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Chinese Journal of Chromatography
2014, Vol. 32, No. 10
Online: 08 October 2014

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Preparation of epitope imprinted particles for transferrin recognition by reversible addition fragmentation chain transfer strategy LI Qinran, YANG Kaiguang, LI Senwu, LIU Jianxi, ZHANG Lihua, LIANG Zhen, ZHANG Yukui 2014, 32 (10):  1029-1033.  DOI: 10.3724/SP.J.1123.2014.06029 Abstract ( 561 )   [Full Text(HTML)] () PDF (2880KB) ( 195 )   A kind of novel epitope surface imprinted particles was prepared by the reversible addition fragmentation chain transfer (RAFT) strategy. The epitope of transferrin, N-terminal peptide of the protein with nine amino acid residues, was chosen as the template and immobilized with covalent interaction on the surface of silica particles through the truss arm glutaraldehyde. The living/controlled polymerization was initialed by 2,2'-azobisisobutyronitrile (AIBN) at 70 ℃ in the solution of N,N-dimethylformamide, with the regulation by triothioester agent 2-(dodecylthiocarbonothioylthio)-2-methylpropanoic acid. Methacrylic acid and 2-hydroxyethyl methacrylate were chosen as the functional monomers and N,N-methylenebisacrylamide was chosen as the cross-linker in this polymerization. For this material, the binding capacity of the nine residue peptide could reach 2.36 mg/g with the imprinting factor (IF) of 1.89, while that for transferrin could reach 4.98 mg/g with IF of 1.61. The equilibrium could be achieved in 120 min for the transferrin recognition. In multi-protein competitive recognition, the imprinted factor of transferrin was the highest in the mixture of transferrin and other competitive proteins, such as cytochrome C and β-lactoglobulin. The results indicated that these epitope surface imprinted particles with RAFT strategy could recognize not only the nine residue peptide but also the transferrin with good selectivity, high binding capacity and fast mass transfer.

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Progresses on the applications of microporous organic polymers in sample preparation techniques ZHANG Chengjiang, PAN Jialiang, ZHANG Zhuomin, LI Gongke 2014, 32 (10):  1034-1042.  DOI: 10.3724/SP.J.1123.2014.06023 Abstract ( 667 )   [Full Text(HTML)] () PDF (932KB) ( 310 )   Microporous organic polymers (MOPs) are a class of novel porous materials consisting of the lighter elements, which possess low framework density, large surface area, tunable pore size and structure, excellent chemical and physical stability. In recent years, MOPs have shown great potential in the field of sample preparation techniques. In this paper, the classification and synthetic methods of MOPs are summarized, and the applications of MOPs in sample preparation techniques such as solid phase extraction, batch adsorption experiments, monolith and sensing film are reviewed.

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Magnetic micro-/nano-materials: functionalization and their applications in pretreatment for food samples GAO Qiang, FENG Yuqi 2014, 32 (10):  1043-1051.  DOI: 10.3724/SP.J.1123.2014.07026 Abstract ( 1308 )   [Full Text(HTML)] () PDF (1294KB) ( 550 )   Magnetic solid phase extraction technique, based on functional magnetic materials, is currently a hot topic in the separation and analysis of complex samples. This paper reviews the reported methods for the functionalization of magnetic micro-/nano-materials, such as surface grafting organic groups, coating carbon or inorganic oxide, grafting or coating polymer, being loaded to the surface or pores of supports, being introduced into the skeleton of supports, and physically co-mixing methods. Moreover, we briefly introduce the applications of the functional magnetic micro-/nano-materials in pretreatment for food samples.

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Advances of metabolite identification in liquid chromatography-mass spectrometry based metabolomics KONG Hongwei, DAI Weidong, XU Guowang 2014, 32 (10):  1052-1057.  DOI: 10.3724/SP.J.1123.2014.05017 Abstract ( 1093 )   [Full Text(HTML)] () PDF (1445KB) ( 642 )   Liquid chromatography-mass spectrometry (LC-MS) based metabolomics has become an important approach in life science research due to its powerful separation and high sensitivity detection. However, because of the lack of an effective mass spectra library for metabolite identification, a vast amount of detected metabolites are unable to be identified. The improvement of the metabolite coverage and the discovery of biomarkers are harmed, leading to the severe loss of chemical and biological information. The metabolite identification has become a major bottleneck in metabolomics studies. This review describes recent advances of metabolite identification based on atmospheric pressure ionization (API)-MS data. In particular, it focuses on the advances in mass spectrometer instruments, assignment of elemental compositions, database and spectral search, computer-aided spectral interpretation, etc.

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Recent advances in analysis of petroleum geological samples by comprehensive two-dimensional gas chromatography GAO Xuanbo, CHANG Zhenyang, DAI Wei, TONG Ting, ZHANG Wanfeng, HE Sheng, ZHU Shukui 2014, 32 (10):  1058-1065.  DOI: 10.3724/SP.J.1123.2014.07010 Abstract ( 589 )   [Full Text(HTML)] () PDF (877KB) ( 206 )   Abundant geochemical information can be acquired by analyzing the chemical compositions of petroleum geological samples. The information obtained from the analysis provides scientifical evidences for petroleum exploration. However, these samples are complicated and can be easily influenced by physical (e. g. evaporation, emulsification, natural dispersion, dissolution and sorption), chemical (photodegradation) and biological (mainly microbial degradation) weathering processes. Therefore, it is very difficult to analyze the petroleum geological samples and they cannot be effectively separated by traditional gas chromatography/mass spectrometry. A newly developed separation technique, comprehensive two-dimensional gas chromatography (GC×GC), has unique advantages in complex sample analysis, and recently it has been applied to petroleum geological samples. This article mainly reviews the research progresses in the last five years, the main problems and the future research about GC×GC applied in the area of petroleum geology.

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Concentration techniques in capillary electrophoresis analysis and their applications HUANG Linfang, HE Man, CHEN Beibei, HU Bin 2014, 32 (10):  1066-1078.  DOI: 10.3724/SP.J.1123.2014.07029 Abstract ( 980 )   [Full Text(HTML)] () PDF (990KB) ( 381 )   Capillary electrophoresis (CE), as a modern analytical technique, has been successfully applied in the analysis of metal ions, organics, proteins, nucleic acids and cells, due to its short analysis time, high separation efficiency, low sample consumption and low cost. Since most commercial CE instruments are equipped with ultraviolet detectors (UV), the application of CE-UV with low sensitivity owing to limited optical pathway of on-capillary photometry and the small sample injection volume, is strictly limited in real sample analysis. On-column preconcentration technique is an efficient approach to greatly improve the sensitivity of CE-UV, which can be achieved by merely adjusting the parameters, without any modification of the instrument. At present, stacking, dynamic pH junction, sweeping and transient isotachophoresis are the commonly used on-column preconcentration techniques in CE analysis, and have been extensively utilized in food science, environmental science and biomedicine fields. On the other hand, for real sample analysis, proper sample pretreatment is often necessary prior to instrumental analysis, aiming to remove sample matrix and enrich target analytes simultaneously. With the development tendency of economy, miniaturization and automation in modern analytical methods, green and miniaturized sample pretreatment techniques such as solid phase microextraction (SPME) and liquid phase microextraction (LPME) have been developed rapidly in recent decades. The combination of miniaturized sample pretreatment techniques and CE on-column preconcentration techniques can provide a promising method for the determination of trace analytes in complicated real samples.

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Novel imidazolium-embedded amine stationary phase: preparation and its performance for hydrophilic interaction chromatography LIU Shijia, QIAO Xiaoqiang, YANG Yanjun, YAN Hongyuan 2014, 32 (10):  1079-1083.  DOI: 10.3724/SP.J.1123.2014.07022 Abstract ( 638 )   [Full Text(HTML)] () PDF (972KB) ( 144 )   The development of the novel and highly efficient hydrophilic interaction chromatography stationary phase is important for the separation of polar compounds. In the present work, a novel imidazolium-embedded amine stationary phase (Sil-IEASP) was designed and prepared for hydrophilic interaction chromatographic separation. The prepared material was respectively characterized by Fourier transform infrared spectrometer, thermogravimetric analyzer and organic element analyzer. The results indicated that the novel stationary phase was successfully prepared with the present used method. The effects of the contents of water, salt concentration and pH on the retention of nucleosides and nucleic acid bases were respectively investigated, and the results indicated that Sil-IEASP is of hydrophilic interaction chromatographic nature. Furthermore, no obvious effect of buffer pH and salt concentration on the retention of these compounds were found. The developed material was further used for the separation of uracil, adenine, cytosine, uridine and positional isomers (o-terphenyl, m-terphenyl and triphenylene). Compared with the commonly used amino stationary phase, improved separation efficiency was achieved with the developed material, indicating the potential merit of the developed stationary phase for highly efficient hydrophilic interaction chromatographic separation. We anticipate that the novel stationary phase is promising for the hydrophilic interaction chromatography of polar compounds in the future research.

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Hydrophilic interaction liquid chromatography coupled with mass spectrometry for metabolomic analysis of Escherichia coli WANG Xiyue, GAO Peng, XU Guowang 2014, 32 (10):  1084-1093.  DOI: 10.3724/SP.J.1123.2014.08008 Abstract ( 572 )   [Full Text(HTML)] () PDF (2190KB) ( 213 )   The zwitterionic hydrophilic interaction liquid chromatography coupled with mass spectrometry (ZIC-HILIC/MS) method was developed and applied for studying the metabolome of Escherichia coli. In this method, the linear ranges of the 52 representative compounds were between 2-6 orders of magnitude. Moreover the lowest limits of detection of most compounds were at ng/mL levels. The analysis for six samples prepared in parallel showed that the method had good reproducibility with more than 85% metabolites with the RSDs of peak area less than 30%. The precision of the method was tested by evaluating the relative recoveries of six internal standards at the low, middle and high concentrations. The results exhibited that the intraday precisions (RSDs) of the six compounds in the same concentrations were less than 20%. The recoveries of most compounds were accepted in the range of 70%-130%. The results of metabolomic analysis of three Escherichia coli strains with genetic modified yfcC gene showed that some small peptides, amino acids, nucleosides, organic acids and phospholipids changed differentially after the yfcC gene modification. These results indicated that the ZIC-HILIC/MS method could detect diverse metabolites and be used for metabolomic analysis purpose with good reproducibility and stability.

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An automatic and sensitive method for the determination of endogenous brassinosteroids in plant tissues by an online trapping-in situ derivatization-ultra performance liquid chromatography-tandem mass spectrometry system DING Jun, JIANG Li, FENG Yuqi 2014, 32 (10):  1094-1103.  DOI: 10.3724/SP.J.1123.2014.08010 Abstract ( 635 )   [Full Text(HTML)] () PDF (976KB) ( 257 )   Brassinosteroids (BRs) are a class of naturally occurring phytohormones with polyhydroxy steroid structure, which regulate general plant growth and many physiological processes. The reported methods for BR analysis were complicated, and the detection sensitivity was relatively low. To realize the automatic analysis of trace BRs in limited plant tissues, an in-tube solid phase microextraction-ultra performance liquid chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS) system was constructed based on two valves-two pumps. Using C18 PEEK column as the trapping column and 4-(dimethylamino)phenylboronic acid (4-DMAPBA) as the derivatization reagent, an on line trapping and in situ derivatization assay method of BRs was developed. BRs could be programmed to fulfill the procedures of injection, extraction, derivatization, LC separation and MS detection in the system. The detection limits of BRs were improved more than one order of magnitude by the online trapping and in situ derivatization techniques, thus endogenous BRs could be quantified in only 300 mg plant tissues.

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International comparison APMP. QM-S6: determination of clenbuterol in porcine meat by isotopic dilution mass spectrometry XU Sen, LI Xiuqin, LUO Ximing, ZHANG Qinghe 2014, 32 (10):  1104-1110.  DOI: 10.3724/SP.J.1123.2014.06024 Abstract ( 1141 )   [Full Text(HTML)] () PDF (877KB) ( 220 )   A method was developed for the determination of clenbuterol in porcine meat by isotopic dilution mass spectrometry (IDMS). National Institute of Metrology of China (NIM) participated in the international comparison activity organized by Asia Pacific Metrology (APMP) and got an international mutual recognition result using this method. The important factors of the method, such as the spray voltage, mobile phase, chromatographic column, extraction, purification and filtration conditions were investigated to acquire optimum conditions. The optimization results showed that the composition and pH value of the mobile phase had effects on the response of the mass spectrum of clenbuterol and the optimal value of the spray voltage. The solvent of sample had influences on the chromatographic retention behavior of clenbuterol. It was found that methanol caused a serious solvent effect, even made chromatographic peak split. Since clenbuterol was easily adsorbed on hydrophilic filter membranes and solid phase extraction columns, there were interference suppressions for the quantification of clenbuterol because of the eluate of the solid phase extraction columns. The homogenate method with extraction solvent of 0.1% (v/v) formic acid in acetonitrile had the highest extraction efficiency. The limit of the detection (LOD, S/N>3) of the method was 0.2 μg/kg. The determination results of clenbuterol in the porcine meat by this method were 5.18 μg/kg±0.50 μg/kg (k=2). This method is accurate, reliable, reproducible, and suitable for the determination of clenbuterol with trace quantity in porcine meat.

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Determination of erythromycin residue in pork samples using molecularly imprinted solid phase extraction coupled with high performance liquid chromatography SONG Bin, LI Jinyi, JING Tao, NIU Jiwei, ZHOU Yusun, MEI Surong 2014, 32 (10):  1111-1116.  DOI: 10.3724/SP.J.1123.2014.06025 Abstract ( 593 )   [Full Text(HTML)] () PDF (3385KB) ( 226 )   Molecularly imprinted polymers (MIPs) for erythromycin (ERY) were prepared by precipitation polymerization, using ERY as template molecule, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker and methanol/acetonitrile (1:4, v/v) as porogens. The characterization of the prepared MIPs and non-imprinted polymers (NIPs) were evaluated by scanning electron microscope (SEM) and equilibrium adsorption experiment. The results showed that the MIPs possessed the specific adsorptivity toward ERY. Scatchard analysis revealed that the apparent maximum binding capacity (Qmax) and the dissociation content (Kd) to ERY were as follows: Qmax1=45.24 mg/g, Kd1=0.028 g/L; Qmax2=87.53 mg/g, Kd2=0.20 g/L. Using the prepared MIPs as selective adsorbent, the proposed molecularly imprinted solid phase extraction (MISPE) coupled with high performance liquid chromatography (HPLC) was successfully applied to determine ERY residue in pork samples. A linear correlation was obtained over a range of 0.5-50 mg/L (r2=0.9994), and the limit of detection was 0.2 mg/kg (S/N=3). The spiked recoveries of ERY were 95.2%-104.2% with the relative standard deviations (RSDs) of less than 5%. The proposed method is selective, sensitive and reliable for the analysis of ERY residue in pork samples.

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Preparation of mixed stationary phase of cellulose and polysiloxane ionic liquid for gas chromatography CHEN Gang, ZHAO Xiaojie, XING Jun, YAO Yuhua, ZHENG Jingjing 2014, 32 (10):  1117-1123.  DOI: 10.3724/SP.J.1123.2014.09010 Abstract ( 800 )   [Full Text(HTML)] () PDF (880KB) ( 273 )   Cellulose has been widely used to synthesize chiral stationary phases for liquid chromatography, but it is still absent in the family of stationary phases of gas chromatography due to its poor film-forming property. Based on the unique dissolution characteristic, ionic liquids provide a great chance to solve this problem. In this paper, cellulose triacetate (CTA) was synthesized, and then mixed with the home-made polysiloxane ionic liquid (PIL-C12-NTf2) to produce a novel mixed stationary phase (CTA@PIL-C12-NTf2). After that, it was used to prepare a capillary column for gas chromatography. The column efficiency was measured to be 3165 plates/m (110 ℃, naphthalene, k=4.95), demonstrating the excellent film-forming capability of this stationary phase, and then the solvation parameter model was employed to find out the interaction parameters of CTA@PIL-C12-NTf2. In the aspect of selectivity, CTA was firstly demonstrated to be able to improve the resolutions of tri-substituted aromatic positional isomers and the six isomers of nonane (C9). Moreover, some mixtures of representative chemicals like di-substituted aromatic positional isomers, n-alkanes, alcohols, aliphatic esters and phthalates can also be separated well on CTA@PIL-C12-NTf2. This work proposed a novel way for the application of cellulose modified stationary phase of gas chromatography, and revealed some features of this stationary phase in selectivity resulting from cellulose.

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Rapid determination of pesticide multiresidues in porphyra by dispersive solid-phase extraction coupled with online gel permeation chromatography-gas chromatography-mass spectrometry SUN Xiaojie, GUO Mengmeng, WANG Suyue, TAN Zhijun, LI Zhaoxin, ZHAI Yuxiu 2014, 32 (10):  1124-1130.  DOI: 10.3724/SP.J.1123.2014.06032 Abstract ( 517 )   [Full Text(HTML)] () PDF (986KB) ( 283 )   A rapid method for the simultaneous identification and quantification of pesticide multiresidues in porphyra was developed using gel permeation chromatography (GPC) coupled to gas chromatography-mass spectrometry (GPC-GC/MS). Nineteen pesticides (organochlorines, organophosphoruses, triazines and pyrethroids) were selected as the target analytes. The pretreatment method was applied consisting of organic solvent extraction followed by dispersive solid-phase extraction with graphitized carbon black (GCB) and primary secondary amine (PSA) adsorbents. GPC was also employed online to remove the large molecules such as pigments and lipids. The quantitative analysis was carried out by external standard method using gas chromatography coupled with mass spectrometry in selective ion monitoring (SIM) mode. Moreover, a large volume of sample was allowed to be injected using the program of GPC programmed-temperature vaporizer of gas chromatography to improve the sensitivity of measurements. The results showed that the calibration curves were linear (r >0.995) in the range of 10-1000 μg/L for all the pesticides. The limits of detection (LODs) for the pesticides in porphyra were from 0.005 to 0.03 mg/kg, and the average recoveries were between 70% and 120%. The advantages of the method are simple, sensitive and shorter operation time for analysis of pesticide residues in porphyra samples.

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Magnetic solid phase extraction combined with gas chromatography-flame photometric detection for the determination of organophosphorus pesticides in juice samples HUANG Qian, HE Man, CHEN Beibei, HU Bin 2014, 32 (10):  1131-1137.  DOI: 10.3724/SP.J.1123.2014.07028 Abstract ( 676 )   [Full Text(HTML)] () PDF (3843KB) ( 302 )   A novel method for the determination of organophosphorous pesticides (OPPs) in fresh juice samples was developed. Fe3O4@P(St-co-MAA) magnetic microparticles were synthesized and modified with styrene (St) and methacrylic acid (MAA) by coating St and MAA on magnetic particles and characterized by a series of techniques. The results indicated that Fe3O4 magnetic nanoparticles (MNPs) have been successfully modified with St and MAA. Based on the prepared Fe3O4@P(St-co-MAA) magnetic microparticles, a novel method of magnetic solid phase extraction (MSPE)-gas chromatography (GC)-flame photometric detection (FPD) was developed for the determination of OPPs. The extraction/desorption conditions of MSPE were optimized, and the analytical performance was evaluated under the optimal conditions. The limits of detection (LODs, S/N=3) for target OPPs were in the range of 0.013-0.305 μg/L with the RSDs (n=7) ranging from 3.1% to 8.8%. The enrichment factors varied from 406 to 951. The linear ranges were over three orders of magnitudes (R2>0.99) and the reproducibilities were 7.4%-14.5% (n=5). Finally, the proposed MSPE-GC-FPD method was successfully applied to the analysis of the five OPPs in fresh tomato and strawberry juice samples, with the recoveries of target OPPs in the range of 85.4%-118.9% for the spiked samples. The proposed MSPE-GC-FPD method is featured with low cost, fast separation and high enrichment factor.

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Determination of ultraviolet filters in environmental aqueous samples by dispersive liquid-liquid microextraction with online derivatization-gas chromatography-mass spectrometry LI Jian, XU Lanying, XUE Shuwen, XU Li 2014, 32 (10):  1138-1143.  DOI: 10.3724/SP.J.1123.2014.05040 Abstract ( 776 )   [Full Text(HTML)] () PDF (895KB) ( 199 )   A method of dispersive liquid-liquid microextraction (DLLME) combined with online derivatization-gas chromatography-mass spectrometry (GC-MS) was developed for the determination of benzophenone-type ultraviolet (UV) filers (BPs) in environmental aqueous samples. It is found that the online derivatization was superior to the off-line derivatization with its simplicity, high reaction efficiency and less consumption of potential poisonous reagents. The influential factors for online derivatization, including the temperature of the injection port, the splitless time, the proportion of derivatization reagent and sample solution, were initially optimized. In addition, the influential factors for DLLME, including the type of the extractant and dispersing solvent, the proportion of the extractant and the dispersing solvent, the volume of sample solution, the pH and the salt concentration of the sample solution were individually optimized in detail. Under the optimized derivatization and DLLME conditions, the limits of detection for the six BPs, benzophenone, 2,4-dihydroxybenzophenone, oxybenzone, 4-hydroxybenzophenone, octabenzone and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, ranged from 0.011 to 0.15 μg/L. The intra-day and inter-day relative standard deviations varied from 0.7% to 16.6%. The method was applied to the analysis of lake and river water with good recoveries. It is cost effective, reliable, easy to operate, environment-friendly and promising in the real applications.

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Characterization of compounds in crude oils by gas purge micro-syringe extraction coupled to comprehensive two-dimensional gas chromatography TONG Ting, ZHANG Wanfeng, LI Donghao, ZHAO Jinhua, CHANG Zhenyang, GAO Xuanbo, DAI Wei, HE Sheng, ZHU Shukui 2014, 32 (10):  1144-1151.  DOI: 10.3724/SP.J.1123.2014.07017 Abstract ( 643 )   [Full Text(HTML)] () PDF (1692KB) ( 161 )   A novel sample pretreatment method, gas purge micro-syringe extraction (GP-MSE), coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC/TOFMS) has been developed for the characterization of volatile and semi-volatile compounds in crude oils. In the sample pretreatment process, the analytes were carried to the microsyringe barrel by inert gas, and at the same time, trapped by an organic solvent. The whole process of extraction takes less than 10 min, and only 20 μ L of organic solvent was needed. Using two custom standard solutions containing alkanes and polycyclic aromatic hydrocarbons (PAHs), the influences of the extraction conditions were investigated. The optimized conditions were as follows: 5 mg crude oil, 20 μ L hexane (extraction solvent), extraction for 3 min at 300 ℃, condensation temperature set at -2 ℃, gas flow rate set at 2 mL/min. Under the optimized conditions, a real crude oil sample was extracted and then analyzed in detail. It showed that the proposed method was very effective in simultaneously analyzing the normal and branched alkanes, cycloalkanes, aromatic hydrocarbons, and biomarkers of crude oil such as steranes and terpanes. The recoveries obtained ranged from 82.0% to 107.3% and the detection limits ranged from 34 to 93 μg/L. The correlation coefficients (R2) were more than 0.99. The relative standard deviations (RSDs, n=5) for all the analytes were below 10%. The results indicate that the proposed method is suitable for the characterization of volatile and semi-volatile compounds in crude oils with easy operation, high sensitivity and efficiency.

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Determination of short chain chlorinated paraffins in leather products by solid phase extraction coupled with gas chromatography-mass spectrometry ZHANG Weiya, WAN Xin, LI Lixia, WANG Chengyun, JIN Shupei, XING Jun 2014, 32 (10):  1152-1156.  DOI: 10.3724/SP.J.1123.2014.08011 Abstract ( 793 )   [Full Text(HTML)] () PDF (983KB) ( 364 )   The short chain chlorinated paraffins (SCCPs) are the additives frequently used in the leather production in China, but they have been put into the list of forbidden chemicals issued by European Union recently. In fact, there is not a commonly recognized method for the determination of the SCCPs in the leather products due to the serious matrix interferences from the leather products and the complex chemical structures of the SCCPs. A method of solid phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was established for the determination of the SCCPs in the leather products after the optimization of the SPE conditions. It was found that the interferences from the leather products were thoroughly separated from the analyte of the SCCPs on a home-made solid phase extraction (SPE) column filled with silica packing while eluted with a mixed solvent of n-hexane-methylene chloride (2:1, v/v). With this method, the recoveries for the SCCPs spiked in the real leather samples varied from 90.47% to 99.00% with the relative standard deviations (RSDs) less than 6.7%, and the limits of detection (LODs) were between 0.069 and 0.110 mg/kg. This method is suitable for qualitative and quantitative analysis of SCCPs in the leather products.

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Determination of tris(2-chloroethyl)phosphate in leather by gas chromatography-mass spectrometry coupled with mixed-mode sorbent solid phase extraction ZHANG Weiya, ZHU Yuling, WANG Chengyun, LI Lixia, ZHANG Junqing, XING Jun 2014, 32 (10):  1157-1162.  DOI: 10.3724/SP.J.1123.2014.09011 Abstract ( 657 )   [Full Text(HTML)] () PDF (858KB) ( 294 )   Leather is one of the important exporting products to European Union (EU), and tris(2-chloroethyl)phosphate (TCEP) is a commonly used flame retardant in leather and leather products. Recently, TCEP has been classified as a kind of substance of very high concern (SVHC) by EU for its carcinogenicity and reproductive toxicity. But to date, there is not a recognized method for the determination of TCEP in leather and leather products due to the serious matrix interferences and relatively low recovery of TCEP. In this work, a home-made mixed-mode sorbent (Silica-WCX) with carboxyl and alkyl groups was tested as the sorbent of solid phase extraction (SPE) to extract TECP from leather. The results demonstrated that, making the carboxyl groups protonized under acidic condition, Silica-WCX exhibited better extraction performance towards TCEP over some frequently used commercial sorbents tested. After the optimization of the SPE conditions based on Silica-WCX, a method of gas chromatography/mass spectrometry (GC-MS) was established for the determination of TCEP in leather samples. The linear range for TCEP ranged from 0.10 to 100.0 μg/L and the limit of quantification (LOQ, S/N=10) was 44.46 ng/kg. The recoveries of TCEP spiked in samples at varied levels were in the range of 91.45%-99.98% with the relative standard deviations (RSDs) of 4.33%-5.97%. The method is simple, sensitive and reliable for the analysis of TCEP in leather and leather products.