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Chinese Journal of Chromatography
2020, Vol. 38, No. 2
Online: 08 February 2020

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Volume 38, Number 2 Content 2020, 38 (2):  0-0.  Abstract ( 27 )   PDF (5096KB) ( 32 )

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Research progress in sample pretreatment and analytical techniques for cosmetics GUO Xiangyu, CHEN Meng, MENG Xianshuang, Lü Yueguang, ZHANG Nan, LIAN Xianhui, WANG Chun, GAO Haiyan, MA Qiang 2020, 38 (2):  151-161.  DOI: 10.3724/SP.J.1123.2019.06031 Abstract ( 132 )   HTML ( 20 )   PDF (973KB) ( 102 )   With the continuous economic development and improvement of living standards, cosmetic products are being widely used as daily consumer products, and there are increasing concerns about their safety. Consequently, there is a substantial increase in the number of cosmetic samples subjected to various analyses, and this in turn necessitates more stringent requirements for the related analytical techniques. However, traditional sample pretreatment and analytical techniques are time-consuming, require large amounts of organic solvents, and have low throughput, thus failing to meet the current demand for green analytical chemistry. To address this issue, researchers have developed numerous environmentally friendly pretreatment techniques as well as high-throughput and rapid on-site methods to ensure the quality and safety of cosmetics. This paper reviews the current progress in sample pretreatment and analytical techniques for cosmetics and discusses the trends and prospects, which may provide technical guidance for researchers and inspectors in the analysis of cosmetic products.

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A liquid chromatography-mass spectrometry-based metabolomic study on the changes of intracellular lipid metabolism regulated by Pokemon JIN Yibao, LI Shangfu, WANG Jue, GAO Dan, LIU Hongxia, JIANG Yuyang, YIN Guo, WANG Tiejie 2020, 38 (2):  162-168.  DOI: 10.3724/SP.J.1123.2019.08013 Abstract ( 60 )   HTML ( 5 )   PDF (2611KB) ( 35 )   Pokemon, a transcriptional repressor, inhibits the transcription of tumor suppressor genes and promotes tumor formation by affecting chromatin recombination or binding directly to the tumor suppressor genes. In this study, the mechanism behind the Pokemon regulation of liver cancer cell metabolism was evaluated using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. Pokemon-overexpressing HL7702 cells were obtained by lipofection. The cells were collected at different time points after transfection and their intracellular metabolites were analyzed using an LC-MS-based metabolomic method. Based on the results of a multivariate statistical analysis, candidate metabolites with significant differences were selected, and 36 of them were confirmed by database and MS/MS analysis. These metabolites were primarily involved in lipid synthesis by KEGG database searches. Further analysis indicated that both the acetyl-coenzyme carboxylase and the fatty acid synthase were activated in the lipid synthesis pathway. The results show that Pokemon can affect cell metabolism by activating the lipid synthesis pathways in cells.

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Separation and characterization of millet starch based on asymmetrical flow field-flow fractionation ZHANG Jing, GUO Panpan, LI Huili, SHEN Shigang, DOU Haiyang 2020, 38 (2):  169-176.  DOI: 10.3724/SP.J.1123.2019.05014 Abstract ( 58 )   HTML ( 11 )   PDF (4982KB) ( 37 )   A method based on asymmetrical flow field-flow fractionation (AF4) coupled with a multi-angle light scattering detector and a differential refractive detector was developed for the separation and characterization of millet starch. In this study, the effects of sample loading, cross-flow rate, half-life, and ionic strength and pH value of the carrier liquid on the AF4 analysis of millet starch were investigated. In addition, the molecular structure of millet starch was determined under the optimum conditions. The optimized operation conditions for the AF4 analysis of millet starch were as follows:injection mass concentration, 0.50 g/L; injection volume, 50 μL; cross-flow rate, 1.2 mL/min; half-life, 3 min; and the carrier liquid, demonized water containing 10 mmol/L pH 7.00 NaNO3 (add 3 mmol/L NaN3). The method developed in this study showed good reproducibility. The relative standard deviations for the radius of gyration (Rg) and molar mass (Mw) were 3.4% and 7.0%, respectively.

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Visualized and quantitative detection of horseradish peroxidase based on redox reaction boundary KONG Hao, ZHANG Qiang, ZHANG Wei, LIU Weiwen, CAO Chengxi, FAN Liuyin 2020, 38 (2):  177-182.  DOI: 10.3724/SP.J.1123.2019.04030 Abstract ( 52 )   HTML ( 9 )   PDF (1617KB) ( 29 )   A new portable method for the detection of horseradish peroxidase (HRP) is reported in this paper. Visualized and quantitative detection of HRP was achieved based on the theory of electrophoresis titration (ET) and redox reaction boundary (RB). The ET-RB model was built on the 3, 3', 5, 5'-tetramethyl benzidine chromogenic system because it significantly increases the efficiency of the chromogenic reaction and can react with L-ascorbic acid. A series of experiments were performed on a tiny and portable titration chip based on the material of polymethyl methacrylate designed for the developed model. The composition of the titration gel was optimized to ensure higher detection sensitivity and stable detection performance. The experimental results manifested a log-linear relationship between the moving distance of the RB and the HRP concentration. The dynamic range of the developed method ranged from 0.002 to 0.073 mg/L, and the detection could be accomplished within 10 min. Visualized and quantitative detection could be realized by reading the moving distance of the colored boundary with the naked eyes instead of using any signal-reading device or analyzing instrument. Thus, this method has great potential for further application to the development of a real-time detection method for various target substances based on the detection of peroxidase activity.

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Research advances in clinical biochemical analysis systems based on microfluidic driving and control technique YUAN Yingxin, FAN Chen, PAN Jianzhang, FANG Qun 2020, 38 (2):  183-194.  DOI: 10.3724/SP.J.1123.2019.05006 Abstract ( 88 )   HTML ( 13 )   PDF (8376KB) ( 62 )   Microfluidic techniques have the features of high throughput, low consumption, as well as ease of miniaturization, integration, and automation, thus emerging as a feasible solution to cost-effective clinical biochemical analysis. Various clinical biochemical analysis systems based on the microfluidic technique, with different driving and control methods, are introduced in this article, in addition to commercially available microfluidic biochemical analysis instruments. The characteristics of these systems are comprehensively reviewed.

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Preparation of magnetic metal-organic frameworks-polydopamine for extraction and detection of cationic dyes from water samples in a fishery YANG Xiaohan, WU Wenqian, WANG Bin, LIN Feng, WU Xiaohai, LU Xin 2020, 38 (2):  195-205.  DOI: 10.3724/SP.J.1123.2019.05045 Abstract ( 74 )   HTML ( 6 )   PDF (11815KB) ( 225 )   The catechol group of dopamine (DA) can chelate with the metal ion in the crystal of molecular organic frameworks (MOFs). Based on this principle, a magnetic metal polydopamine (PDA) framework (Fe3O4@Z67D) was prepared using ZIF-67 as the template, which was etched by DA, followed by polymerization of the DA monomers to form a PDA coating with a porous structure. The morphology, structure, and properties of the material were determined by various characterization methods. Fe3O4@Z67D was used as an adsorbent, and a magnetic solid-phase extraction/high-performance liquid chromatography method for the determination of two cationic dyes, methylene blue (MB) and crystal violet (CV), was established. Under the optimized extraction and detection conditions, the linear ranges for MB and CV were 0.5-200 μg/L and 0.01-50 μg/L, respectively, and the corresponding detection limits were 0.04 μg/L and 0.008 μg/L. The experimental results showed that the enrichment factors of Fe3O4@Z67D for the two dyes were 777 and 688, respectively. The extraction performance was largely unaffected even after the new material was reused 10 times. The method was applied successfully for the adsorption and detection of the above mentioned two dyes in fishpond water. The spiking recoveries of the two cationic dyes ranged from 82.0% to 109.0%, and the RSD was lower than 2.9%.

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Rat serum and heart tissue metabolomics in myocardial ischemia based on liquid chromatography-mass spectrometry YIN Chunyuan, SUN Mingqian, JIN Long, LIN Li, MIAO Lan, LIU Jianxun 2020, 38 (2):  206-211.  DOI: 10.3724/SP.J.1123.2019.07019 Abstract ( 77 )   HTML ( 17 )   PDF (1332KB) ( 61 )   A rat model with isoproterenol (ISO)-induced myocardial ischemia was obtained. Liquid chromatography-mass spectrometry (LC-MS)was conducted on the serum and heart tissue metabolites of normal and model rats. Principal component analysis (PCA) and differentiation analysis of supervised partial least-squares method (PLS-DA) were applied to the metabolomics data for multidimensional statistical analysis, and the resulting biomarkers were screened. Compared with the normal group, 18 different endogenous metabolites in plasma and tissues were detected, including the products of arginine and proline metabolism; glycine, serine, and threonine metabolism; glutamine and glutamate metabolism; and taurine and hypotaurine metabolism. These metabolites can be used as important biomarkers for myocardial ischemia. The results of this study can help reveal the pathogenesis of myocardial ischemia and aid clinical diagnosis.

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Determination of four protease inhibitors in chicken by ultra performance liquid chromatography-tandem mass spectrometry Lü Jiale, LIU Zhengcai, YAO Minna, LIN Yuandi 2020, 38 (2):  212-217.  DOI: 10.3724/SP.J.1123.2019.04047 Abstract ( 54 )   HTML ( 8 )   PDF (1340KB) ( 39 )   A method was developed for the determination of four protease inhibitors (saquinavir, ritonavir, nelfinavir and indinavir) in chicken using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted by shaking with 30% (v/v) acetonitrile aqueous solution (containing 1% (v/v) trichloroacetic acid), and purified by using mixed-mode cationic-exchanger (MCX) cartridges. The samples were separated on a Luna® C8 column (150 mm×2 mm, 3 μm) using 0.2% (v/v) formic acid aqueous solution (containing 5 mmol/L ammonium acetate) and acetonitrile as the mobile phases with gradient elution. The determination was carried out by using an electrospray ion source in the positive and multiple-reaction monitoring (MRM) modes. The calibration curves showed good linearities in the range of 0.1-20.0 μg/L, and the correlation coefficients (r2) were greater than 0.99. The limits of quantification (LOQs, S/N=10) of the four protease inhibitors varied from 0.20 μg/kg to 0.90 μg/kg. At the spiked levels of 1.0, 2.0, and 10.0 μg/kg, the average recoveries of the four protease inhibitors were ranging from 69.0% to 106.0%. The intra-day and inter-day relative standard deviations (RSDs) were 2.2%-13.8% (n=6) and 3.6%-14.6% (n=3), respectively. The method is simple, efficient, sensitive and accurate, and it can be used to detect residues of saquinavir, ritonavir, nelfinavir and indinavir in chicken.

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Determination of chlormequat chloride residues in animal derived foods by high performance liquid chromatography-tandem mass spectrometry XIAO Yong, WU Haizhi, YUAN Liejiang, TANG Jiwang, WANG Shuxia, WANG Xiu, DENG Hang, WU Lin 2020, 38 (2):  218-223.  DOI: 10.3724/SP.J.1123.2019.04036 Abstract ( 66 )   HTML ( 10 )   PDF (972KB) ( 54 )   A method for the determination of chlormequat chloride (CCC) residues in animal derived foods by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The samples were extracted with acetonitrile containing 1% (v/v) acetic acid and defatted with n-hexane, followed by clean-up on a cationic solid phase extraction column. The analytes were separated on a Venusil MP C18(2) column (150 mm×2.1 mm, 3 μm) under a gradient elution program using acetonitrile and 0.1% (v/v) formic acid aqueous solution as the mobile phases. Then, the analytes were detected by tandem mass spectrometry using a positive electrospray ionization (ESI+) source in the multiple reaction monitoring (MRM) mode. Matrix-matched internal standard calibration curves were used for quantitative analysis. The calibration curves showed good linearity in the range of 0.200-500 μg/L for CCC, with correlation coefficients (r2) no less than 0.9993. The limit of quantification (LOQ) of the method was 0.500 μg/kg. The average recoveries of CCC in pork, beef, mutton, chicken, egg, pig kidney, beef liver, sheep kidney, chicken liver and milk matrices at spiked levels of 0.500-500 μg/kg were 93.4%-101%, and the relative standard deviations were 2.3%-8.0%. The method has less matrix interference, with high sensitivity, accuracy and reliability, and it is suitable for the quantitative detection of CCC residues in animal derived foods.

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Determination of seven heterocyclic aromatic amines in oils and fried foods by ultra performance liquid chromatography-triple quadrupole mass spectrometry ZHANG Chenxia, MA Yuxiang, ZHAO Tianpei, XI Jun, LI Pan, GUO Qing, SHI Lili, WANG Xuede 2020, 38 (2):  224-231.  DOI: 10.3724/SP.J.1123.2019.04046 Abstract ( 94 )   HTML ( 10 )   PDF (1227KB) ( 92 )   An ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) method was developed for the determination of seven heterocyclic aromatic amines (HCAs) in oil and fried food samples. The samples were extracted with acetonitrile containing 1% (v/v) ammonia water, defatted by n-hexane saturated with acetonitrile, and cleaned up with PCX solid phase extraction column. The extracts were separated on a Waters ACQUITY UPLC BEH C18 reversed-phase column (50 mm×2.1 mm, 1.7 μm) with gradient elution by using acetonitrile-10 mmol/L ammonium formate aqueous solution as the mobile phase. Quantitative detection was performed by using a positive-ion electrospray ionization source in the multiple reaction monitoring (MRM) mode, employing an internal isotope standard. The method showed good linear relationships in the range of 0.5-100 μg/L for the seven HCAs with correlation coefficients (R2)>0.999. The average recoveries ranged from 64.31% to 113.8% with the relative standard deviations of 0.18%-9.26% at the three spiked levels in oil and fried food samples. The limits of detection (LODs) and limits of quantification (LOQs) were 0.01-0.14 ng/g and 0.09-0.38 ng/g, respectively. The method is sensitive, accurate, and suitable for the determination and confirmation of the seven HCAs in oil and fried food samples.

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Study and comparison of detection methods for prochloraz and its metabolite residue in garlic bolting CHEN Keyun, LI Ling, JU Xiang, WANG Yanli, LIU Yanming 2020, 38 (2):  232-237.  DOI: 10.3724/SP.J.1123.2019.04008 Abstract ( 73 )   HTML ( 9 )   PDF (867KB) ( 55 )   Two analytical methods for the determination of prochloraz and its metabolite residues in garlic bolting were established and compared. In the QuEChERS method, the sample was extracted with acetonitrile and purified in a QuEChERS purification tube, and then, the contents of prochloraz and its metabolite 2, 4, 6-trichlorophenol were determined by gas chromatography. The hydrolysis method involved extraction of the sample with acetonitrile, hydrolysis by pyridine hydrochloride, purification with sulfuric acid, and determination of the prochloraz content by gas chromatography. The standard curve in the hydrolysis and QuEChERS methods showed a good linear relationship in the concentration range of 0.01-2 mg/L, and the correlation coefficient (r2) was greater than 0.999. The limit of quantitation (LOQ) for prochloraz in the hydrolysis method was 0.005 mg/kg. The LOQ for prochloraz in the QuEChERS method was 0.039 mg/kg, and that for 2, 4, 6-trichlorophenol was 0.003 mg/kg. At three spiked levels in the sample, the recoveries were 81.5%-105.4%, and the relative standard deviations (RSDs) were between 1.3%-6.8%. In the determination of positive samples, the hydrolysis method can detect the total amount of prochloraz and its main metabolites. QuEChERS method can detect the presence and contents of prochloraz and its main metabolite 2, 4, 6-trichlorophenol. These two methods can complement each other for the detection and confirmation of prochloraz and its metabolites in garlic bolting.

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Determination of hydroxy terminated polybutadiene in the blends by liquid critical condition chromatography WANG Mingfang, JIA Qiangqiang, WANG Yuerong, ZHANG Hongyang, ZHANG Min, HU Ping 2020, 38 (2):  238-243.  DOI: 10.3724/SP.J.1123.2019.03042 Abstract ( 78 )   HTML ( 8 )   PDF (851KB) ( 42 )   A method based on liquid critical condition chromatography (LCCC) was established for the quantification of hydroxy-terminated polybutadiene (HTPB) in polymer blends. The critical conditions for HTPB were investigated using a C18 column as the stationary phase, and tetrahydrofuran (THF)-acetonitrile (ACN) or THF-water as the mobile phase. Irrespective of the relative molecular mass, HTPB was eluted under the critical conditions of THF-ACN (70.7:29.3, v/v) or THF-water (92:8, v/v). Under the optimal conditions, the HTPB exhibited satisfactory linearity in the range of 46.7-216.4 mg/L, with a correlation coefficient (r) of 0.997. The limit of detection reached 4.2 mg/L. The recoveries of HTPB from the prepared mixtures of HTPB and mineral oil ranged from 89.2% to 101.1%, with a relative standard derivation of less than 0.66% (n=6). This method was successfully applied to the quantitative analysis of HTPB in a commercial polyurethane adhesive, and 26.6% of HTPB was detected in the product. This LCCC method is simple, convenient, highly selective, and reliable for quality control and failure studies of formulated products.

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Conversion method for linear retention indices in gas chromatography acquired using n-alkanes and n-fatty acid methyl esters LI Yong, PANG Tao, SHI Junli, DENG Xiaopeng, KONG Guanghui, LU Xiuping 2020, 38 (2):  244-249.  DOI: 10.3724/SP.J.1123.2019.05018 Abstract ( 68 )   HTML ( 8 )   PDF (1237KB) ( 88 )   Supporting Information Retention index (RI) is a powerful tool for gas chromatography-based structure elucidation of various compounds. In this study, linear RIs based on n-alkanes and n-fatty acid methyl esters in different temperature programs were fitted. Nearly identical first-order linearities were acquired with different temperature programs. The linear equations were y=1.0051x+318.51 (r2=1) and y=1.0362x+562.519 (r2=1) for polar (packed with polyethylene glycol) and semi-standard non-polar (packed with 5% diphenyl/95% dimethylpolysiloxane) columns, respectively. The variables x and y in the equations stand for RIs based on n-fatty acid methyl esters and n-alkanes, respectively. The established linearity was then verified using the reference RIs collected in the NIST mass spectral library, Golm metabolite library, and Fiehnmetabolite library. The RI values converted using both the acquired equations finely matched those in the references. The established relationship between the two kinds of RIs can be used to expand the RI references and decrease the number of RI acquisition experiments.

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Analysis of fatty acids in rice by pseudotargeted metabolomics method based on gas chromatography-mass spectrometry WANG Xiyue, MING Ming, LIAN Lili, ZHANG Hao, LOU Dawei 2020, 38 (2):  250-254.  DOI: 10.3724/SP.J.1123.2019.05041 Abstract ( 108 )   HTML ( 18 )   PDF (1361KB) ( 87 )   A pseudotargeted metabolomics method based on gas chromatography-mass spectrometry (GC-MS) was developed for the analysis of fatty acids in rice. A total of 16 fatty acids were detected in rice. The method was used to identify the difference between fatty acid profiles in rice. The total intensity of the saturated and unsaturated fatty acids was used as the evaluation index. The effects of six extraction methods and four extraction solvents on the extraction efficiencies of the fatty acids were compared. The developed method was used to investigate the fatty acid profiles in five types of rice (Daohuaxiang, Jixing, Jinlangzi, Nongda, and Zhuangyuan). The fatty acid profile in Daohuaxiang rice was different from that in the other four species. The fatty acids in Jinlangzi and Nongda rice were markedly different, while those in Jixing and Jinlangzi rice were similar. The method is simple, stable and accurate, and it can provide basic data for the improvement of rice quality and nutritional value.

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Determination of trace azo dyes in textile wastewater by liquid-liquid extraction and dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry YE Xiwen, HE Jing, LI Ying, NIU Zengyuan, ZHANG Tiantian, LUO Xin, ZOU Li, LIAN Sumei 2020, 38 (2):  255-263.  DOI: 10.3724/SP.J.1123.2019.07012 Abstract ( 93 )   HTML ( 10 )   PDF (2161KB) ( 52 )   An efficient method based on liquid-liquid extraction and dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry was developed for the determination of trace azo dyes in textile wastewater. The azo dyes were reduced to aromatic amines by sodium dithionite under alkaline conditions. The main pretreatment conditions that affected the extraction efficiency were optimized. Under the optimized experimental conditions, the linear ranges of this method were as follows:0.05-10 μg/L for 13 aromatic amines; 0.05-5 μg/L for 7 aromatic amines; and 20-100 μg/L for 2, 4-diaminoanisole. The correlation coefficients were in the range of 0.996-0.999. The limits of detection reached 0.05 μg/L for all the 20 aromatic amines, and the detection limit of 2, 4-diaminoanisole was 20 μg/L. Actual wastewater-spiked experiments involving printing, dyeing, and weaving showed that the average recoveries of the amines were in the range of 75.6%-115.1%. The developed method has high enrichment multiples and low detection limits, and it is suitable for the detection of trace levels of banned azo dyes in textile wastewater.