FeiFang Zhang - Cochemist

A positively charged porous graphitic carbon stationary phase for hydrophilic interaction liquid chromatography

Co-reporter:Yanjie Hou, Feifang Zhang, Xuefang Liu, Yanjun Ren, Bingcheng Yang

Talanta 2017 Volume 164() pp:159-163

Publication Date(Web):1 March 2017

DOI:10.1016/j.talanta.2016.11.033

•The first fully pH-stable, quaternary ammonium functionalized HILIC stationary phase.•It offers excellent hydrophilic and positively charged characters.•The phase exhibits much lower bleeding and wider pH tolerance range.High chemical inertness of porous graphitic carbon particles (PGC) makes their surface modification rather difficult. Here a facile way is proposed to prepare a PGC stationary phase with quaternary ammonium-polyvinyl alcohol mixed functional groups for hydrophilic interaction liquid chromatography (HILIC) by generating a thin layer of polyvinyl alcohol (PVA) and poly(diallyldimethylammonium chloride) (DDAC) copolymer onto PGC particles. The phase shows obvious positively electrostatic character and typical HILIC character, exhibiting different selectivity relative to several HILIC phases and bare PGC. To the best of our knowledge, this is the first fully pH-stable, quaternary ammonium functionalized HILIC phase. It is much superior to silica-based HILIC phases in terms of wide pH tolerance (2.1–12.7) and low bleeding.A fully pH-stable, positively charged HILIC phase is firstly described by generating a thin coating of polyvinyl alcohol (PVA) and poly(diallyldimethylammonium chloride) (DDAC) copolymer onto porous graphic carbon.

A magnetic restricted access material for rapid solid phase extraction of multiple macrolide antibiotics in honey

Co-reporter:Lijun Liu;Bingcheng Yang;Xinmiao Liang

Analytical Methods (2009-Present) 2017 vol. 9(Issue 20) pp:2990-2996

Publication Date(Web):2017/05/25

DOI:10.1039/C7AY00478H

A magnetic restricted access material (MRAM) sorbent has been synthesized and for the first time used for the extraction of macrolide antibiotics (MACs). It was prepared using Fe3O4@SiO2 nanoparticles as a support substrate through silanization, atom transfer radical polymerization and hydrolysis reaction. The high magnetic characteristic of the MRAM offers simple isolation from solution and simplified operation procedures as well. The sorbent showed an effective enrichment effect for model MACs (enrichment factor ∼ 520) and also a good exclusion effect towards protein. After treatment with the sorbent, liquid chromatography (LC) coupled with a common ultraviolet absorbance detector offered low limits of detection of 0.076–0.286 μg L−1. The residue of four model MACs in honey samples was determined with recoveries ranging from 92.7% to 109.3%.

Study of matrix effects for liquid chromatography–electrospray ionization tandem mass spectrometric analysis of 4 aminoglycosides residues in milk

Co-reporter:Yuan Wang, Shaohui Li, Feifang Zhang, Yifeng Lu, Bingcheng Yang, Feng Zhang, Xinmiao Liang

Journal of Chromatography A 2016 Volume 1437() pp:8-14

Publication Date(Web):11 March 2016

DOI:10.1016/j.chroma.2016.02.003

•Matrix effect for aminoglycoside analysis in milk by LC–MS was explored.•Consecutive SPE pretreatment was used to reduce matrix effect.•Lower matrix effect was obtained by optimal strategies.Matrix effect (ME) is always a major issue for the development of LC–MS/MS method. ME resulting from co-eluting residual matrix components can affect the ionization efficiency of target analytes, leading to quantification errors of the analytes of interest. The present work evaluates MEs of milk samples on simultaneous analysis of four aminoglycosides residues via LC–ESI/MS/MS including streptomycin, dihydrostreptomycin, spectinomycin and kanamycin. Approaches to reduce MEs were examined: optimization of the sample preparation, sample dilution and lower flow rate used. Three commercial sorbents were tested including Oasis MCX, Oasis HLB and Oasis WCX. WCX behaved better for all analytes, but high MEs (80.8–134.9%) were obtained. Therefore, a consecutive SPE of tC18-WCX was found to effectively reduce ME. Milk samples from different manufacturers were analyzed and low MEs (85.6–112.9%) were obtained.

Separation analysis of macrolide antibiotics with good performance on a positively charged C18HCE column

Co-reporter:Jie Wei;Aijin Shen;Jingyu Yan;Gaowa Jin;Bingcheng Yang;Zhimou Guo;Xinmiao Liang

Journal of Separation Science 2016 Volume 39( Issue 6) pp:1073-1081

Publication Date(Web):

DOI:10.1002/jssc.201500923

The separation of basic macrolide antibiotics suffers from peak tailing and poor efficiency on traditional silica-based reversed-phase liquid chromatography columns. In this work, a C18HCE column with positively charged surface was applied to the separation of macrolides. Compared with an Acquity BEH C18 column, the C18HCE column exhibited superior performance in the aspect of peak shape and separation efficiency. The screening of mobile phase additives including formic acid, acetic acid and ammonium formate indicated that formic acid was preferable for providing symmetrical peak shapes. Moreover, the influence of formic acid content was investigated. Analysis speed and mass spectrometry compatibility were also taken into account when optimizing the separation conditions for liquid chromatography coupled with tandem mass spectrometry. The developed method was successfully utilized for the determination of macrolide residues in a honey sample. Azithromycin was chosen as the internal standard for the quantitation of spiramycin and tilmicosin, while roxithromycin was used for erythromycin, tylosin, clarithromycin, josamycin and acetylisovaleryltylosin. Good correlation coefficients (r² > 0.9938) for all macrolides were obtained. The intra-day and inter-day recoveries were 73.7–134.7% and 80.7–119.7% with relative standard deviations of 2.5–8.0% and 3.9–16.1%, respectively. Outstanding sensitivity with limits of quantitation (S/N ≥ 10) of 0.02–1 μg/kg and limits of detection (S/N ≥ 3) of 0.01–0.5 μg/kg were achieved.

A polyvinyl alcohol-functionalized sorbent for extraction and determination of aminoglycoside antibiotics in honey

Co-reporter:Yuan Wang, Shunli Ji, Feng Zhang, Feifang Zhang, Bingcheng Yang, Xinmiao Liang

Journal of Chromatography A 2015 Volume 1403() pp:32-36

Publication Date(Web):17 July 2015

DOI:10.1016/j.chroma.2015.05.032

•A novel polyvinyl alcohol-coated silica gel (PVA-Sil) hydrophilic sorbent.•A facile and simple way to prepare PVA-Sil sorbent.•PVA-Sil sorbent demonstrated good ability for extraction aminoglycoside antibiotics.A novel highly hydrophilic sorbent simply prepared by coating polyvinyl alcohol (PVA) onto silica gel was used for extraction and determination of aminoglycoside antibiotics (AAs). The fabricated PVA coating is aimed to effectively protect core silica gel inside and offers good hydrophilic property. In combination of hydrophilic interaction chromatography tandem mass spectrometry, the performance of the sorbent was evaluated by selecting four model AAs (dihydrostreptomycin, streptomycin, kanamycin, spectinomycin). The sorbent was found to have effective adsorption ability to hydrophilic AAs, which was superior or comparable to those of commercial ones. Good recoveries (84–112%) of model AAs spiked in honey were obtained with good precision (<12.4%) and the limit of quantitation for the proposed method was in the range of 7.8–19.4 ng/mL.

An arginine-functionalized stationary phase for hydrophilic interaction liquid chromatography

Co-reporter:Shengjie Wu, Xiuling Li, Feifang Zhang, Ge Jiang, Xinmiao Liang and Bingcheng Yang

Analyst 2015 vol. 140(Issue 12) pp:3921-3924

Publication Date(Web):23 Apr 2015

DOI:10.1039/C5AN00570A

An arginine-functionalized stationary phase for hydrophilic interaction liquid chromatography (HILIC) has been prepared for the first time by clicking arginine onto silica gel. It offers an efficient separation of organic acids, nucleotides and sugars. More interestingly, it exhibited excellent selectivity and enrichment toward acidic glycopeptides, even at a ratio of 1:150 to non-glycopeptides.

A polyvinyl alcohol-coated silica gel stationary phase for hydrophilic interaction chromatography

Co-reporter:Shunli Ji, Yang Zheng, Feifang Zhang, Xinmiao Liang and Bingcheng Yang

Analyst 2015 vol. 140(Issue 18) pp:6250-6253

Publication Date(Web):06 Aug 2015

DOI:10.1039/C5AN01159K

Multiple layers of polyvinyl alcohol (PVA) coating are generated onto silica gel by thermal immobilization to form a stationary phase applied for hydrophilic interaction liquid chromatography (HILIC). It offers an easy way to manipulate the thickness of PVA coating and the obtained stationary phase demonstrated high efficiency and high chemical stability.

Highly selective separation of aminoglycoside antibiotics on a zwitterionic Click TE-Cys column

Co-reporter:Jie Wei;Aijin Shen;Huihui Wan;Jingyu Yan;Bingcheng Yang;Zhimou Guo;Xinmiao Liang

Journal of Separation Science 2014 Volume 37( Issue 14) pp:1781-1787

Publication Date(Web):

DOI:10.1002/jssc.201400080

Hydrophilic interaction liquid chromatography has emerged as a valuable alternative approach to ion-pair chromatography for the separation of aminoglycoside antibiotics in recent years. However, the resolution of structurally related aminoglycosides is a great challenge owing to the limited selectivity. In this work, a cysteine-based zwitterionic stationary phase (named Click TE-Cys) was utilized and compared with five commonly used hydrophilic interaction liquid chromatography columns. Click TE-Cys displayed much better selectivity for structurally similar aminoglycosides. The retention behaviors of aminoglycosides were investigated in detail, revealing that low pH (2.7 or 3.0) and high buffer concentration (≥50 mM) were preferable for achieving good peak shape and selectivity. Effective resolution of ten aminoglycosides including spectinomycin, dihydrostreptomycin, streptomycin, gentamicin C1, gentamicin C2/C2a, gentamicin C1a, kanamycin, paromonycin, tobramycin, and neomycin was realized at optimized conditions. Additionally, spectinomycin and its related impurities were successfully resolved. The results indicated the great potential of the Click TE-Cys column in the separation of aminoglycoside mixtures and related impurities.

Graphene nanoplatelets as a highly efficient solid-phase extraction sorbent for determination of phthalate esters in aqueous solution

Co-reporter:Xi Luo, FeiFang Zhang, Shunli Ji, Bingcheng Yang, Xinmiao Liang

Talanta 2014 Volume 120() pp:71-75

Publication Date(Web):March 2014

DOI:10.1016/j.talanta.2013.11.079

•Graphene nanoplatelet was first used as an SPE sorbent for phthalate ester.•The sorbent demonstrated better performance relative to commons sorbents.•Graphene nanoplatelet sorbent can be recyclable.Graphene nanoplatelet (GN) as a solid-phase extraction (SPE) sorbent in combination with high performance liquid chromatography has been used for the determination of five phthalate esters (PAEs) in aqueous solution. The operation parameters affecting the extraction efficiency were optimized. Comparative studies showed that GN was superior to other common SPE sorbents in terms of recovery and adsorption capacity. Under optimization conditions, detection limits of 0.09–0.33 ng mL−1 were achieved for five PAEs and enrichment factors of 402–711 for the analytes were obtained. The proposed method was successfully applied for the determination of PAEs in tap water and drink samples with recoveries ranging from 87.7% to 100.9%.Graphene nanoplatelet was proved to be a highly efficient SPE sorbent for determination of phthalate esters in aqueous solution.

Preparation of C18-functionalized Fe3O4@SiO2 core–shell magnetic nanoparticles for extraction and determination of phthalic acid esters in Chinese herb preparations

Co-reporter:Bize Guo, Shunli Ji, Feifang Zhang, Bingcheng Yang, Jiangping Gu, Xinmiao Liang

Journal of Pharmaceutical and Biomedical Analysis 2014 100() pp: 365-368

Publication Date(Web):

DOI:10.1016/j.jpba.2014.08.027

Determination of aristolochic acids in rat serum by high performance liquid chromatography-Q-TOF tandem mass spectrometry

Co-reporter:Jiangping Gu, Pinjie Zhang, Feifang Zhang, HeQing Shen, Bingcheng Yang, Xinmiao Liang and Xiaogang Chu

Analytical Methods 2013 vol. 5(Issue 3) pp:718-721

Publication Date(Web):12 Nov 2012

DOI:10.1039/C2AY25860A

Four aristolochic acids (AAs) including AA-I, AA-II, AA-IIIa and AA-IVa in rat serum were simultaneously determined by HPLC-Q-TOF-MS. A new solid phase extraction (SPE) resin with reversed-phase/strong anion exchange mixed groups (C18-SAX) was used to effectively purify and enrich the analytes, which demonstrated much better performance in comparison with common C18-SPE resin in terms of noise level and recovery. The chromatographic separation was performed on a C18 column under isocratic elution, and the effluent was analyzed by TOF-MS-MS in the mode of positive multiple reaction. Naproxen was used as the internal standard (IS). The limit of detection was 3, 6, 0.09 and 1.5 ng mL−1 for AA-I, AA-II, AA-IIIa and AA-IVa, respectively. Intra- and inter-day precisions measured as relative standard deviation of retention time were less than 1.1% and 1.5%, respectively.

A new reversed-phase/strong anion-exchange mixed-mode stationary phase based on polar-copolymerized approach and its application in the enrichment of aristolochic acids

Co-reporter:Jie Wei, Zhimou Guo, Pinjie Zhang, Feifang Zhang, Bingcheng Yang, Xinmiao Liang

Journal of Chromatography A 2012 Volume 1246() pp:129-136

Publication Date(Web):13 July 2012

DOI:10.1016/j.chroma.2012.03.047

A novel silica-based reversed-phase/strong anion-exchange mixed-mode stationary phase named C18SAX was synthesized based on the polar-copolymerized approach. C18SAX stationary phase showed excellent compatibility with 100% aqueous mobile phase and comparable performance with commercial SunFire™ C18 column in terms of column efficiency and methylene selectivity. And the results indicated that hydrophobic interaction and anion-exchange mechanism dominate the separation process of aristolochic acids. The utility of C18SAX material-based SPE was demonstrated for the enrichment of aristolochic acids extracted from Caulis Aristochiae Manshuriensis. The SPE method was developed rapidly and simply by HPLC evaluation. Under the optimized SPE conditions, the average recoveries of aristolochic acid I and aristolochic acid II in crude sample were 72.36% and 105.59%, with RSDs of 5.77% and 1.13%, respectively. The complexity of sample matrices was significantly simplified after the SPE procedure and further preparation and purification of target compounds was performed on a preparative C18TDE column. Four aristolochic acids, including aristolochic acid I (31.8 mg), II (8.9 mg), IIIa (6.1 mg) and IVa (4.3 mg) were purified with HPLC purities all above 93%. The results proved that the aristolochic acids could be efficiently enriched by C18SAX material and easily eluted in acidic conditions, indicating its great potential in the enrichment of acidic compounds from complex matrices.Highlights► A C18SAX stationary phase was synthesized based on polar-copolymerized approach. ► The mixed-mode C18SAX material could be used both in SPE and HPLC. ► The SPE method was efficiently developed on the basis of HPLC evaluation. ► Aristolochic acids were enriched with high selectivity from complex matrices. ► The C18SAX material has great potential in the enrichment of acidic compounds.

Separation of β-agonists in pork on a weak cation exchange column by HPLC with fluorescence detection

Co-reporter:Wenying Meng, Jie Wei, Xi Luo, Feifang Zhang, Bingcheng Yang, Zhimou Guo and Xinmiao Liang

Analytical Methods 2012 vol. 4(Issue 4) pp:1163-1167

Publication Date(Web):08 Mar 2012

DOI:10.1039/C2AY05936C

The separation of β-agonists was performed for the first time on a silica-based weak cation exchange (WCX) stationary phase in which aqueous electrolyte solution with small amount of organic solvent was used as the mobile phase. Compared to the organic solvent used in reverse phase HPLC mode, the merits of using an aqueous mobile phase include unique selectivity, environment-friendly operation and reduced operation costs. The effective separation of four commonly used β-agonists including salbutamol, terbutaline, metoprolol and ractopamine, were achieved with the mobile phase of 20 mM ammonium formate/acetonitrile (5%). The interference from the hydrophobic analytes could be easily eliminated due to their poor retention under this mode. The detection limits for the above analytes when fluorescence detection is employed were in the range of 3.55–8.32 μg kg−1 and the spiked recoveries for metoprolol for the spike sample reached about 83% and the relative standard deviation (RSD) was 4.7%.

Preparation and evaluation of anion exchange open tubular column

Co-reporter:Xuefang Diao, Feifang Zhang, Feng Feng, Bingcheng Yang, Xinmiao Liang, Xiaogang Chu

Talanta 2012 Volume 101() pp:91-95

Publication Date(Web):15 November 2012

DOI:10.1016/j.talanta.2012.08.036

An anion open tubular column (OTC) by coating cationic latex particle onto the silica capillary with surface sulfonate functionalized has been prepared and evaluated. The performance of the OTC was observed to be superior to that of those prepared by the bare silica capillary without sulfonation in term of separation efficiency. To increase the surface area of the capillary, acid and base-based etching method for treating silica capillary wall was carried out and compared. An OTC with multiple layers was prepared by alternatively coating cationic and anionic latex particles aiming to further increase the column capacity. The anion OTC with size of 50 μm i.d.×1 m long demonstrated good separation of common inorganic anions with high efficiency (e.g. for NO2−, its theory plate number is 11655 plate/m).Highlights► A simple way for preparing anion exchange open tubular column was presented. ► Acid and base etching methods were quantitatively compared. ► The open tubular column demonstrated good separation of inorganic anions.

Analysis of cephalosporins by hydrophilic interaction chromatography

Co-reporter:Qiaoxia Liu, Lingyan Xu, Yanxiong Ke, Yu Jin, Feifang Zhang, Xinmiao Liang

Journal of Pharmaceutical and Biomedical Analysis 2011 54(3) pp: 623-628

Publication Date(Web):

DOI:10.1016/j.jpba.2010.09.040

Determination of aristolochic acids in rat serum by high performance liquid chromatography-Q-TOF tandem mass spectrometry

Co-reporter:

Analytical Methods (2009-Present) 2013 - vol. 5(Issue 3) pp:NaN721-721

Publication Date(Web):2012/11/12

DOI:10.1039/C2AY25860A

Four aristolochic acids (AAs) including AA-I, AA-II, AA-IIIa and AA-IVa in rat serum were simultaneously determined by HPLC-Q-TOF-MS. A new solid phase extraction (SPE) resin with reversed-phase/strong anion exchange mixed groups (C18-SAX) was used to effectively purify and enrich the analytes, which demonstrated much better performance in comparison with common C18-SPE resin in terms of noise level and recovery. The chromatographic separation was performed on a C18 column under isocratic elution, and the effluent was analyzed by TOF-MS-MS in the mode of positive multiple reaction. Naproxen was used as the internal standard (IS). The limit of detection was 3, 6, 0.09 and 1.5 ng mL−1 for AA-I, AA-II, AA-IIIa and AA-IVa, respectively. Intra- and inter-day precisions measured as relative standard deviation of retention time were less than 1.1% and 1.5%, respectively.

Separation of β-agonists in pork on a weak cation exchange column by HPLC with fluorescence detection

Co-reporter:

Analytical Methods (2009-Present) 2012 - vol. 4(Issue 4) pp:

Publication Date(Web):

DOI:10.1039/C2AY05936C

The separation of β-agonists was performed for the first time on a silica-based weak cation exchange (WCX) stationary phase in which aqueous electrolyte solution with small amount of organic solvent was used as the mobile phase. Compared to the organic solvent used in reverse phase HPLC mode, the merits of using an aqueous mobile phase include unique selectivity, environment-friendly operation and reduced operation costs. The effective separation of four commonly used β-agonists including salbutamol, terbutaline, metoprolol and ractopamine, were achieved with the mobile phase of 20 mM ammonium formate/acetonitrile (5%). The interference from the hydrophobic analytes could be easily eliminated due to their poor retention under this mode. The detection limits for the above analytes when fluorescence detection is employed were in the range of 3.55–8.32 μg kg−1 and the spiked recoveries for metoprolol for the spike sample reached about 83% and the relative standard deviation (RSD) was 4.7%.