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Chinese Journal of Chromatography
2017, Vol. 35, No. 6
Online: 08 June 2017

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Preparation of large-pore silica microspheres using templating method and their applications to protein separation with high performance liquid chromatography NIU Mengna, MA Hongyan, HU Fei, WANG Shige, LIU Lu, CHANG Haizhou, HUANG Mingxian 2017, 35 (6):  565-571.  DOI: 10.3724/SP.J.1123.2017.03018 Abstract ( 606 )   [Full Text(HTML)] () PDF (9078KB) ( 166 )   Large-pore silica microspheres were synthesized by utilizing weak cation exchange polymer beads as templates, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMSPTMA) as a structure-directing agent, tetraethoxysilane (TEOS) as a silica precursor, and triethanolamine as a weak base catalyst. The hydrolysis and condensation of the silica precursors occurred inside the templating polymer beads yielded polymer/silica composite microspheres. After the organic polymer templates were removed in the calcination step, large-pore silica microspheres were produced. The effects of different reaction conditions on the morphology, structure and dispersibility of the formed silica microspheres were investigated. It has been shown that when the volume ratio of TMSPTMA, TEOS and triethanolamine was 1:2:2, silica microspheres with pore size range of 50-150 nm and particle size around 2 μm were obtained. The as-prepared silica microspheres were then bonded with chlorodimethyloctadecylsilane (C18), packed into a 50 mm×4.6 mm column, and evaluated for the separations of some common standard proteins and soybean isolation proteins. The results showed that the large-pore silica spheres from this work have potentials for protein separation in HPLC.

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Preparation and chiral recognition of heterosubstituted amylose derivatives-based chiral stationary phases WANG Baocun, BAO Minghui, LIN Sufei, MA Jieyu, TANG Shouwan 2017, 35 (6):  572-577.  DOI: 10.3724/SP.J.1123.2017.02011 Abstract ( 473 )   [Full Text(HTML)] () PDF (882KB) ( 104 )   Two novel amylose derivatives, namely amylose 2-benzoate-3-(4-methylphenylcarbamate)-6-(3,5-dichlorophenylcarbamate) and amylose 2-benzoate-3-(3,5-dichlorophenylcarbamate)-6-(4-methylphenylcarbamate), were prepared utilizing a serial regioselective process. After coated onto aminopropyl silica gel, they were utilized as chiral stationary phases (CSPs) for high performance liquid chromatography. Investigations indicated that the CSPs exhibited characteristic chiral recognition and their chiral recognition abilities were much higher than those of amylose tris(3,5-dichlorophenylcarbamate) (ADCPC), a homosubstituted derivative. The nature and position of the substituents at 3-, and 6-positions of a glucose unit had great influence on the chiral resolution abilities of the amylose derivatives. Some chiral compounds which were not effectively resolved on the commercial column Chiralpak AD were effectively separated on the new CSPs. Moreover, with all the eight tested racemates resolved, amylose 2-benzoate-3-(4-methylphenylcarbamate)-6-(3,5-dichlorophenylcarbamate) exhibited relatively high chiral recognition and might be a potential useful CSP.

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Investigation on silymarin impact on lipopolysaccharide induced inflammation model based on arachidonic acid metabolism pathway MAI Danti, YANG Chan, XUE Yun, WANG Yan, YAN Chao 2017, 35 (6):  578-586.  DOI: 10.3724/SP.J.1123.2017.01026 Abstract ( 630 )   [Full Text(HTML)] () PDF (1631KB) ( 170 )   The objective of this research is to investigate the suppressive effect of silymarin on vitro cell culture model of inflammatory macrophage RAW264.7 induced by Kdo2-Lipid A, and explore its mechanism based on cell metabonomics. Ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method was used in the cell metabonomic assay to quantitative analysis of metabolites related to eicosanoids pathway. Then chemometric approaches such as principal component analysis were used to process the metabolic data. Within the established method, a total of 59 eicosanoids standards (containing 15 deuterated internal standards) were simultaneously separated in a single 5 min run, and the analytical method is proved to be rapid, sensitive and accurate. Whereafter, the metabolites with VIP> 1 and P value< 0.05 were considered as biomarkers. 12-OxoLeukotriene B4 (12-OxoLTB4) was eventually identified as metabolic biomarkers of silymarin treatment group in this research, and according to the related inflammatory pathways, we speculated silymarin has anti-inflammatory activities by inhibiting the 5-lipoxygenase (5-LOX) activity and blocking lipid peroxidation in 5-LOX metabolic pathways to reduce the formation of peroxides and oxygen free radicals. This study provide a novel approach to the mechanism research on the silymarin treatment on RAW264.7 cells based on cell metabonomics.

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Tracking casein phosphopeptides during fermentation by high performance liquid chromatography-tandem mass spectrometry DONG Hao, YU Yang, YAN Jiaze, JIN Yan 2017, 35 (6):  587-593.  DOI: 10.3724/SP.J.1123.2017.03012 Abstract ( 450 )   [Full Text(HTML)] () PDF (4436KB) ( 176 )   Casein phosphopeptides (CPPs) are phosphorylated fragments of casein, which have a variety of biological functions such as promotion of mineral absorption, antioxidation and prevention of dental caries. This study investigated CPPs in milk and yogurt fermented by Lb. bulgaricus (Lactobacillus debrueckii subsp. bulgaricus) and S. thermophilus (Streptococcus thermophilus) with high performance liquid chromatography-tandem mass spectrometry. The results showed that milk contained endogenous CPPs, which were mainly derived from high abundance of caseins αs1-CN and β-CN, in the role of endogenous protease. After milk fermented with Lb. bulgaricus and S. thermophilus, more CPPs and phosphorylation sites were released in the action of lactic acid bacteria proteases. The CPPs with the character of SpSpSpEE were identified in yogurt. The structure of caseins played an important role in CPPs releasing in the process of fermentation. In conclusion, fermentation by lactic acid bacteria is helpful to release CPPs containing SpSpSpEE, which can promote mineral absorption.

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Determination of 34 illegally adulterated weight loss compounds in foods by ultra high performance liquid chromatography- triple quadrupole mass spectrometry HU Qing, SUN Jian, FENG Rui, ZHANG Su, YU Hong, ZHANG Jingxian, MAO Xiuhong, JI Shen 2017, 35 (6):  594-600.  DOI: 10.3724/SP.J.1123.2017.03007 Abstract ( 548 )   [Full Text(HTML)] () PDF (1115KB) ( 124 )   An analytical method was developed for the determination of 34 illegally adulterated weight loss compounds in foods and dietary supplements by ultra high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS). A Waters CORTECS T3 column (100 mm×2.1 mm, 2.7 μm) was used with 0.1% (v/v) formic acid aqueous solution-acetonitrile containing 0.1% (v/v) formic acid as mobile phases by gradient elution. The compounds were detected by electrospray ion source in positive or negative mode with multiple reaction monitoring (MRM) mode. The calibration curves showed good linearity in the range of 0.5-10 μg/L for 29 compounds such as sibutramine, and in the range of 2.5-50 μg/L for five compounds such as chlorothiazide. The correlation coefficients (r) of the standard calibration curves for the 34 analytes were all greater than 0.99. The recoveries of the 29 compounds at spiked levels of 5, 10 and 20 μg/kg were in the range of 49.2%-136.2%, and the RSDs were 0.7%-15.0% (n=6). The recoveries of the five compounds at spiked levels of 25, 50 and 100 μg/kg were in the range of 51.5%-130.9%, and the RSDs were 0.8%-14.0% (n=6). The limits of detection (LODs) and limits of quantification (LOQs) were 5 μg/kg and 10 μg/kg for the 29 compounds, 25 μg/kg and 50 μg/kg for the five compounds, respectively. The method was successfully applied to the analysis of actual samples, and 12 compounds were checked out, which combated the illegal adulteration behavior effectively.

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Simultaneous determination of five mycotoxins in various grains and their products by liquid chromatography-tandem mass spectrometry with isotope internal standard GAO Bei, JIANG Deming, YANG Yongtan 2017, 35 (6):  601-607.  DOI: 10.3724/SP.J.1123.2016.12028 Abstract ( 576 )   [Full Text(HTML)] () PDF (1021KB) ( 93 )   A rapid method was established for the determination of zearalenone (ZON), nivalenol (NIV), deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ACDON) and 15-acetyl-deoxynivalenol (15-ACDON) in various grains and their products by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted by acetonitrile-water (84:16, v/v), and cleaned-up by multifunctional column without any further step. The separation was carried out on an Acquity UPLC® BEH C18 column (100 mm×2.1 mm, 1.7 μm) with gradient elution using acetonitrile-water as mobile phases. The analytes were quantified by isotope internal standard method. The correlation coefficients (r2) were all above 0.99. The limits of detection (LODs, S/N=3) ranged from 5 μg/kg to 20 μg/kg. The recoveries of the five mycotoxins spiked in blank grain and its product samples varied from 84.2% to 114.5%, with the relative standard deviations (RSDs) of 0.4%-9.9% (n=6). The method is accurate, efficient, sensitive and practical.

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Rapid determination of benzo[a]pyrene in foods by ultra performance liquid chromatography-triple quadrupole mass spectrometry with atmospheric pressure chemical ionization ZHANG Xiaoyi, ZHANG Xiuyao, CAI Xinxin, LI Ruifen 2017, 35 (6):  608-612.  DOI: 10.3724/SP.J.1123.2017.02021 Abstract ( 623 )   [Full Text(HTML)] () PDF (832KB) ( 82 )   A method for the determination of benzo[a]pyrene in foods was developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) based on isotope dilution and molecularly imprinted solid-phase extraction (MIP-SPE). The target analyte in samples was extracted with n-hexane after spiked with benzo[a]pyrene-d12, and purified using MIP-SPE to eliminate most of the coextracts. The separation of benzo[a]pyrene was carried out on an XBridge BEH C18 column with gradient elution of methanol and water. An atmospheric pressure chemical ionization (APCI) interface was used as the ion source and the analysis was performed in the multiple reaction monitoring (MRM) mode. Benzo[a]pyrene levels in the range of 0.07-50 μg/kg were measured accurately by this method, and the limit of quantification (LOQ) was 0.07 μg/kg. The average recoveries were between 86% and 104% with the relative standard deviations within 2.3%-14%. The method was sensitive and accurate, and it has been successfully applied to the measurement of benzo[a]pyrene in food samples.

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Determination of amanitins and phallotoxins in wild mushrooms by online liquid chromatography-diode array detector-tandem mass spectrometry XU Xiaomin, ZHANG Jingshun, CAI Zengxuan, ZHANG Jing, HUANG Baifen, XU Jiaojiao, CHEN Qing 2017, 35 (6):  613-619.  DOI: 10.3724/SP.J.1123.2017.02008 Abstract ( 477 )   [Full Text(HTML)] () PDF (1055KB) ( 136 )   A fast and wide linear range method was established for the determination of mushroom toxins amanitins (α-amanitin,β-amanitin and γ-amanitin) and phallotoxins (phallacidin and phalloidin) in wild mushrooms by online liquid chromatography-diode array detector-tandem mass spectrometry (LC-DAD-MS/MS). The mushroom toxins were extracted with methanol, and diluted with water. The extracts were separated on an XBridgeTM BEH C18 column (150 mm×3.0 mm, 2.5 μm) under pH 10.7, measured by DAD and then analyzed by MS/MS. Basic mobile phase conditions were applied to improve the ionization efficiency of hydrogen ion adducts. The baseline separation of the analytes was obtained within 15 min. The limits of detection (LODs) of the sample matrix were 0.005-0.02 mg/kg. The toxins were quantified by the results measured by MS/MS when the toxin contents less than 2 mg/kg, and quantified by the results obtained from DAD when the contents more than 2 mg/kg. The linear range was 0.05-500 mg/kg for the whole method in one injection. The method was successfully applied to the analyses of amanitins and phallotoxins in Lepiota brunneoincarnata and white Amanita.

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Simultaneous determination of pyraclostrobin and thiophanate-methyl and its metabolite carbendazim residues in soil and citrus by QuEChERS-liquid chromatography- tandem mass spectrometry LI Fuqin, SHI Lihong, WANG Fei, SUN Caiyuan, KANG Di, ZHANG Yuping, CHEN Lingzhu, HU Deyu 2017, 35 (6):  620-626.  DOI: 10.3724/SP.J.1123.2017.01031 Abstract ( 761 )   [Full Text(HTML)] () PDF (1271KB) ( 172 )   A QuEChERS-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of pyraclostrobin, thiophanate-methyl and its metabolite carbendazim in soil and citrus. The samples were extracted with methanol or acetonitrile, purified by primary secondary amine (PSA), then separated by LC, detected in multiple reaction monitoring (MRM) mass spectrometry mode via positive electrospray ionization. The analytes were quantified by matrix-matched standard solutions with external standard method. The limits of quantification (LOQs) of pyraclostrobin, thiophanate-methyl and carbendazim in different matrices were 5.8-7.0 μg/kg, 9.3-14.1 μg/kg and 2.1-2.6 μg/kg, respectively. For all the samples, the spiked recoveries ranged from 75.48% to 109.18%, and the relative standard deviations (RSDs) were 0.60%-5.11% (n=5). The method is quick, easy, effective, sensitive and accurate. The matrix-matched calibration solutions can efficiently compensate matrix effects of the pyraclostrobin, thiophanate-methyl and carbendazim in LC-MS/MS analysis. The established method can be applied to the residue analysis of the real samples of soil, citrus peel, citrus pulp and citrus fruits.

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Simultaneous determination of 30 mycotoxins in different feed products by ultra high performance liquid chromatography-tandem mass spectrometry FAN Zhichen, HAN Zheng, GUO Wenbo, ZHAO Zhihui 2017, 35 (6):  627-633.  DOI: 10.3724/SP.J.1123.2017.02010 Abstract ( 654 )   [Full Text(HTML)] () PDF (943KB) ( 175 )   A method for the simultaneous determination of 30 mycotoxins in different feed products was developed using a QuEChERS pretreatment procedure coupled with ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The samples were extracted with 5 mL water and 5 mL acetonitrile containing 1% (v/v) formic acid. An aliquot of the supernatant was dried by nitrogen gas, re-dissolved by 1mL water containing 5 mmol/L ammonium acetate-acetonitrile (80:20, v/v), and analyzed by UHPLC-MS/MS. Matrix-matched calibration curves and internal standards were used for accurate quantification. Satisfactory recoveries at low, medium and high spiked levels were ranged from 72.0% to 118.4% (n=5). Good linear relationships were obtained, the correlation coefficients (r2) were greater than 0.99. The limits of detection (LODs, S/N=3) and the limits of quantification (LOQs, S/N=10) ranged from 0.7 μg/L to 20 μg/L and from 2 μg/L to 50 μg/L, respectively. The proposed method is simple, rapid and valuable, which can be a powerful tool for quantitative analysis of the 30 mycotoxins in premixed feed, concentrated feed and formula feed products.

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An improvement of the calibration results for grey analytical system in high performance liquid chromatography applying constrained background bilinearization method based on genetic algorithm optimization strategy ZHANG Yaxiong, NIE Xianling 2017, 35 (6):  634-642.  DOI: 10.3724/SP.J.1123.2016.12017 Abstract ( 455 )   [Full Text(HTML)] () PDF (1144KB) ( 68 )   Constrained background bilinearization (CBBL) method was applied for multivariate calibration analysis of the grey analytical system in high performance liquid chromatography (HPLC). By including the variables of the concentrations and the retention time of the analytes simultaneously, the standard CBBL was modified for the multivariate calibration of the HPLC system with poor retention precision. The CBBL was optimized globally by genetic algorithm (GA). That is to say, both the concentrations and the retention times of the analytes were optimized globally and simultaneously by GA. The modified CBBL was applied in the calibration analysis for both simulated and experimental HPLC system with poor retention precision. The experimental data were collected from HPLC separation system for phenolic compounds. The modified CBBL was verified to be useful to prevent the inherent limitation of the standard CBBL, which means that the standard CBBL may result in poor calibration results in the case of poor retention precision in chromatography system. Moreover, the modified CBBL can give not only the concentrations but also the retention time of the analytes. i. e., more useful information of the analytes can be generated by the modified CBBL. Subsequently, nearly ideal calibration results were obtained. On the other hand, comparing with the calibration results by the classical rank annihilation factor analysis (RAFA) and residual bilinearization (RBL) method, the results given by the modified CBBL were also improved significantly for the HPLC systems studied in this work.

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A novel pattern for predicting the quality of Chinese herba preparation intelligently by high performance liquid chromatographic formula fingerprints GONG Dandan, DONG Jiajun, SUN Guoxiang, ZHANG Jing, ZHANG Yujing, SUN Wanyang 2017, 35 (6):  643-649.  DOI: 10.3724/SP.J.1123.2016.12041 Abstract ( 515 )   [Full Text(HTML)] () PDF (1014KB) ( 137 )   In order to build the fusion models, the high performance liquid chromatographic (HPLC) fingerprints of scutellariae radix (SR), rhei radix et rhizoma (RRR), coptidis rhizoma (CR) and their synthesizing fingerprints were developed in this study. After exploring the consistency between the fingerprints of compound synthesizing fingerprints (CSF) and the sample, the quality of traditional Chinese medicine preparation was predicted intelligently using CSF. HPLC coupled with diode array detector was used to obtain chromatograms of SR, RRR, CR and Yi Qing Tablet (YQT) samples at 268 nm. Meanwhile, the quality of CSF and the 15 batches of YQT samples was evaluated by systematically quantified fingerprint method (SQFM) qualitatively and quantitatively. The chromatograms showed that CSF covered the main fingerprints' information of each herb and the 55 common peaks of CSF covered the main information of the 50 common peaks in YQT sample. The evaluation results showed that among the 15 batches of YQT samples, only YQT-S01 was grade 5 and the others were all above grade 3. Most of the CSFs were grade 2 or grade 1 except CSF-2 which was grade 6. The fingerprints of Chinese herba preparation could be replaced by CSF to achieve a novel pattern for predicting the quality of TCM preparation intelligently by studying the relationship between the standard fingerprints and the CSF, and simultaneously developing first-class evaluation software.

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Separation and purification of the components in Trachelospermum jasminoides by two dimensional hydrophilic interaction liquid chromatography- reversed-phase liquid chromatography JIA Youmei, CAI Jianfeng, XIN Huaxia, FENG Jiatao, FU Yanhui, FU Qing, JIN Yu 2017, 35 (6):  650-655.  DOI: 10.3724/SP.J.1123.2017.01010 Abstract ( 574 )   [Full Text(HTML)] () PDF (1444KB) ( 111 )   A preparative two dimensional hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography (Pre-2D-HILIC/RPLC) method was established to separate and purify the components in Trachelospermum jasminoides. The pigments and strongly polar components were removed from the crude extract after the active carbon decolorization and solid phase extraction processes. A Click XIon column (250 mm×20 mm, 10 μm) was selected as stationary phase and water-acetonitrile as mobile phases in the first dimensional HILIC. Finally, 15 fractions were collected under UV-triggered mode. In the second dimensional RPLC, a C18 column (250 mm×20 mm, 5 μm) was selected and water-acetonitrile was used as mobile phases. As a result, 14 compounds with high purity were obtained, which were further identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). Finally, 11 lignan compounds and three flavonoid compounds were obtained. The method has a good orthogonality, and can improve the resolution and the peak capacity. It is significant for the separation of complex components from Trachelospermum jasminoides.

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Ionic liquid based ultrasonication-assisted extraction of essential oil from the leaves of Persicaria minor and conductor-like screening model for realistic solvents study Habib ULLAH, Cecilia D WILFRED, Maizatul S SHAHARUN 2017, 35 (6):  656-664.  DOI: 10.3724/SP.J.1123.2017.02002 Abstract ( 666 )   [Full Text(HTML)] () PDF (1290KB) ( 119 )   Ionic liquids (ILs) based ultrasonic-assisted extract has been applied for the extraction of essential oil from Persicaria minor leaves. The effects of temperature, sonication time, and particle size of the plant material on the yield of essential oil were investigated. Among the different ILs employed, 1-ethyl-3-methylimidazolium acetate was the most effective, providing a 9.55% yield of the essential oil under optimum conditions (70 ℃, 25 min, IL:hexane ratio of 7:10 (v/v), particle size 60-80 mesh). The performance of 1-ethyl-3-methylimidazolium acetate in the extraction was attributed to its low viscosity and ability to disintegrate the structural matrix of the plant material. The ability of 1-ethyl-3-methylimidazolium acetate was also confirmed using the conductor like-screening model for realistic solvents. This research proves that ILs can be used to extract essential oils from lignocellulosic biomass.

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Determination of residual toluene diisocyanate in sponge bra by gas chromatography WANG Aixia, YE Ping, HUANG Nan, CHEN Yan, LI Xinggen 2017, 35 (6):  665-668.  DOI: 10.3724/SP.J.1123.2017.01029 Abstract ( 587 )   [Full Text(HTML)] () PDF (806KB) ( 110 )   A gas chromatography (GC) with internal standard method was developed for the determination of residual toluene diisocyanate (TDI) in sponge bra. The samples were extracted with ethyl acetate dehydrated, and cleaned up with 0.22 μm microfiltration membrane. The residual toluene diisocyanate was separated on a DB-624 capillary column using temperature programming. The flame ionization detector (FID) was used at 250 ℃. The inlet temperature was 180 ℃ with nitrogen as carrier gas. The linear range was 10-200 mg/L (R2=0.9989) for TDI. The average recovery ranged from 80.5% to 91.6% with RSD not more than 7.9%(n=6). The limit of detection (LOD) and limit of quantification (LOQ) were 10 mg/kg and 100 mg/kg, respectively. The developed method was then utilized to analyse the 100 batches of sponge bra samples from the manufacturing enterprises, the entity shops and electric business platforms. The method is simple, time-saving and environment friendly with high sensitivity and good reproducibility, and has practical application value due to its low-cost and short-circle.

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Determination of polycyclic aromatic hydrocarbons in airborne particles by microwave extraction-high performance liquid chromatography WANG Meifei, YANG Lili, HU Enyu 2017, 35 (6):  669-673.  DOI: 10.3724/SP.J.1123.2017.01023 Abstract ( 498 )   [Full Text(HTML)] () PDF (840KB) ( 63 )   A method by using microwave extraction and high performance liquid chromatography was developed to determine polycyclic aromatic hydrocarbons (PAHs) in airborne particles. The glass/quartz fiber filter, on which particles adsorbed, was extracted with a mixed solvent n-hexane/acetone (1:1, v/v) using microwave, and the subsequent purification of the extract was carried out by a florisil cartridge. The prepared sample was determined by high performance liquid chromatography coupled with photodiode array (PDA) and fluorescence dual-detector. The target compounds showed good linearity between the mass concentration of 20.0 μg/L and 500 μg/L, with the correlation coefficients not less than 0.9960. The spiked recoveries of target compounds in blank filter ranged from 56.3%-101%. The current method has been applied to investigate the distribution of PAHs in airborne particles in Nanjing City.