction performance of poly(1-vinyl-3-hexylimidazolium bromide)-graphene oxide-grafted silica (poly(VHIm+Br−)@GO@Sil). Graphene oxide (GO) was first coated onto the silica using a layer-by-layer fabrication method, and then the anion of poly(VHIm+Br−)@GO@Sil was changed into hexafluorophosphate (PF6−) by in situ anion exchange. The interaction energies between two PILs and four flavonoids were calculated with the Gaussian09 suite of programs. A Box-Behnken design was used for the optimization of four greatly influential parameters after single-factor experiments to obtain more accurate and precise results. Coupled to high performance liquid chromatography, the poly(VHIm+PF6−)@GO@Sil method showed acceptable extraction recoveries for the four flavonoids, with limits of detection in the range of 0.1–0.5 μg L−1, and wide linear ranges with correlation coefficients (R) ranging from 0.9935 to 0.9987. Under the optimum conditions, the proposed method was applied to analyze the urines collected from a healthy volunteer. The excretion amount-time profiles revealed that 4–15 h was the main excretion time for the detected flavonoids. The results indicated that the newly developed method offered the advantages of being feasible, green and cost-effective, and could be successfully applied to the extraction and enrichment of flavonoids in human body systems allowing the study of the metabolic kinetics.
Co-reporter:Hui Yu, Linying Cao, Feifei Li, Qingfeng Wu, Qiang Li, Shuai Wang and Yong Guo
RSC Advances 2015 vol. 5(Issue 78) pp:63655-63661
Publication Date(Web):20 Jul 2015
DOI:10.1039/C5RA06129F
A rhodamine-nitroxide probe (R-NO˙), combining rhodamine fluorophore with a 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) receptor unit was introduced to probe glutathionyl radicals (GS˙) with high sensitivity and selectivity. The R-NO˙ probe could effectively scavenge GS˙ radicals with fluorescence enhancement since the nitroxide group restored the fluorescence properties. In this work, horseradish peroxidase (HRP)-catalyzed and metal-catalyzed oxidation systems were selected as the model of simulating the generation of GS˙, and we found that the metal-catalyzed system had the same experimental results with the HRP-catalyzed system, which provided a new approach to demonstrate the strong oxidant ability of the hydroxyl radical (˙OH) to initiate toxic GS˙. Furthermore, we confirmed that the production of GS˙ abided by a radical-initiated peroxidation mechanism of GSH with the mass spectrometry (MS) analysis and fluorescence spectroscopy. By using combined high-performance liquid chromatography (HPLC) detection and MS analysis, we also demonstrated that the R-NO˙ was converted into fluorescent secondary amine derivative (R-NH). The application of the probe in biological system was explored to monitor GS˙ in HL-60 cells and secondary amine fluorescence was observed upon stimulation by hydrogen peroxide and phenol. Development of fluorescence was prevented via preincubation with the thiol-blocking reagent N-ethylmaleimide (NEM).
Co-reporter:Lili Xu, Hongbo Suo, Xiaojing Liang, Licheng Wang, Yong guo and Shengxiang Jiang
RSC Advances 2015 vol. 5(Issue 52) pp:41536-41543
Publication Date(Web):13 Apr 2015
DOI:10.1039/C4RA16740F
A novel solid-phase microextraction (SPME) fiber based on a stainless steel wire coated with Au nanoparticle decorated graphene oxide was prepared using a novel protocol. Coupled with gas chromatography-flame ionization detection (GC-FID), the extraction performance of the fiber was tested with aromatic hydrophobic organic chemicals as the model analytes. The fiber showed excellent extraction efficiency, good mechanical strength, and good stability in acid, alkali and organic solutions, and under high temperature. Effects of extraction time, extraction temperature, ionic strength and desorption conditions were investigated and optimized. The relative standard deviations for the single fiber repeatability and fiber-to-fiber reproducibility were less than 6.90 and 16.87%, respectively. Compared with graphene oxide/solid-phase microextraction fibers and Au nanoparticle/solid-phase microextraction fibers, the fiber has lower detection limits (≤60 ng L−1) and a better linear range for all analytes. Correlation coefficients ranged from 0.9958 to 0.9993. The as-established SPME-GC-FID method was successfully used for two real natural samples, and recovery of the analytes spiked at 10 μg L−1 ranged from 82.65% to 126.06%.
Co-reporter:Houmei Liu, Xiaojing Liang, Xusheng Wang, Yong Guo and Xia Liu
RSC Advances 2015 vol. 5(Issue 6) pp:4420-4427
Publication Date(Web):09 Dec 2014
DOI:10.1039/C4RA13331E
In this paper, a novel sorbent, poly(diallyldimethylammonium chloride) assembled graphene oxide coated silica (PDDA@GO@SiO2), was prepared and used as a sorbent for solid-phase extraction of cinnamic acid and its derivatives. The synthesized sorbent material was characterized by elemental analysis and field emission scanning electron microscopy, which confirmed the success of binding and assembling. The extraction properties of the resultant sorbent were evaluated by using cinnamic acid and its derivatives (caffeic acid, trans-4-hydroxycinnamic acid, isoferulic acid, 3,4-dimethoxycinnamic acid, cinnamic acid and 4-methylcinnamic acid) as the test analytes. Extraction efficiencies of PDDA@GO@SiO2 were apparently superior to those of PDDA@SiO2 and commercial C18 sorbents. Under the optimal conditions, good linearities with R2 ranging from 99.8% to 100% were obtained and the LODs and LOQs were found to be in the range of 0.5–2 μg L−1 and 3–5 μg L−1, respectively. The proposed method was successfully applied for the analysis of cinnamic acid in Gobi sherry and isoferulic acid in BuzhongYiqi pill.
Co-reporter:Licheng Wang;Xiudan Hou;Jubai Li;Shujuan Liu
Journal of Separation Science 2015 Volume 38( Issue 14) pp:2439-2446
Publication Date(Web):
DOI:10.1002/jssc.201500308
A novel graphene oxide decorated with silver nanoparticles coating on a stainless-steel fiber for solid-phase microextraction was prepared. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the coating surface and showed that silver nanoparticles were dispersed on the wrinkled graphene oxide surface. Coupled to gas chromatography with flame ionization detection, the extraction abilities of the fiber for polycyclic aromatic hydrocarbons were examined in the headspace solid-phase microextraction mode. The extraction parameters including adsorption time, adsorption temperature, salt concentration, desorption time and desorption temperature were investigated. Under the optimized condition, wide linearity with low limits of detection from 2 to 10 ng/L was obtained. The relative standard deviations for single-fiber repeatability and fiber-to-fiber reproducibility were less than 10.6 and 17.5%, respectively. The enrichment factors were from 1712.5 to 4503.7, showing the fiber has good extraction abilities. Moreover, the fiber exhibited a good stability and could be reused for more than 120 times. The established method was also applied for determination of polycyclic aromatic hydrocarbons in two real water samples and the recoveries of analytes ranged from 84.4–116.3% with relative standard deviations less than 16.2%.
Co-reporter:Licheng Wang;Sheng Tang;Shuai Wang;Xiaojing Liang
Journal of Separation Science 2015 Volume 38( Issue 8) pp:1326-1333
Publication Date(Web):
DOI:10.1002/jssc.201401261
CdS nanoparticles coated on a stainless-steel wire for solid-phase microextraction was prepared. Scanning electron microscopy showed that the CdS nanoparticles clustered together to form a porous structure and X-ray diffraction confirmed that the CdS nanoparticles were the wurtzite phase. Coupled to gas chromatography with flame ionization detection, the extraction abilities of the fiber for polycyclic aromatic hydrocarbons were examined by the headspace method. The parameters of adsorption time, adsorption temperature, salt concentration, desorption time, and desorption temperature were investigated and optimized. For the method, wide linearity and low limits of detection from 5 to 15 ng/L were obtained. The relative standard deviations for single-fiber repeatability and fiber-to-fiber reproducibility were less than 10.2 and 12.6%, respectively. The enrichment factors were from 1155.6 to 3905.4, showing the fiber has good extraction capacity for polycyclic aromatic hydrocarbons. Moreover, the fiber can be used more than 50 times, exhibiting good stability. The established method was also used to analyze the polycyclic aromatic hydrocarbons in two real samples, and the recoveries from 82.7 to 114.2% further proved the reliability of the method.
Co-reporter:Xiaojing Liang, Shujuan Liu, Shuai Wang, Yong Guo, Shengxiang Jiang
Journal of Chromatography A 2014 Volume 1357() pp:53-67
Publication Date(Web):29 August 2014
DOI:10.1016/j.chroma.2014.04.039
•Using CNTs as sorbent in different extraction modes has been summarized.•CNTs-based sorbents have been used to extract several of targets.•Modified MWCNTs are more widely sued to achieve the selective adsorption.•CNTs-based extraction technology tends to miniaturization and automation.Carbon nanotubes (CNTs), as an advanced material, have been widely used in various fields since its discovery in 1991. In recent years, as an excellent adsorption material, the pure and modified CNTs are successfully used for the purification and enrichment of food, medicine, environmental samples and so on. In this review, we focus on the detailed description of different CNTs-based extraction modes such as solid-phase extraction (SPE) (including cartridge and disk SPE, dispersive SPE, and μ-SPE) and solid-phase microextraction (SPME) (including fiber SPME, electrosorption-enhanced SPME, stir bar sorptive extraction, needle trap SPME, and hollow fiber SPME).
Co-reporter:Sheng Tang, Shujuan Liu, Yong Guo, Xia Liu, Shengxiang Jiang
Journal of Chromatography A 2014 Volume 1357() pp:147-157
Publication Date(Web):29 August 2014
DOI:10.1016/j.chroma.2014.04.037
•The latest advances of ILs in CE and CEC are specifically highlighted.•The recent development of PILs in CE and CEC is first summarized.•ILs and PILs have made significant contributions in the improvement of CE and CEC.•Introduction of ILs and PILs in CE and CEC has good prospects in separation science.•Ongoing studies and future perspectives in these areas are discussed.Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed.
Co-reporter:Sheng Tang, Shujuan Liu, Haixia Ren, Xiaojing Liang, Hongdeng Qiu, Yong Guo, Xia Liu and Shengxiang Jiang
RSC Advances 2014 vol. 4(Issue 49) pp:25819-25826
Publication Date(Web):29 May 2014
DOI:10.1039/C4RA03460K
A new imidazolium-based organic–silica hybrid monolith by binding the imidazole-1-acetic acid onto the surface of monolithic silica was prepared through a simple route. The obtained monolith exhibited per aqueous capillary electrochromatography (PACEC) characteristics in water-rich mobile phases. A typical per aqueous chromatography behavior was observed for the test solutes (an increase in H2O content resulted in an increase in retention). The effects of water content, pH and ion strength of mobile phase on the retention of test compounds in highly aqueous eluents were investigated in detail. PACEC in itself is a green chromatography mode that makes green capillary electrochromatography possible. Various hydrophilic compounds including amino acids were baseline separated with enhanced resolution of the obtained monolith under PACEC mode. It is evidenced that solutes were retained predominantly by hydrophobic interactions under PACEC conditions. Therefore, PACEC has the potential to replace hydrophilic interaction chromatography and meanwhile it is complementary to the reverse-phase chromatography.
Co-reporter:Linying Cao, Hui Yu, Shijun Shao, Shuai Wang and Yong Guo
Analytical Methods 2014 vol. 6(Issue 18) pp:7149-7153
Publication Date(Web):08 Jul 2014
DOI:10.1039/C4AY01276C
A spin-labeled fluorescence probe (RNO˙) was employed to evaluate the antioxidant capacity of polyphenols. The hydrogen-transfer mechanism was proposed by kinetic studies using fluorescence spectroscopy, and the product was confirmed to be RNOH by HPLC-MS with little side products. The HPLC-UV/vis method devoted to the simultaneous monitoring of the RNO˙ and RNOH at 556 nm was developed, which can distinguish the antioxidant capacity of polyphenols with similar structure. The method has the potential to be used to screen antioxidants when modifying or optimizing natural antioxidants.
Co-reporter:Linying Cao, Qingfeng Wu, Qiang Li, Shijun Shao and Yong Guo
New Journal of Chemistry 2013 vol. 37(Issue 10) pp:2991-2994
Publication Date(Web):14 Aug 2013
DOI:10.1039/C3NJ00674C
A novel rhodamine nitroxide probe was synthesized for monitoring the cellular redox environment based on the reduction of the nitroxide to hydroxylamine. It displayed selective and sensitive response to biological reducing compounds. The different effects of anticancer agent 2-deoxyglucose on the redox environment of normal human liver cells and human hepatoma cells were studied by fluorescence imaging.
Co-reporter:Jing Jia, Xiaojing Liang, Licheng Wang, Yong Guo, Xia Liu, Shengxiang Jiang
Journal of Chromatography A 2013 1320() pp: 1-9
Publication Date(Web):
DOI:10.1016/j.chroma.2013.10.042
Co-reporter:Ying Yue, Yong Guo, Jian Xu and Shijun Shao
New Journal of Chemistry 2011 vol. 35(Issue 1) pp:61-64
Publication Date(Web):29 Nov 2010
DOI:10.1039/C0NJ00720J
A method for the selective fluorescence sensing of homocysteine (Hcy) and cysteine (Cys) under neutral pH conditions, based on the reaction of the simple aldehyde containing Bodipy dye with Hcy/Cys, has been developed. The location of the aldehyde group at the Bodipy core is important and has an effect on the cyclization with Hcy/Cys.
Co-reporter:Yongjun Lv, Yong Guo, Jian Xu, Shijun Shao
Journal of Fluorine Chemistry 2011 Volume 132(Issue 11) pp:973-977
Publication Date(Web):November 2011
DOI:10.1016/j.jfluchem.2011.08.001
Three simple colorimetric anion sensors (1, 2, and 3) containing anthrone, 1,3-indanedione, and malononitrile as signaling chromophores and an indole binding site have been designed and synthesized. The introduction of electron-withdrawing groups can not only provide chromogenic signal output, but also tune the sensitivity and selectivity of indole-based anion sensors by electron push–pull features. Their anion binding and sensing properties were investigated in detail by dramatic color changes, UV–vis absorption, and 1H NMR. As results revealed, sensor 1 showed high selectivity for F− over AcO− and H2PO4− with a distinct change in color due to the deprotonation of indole NH group. The excellent selectivity of 1 for F− can be attributed to the fitness in the acidity of its NH-group, which is tuned to be able to distinguish the subtle difference in the affinity of F−, AcO−, and H2PO4− to NH proton.Graphical abstract. Three simple colorimetric indole-based sensors show different anion binding properties with the introduction of different electron-withdrawing chromophore. The most electronegative F− can induce significant UV–vis absorption and color changes of three sensors in CH3CN, which is attributed to the fitness in the acidity of indole NH and F−.Highlights► Synthesis of three novel and simple indole-based colorimetric anion receptors. ► Tuning anion selectivity by introduction of three chromophores. ► F− Sensing through color changes based on deprotonation.
Co-reporter:YongJun Lv;Jian Xu;ShiJun Shao
Science China Chemistry 2011 Volume 54( Issue 5) pp:
Publication Date(Web):2011 May
DOI:10.1007/s11426-011-4237-7
A boradiazaindacenes (BODIPY)-phenol conjugate, 1, can act as a colorimetric and fluorometric sensor for sensitive and selective measurement of F− over AcO− and H2PO4− in CH3CN. Sensor 1 gives response to F− in a 1:1 ratio via the deprotonation of the phenolic OH proton, which results in color change from pale yellow to light green and quenching of bright green fluorescence.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 18) pp:
Publication Date(Web):
DOI:10.1039/C4AY01276C
A spin-labeled fluorescence probe (RNO˙) was employed to evaluate the antioxidant capacity of polyphenols. The hydrogen-transfer mechanism was proposed by kinetic studies using fluorescence spectroscopy, and the product was confirmed to be RNOH by HPLC-MS with little side products. The HPLC-UV/vis method devoted to the simultaneous monitoring of the RNO˙ and RNOH at 556 nm was developed, which can distinguish the antioxidant capacity of polyphenols with similar structure. The method has the potential to be used to screen antioxidants when modifying or optimizing natural antioxidants.
![1,2-dimethoxy-12-methyl[1,3]benzodioxolo[5,6-c]phenanthridinium](http://img.cochemist.com/ccimg/34400/34316-15-9.png)
![1,2-dimethoxy-12-methyl[1,3]benzodioxolo[5,6-c]phenanthridinium](http://img.cochemist.com/ccimg/34400/34316-15-9_b.png)
