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Chinese Journal of Chromatography
2018, Vol. 36, No. 12
Online: 08 December 2018

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Volume 36, Number 12 Content 2018, 36 (12):  0-0.  Abstract ( 285 )   PDF (6091KB) ( 61 )

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Recombination of human galectin-3 with the carbohydrate recognition domain to achieve glycoprotein/glycopeptide enrichment ZHAO Yang, ZHANG Yong, WANG Mingchao, MENG Bo, YING Wantao, QIAN Xiaohong 2018, 36 (12):  1197-1205.  DOI: 10.3724/SP.J.1123.2018.08017 Abstract ( 358 )   [Full Text(HTML)] () PDF (3343KB) ( 200 )   Though plant lectins have been widely used for the enrichment of glycoproteins/glycopeptides, mammalian lectins have rarely been explored for this purpose. Using the conserved sequence of the carbohydrate recognition domain (CRD) of the human galectin-3 protein, we engineered the following two novel human galectins:Gal3C (containing one CRD) and Tetra-Gal3C (containing four tandem CRDs). Moreover, we designed a galectin affinity column that could be used for glycoprotein/glycopeptide enrichment, by taking advantage of the ability of these recombinant galectins to become immobilized onto streptavidin agarose beads. SDS-PAGE, western blotting, and mass spectrometry were used to characterize the biological features and glycoprotein/glycopeptide enrichment abilities of both these recombinant galectins. Our results showed that both Gal3C and Tetra-Gal3C predominantly enrich glycoproteins/glycopeptides and that this enrichment process has a high specificity and sensitivity. Because Tetra-Gal3C contains three more CRD structural domains, it exhibited a better ability to achieve enrichment than Gal3C. Moreover, the immobilized Gal3C and Tetra-Gal3C were successfully used for the enrichment of glycoproteins from HepG2 cells, which indicated the selective glycoprotein/glycopeptide enrichment potential of recombinant galectins in complex samples.

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Preparation and characterization of a latex-agglomerated anion exchange chromatographic stationary phase SUN Yu'an, WANG Chaowei, LI Zhenxing, YU Wenhao, LIU Junwei, ZHU Yan 2018, 36 (12):  1206-1210.  DOI: 10.3724/SP.J.1123.2018.09034 Abstract ( 394 )   [Full Text(HTML)] () PDF (3969KB) ( 188 )   Allyl glycidyl ether (AGE) was selected as the copolymerization monomer to prepare a copolymer latex-agglomerated anion exchange chromatography stationary phase for ion chromatography (IC). First, allyl glycidyl ether-styrene (AGE-ST) copolymer latex was prepared by the saponification emulsion polymerization method. It was then quaternized by reacting alternatively with methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDGE) and agglomerated on the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) microspheres to obtain a copolymer latex-agglomerated anion exchange chromatography stationary phase. The stationary phase was characterized by scanning electron microscopy (SEM), FT-IR and elemental analysis (EA). It was found that the diameters of the PS-DVB microsphere and AGE-ST copolymer latex were about 6 μm and 300 nm, respectively. The quaternized AGE-ST copolymer latex was successfully agglomerated on the surface of PS-DVB microspheres and the nitrogen content increased as quaternization time was increased. The chromatographic properties were evaluated by separating conventional anions and organic acids. The results showed that the quaternized AGE-ST copolymer latex-agglomerated PS-DVB anion exchange column exhibited good separation properties toward anions. Therefore, based on the good pH toleration and reaction activity of the newly developed stationary phase, it was concluded that using AGE as a monomer was a good choice.

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Determination of 105 pesticide residues in vegetables by QuEChERS-liquid chromatography-tandem mass spectrometry DENG Huifen, ZHANG Jianying, HUANG Ke, ZHONG Tiantian, LIN Limin 2018, 36 (12):  1211-1222.  DOI: 10.3724/SP.J.1123.2018.09012 Abstract ( 432 )   [Full Text(HTML)] () PDF (3123KB) ( 120 )   After optimization of the QuEChERS pretreatment method, combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology, a multi-residue determination method was established for 105 typical insecticides, bactericides, herbicides, and plant growth regulators in vegetables. The target compounds were extracted by acetonitrile, purified with 150 mg primary secondary amine (PSA), 150 mg EC-C18, and 30 mg graphitized carbon black (GCB) adsorbents. The standard curves of 105 target compounds were linear in the concentration range of 0.010-0.200 mg/L, with correlation coefficients (r)>0.99. The limit of quantification was 0.010 mg/kg, the recoveries were between 68.2% and 108% at three spiked levels, and the RSDs of the method were between 1.02% and 11.8%. The method is suitable for the rapid determination of the common pesticides in vegetables owing to its advantages of rapidity, simplicity, and better purification.

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Determination of bisultap residue in tropical fruits by ultra performance liquid chromatography-tandem mass spectrometry LIN Tao, SHAO Jinliang, LIU Xingyong, WANG Jing, ZOU Yanhong, LI Maoxuan, LIU Hongcheng 2018, 36 (12):  1223-1227.  DOI: 10.3724/SP.J.1123.2018.08018 Abstract ( 341 )   [Full Text(HTML)] () PDF (867KB) ( 94 )   A method for the determination of bisultap in tropical fruits was developed by modified QuEChERS method and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The tropical fruit samples were twice extracted with acetonitrile containing 1% (v/v) acetic acid, and purified by 200 mg of primary secondary amine (PSA), 100 mg of C18, 300 mg of MgSO4 and 500 mg of disodium hydrogen citrate. The analyte was separated on a CAPCELL CORE PC hydrophilic column, detected in the negative ion multiple reaction monitoring (MRM) mode, and quantified by external standard method. A good linear relationship in the range of 0.1-10.0 μg/L was obtained with the correlation coefficient (r2) of 0.9993. The limit of detection and limit of quantification were 0.015 μg/kg and 0.05 μg/kg, respectively. The spiked recoveries were in the range of 81.0%-88.3% with the relative standard deviations from 3.9% to 6.2%. The method has good purification effect and high sensitivity, and is suitable for the rapid analysis of the bisultap residues in tropical fruits.

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Rapid determination of 95 herbicide residues in tea by modified QuEChERS coupled with ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry ZHANG Rong, LIU Xin, PENG Yuan, LIU Weihua, ZHANG Licheng, DAI Ying, LI Shasha, GAO Zhixian 2018, 36 (12):  1228-1237.  DOI: 10.3724/SP.J.1123.2018.08027 Abstract ( 340 )   [Full Text(HTML)] () PDF (976KB) ( 144 )   A qualitative and quantitative method was established based on modified QuEChERS for the simultaneous determination of 95 herbicide residues in tea using ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). The effects of multi-walled carbon nanotubes (MWCNTs), graphitized carbon black (GCB), primary secondary amine (PSA) and toluene on the precondition step were evaluated in terms of matrix-spiked recovery and pigment clean-up effect. Finally, the modified QuEChERS method was applied, which involved sample extraction with an acetonitrile-toluene (9:1, v/v) mixture containing 1% (v/v) acetic acid, followed by cleaning with 12.5 mg GCB, 12.5 mg MWCNTs and 150 mg PSA. The sample extract was separated on a Hypersil Gold C18 column and analyzed in full scan/data-dependent MS2(Full MS/dd-MS2) mode. The target herbicides were quantified by using the matrix-matched standard calibration. The three-level spiked recoveries were between 63.3% and 129.1% with the precision of 0.7%-15.2%. This method is easy, sensitive and rapid and can be applicable to the determination of trace herbicide residues in tea and other plant-derived complex matrix samples.

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Determination of ethylenethiourea residues in tea using precolumn derivatization with ultra-performance liquid chromatography-tandem mass spectrometry ZHENG Xiaoyan 2018, 36 (12):  1238-1244.  DOI: 10.3724/SP.J.1123.2018.08003 Abstract ( 278 )   [Full Text(HTML)] () PDF (912KB) ( 91 )   A method based on precolumn derivatization along with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of ethylenethiourea residues in tea. The sample was extracted using acetonitrile; the extracting solution was purified by matrix-dispersed solid phase extraction and precolumn derivatization using 9-fluorenylmethyl chloroformate (FMOC-CL). The UPLC separation was carried out on an Acquity BEH C18 column (100 mm×2.1 mm, 1.7 μm) and quantified using the isotope internal standard method. The mobile phase was 0.1% (v/v) formic acid and acetonitrile. For tea samples, the detection limit of this method was 1.3 μg/kg and the limit of quantitation was 4.2 μg/kg. The recoveries were in the range 97.7%-107.5% with relative standard deviation (RSD) of 2.1%-10.0% (n=6). The linear correlation coefficient (r) was 0.9993 over the concentration range 1.0-203.4 μg/L. This method showed high sensitivity, good reproducibility, and qualitative and quantitative accuracy, and could be suitable for the detection of ethylenethiourea residues in tea.

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Determination of 63 compounds illegally added in tea, substitute tea and beverage foods by ultra-high performance liquid chromatography-tandem mass spectrometry TANG Weiying, HUANG Zewei, QIAN Guangsheng, WEI Yutao, HUANG Ying, XU Xiaoping, YU Xiaoqin 2018, 36 (12):  1245-1260.  DOI: 10.3724/SP.J.1123.2018.06025 Abstract ( 308 )   [Full Text(HTML)] () PDF (3539KB) ( 106 )   A method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 63 compounds illegally added in tea, substitute tea, and beverage products. The samples were extracted by ultrasonic extraction using methanol, and the analytes were separated on the Thermo Acclaim RSLC C18 chromatographic column (100 mm×2.1 mm, 2.2 μm) by gradient elution using 5 mmol/L ammonium formate solution containing 0.1% (v/v) formic acid and 0.1% (v/v) formic acid acetonitrile as the mobile phase. The electrospray ion source was operated in the positive ion mode using the dynamic multi-reaction monitoring (dMRM) method, and the results were quantified by the external standard method. The correlation coefficients (R2) of the linear calibration curves were greater than 0.99 in the corresponding mass concentration ranges, and the limits of quantification (LOQs) for the analytes were 0.10-2.50 mg/kg. The average recoveries at three spiked levels ranged from 62.4% to 129.4%. The RSDs of the injection precision and the repeatability of samples were in the range 0.3%-9.6% (n=6). Thus, the proposed method is simple, rapid, accurate, reliable, and applicable for the detection of the illegal addition of antipyretic and analgesic affect compounds in tea, substitute tea and beverage food.

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Determination of 39 veterinary drug residues in Procambarusclarkii by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry SONG Wei, ZHAO Muyu, HAN Fang, LÜ Yaning, DING Lei, ZHOU Dianbing, DENG Xiaojun, HU Yanyun, ZHENG Ping, SHENG Xuan 2018, 36 (12):  1261-1268.  DOI: 10.3724/SP.J.1123.2018.08037 Abstract ( 291 )   [Full Text(HTML)] () PDF (1296KB) ( 132 )   An ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) method was developed for determination of 39 veterinary drugs in Procambarusclarkii. Samples were extracted with acidified acetonitrile and purified with enhanced matrix removal-lipid (EMR-Lipid) adsorbent and graphitized multi-walled carbon nanotubes (GMWNTs). Extracts were analyzed by UHPLC-Q-TOF-MS. Target compounds were screened according to accurate mass, isotopic ratio, and retention time, and confirmed by library search. Target analytes were quantified using the chromatographic peak area of each compound. For each of the drugs of interest, calibration curves were linear in their respective ranges with correlation coefficients greater than 0.99. The limits of quantification (LOQs) were 3-15 μg/kg. The recoveries for target compounds spiked in Procambarusclarkii ranged from 62.4% to 105.8%, with relative standard deviations (RSDs) ranging from 2.5% to 13.5%. This method is simple, rapid, accurate, and suitable for simultaneous determination of 39 veterinary drugs, including sulfonamides, quinolones, and triphenylmethane, extracted from Procambarusclarkii.

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Identification of meat marker peptides and detection of adulteration by liquid chromatography-tandem mass spectrometry GU Shuqing, ZHAN Lina, ZHAO Chaomin, ZHENG Jiang, CAI Yicun, DENG Xiaojun 2018, 36 (12):  1269-1278.  DOI: 10.3724/SP.J.1123.2018.08005 Abstract ( 428 )   [Full Text(HTML)] () PDF (2688KB) ( 168 )   A liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the identification of meat marker peptides and quantitative detection of common exogenous meat in mutton adulteration. Samples were prepared by protein extraction, trypsin hydrolysis, and solid phase extraction. Proteins and peptides were identified using ultra-performance liquid chromatography-quadrupole/electrostatic orbitrap-high resolution mass spectrometry (UPLC-Q/Exactive-HRMS) combined with Proteinpilot software. Twenty species-specificity marker peptides in mutton, duck, pork, and chicken were identified by comparison of the basic local alignment search tool (BLAST) with the Uniprot database. Verification and multiple reaction monitoring (MRM) of these marker peptides were performed quantitatively using a UPLC-triple-quadrupole mass spectrometry (QqQ-MS) system. Duck, pork, and chicken were added to mutton at mass percentages of 1%, 5%, 10%, 20%, and 50%. The limit of detection for the adulterants was 0.25% for duck, 0.17% for pork, and 0.10% for chicken.

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Simultaneous determination of perfluoric acid, perfluorooctane sulfonic acid, bisphenol A, nonylphenol in infant milk powder by high-performance liquid chromatography-tandem mass spectrometry WANG Hao, SHAO Mingyuan, JIA Jingyi, LIU Mingyan, PEI Fan 2018, 36 (12):  1279-1283.  DOI: 10.3724/SP.J.1123.2018.07011 Abstract ( 363 )   [Full Text(HTML)] () PDF (857KB) ( 158 )   A rapid confirmative method was developed for determining the residues of perfluoric acid (PFOA), perfluorooctane sulfonic acid (PFOS), bisphenol A (BPA), and nonylphenol (NP) in infant milk powder by HPLC-MS/MS. The sample was dissolved in water by ultrasonication, and the protein was removed by dissolving in acetonitrile. The analytes were separated on a Hypersil GOLD C18 column (150 mm×2.0 mm, 5 μm) using 30 mmol/L ammonium acetate solution and methanol as mobile phases, with gradient elution at a flow rate of 0.3 mL/min. Finally, the samples were determined by HPLC-MS/MS. Internal matrix-matched calibration was used for quantification. The limits of quantification (LOQs, S/N=10) of PFOA, PFOS, BPA, and NP were 0.5, 1.0, 10.0, and 5.0 μg/kg, respectively. The recoveries ranged from 86.1% to 106.8%, and the relative standard deviations (RSDs) were in the range from 2.87% to 9.53%. The method was also applied to real samples. The results showed that the method was simple and accurate, and can be used for determining the residues of PFOA, PFOS, BPA, and NP in infant milk powder.

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Determination of chloramphenicol in propolis and propolis-derived dietary supplements by high performance liquid chromatography-tandem mass spectrometry WEN Jiaxin, WU Fengdan, CAO Yajing, HE Jiawen, HUANG Zhiye, HUANG Yanting, TAN Wanqing, LUO Wenjing, LAI Yuhong 2018, 36 (12):  1284-1289.  DOI: 10.3724/SP.J.1123.2018.08012 Abstract ( 295 )   [Full Text(HTML)] () PDF (1380KB) ( 155 )   A method for determining chloramphenicol (CAP) in both propolis and propolis-derived dietary supplements was developed by utilizing high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The flavones in the samples were removed with a lead acetate solution and ammonia, and the fat-soluble interferences, such as beewax and vegetable oils, were removed with n-hexane after the sample dissolved in ethanol. Tert-butyl methyl ether was used as the back-extraction solvent to reduce co-extracting compounds, such as polyethylene glycol 400 (PEG 400) and glycerol, which are common adjuvants of dietary supplements, and some polar interferences. CAP was detected by HPLC-MS/MS and quantified by the internal standard method. The calibration curve showed a good linearity in the range of 0.20-50.0 μg/L. The limits of detection and the limits of quantification were 0.03 and 0.1 μg/kg, respectively. The recoveries in four different matrices at three spiked levels were in the 86.0%-114.4% range with the relative standard deviations from 0.3% to 4.9%. With the advantages of excellent universality, ease of operation, high sensitivity, and strong anti-interference capability, the proposed method was suitable for the determination of CAP in both propolis and propolis-derived dietary supplements.

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Analysis of methamphetamine and amphetamine chiral enantiomers in hair by high performance liquid chromatography-tandem mass spectrometry ZHANG Yingyi, LI Liang, XING Xuqin, ZHOU Zhengzheng, MA Ande 2018, 36 (12):  1290-1296.  DOI: 10.3724/SP.J.1123.2018.08040 Abstract ( 335 )   [Full Text(HTML)] () PDF (1115KB) ( 87 )   A chiral separation method was developed for the analysis of methamphetamine (METH) and amphetamine (AM) in hair by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The samples were extracted using methanol by ultrasonication in a high-temperature water bath. The chromatographic separation was performed on a SUPELCO Astec CHIROIOTIC® V2 column with the mobile phase of methanol-20 mmol/L ammonium acetate aqueous solution containing 0.1% (v/v) formic acid (99:1, v/v). All the compounds showed linear relationship in the range of 15-300 ng/mg (r>0.99). The limits of detection (LODs) of METH and AM were 0.1 ng/mg and 0.15 ng/mg, respectively. The limits of quantification (LOQs) of METH and AM were 0.4 ng/mg and 0.5 ng/mg, respectively. The inter-day precisions were all ≤ 6.8%, and the intra-day precisions were all ≤ 11.4%. Fifty drug abuse samples were determined by this method. Up to 70% of the cases were determined as S-(+)-METH and S-(+)-AM, while 18% of the cases were S-(+)-METH, S-(+)-AM, R-(-)-METH and R-(-)-AM. The proposed method is rapid, simple, and provides technical support and a scientific basis for the chiral analysis in actual hair samples for forensic toxicant identification.

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Determination of anserine, homocarnosine and carnosine in meat products by ion chromatography with integrated pulsed amperometric detection ZHU Zuoyi, ZHANG Yu, WANG Junhong, LI Xue, WANG Wei, YANG Hua, ZHU Yan 2018, 36 (12):  1297-1302.  DOI: 10.3724/SP.J.1123.2018.08029 Abstract ( 331 )   [Full Text(HTML)] () PDF (888KB) ( 115 )   A method was developed for the simultaneous determination of anserine, homocarnosine and carnosine in meat samples using ion chromatography (IC) with integrated pulsed amperometric detection (IPAD). The samples were separated on a high performance anion exchange AminoPac PA10 column (250 mm×2 mm) using 100 mmol/L NaOH as the eluent. The flow rate was kept at 0.2 mL/min and the column temperature was set at 30℃. The three target compounds were separated within 15 min, and there were no interferences from 17 tested amino acids in their determination. Under the optimal chromatographic conditions, anserine, homocarnosine and carnosine showed good linearity in the range of 0.05-5 mg/L with correlation coefficients (r) greater than 0.99. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 8.9-22.1 μg/L and 29.6-73.6 μg/L, respectively. The proposed method was applied to the analysis of duck breast and goose breast meat samples. The average spiked recoveries ranged from 92.4% to 104.5%. This simple and sensitive method can be applied to the determination of related nutrients in meat products.

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Determination of nine pyrethroid pesticide residues in tea by gas chromatography-tandem mass spectrometry combined with accelerated solvent extraction and solid phase extraction HUANG Wei, LI Na, XU Ruihan, LI Ting, LI Chongyong 2018, 36 (12):  1303-1310.  DOI: 10.3724/SP.J.1123.2018.09019 Abstract ( 347 )   [Full Text(HTML)] () PDF (2061KB) ( 123 )   A method has been developed for the simultaneous detection of nine pyrethroid pesticide residues in tea by gas chromatography-tandem mass spectrometry (GC-MS/MS) combined with accelerated solvent extraction (ASE) and solid-phase extraction (SPE). The pesticide residues in tea were extracted using acetone/n-hexane (1:1, v/v) for 5 min at 100℃ before preheating the extraction pool for 3 min, under extractive pressure of 10 MPa for one cycle. After extraction, the extraction pool was washed with acetone/n-hexane (1:1, v/v) having volume of 40% of the pool volume, followed by purging for 100 s with nitrogen. The extract was purified by a Cleanert TPT solid-phase extraction column. After purification, the target compounds were detected by GC-MS/MS and quantified by the external standard method. Under the optimized conditions, good linearities were obtained for the nine pyrethroid pesticides in the range of 2-1000 μg/L, with correlation coefficients exceeding 0.99. The limits of detection (LODs) were 0.2-4.5 μg/kg and the limits of quantitation (LOQs) were 0.8-15.0 μg/kg. At four spiked levels (0.02, 0.1, 0.4 mg/kg, and the LOQ level) in green tea and black tea, the recoveries of all the pesticides were between 69.87% and 110.0%, with relative standard deviations (RSDs) varying from 0.7% to 11.2%. This method effectively reduces the matrix interference and shows high sensitivity, good reproducibility, and stable recovery, and can thus be used for the detection of pyrethroid pesticide residues in tea.

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Determination of airborne formaldehyde and ten other carbonyl pollutants using programmed temperature vaporization-large volume injection-gas chromatography Stefano DUGHERI, Nicola MUCCI, Ilenia POMPILIO, Giovanni CAPPELLI, Costanza BOSSI, Alessandro BONARI, Giulio ARCANGELI 2018, 36 (12):  1311-1322.  DOI: 10.3724/SP.J.1123.2018.08050 Abstract ( 271 )   [Full Text(HTML)] () PDF (3007KB) ( 110 )   Long-term indoor-air limit for formaldehyde stipulated by the European Commission is 1 μg/m3, while the World Health Organization has set a threshold of 100 μg/m3 that should not be exceeded for more than 30 min. To date, however, only a few analytical techniques have been developed that can be used to detect formaldehyde at these very restrictive limits. Thus, there is a need to develop for comprehensive methods for analyzing airborne formaldehyde and other carbonyl pollutants in the ambient environment. The aim of this study is to develop a highly sensitive online automated preconcentration gas chromatographic method using large-volume injection with a programmed temperature vaporization injector for the analysis of airborne formaldehyde and ten other carbonyl compounds. The influence of several parameters, such as the maximum volume injected, programmed temperature vaporization transfer time and temperature, carrier gas flow rate, and type of packing material was investigated. After optimization, highly satisfactory results in terms of the absolute and methodological detection limits were achieved, i. e. as low as the μg/m3 level for all the carbonyl pollutants studied. A commercially available sampler, originally designed for active sampling, was evaluated as a passive sampling device; this optimized technique was applied to monitor the concentrations of carbonyl pollutants in the indoor air of ten public buildings in Florence. The strength of this methodology lies both in the low detection limits reached in the simultaneous analysis of a wide group of 2,4-dinitrophenylhydrazine derivatives, and the potential adaptability of this method to other gas chromatographic applications to achieve lower sensitivity.

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Preparation of nickel-titanium alloy fiber/organosilicone-polyurethane solid phase microextraction head and its application to the determination of seven substituted benzenes in water SHEN Shuchang, REN Fangxiu, LÜ Weichao 2018, 36 (12):  1323-1329.  DOI: 10.3724/SP.J.1123.2018.08047 Abstract ( 234 )   [Full Text(HTML)] () PDF (3731KB) ( 72 )   Toluene-2,4-diisocyanate, polyester polyol, and hydroxy silicone oil were used as raw materials; stannous octoate was used as the catalyst; and cyclohexanone was used as the solvent to synthesize organosilicone-polyurethane (SP). The polymer was coated on the surface of a nickel-titanium alloy fiber treated hydrothermally with potassium hydroxide. It was the prepared for headspace solid phase microextraction (HS-SPME). The polymer structure was analyzed by infrared spectroscopy, the highest temperature of the coating was determined by thermogravimetric analysis, and the surface morphology of the extraction head was observed by scanning electron microscopy. The benzene series of toluene, xylene, m-dichlorobenzene, o-dichlorobenzene, ethyl benzoate, nitrobenzene and benzyl alcohol in water were determined by HS-SPME-gas chromatography (GC) method. There was a good linear relationship between the chromatographic peak area and mass concentration of each measured object. The correlation coefficients (R2) were 0.9926-0.9998. The limits of detection were 0.08-0.24 μg/L. The recoveries of the spiked samples were 95.9%-105.4%, and the relative standard deviations were 1.4%-5.0%. The coating of SPME head adhered more firmly, and had a better adsorption performance for the substituted benzenes in water.

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Simultaneous determination of nine mycotoxins in cereal and cereal products by high performance liquid chromatography with composite immunoaffinity clean-up column WANG Weigang, QIANG Min, DUAN Liqin 2018, 36 (12):  1330-1336.  DOI: 10.3724/SP.J.1123.2018.08008 Abstract ( 326 )   [Full Text(HTML)] () PDF (916KB) ( 98 )   A rapid analytical method using high performance liquid chromatography (HPLC) with post-column derivatization was established for the simultaneous determination of nine mycotoxins in cereal and cereal products. The nine mycotoxins were extracted from the samples by using acetone-water (80:20, v/v). The extract was purified by a self-made composite immunoaffinity clean-up column and was analyzed by HPLC. Mycotoxins were detected by fluorescence detection after on-line photochemical derivatization and were quantified by an external standard method. The nine compounds showed good linearities in their concentration ranges with the correlation coefficients (R2) exceeding 0.999. The spiked recoveries in real samples for the nine mycotoxins were above 80%, while the relative standard deviations (RSDs) were in the range of 1.0%-5.6%. The limits of detection (LODs) and the limits of quantification (LOQs) were 0.02-5.00 and 0.07-16.70 μg/kg, respectively. The developed method is simple, sensitive, and has good repeatability, and thus can be used for the routine analysis of the nine mycotoxins in cereal and cereal products.

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Determination of the relative molecular mass distribution of the ultrafiltration fractionation product of lignosulfonate by advanced polymer chromatography QIAN Chen, FANG Hongxia, CAI Qun, CAI Fang, GAO Xinyu, LI Dandan 2018, 36 (12):  1337-1341.  DOI: 10.3724/SP.J.1123.2018.08010 Abstract ( 259 )   [Full Text(HTML)] () PDF (865KB) ( 89 )   The effects of testing conditions, such as pH and ionic strength of the mobile phase, on the relative molecular mass obtained by advanced polymer chromatography (APC) were investigated systematically. The non-size exclusion effects were discussed for lignosulfonate and its ultrafiltration fractionation product. The relative molecular mass distribution of lignosulfo-nate was well-characterized by an APC system using three columns in series, with a 10 μ L injection volume and 0.1 mol/L NaNO3 as the aqueous mobile phase, at a flow rate of 0.5 mL/min. The relative molecular mass distribution is in the eight molecular mass ranges. Optimized test conditions were used to characterize the ultrafiltration fractionation product of lignosulfonate. The obtained number average relative molecular masses (Mn) of the three components were 40410, 12208, and 1516 Da, indicating that lignosulfonate was well separated into three fractions by ultrafiltration membrane separation. The APC technique presented herein provides the basis for further application of the fractional separation products of lignosulfonate.

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Simultaneous determination of 27 solvent residuals in ultraviolet curable offset inks by headspace gas chromatography-mass spectrometry GUO Leilei, LI Ying, LI Haishan, LIAN Zengbin 2018, 36 (12):  1342-1348.  DOI: 10.3724/SP.J.1123.2018.09010 Abstract ( 260 )   [Full Text(HTML)] () PDF (1124KB) ( 114 )   A headspace gas chromatography-mass spectrometry (HS-GC-MS) method was developed for the determination of 27 solvent residuals (volatile organic compounds, VOCs) in ultraviolet (UV) curable offset inks. Ink samples of a given area and thickness were prepared using an ink-scraping instrument and baked under a UV lamp for 1 min. The experimental conditions such as headspace temperature and time, and the GC-MS analytical conditions, were optimized. The ink samples were treated at 80℃ for 45 min, and the evolved products were separated on a special VOC column, identified by MS, and quantified by an external-standard method. The calibration curves for all 27 VOCs showed good linearity with correlation coefficients (R2) no lower than 0.9950. The limits of detection (S/N=3) were in the range of 0.001-0.310 mg/m2 and the limits of quantification (S/N=10) were in the range of 0.003-0.920 mg/m2. The average recoveries of the 27 VOCs ranged from 80% to 108% at various spiked levels, with relative standard deviations less than 6% (n=6). Thus, this method has a high sensitivity and good precision and accuracy, and it is suitable for the determination of 27 solvent residuals in various UV offset inks.