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Chinese Journal of Chromatography
2013, Vol. 31, No. 5
Online: 28 May 2013

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Determination of monosialogangliosides in sea cucumbers and sea urchins using liquid chromatography-tandem mass spectrometry CONG Peixu, LI Zhaojie, XU Jie, YU Jiajia, CHANG Yaoguang, XUE Changhu 2013, 31 (5):  399-403.  DOI: 10.3724/SP.J.1123.2012.12031 Abstract ( 1545 )   [Full Text(HTML)] () PDF (922KB) ( 246 )   An approach based on liquid chromatography-tandem mass spectrometry was developed for the quantification of monosialogangliosides (MG) in sea cucumbers and sea urchins. The gangliosides of sea cucumbers and sea urchins were extracted according to the Svennerholm method and cleaned up by C8 solid phase extraction column. The extracts were separated on an APS-2 NH2 column (150 mm×2.1 mm, 3 μm) with the mobile phases of acetonitrile and 50 mmol/L ammonium acetate (pH 5.6) under gradient elution. Multiple reaction monitoring(MRM) was performed for quantification of each analyte in the samples. The method was capable to distinguish gangliosides with different types of sialic acid in a single run. The limit of quantification was 0.22 ng for nonsulfated monosialoganglioside (NMG) and 0.29 ng for sulfated monosialoganglioside (SMG), and the linear range was 1-40 ng for both compounds. Only NMG was detected in sea cucumbers while both NMG and SMG were detected in sea urchins. Quantification results suggested that NMG was most abundant in Parastichopus californicus among all the sea cucumbers detected and SMG was most abundant in Anthocidaris crassispina among all the sea urchins. The contents of MGs in sea urchins (4.30-6.40 mg/g) were much higher than those in sea cucumbers (8-131 μg/g). The method is suitable for the quantification of monosialogangliosides in sea urchins and sea cucumbers.

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Determination of dicyandiamide, melamine and cyanuric acid in milk and milk powder by ultra performance liquid chromatography-tandem mass spectrometry YUN Huan, YAN Hua, ZHANG Zhaohui, LI Jianhui, LU Xiaoyu, LIU Xin 2013, 31 (5):  404-409.  DOI: 10.3724/SP.J.1123.2013.02009 Abstract ( 2320 )   [Full Text(HTML)] () PDF (822KB) ( 424 )   A method for the determination of dicyandiamide (DCD), melamine (MEL) and cyanuric acid (CY) in milk and milk powder has been developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After extracted by 5% (mass fraction) trichloroacetic acid, the samples were loaded onto an Acquity UPLC HSS T3 column (50 mm×2.1 mm, 1.8 μm) and separated using acetonitrile and ammonium acetate as mobile phases in a gradient elution mode. The electrospray was operated in the positive mode and negative mode, and monitored by the multiple reaction monitoring (MRM) mode. The calibration curves showed a good linearity in the range of 5.0-200.0 μg/L, and the correlation coefficients (r) were not less than 0.995. When the spiked levels were 0.02, 0.10 and 0.20 mg/kg, the recoveries of DCD, MEL and CY in milk ranged from 60.0%. to 105.8%, with the relative standard deviations (RSDs) of 4.2%-13.6%; while the spiked levels were 0.05, 0.10 and 0.20 mg/kg in milk powder, the recoveries ranged from 78.0% to 115.0% with the RSDs of 2.7%-7.5%. The limits of quantification (LOQs, S/N=10) were 0.02 mg/kg for milk samples and 0.05 mg/kg for milk powder samples. The results indicate that the method is simple, rapid, sensitive and suitable for the qualitative and quantitative analyses of DCD, MEL and CY in milk and dairy product samples.

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Determination of 11 ultraviolet absorbents in sun-screening cosmetics by liquid chromatography-tandem mass spectrometry LIN Weixuan, SUN Xingquan, MA Jie 2013, 31 (5):  410-415.  DOI: 10.3724/SP.J.1123.2012.11015 Abstract ( 1487 )   [Full Text(HTML)] () PDF (880KB) ( 278 )   A method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been established for the simultaneous determination of eleven ultraviolet absorbents in sun-screening cosmetics. The cosmetic sample was extracted by methanol-ethanol-water (80:10:10, v/v/v). The extract was separated by reversed-phase high performance liquid chromatography on an Eclipse XDB-C18 chromatographic column (150 mm×4.6 mm, 5 μm) with a gradient elution of acetonitrile and water containing 0.1% formic acid. The analyte was detected by MS/MS with the multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention time and the relative abundance ratio of the characteristic ions, and quantitative analysis on calibration curve method. The research results showed that the limits of quantification (LOQ, S/N=10) of the eleven ultraviolet absorbents ranged from 200 to 500 mg/kg and the average recoveries ranged from 77.17% to 98.32% with the relative standard deviations from 2.40% to 11.11%. The method is suitable to detect the eleven ultraviolet absorbents in cream and milky sun-screening cosmetics.

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Simultaneous determination of eight furocoumarines in cosmetics by high performance liquid chromatography and verification by liquid chromatography-tandem mass spectrometry MA Huijuan, MA Qiang, LI Wentao, MENG Xianshuang, LI Jingrui, BAI Hua, JIAO Yang, ZHANG Xiaoli 2013, 31 (5):  416-422.  DOI: 10.3724/SP.J.1123.2012.12006 Abstract ( 1994 )   [Full Text(HTML)] () PDF (872KB) ( 330 )   A method using high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of eight furocoumarines (8-hydroxypsoralen, psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin) in cosmetics. The cosmetic samples, including cream, lotion, shampoo, powder and lipstick, were supersonically extracted with appropriate solvents. The extract was centrifuged, and the supernatant was filtered through a membrane, and then separated on an Agilent Zorbax SB-Phenyl chromatographic column (250 mm×4.6 mm, 5 μm) by gradient elution at a flow rate of 1.0 mL/min with methanol-acetonitrile-water as mobile phases. The column temperature was set at 30 ℃. The wavelength of detection was 250 nm. The limits of quantification (LOQs) were 0.25 mg/kg for 8-hydroxypsoralen and 0.5 mg/kg for psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin. The recoveries at three spiked levels were in the range of 85.0%-105.8% with the relative standard deviations (RSDs) of 0.41%-7.90%. The intra-day precision (n=6) was less than 1%, and the inter-day precision (n=6) was less than 2% for the peak areas of the eight furocoumarines in a mixed standard solution. The method is accurate, simple, rapid and suitable for the determination of the eight furocoumarines in various cosmetic samples.

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A novel immobilized trypsin on hydrophilic polymer modified silica beads for proteome characterization FAN Chao, SONG Zifeng, QIN Weijie, CAI Yun, QIAN Xiaohong 2013, 31 (5):  423-428.  DOI: 10.3724/SP.J.1123.2013.01007 Abstract ( 1604 )   [Full Text(HTML)] () PDF (512KB) ( 172 )   A new type of immobilized trypsin was prepared using hydrophilic polymer modified silica microparticles (HPMSM) synthesized by atom transfer radical polymerization (ATRP) as the substrate material. ATRP modification led to densely packed hydrophilic polymer chains grafted on the microparticles surface which resulted in largely increased trypsin loading amount and minimized the nonspecific adsorption of proteins and peptides. Therefore, ultra-fast and highly efficient protein digestion was achieved with minimized sample loss. For standard protein bovine serum albumin (BSA), 1 min digestion led to the identification of 93 peptides, which covered 91% amino acid sequence of the protein. This immobilized trypsin was further successfully applied to the digestion of complex protein samples from yeast and 666 proteins were identified after 3 min digestion, which exceeded the number of identified proteins after 12 h solution digestion.

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Separation and identification of β-casein from Chinese human milk by ion exchange chromatography-matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry HUANG Yu, REN Haowei, LIU Biao, LIU Ning, LI Meng, WANG Dongmao 2013, 31 (5):  429-434.  DOI: 10.3724/SP.J.1123.2013.01010 Abstract ( 1727 )   [Full Text(HTML)] () PDF (413KB) ( 200 )   The selective precipitation of whole casein from skimmed milk was achieved by the addition of calcium salt under acidic pH. The effects of pH, centrifugal force and final concentration of CaCl2 on the separation of casein were studied by measuring the purity of final products using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that casein with the highest purity could be obtained with the pH of 4.3, the centrifugal force of 10 400 g and the final concentration of CaCl2 of 60 mmol/L. The casein was processed with DEAE anion exchange chromatography and three peaks were obtained. Then the third peak (peak Ⅲ) was identified with Western-Blot method and matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). The identification of Western-Blot showed that peak Ⅲ can combine with the specificity of human milk β-casein antibody, and it is proved to be human milk β-casein. The fingerprints of peak Ⅲ were analyzed by Mascot searching, and the sequence coverage was 50%, further supporting it is human milk β-casein. In conclusion, an effective method to obtain human milk β-casein from milk samples through DEAE anion exchange chromatography was established, and it is suitable for the proteomics research requirements of the β-casein from human milk.

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Determination of four polycyclic aromatic hydrocarbons in anthracene oil for toys by high performance liquid chromatography with diode array detection and fluorescence detection HE Qiaosang, LU Yan, LIAO Shangfu, LI Xiudi 2013, 31 (5):  435-440.  DOI: 10.3724/SP.J.1123.2012.12047 Abstract ( 1614 )   [Full Text(HTML)] () PDF (925KB) ( 158 )   A method using high performance liquid chromatography with diode array detection coupled with fluorescence detection was applied to determine four polycyclic aromatic hydrocarbons in anthracene oil for toys. This method showed good abilities of the baseline separation and high sensitivity under the optimized analytical conditions. The limits of the fluorescence detection were 0.5-1000 μg/L, while the limits of the diode array detection were 0.5-1000 mg/L. The precisions of the method were 0.7%-8.8%. The recoveries of the standard samples were 70.0%-120%. The limits of detection (LOD) of anthracene, pyrene, phenanthrene and fluoranthene were 0.1, 0.1, 0.2 and 0.3 μg/L, and the limits of quantitation (LOQ) of the four substances were 0.4, 0.2, 0.5 and 0.8 μg/L, respectively. In comparison with other methods, the method has higher detection speed and lower detection limits, which is useful to analyze rapidly those four polycyclic aromatic hydrocarbons in anthracene oil for toys.

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Simultaneous determination of three β-lactamase inhibitor residues in dairy products by high performance liquid chromatography LIN Qin 2013, 31 (5):  441-446.  DOI: 10.3724/SP.J.1123.2012.12049 Abstract ( 1616 )   [Full Text(HTML)] () PDF (415KB) ( 152 )   An improved method has been developed for the determination of clavulanate potassium, tazobactam and sulbactam in dairy products. High performance liquid chromatography with photodiode array detector (HPLC-PAD) was used in this method. The separation was performed on a CAPCELL PAK MG-C18 column (150 mm×4.6 mm, 5 μm). The mobile phase was 0.03% (volume fraction unless otherwise specified) phosphate-acetonitrile. This method offered effective sample preparation procedures including dissolution with water, protein isolation with acetone, clean-up and enrichment by solid-phase extraction (SPE) with PWAX cartridges (60 mg/3 mL) under weak acidic condition and further elution with 0.05% ammonia-methanol solution. The analytical method was well validated and good results were obtained with the RSDs of 2.2%-7.4% and the recoveries of 84.6%-101.7%. The detection limits of clavulanate potassium, tazobactam and sulbactam were 0.03 mg/L. All of the target compounds exhibited good linearities (r>0.999) over the mass concentration range of 0.05-5 mg/L. With the advantages of good purification effect, high sensitivity, good recovery and repeatability, the method is suitable for the detection of β-lactamase inhibitors in dairy products.

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Separation of racemic flavonoids by high performance liquid chromatography using chiral mobile phase additive SUN Yanan, LI Tong, MA Chen 2013, 31 (5):  447-450.  DOI: 10.3724/SP.J.1123.2012.12054 Abstract ( 1722 )   [Full Text(HTML)] () PDF (784KB) ( 276 )   To perform chiral separation of three flavonoid racemates, including dihydrodaidzein, equol and alpinetin, a simple and effective method was developed by using sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as a mobile phase additive in HPLC system. The effects of different factors on the chiral separation were investigated, including cyclodextrin (CD) types (α-CD, γ-CD, β-CD, methyl β-CD), CD concentration (5, 10, 20 mmol/L), pH value, nature of organic solvents (methanol, ethanol, acetonitrile) and phosphate buffer concentration. The analysis was carried out on a Kromasil 100-5C18 column (250 mm×4.6 mm, 5 μm). The mobile phase consisted of acetonitrile and 10 mmol/L SBE-β-CD aqueous solution(containing 20 mmol/L KH2PO4, at pH 4.0 adjusted with phosphoric acid)(20:80, v/v). The flow rate was set at 1 mL/min, the column temperature was 25 ℃, and the UV detections of dihydrodaidzein, equol and alpinetin were carried out at 276, 280 and 290 nm, respectively. The established method was able to separate the three racemates, and the resolutions of the enantiomers (dihydrodaidzein, equol and alpinetin) were 1.8, 1.9 and 1.4, respectively. This method might be applied to separate various types of flavanoid enantiomers in chemical structure.

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Online enrichment ability of restricted-access column coupled with high performance liquid chromatography by column switching technique for benazepril hydrochloride ZHANG Xiaohui, WANG Rong, XIE Hua, YIN Qiang, LI Xiaoyun, JIA Zhengping, WU Xiaoyu, ZHANG Juanhong, LI Wenbin 2013, 31 (5):  451-455.  DOI: 10.3724/SP.J.1123.2012.11021 Abstract ( 1419 )   [Full Text(HTML)] () PDF (393KB) ( 149 )   The online enrichment ability of the restricted-access media (RAM) column coupled with high performance liquid chromatography by column switching technique for benazepril hydrochloride in plasma was studied. The RAM-HPLC system consisted of an RAM column as enrichment column and a C18 column as analytical column coupled via the column switching technique. The effects of the injection volume on the peak area and the systematic pressure were studied. When the injection volume was less than 100 μL, the peak area increased with the increase of the injection volume. However, when the injection volume was more than 80 μL, the pressure of whole system increased obviously. In order to protect the whole system, 80 μL was chosen as the maximum injection volume. The peak areas of ordinary injection and the large volume injection showed a good linear relationship. The enrichment ability of RAM-HPLC system was satisfactory. The system was successfully used for the separation and detection of the trace benazepril hydrochloride in rat plasma after its administration. The sensitivity of HPLC can be improved by RAM pre-enrichment. It is a simple and economic measurement method.

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Evaluation of Renshen Guipi Wan quality by linearly quantified fingerprint method based on three-wavelength high performance liquid chromatographic fingerprints SUN Guoxiang, DOU Xiaowen, YANG Lanping, LIU Zhongbo 2013, 31 (5):  456-461.  DOI: 10.3724/SP.J.1123.2012.12004 Abstract ( 1968 )   [Full Text(HTML)] () PDF (487KB) ( 234 )   The theoretical model of linearly quantified fingerprint method (LQFM) for qualitative and quantitative control traditional Chinese medicine (TCM) has been developed based on the relationship of linear function between a sample and the reference fingerprint vector, as the concepts of correlation coefficient r, slope a, intercept b, linearly qualitative similarity SL, linearly quantitative similarity ML and so on were introduced into the study. The high performance liquid chromatography coupled with diode array detector (DAD) was used to simultaneously obtain chromatograms of ten batches of Renshen Guipi Wan (RSGPW) at 203, 228 and 326 nm, separately. The model of LQFM was applied to evaluate the three-wavelength fingerprints for the quality control of RSGPW, it could obviously distinguish RSGPW from different resources and the results showed the quality was almost consistent from the same manufacture. The results of LQFM were compared with those of the systematically quantified fingerprint method (SQFM), a known method for quality control of TCM. It proved that LQFM can evaluate qualitatively and quantitatively the complex system of TCM which is composed of diverse chemical components. The quality control can be better and more reliable by multiple-wavelength fingerprints which give full consideration of the ultraviolet absorption characteristics of different components.

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Analysis of the reaction solution for dehydroacetic acid preparation by ethyl acetoacetate using high performance liquid chromatography CHEN Qiuyun, DUAN Zhengkang, LI Haitao, YAN Zhixiang, PENG Ye, ZENG Hangri 2013, 31 (5):  462-466.  DOI: 10.3724/SP.J.1123.2012.12003 Abstract ( 2333 )   [Full Text(HTML)] () PDF (803KB) ( 381 )   A way of ethyl acetoacetate by the Claisen condensation reaction is one of the main methods of the industrial production of dehydroacetic acid. There are the problems of the differences in absorbance value and the maximum absorption wavelength, and the chromatographic peak is prone to the phenomena such as bifurcation and tailing when using liquid chromatography to the analysis of ethyl acetoacetate. To avoid the interference of the enol of ethyl acetoacetate, and making the peak shape of ethyl acetoacetate better and quantitatively more accurate, we converted the enol to ketone through optimizing the chromatographic conditions. As a result, qualitative and quantitative analyses of ethyl acetoacetate were replaced by those of the ethyl acetoacetate ketone. A method was developed for the simultaneous determination of dehydroacetic acid and ethyl acetoacetate by HPLC in the reaction mixture for producing dehydroacetic acid. An Agilent HC-C18 column (250 mm×4.6 mm, 5 μm) was used for the separation. The ultraviolet wavelength was 290 nm and the column temperature was 35 ℃, and methanol-0.3% ammonium acetate buffer (5:95, v/v) with pH 6.0 adjusted by acetic acid as mobile phase, and the flow rate was 0.6 mL/min. The correlation coefficients of dehydroacetic acid and ethyl acetoacetate were 0.99995and 0.99992, and the spiked recoveries were 98.5% and 101.3%, respectively; and the relative standard deviations were less than 1.0%. This method has the advantages of good accuracy and high sensitivity, and it can analyse both qualitatively and quantitatively dehydroacetic acid and ethyl acetoacetate rapidly and simply. And it can provide the reference for producing dehydroacetic acid by the way of ethyl acetoacetate.

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Analysis of part of flavor compounds in wheat by headspace sorptive extraction-gas chromatography WANG Tongbo, YAN Xiao, LAN Xiaozheng 2013, 31 (5):  467-472.  DOI: 10.3724/SP.J.1123.2012.12041 Abstract ( 1397 )   [Full Text(HTML)] () PDF (430KB) ( 183 )   A method has been established for the analysis of flavor compounds in wheat by headspace sorptive extraction (HSSE). The sorptive extraction bar was composed of a silicon rubber coating and a capillary glass with an inner iron rod. The silicon rubber coating was condensed inside a stainless steel mold from the silicon precursors with a sol-hot air vulcanization method. The coating of the extraction bar has a volume of about 87 μL and is thermally stable until 390 ℃. The flavor compounds extracted by the bar were desorbed in a homemade thermal desorption unit (TDU) and introduced directly into a pre-column in a gas chromatograph for analysis. Experimental parameters for the extraction efficiency were optimized including extraction temperature and time, phase ratio and thermal desorption conditions. The standard wheat flour samples spiked with seven flavor compounds were analyzed under the optimized conditions, and showed good linear relationships (r>0.9979), limits of detection (LOD) of 0.09-1.00 μg/kg, good recoveries (95%-121%) and repeatabilities (relative standard deviations, RSD, 2.2%-7.8%). By external calibration method, the absolute contents of the seven flavor compounds in a real wheat sample were determined. The method is rapid, simple with low limits of detection, and is applicable for the rapid quantitative analysis of the flavor compounds in wheat.

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Rapid simultaneous screening and detection of ten anticoagulant rodenticides in foods by ultra-high performance liquid chromatography-tandem mass spectrometry ZHU Feng, LIU Hualiang, CHEN Bei, RONG Weiguang, MA Yongjian 2013, 31 (5):  473-476.  DOI: 10.3724/SP.J.1123.2012.11026 Abstract ( 1579 )   [Full Text(HTML)] () PDF (789KB) ( 280 )   A rapid method for the simultaneous screening and detection of ten anticoagulant rodenticides in foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After the extraction by acetonitrile and clean-up by QuEChERS, the extract was separated on a Poroshell 120 EC-C18 column (100 mm×2.1 mm, 2.7 μm) with the gradient elution of 5 mmol/L ammonium acetate and acetonitrile. The detection was carried out by UPLC-MS/MS using a negative electrospray ionization interface in multiple reaction monitoring (MRM) mode. The ten anticoagulant rodenticides showed a good linear relationship (r>0.99) in the range of 5-500 μg/L. In the four samples of chili sauce, flour, vinegar and soy sauce, the spiked recoveries were in the range of 72.6%-112%, and the relative standard deviations (RSD) were all not more than 11.2%. The limits of detection (LOD) were all in the range of 0.5-4.5 μg/kg. This method is rapid, simple, sensitive, accurate and of good specificity for the satisfactory rapid screening and detection of the ten anticoagulant rodenticides in the sudden public health security events.

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Simultaneous determination of melamine and creatinine in milk and milk products by gas chromatography-mass spectrometry ZENG Kai, LIU Zhirong, NING Yajun, LI Jinlin, TANG Jun, ZHANG Min 2013, 31 (5):  477-480.  DOI: 10.3724/SP.J.1123.2012.11008 Abstract ( 1750 )   [Full Text(HTML)] () PDF (774KB) ( 190 )   A method established for determining melamine and creatinine in milk and milk products. The samples were extracted with 1% trichloracetic acid solution. The extract was cleaned-up by using a mixed-mode cation ion exchange SPE column and evaporated to dryness under nitrogen. The residue was derived by bis(trimethylsilyl)trifluoroacetamide-chlorotrimethylsilane (BSTFA-TMCS), then determined by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Melamine and creatinine had good linearity in the range of 0.1-50 mg/L with the correlation coefficients higher than 0.99, and the limits of quantification were 0.10 mg/kg and 0.20 mg/kg, respectively. The recoveries of melamine and creatinine were 80.7%-116.8% and 77.6%-107.5% with RSD no more than 9.4% and 8.5% in the spiked range of 10-100 mg/kg and 0.1-5.0 mg/kg, respectively. The method is accurate, sensitive, and suitable for the determination of creatinine in milk and milk products.

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Determination of dioxane residue in cosmetics by isotope dilution-headspace gas chromatography-mass spectrometry LI Jingrui, MA Qiang, LI Wentao, WANG Chao, BAI Hua, MA Huijuan, CAI Tianpei, JIAO Yang, ZHANG Xiaoli 2013, 31 (5):  481-484.  DOI: 10.3724/SP.J.1123.2013.01012 Abstract ( 1694 )   [Full Text(HTML)] () PDF (773KB) ( 256 )   A comprehensive analytical method based on isotope dilution-headspace gas chromatography-mass spectrometry was developed for the determination of dioxane residue in the cosmetics. Cosmetic sample (2 g) was placed in a headspace vial. Then, 1 g sodium chloride, 1 mL d8-dioxane solution (20 mg/L) and 9 mL water were added. The vial was sealed and heated at 70 ℃ for 40 min. The qualitative and quantitative analyses were carried out for the analyte in selected ion monitoring (SIM) mode after the chromatographic separation on an HP-5MS column (30 m×0.25 mm×0.25 μm). The limit of quantification (LOQ) for dioxane was 2.5 mg/kg. The mean recoveries were 90.5%-104.0% at the spiked levels of 2.5-50 mg/kg with the relative standard deviations in the range of 1.26%-3.98%. The method is accurate, simple, rapid, and applicable for the inspection of dioxane residue in cosmetics.

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Determination of musk ketone in aquatic products by gas chromatography-mass spectrometry with dispersive solid phase extraction DING Liping, GUO Jing, CHEN Zhitao, ZHAO Jianhui, ZHENG Ling, CAI Wei 2013, 31 (5):  485-489.  DOI: 10.3724/SP.J.1123.2012.11017 Abstract ( 1507 )   [Full Text(HTML)] () PDF (818KB) ( 329 )   A dispersive solid phase extraction coupled with gas chromatography-mass spectrometry (GC-MS) method was established for the determination of trace amounts of musk ketone in aquatic products. The target analyte in the samples was extracted with acetonitrile containing 1% acetic acid, cleaned-up with the mixture of N-propyl-ethylenediamine (PSA), C18 and graphitized carbon (GCB), and analyzed by GC-MS under selected ion monitoring (SIM) mode and quantified by the external standard method. The orthogonal experiment was carried out to optimize the pre-treatment conditions. Under the optimal conditions, good linear relationship was obtained in the range of 1-50 μg/L for musk ketone with correlation coefficient not less than 0.999, and the limits of detection (S/N=3) was 0.30 μg/kg. The recoveries of musk ketone in the prawn and tilapia blank samples at three spiked levels of 1.0, 2.0 and 10.0 μg/kg ranged from 91.8% to 110.6% with RSDs in the range of 2.6%-8.4%. The method is simple, rapid and accurate, and can be used for the routine analysis of musk ketone in aquatic products.

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Simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction and high performance liquid chromatography ZHAO Fei, GAO Guanghui, NA Haiqiu, MA Dianjun, WANG Xiaoli 2013, 31 (5):  490-493.  DOI: 10.3724/SP.J.1123.2012.12012 Abstract ( 1533 )   [Full Text(HTML)] () PDF (779KB) ( 214 )   A method for the simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction (SPE) and high performance liquid chromatography with variable wavelengths was established. After degreased with petroleum ether, extracted, purified with SPE, and concentrated, the sample was separated on a C18 column with a gradient elution of 0.02 mol/L ammonium acetate and methanol, and detected at 230, 510, 484 and 510 nm, separately. The saccharin sodium and synthetic colours were separated with this method. The recoveries were 88.6%-97.1% with the RSD<5%. The limit of detection was 0.05 mg/kg for all the analytes. The proposed method is simple, reliable and reproducible, and especially suitable for a lot of sample detections of saccharin sodium and synthetic colours in flavourings.