List of Issues

Chinese Journal of Chromatography
2016, Vol. 34, No. 9
Online: 08 September 2016

Previous Issue    Next Issue



For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Communications

Select

Comparison of reliabilities of mass spectrometry-based label-free quantitation methods for histone post-translational modification analysis LIU Zhiwei, ZHU Mingrui, ZHAI Linhui, TAN Minjia 2016, 34 (9):  825-830.  DOI: 10.3724/SP.J.1123.2016.04040 Abstract ( 468 )   [Full Text(HTML)] () PDF (845KB) ( 87 )   Histone post-translational modifications (PTMs) play critical roles in epigenetic regulations of cellular physiology. The rapid development of mass spectrometry based on proteomics makes it possible to systematically widely identify and quantify the dynamic changes of histone PTMs. There are three widely used label-free quantitation methods (spectra count, peak area and intensity) for mass spectrometry data analysis, but by which method is the most reliable one for histone PTM quantification has not been systematically investigated. To this goal, we quantified histone acetylome in stable isotope amino acid labeled SH-SY5Y cells by SAHA (a pan histone deacetylase inhibitor) treatment. By comparing the standard deviations (SDs) of quantitation results from the three methods, we showed that quantification based on peak area method is the most reliable one. Therefore, our study provided new insight for label-free histone mark analysis, especially for clinical and large-scale samples.

Mini-reviews

Select

Advances in chiral stationary phases with dual chiral selectors CUI Dongxiao, JIA Yanyan, LI Guangqing, WEN Aidong, WANG Xifang 2016, 34 (9):  831-834.  DOI: 10.3724/SP.J.1123.2016.06013 Abstract ( 460 )   [Full Text(HTML)] () PDF (799KB) ( 116 )   The chiral stationary phases (CSPs) as core technology play important roles in the identification and separation of chiral compounds. The CSPs with dual chiral selectors become the main issue in recent years. Many studies indicate that CSPs containing two efficient chiral selectors increase chiral recognition sites, and exhibit good chiral separation performance. This paper introduces chiral stationary phases with dual chiral selectors in the research development of chiral separation in recent years, and the development prospects are also discussed.

Articles

Select

Rapid detection of 248 pesticide residues in vegetables by ultra high performance liquid chromatography-tandem mass spectrometry LI Lingyun, XU Xiaomin, LIN Huan, ZHAO Wen, YE Rong, HUANG Xiaodong, ZHENG Shuning, LIU Xinyan, LIU Su, XU Donghui 2016, 34 (9):  835-849.  DOI: 10.3724/SP.J.1123.2016.04004 Abstract ( 601 )   [Full Text(HTML)] () PDF (1918KB) ( 252 )   A multiresidue analytical method for rapid detection of 248 pesticide residues in vegetables using an ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) technique was successfully developed. The vegetable samples were extracted by acetonitrile. After salting out, the solvent extracts were analyzed by UHPLC-MS/MS directly. And further purification was not needed. The positive and negative ion modes and multiple reaction monitoring (MRM) mode were used to identify and quantify the 248 pesticide residues in vegetables. The results showed that 245 pesticides had good linearity within their respective linear ranges (r>0.99). Except four pesticides (carbosulfan, cyromazine, tribenuron-methyl, quinclorac), the average recoveries of the other 244 pesticides at three spiked levels ranged from 63.0% to 126.4% with the relative standard deviations (RSDs) from 0.5% to 26.7%. The limits of quantification of this method were in the range of 0.001-0.030 mg/kg. In comparison with other pretreatment methods for pesticide residues, this method not only shortened the time of sample pretreatment, but also enhanced significantly the recoveries of pesticides. The results in this study suggested that it is a simple, rapid, sensitive and accurate method for pesticide residue determination, and suitable for rapid screening of pesticide residues in vegetables.

Select

Magnetic graphene based dispersive micro-solid-phase extraction coupled with liquid chromatography-tandem quadrupole mass spectrometry for the analysis of nine non-steroidal anti-inflammatory drugs in livestock and poultry meat DONG Chanchan, HU Yanyun, LÜ Yaning, SONG Wei, HAN Fang, ZHENG Ping, DENG Ning 2016, 34 (9):  850-859.  DOI: 10.3724/SP.J.1123.2016.04039 Abstract ( 543 )   [Full Text(HTML)] () PDF (5213KB) ( 90 )   A novel analytical method was developed for the determination of nine non-steroidal anti-inflammatory drugs (NSAIDs) in meat samples by magnetic graphene nanocomposite (Fe3O4-G) based on dispersive micro-solid-phase extraction (μ-SPE) coupled with liquid chromatography-mass spectrometry detection. Samples were homogenized and extracted with acidified acetonitrile. After defatting with the high speed frozen centrifugation, the sample solutions were defatted with n-hexane followed by μ-SPE. Some important parameters influencing the extraction efficiency including the extraction time, the pH value of sample solution and the elution conditions were optimized. The limits of detection (LODs, S/N=3) of the nine NSAIDs ranged from 0.2 to 8.2 μg/kg, and the limits of quantification (LOQs, S/N=10) ranged from 0.5 to 25.4 μg/kg. The average recoveries were 83.3%-104.5% with the relative standard deviations between 1.2% and 6.8% obtained from samples spiked at LOQ, 2LOQ and 10LOQ levels. Compared with Sep-Pak Vac NH2 and Oasis HLB cartridges, Fe3O4-G has excellent purification effect, high loading amounts and good reusability. The results demonstrated that the method provide a novel pretreatment technique for the determination of NSAID residues in meat samples.

Select

Multi-residue determination of veterinary drugs in porcine muscle by QuEChERS and liquid chromatography-tandem mass spectrometry ZHANG Keming, LIANG Feiyan, DENG Ming, LIU Xianghong, XU Yangbiao, ZHAO Zhuang 2016, 34 (9):  860-867.  DOI: 10.3724/SP.J.1123.2016.06010 Abstract ( 581 )   [Full Text(HTML)] () PDF (1497KB) ( 159 )   A liquid chromatography-tandem mass spectrometric method with modified QuEChERS procedure for sample preparation was developed for the simultaneous determination of 7 classes of 35 veterinary drugs including sulfonamides, sulfonamide potentiators, beta-agonists, tetracyclines, amnatadine and sex hormones in porcine muscle. The drugs were extracted with 0.1 mol/L Na2EDTA (ethylene diamine tetraacetic acid)-Mcllvaine buffer solution and acetonitrile containing 2.5% (v/v) acetic acid, and then the extracts were purified using dispersive-solid phase extraction with NH2 sorbent, and finally analyzed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode via positive electrospray ionization. The correlation coefficients of the standard calibration curves for the 35 veterinary drugs were all above 0.996. The blank samples were spiked at three levels, and the average recoveries ranged from 71.8% to 113.5% with the relative standard deviations from 0.6% to 9.8% (n=6). The limits of detection and the limits of quantification were 0.01-1.01 μg/kg and 0.04-3.37 μg/kg respectively. The method developed is easy to operate, sensitive, with good purification effect and suitable for the determination of residues in porcine muscle.

Select

Determination of 31 phthalate esters in baked foods and plastic packaging materials by high performance chromatography-tandem mass spectrometry BO Yanna, LI Rong, ZHANG Pengjie, LIN Qinbao, ZHANG Xianchen, CHEN Lisi, HU Yiguang, HUANG Zhiqiang 2016, 34 (9):  868-879.  DOI: 10.3724/SP.J.1123.2016.05008 Abstract ( 555 )   [Full Text(HTML)] () PDF (1672KB) ( 100 )   A high performance liquid chromatography-tandem mass spectrometric method for the analysis of 31 phthalate acid esters (PAEs) in baked foods and plastic packaging materials was developed. The food samples were extracted with ethyl acetate. Then, the extracts were frozen at -18℃, cleaned up at low temperature and high speed centrifuge before analyzed by HPLC-MS/MS. While for plastic packaging materials, after cut into small pieces, mixed solvent of methyl alcohol-acetone-n-hexane (1:1:1, v/v/v) was applied to ultra-sonic extraction of the target PAEs. The separation was performed on an MGⅢC18 capillary column (2.0 mm×100 mm, 5 μm), and determined by MS/MS in selected reaction monitoring (SRM) mode. The results indicated that the method had good linear relationships with r2 not less than 0.9958. The average recoveries (n=6) of the 31 PAEs were in the range of 80.1%-113.0% except for bis-dodecyl ester (DLP), whose average recoveries were 70.9%-109.7%, and the relative standard deviations were in the range of 1.0%-13.7%. The limits of detection (LODs) were 0.02-8.15 μg/kg, and the limits of quantification (LOQs) were 0.07-27.17 μg/kg. The method was successfully applied to determine the 31 PAEs in four kinds of baked foods (bread, biscuits, pastry and filling) and their plastic packaging. The method is suitable for the determination of the 31 PAEs in baked foods and packaging with easy operation, high accuracy and precision.

Select

Rapid screening of illegally added insecticides in pesticide formulations by ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry CHEN Jianbo, MA Lin, HUANG Lanqi, WU Aijuan, ZHAN Xiuping, ZHAO Li 2016, 34 (9):  880-887.  DOI: 10.3724/SP.J.1123.2016.05009 Abstract ( 477 )   [Full Text(HTML)] () PDF (903KB) ( 74 )   An analytical method was established for the rapid screening of 48 illegally added insecticides in pesticide formulations by ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF MS). Three pesticide formulations of wettable powder, emulsifiable concentrate, suspension concentrate were extracted with methanol, then detected by UPLC-Q-TOF MS. The calibration curves were linear in the range of 0.5-20 mg/L with the correlation coefficients more than 0.99 for the 48 insecticides. The limits of quantification (LOQs) were 0.05-0.4 mg/kg. The limits of detection (LODs) were 0.01-0.2 mg/kg. The added recoveries for all the insecticides were 86.3%-101.5% with the relative standard deviations ranging from 1.7% to 4.0%. This method has the characteristics of rapid and accurate screening, which can meet the requirement of the determination of the 48 insecticides in pesticide formulations.

Select

Simultaneous determination of the residues of eight isocyanates in synthesized leathers using ultra performance liquid chromatography-orbitrap high resolution mass spectrometry WANG Chengyun, LI Lixia, LIN Junfeng, CHU Naiqing, XIE Tangtang 2016, 34 (9):  888-894.  DOI: 10.3724/SP.J.1123.2016.04037 Abstract ( 381 )   [Full Text(HTML)] () PDF (1317KB) ( 92 )   An effective method of ultra performance liquid chromatography-orbitrap high resolution mass spectrometry (UPLC-Orbitrap HRMS) was established for the simultaneous determination of the residues of eight isocyanates in synthesized leathers. Residual isocyanates in synthesized leathers were ultrasonically extracted using dichloromethane as the extraction solvent and derivatized by 9-(methylaminomethyl) anthracene (MAMA) at the same time. The derivatives were concentrated and analyzed by UPLC-Orbitrap HRMS technique. The concentration of each analyte was calibrated by the external standard method. The derivatives were separated on a Hypersil GOLD column (100 mm×2.1 mm, 1.9 μm) with a gradient elution of acetonitrile and 0.1% (v/v) formic acid aqueous solution, and analyzed by Orbitrap HRMS in positive ESI mode. The qualitative analyses were carried out by the exact masses of quasi-molecular ions and the retention times. The quantitative analyses were carried out by the peak areas in extracted chromatograms. The limits of quantification (LOQs) were 0.2 μg/kg for all the eight isocyanates. The analytes were spiked in blank samples at three levels and the average recoveries varied from 85.41% to 95.53% with the relative standard deviations (RSDs) of 2.55%-6.87%. The proposed method was applied in the analysis of synthesized leather products and isophorone diisocyanate (IPDI) was detected in a real sample. The proposed method was accurate and sensitive, and applicable to the determination of the residues of isocyanates in synthesized leathers.

Select

Fatty acid and solidification floating organic drop-based dispersive liquid-liquid microextraction method coupled with high performance liquid chromatography for the determination of 4-ethylphenol and 4-ethylguaiacol in wines FU Bo, ZHANG Jiping, JIANG Hui, ZHOU Lu 2016, 34 (9):  895-900.  DOI: 10.3724/SP.J.1123.2016.06021 Abstract ( 438 )   [Full Text(HTML)] () PDF (869KB) ( 81 )   A method of fatty acid and solidification floating organic drop-based dispersive liquid-liquid microextraction (FA-DLLME-SFO) coupled with high performance liquid chromatography to determine 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) in wine samples was developed. The method required less than 4 min to extract the two target analytes from wine samples, and only three kinds of eco-friendly solvents including fatty acid, ammonium hydroxide and sulfuric acid were used. The analytical parameters affecting the extraction efficiency including the volumes of the sample, the nature and volumes of the extraction solvent, the volumes of ammonium hydroxide and sulfuric acid, and the amount of salt addition were optimized. Under the optimum conditions (10 mL sample, 100 μL octanoic acid, 110 μL 25%-28% (mass percentage) NH4OH, 0.8 mL 98% (mass percentage) H2SO4, 3.0 g NaCl), the linear ranges were 0.02-1.0 mg/L with correlation coefficients of 0.9997 and 0.9999 for 4-ethylphenol and 4-ethylguaiacol, and the relative standard deviations (RSDs) were 6.2% and 3.5%, respectively. The LODs were 6.33 μg/L and 5.81 μg/L, and the enrichment factors (EFs) were 79 and 86 for 4-ethylphenol and 4-ethylguaiacol, respectively. The present method was applied to the determination of the two analytes in white wine and beer samples, and the recoveries of them were in the range of 81.4%-108.7% with the RSDs less than 8.9%. The method is simple and eco-friendly for rapid analysis of 4-ethylphenol and 4-ethylguaiacol in wine samples.

Select

Relative multicomponent quantitative and identification method of bugloss based on the fingerprint CHU Ganghui, MUHETAER·Tu'erhong, YIN Xuebo, MUNIRA·Abudukeremu 2016, 34 (9):  901-905.  DOI: 10.3724/SP.J.1123.2016.05011 Abstract ( 277 )   [Full Text(HTML)] () PDF (820KB) ( 93 )   Chromatographic fingerprint plays a key role in the identification of habitat for Chinese herbs or Chinese patent medicines. However, peaks' intensities and positions can be affected by the extraction and separation conditions of target, and it is very significant to develop a more precise fingerprint. The certain component (rutin) as the internal standard was used to confirm the relative contents of other components, which was applied in chemical pattern recognition. To verify the idea, according to the peak of rutin as reference, the relative contents of the other defined fingerprint peaks were obtained. A multicomponent quantitative and identification method was established by the fingerprint of bugloss. The obtained fingerprints were used for the chemical pattern recognition, including hierarchical cluster analysis and the principal component analysis, and the bugloss collected from different places could be distinguished effectively. A relative multicomponent quantitative and identification method for bugloss was established. The established method is economic, feasible, and significant for quality control of other herbs and patent medicines.

Select

Determination of 10 chlorinated phenols in textiles by high performance liquid chromatography with hollow fiber liquid phase micro-extraction GAO Yonggang, NIU Zengyuan, ZHANG Yanyan, YE Xiwen, BAO Yan, CAI Fa, WANG Xin, SU Jie, QU Jingwu 2016, 34 (9):  906-911.  DOI: 10.3724/SP.J.1123.2016.05012 Abstract ( 455 )   [Full Text(HTML)] () PDF (881KB) ( 84 )   A method was investigated for the determination of 10 chlorinated phenols in textiles by hollow fiber liquid phase micro-extraction (HF-LPME) coupled with high performance liquid chromatography (HPLC). The experimental conditions of hollow fiber liquid-phase micro-extraction were optimized, such as the nature of organic solvent, the concentration of acceptor phase, stirring rate, extraction time. The optimum extraction conditions were as follows: hexane was used as the organic solvent; the concentration of NaOH solution as acceptor phase was 0.10 mol/L; the stirring rate was 600 r/min; and the extraction time was 60 min. Under the optimal conditions, the calibration curves of the 10 chlorinated phenols were obtained in the range of 0.01-1.00 mg/L (r>0.999); the limits of detection (S/N=3) of the chlorinated phenols were 0.01 mg/kg; and the enrichment factors were 95-101. The proposed method was applied for the determination of the 10 chlorinated phenols in real textile samples. The average recoveries were in the range of 78.8%-105.1% at the spiked levels of 0.01, 0.05 and 0.1 mg/kg; and the relative standard deviations (RSDs) were in the range of 0.3%-7.3%. This method is sensitive, simple, accurate and suitable for the determination of chlorinated phenols in textile samples.

Select

Determination of coumarin rodenticides in soils by high performance liquid chromatography CHEN Wen, GENG Meimei, ZHANG Liping, XU Liwei, YUAN Hongzhao, LI Chunyong, PENG Can, WANG Jiurong, ZHANG Meiwen 2016, 34 (9):  912-917.  DOI: 10.3724/SP.J.1123.2016.03034 Abstract ( 410 )   [Full Text(HTML)] () PDF (853KB) ( 86 )   A method for the determination of warfarin, coumatetralyl, bromadiolone, flocoumafen and brodifacoum residues in soils with post-column derivatization and fluorescence detection by high performance liquid chromatography (HPLC) was established. The samples were extracted with a mixed solution of acetone, ammonium and methanol (100:3:100, v/v/v) after adding ratilan as internal standard. The extracts were vacuum-concentrated and dissolved in 5 mL mixed solution of hexane and chloroform (3:1, v/v) for solid phase extraction (SPE) clean up on an aminopropyl column. The analytes were eluted from the column using 15 mL of 50 mmol/L tetrabutylammonium dihydrogen phosphate in methanol. The solvent was evaporated and the sample was dissolved in a mixed solution of methanol and 0.25% (v/v) acetic acid aqueous solution (3:2, v/v). The coumarin rodenticides were separated on a C18 column by HPLC and on-line derivatized with a mixed solution of methanol, ammonium and water (1:1:8, v/v/v) and detected with a fluorescence detector. Good linearities of the analytes were achieved over the mass concentration of 0.02-10.00 mg/L, with correlation coefficients above 0. 999. The limits of quantification (LOQ, S/N=10) were 2.2-18.5 μg/L for the five coumarin rodenticides. The recoveries were 94.6%-118.0% at the spiked levels of 0.1-0.3 mg/kg in soil with the relative standard deviations of 0.8%-10.2% (n=3). The results indicated that the method is sensitive and accurate with repeatability.

Select

Simultaneous determination of methylmercury and inorganic arsenics in aquatic products by gas chromatography-mass spectrometry with aqueous derivatization HUANG Huiqiu, HUANG Lilai, XIA Ping 2016, 34 (9):  918-924.  DOI: 10.3724/SP.J.1123.2016.04032 Abstract ( 500 )   [Full Text(HTML)] () PDF (916KB) ( 116 )   A fast analytical method based on gas chromatography-mass spectrometry (GC-MS) with aqueous derivatization was established for the simultaneous determination of methylmercury and inorganic arsenics in aquatic products. Methylmercury and inorganic arsenics in samples were extracted with hydrochloric acid (6 mol/L) by ultrasonic extraction. After centrifugation at -10℃, inorganic arsenics (As3+ and As5+) were derivatized under 35℃ water bath for 30 min with 2,3-dimercapto-1-propanol (BAL), then the derivative and methylmercury were extracted with toluene. The non-fatty components in the hydrochloric acid extract were avoided to get into the toluene by adding absolute ethanol before extraction, so the tested solution was purified. Then sodium tetraphenylborate solution (pH 3.6) was added to toluene extraction solution as the derivatization reagent. After centrifugation, the derivatives in organic phase were determined by GC-MS with selected ion monitoring (SIM) mode, and quantified with external standard method. The results showed that the calibration curves were linear in the range of 5-2000 μg/L for methylmercury and inorganic arsenic with correlation coefficients (r) greater than 0.999, and the limits of detection (LODs) were 0.7-3 μg/kg (S/N=3). The recoveries were 80.0%-110.0% at three spiked levels (10, 100, 1000 μg/kg), and the relative standard deviations (RSDs) were 2.5%-9.4% (n=6). The new method is simple, accurate and sensitive, and it has been successfully applied to the determination of methylmercury and inorganic arsenics in real aquatic products for the risk monitoring of food pollutants.

Select

Simple identification approach for trace heteroatom-containing compounds in petroleum fraction by Automated Mass Spectral Deconvolution and Identification System Nagy E. MOUSTAFA, Kout El-Kloub Fars MAHMOUD 2016, 34 (9):  925-932.  DOI: 10.3724/SP.J.1123.2016.05010 Abstract ( 518 )   [Full Text(HTML)] () PDF (1332KB) ( 85 )   Here we present a simple yet effective gas chromatography-mass spectrometry (GC-MS) identification approach for the detection of heteroatom-containing compounds (HACCs) in petroleum fractions. The MS/AMDIS (Automated Mass Spectral Deconvolution and Identification System) program was used to identify parts per million (ppm) HACC concentrations in petroleum fractions in place of traditional techniques (extraction and standard injection). Polycyclic aromatic sulfur heterocycles (S-PAHs) were used as model compounds to confirm the validity of the AMDIS identifiers, which were compared with extracted results using the off-line X-calibur software. AMDIS was able to identify ppm concentrations of S-PAHs in oil condensate. There was good agreement between experimental and AMDIS identification results for S-PAHs in oil condensate. AMDIS was also used to detect nitrogen-containing compounds (NCCs) and alkylphenols in oil condensate. Our results confirmed the presence of 2-methylbenzothiazole, carbazole, and 2,4-ditertbutyl phenol. In a crude oil sample, AMDIS identification of m/z=191 biomarkers was consistent with empirical results. Therefore, AMDIS can help to reduce the number of experimental steps in identification protocols.

Select

Determination of solubility parameters and the related thermodynamic properties of polyvinyl alcohol using inverse gas chromatography and Hansen solubility parameters NI Haiyue, REN Shixue, FANG Guizhen, MA Yanli 2016, 34 (9):  933-939.  DOI: 10.3724/SP.J.1123.2016.05015 Abstract ( 794 )   [Full Text(HTML)] () PDF (982KB) ( 190 )   An inverse gas chromatography (IGC) method was used to study the solubility parameters (δ2) and the related thermodynamic properties of polyvinyl alcohol (PVA) that was used for the stationary phase. Totally 5 classes of 18 organic solvent molecules (aliphatic, aromatic hydrocarbons, alcohols, ketones and halohydrocarbons) were used for the probe molecules at 383.15-423.15 K. And the δ2 was compared with the solubility parameter (δT) that was measured by the Hansen solubility parameter (HSP) method. The results showed that the solving ability of PVA decreased in the 5 classes of solvents in the following sequence: ketones > alcohols > halohydrocarbons, aromatic hydrocarbons, aliphatics >alicyclics, and the halohydrocarbons, aromatic hydrocarbons, aliphatics had similar solving abilities. The δ2 increased with the increase of temperature at 383.15-423.15 K. The δ2 of PVA that was derived as 27.69 (J/cm3)0.5 by analytical extrapolation method at room temperature (298.15 K) was consistent with the δT of PVA that was measured as 27.77 (J/cm3)0.5 by the HSP method at room temperature. The determination of solubility parameters and the related thermodynamic parameters can be used as a reference to the application and research of PVA.