Comparison of two Analytical Methods (ELISA and LC-MS/MS) for Determination of Aflatoxin B1 in Corn and Aflatoxin M1 in Milk

The aim of this paper is to assess the closeness of agreement between results of ELISA and LC-MS/MS methods for determination of aflatoxin B₁ in corn and aflatoxin M₁ in milk. Samples of corn (n=100) and milk (n=250) were simultaneously analyzed using ELISA and LC-MS/MS methods, after the severe drought that affected Serbia in summer 2012 resulting in occurrence of aflatoxin B1 in corn and aflatoxin M₁ in milk. Regression analysis showed higher level of agreement between aflatoxin B₁ samples (R²=0.994), compared to aflatoxin M₁ samples (R²=0.920). However, both techniques were satisfactory in meeting the requirements for official control purposes.     

Rapid and Sensitive Liquid Chromatography-Tandem Mass Spectrometry for Quantification of Glycyrrhetic Acid in Human Plasma

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) for the determination of glycyrrhetic acid in human plasma with ginsenoside Rh2 as internal standard was developed and validated. The plasma samples were prepared via liquid-liquid extraction with ethyl acetate. Chromatographic separation was accomplished on a Venusil MP-C18(50 mm×2.1 mm, 5μm i.d.) column at 25℃. The mobile phase consisted of acetonitrile/5 mmol·L-1 ammonium acetate(10:90, volume ratio) at a flow rate of 0.4 mL/min. Negative electrospray ionization was utilized as the ionization source. Glycyrrhetic acid and internal standard were determined via the mutiple reaction monitoring of precursor→production ion transitions at m/z 469→425, 409 and m/z 621→161,respectively. Each sample was chromatographed within 2.5 min. The lower limit of uantification was 0.50 ng/mL for 200 μL of plasma sample and the linear range was from 0.50 ng/mL to 800 ng/mL. The intra-and inter-day precisions were less than 8.76% in terms of relative standard deviation(RSD), and the accuracy was within a range of -3.25%-1.32% in terms of relative error(RE). The method was successfully applied to the pharmacokinetic studies of glycyrrhetic acid in healthy male Chinese volunteers after a single oral administration of 75 mg of glycyrrhizin.     

药物免修饰的药靶鉴定蛋白质组方法研究进展

药物靶蛋白的筛选是现代药物研发过程必不可少的步骤.传统的药物靶点筛选通常使用假设驱动的生物学实验进行药物靶点的逐个验证,近年来高通量、高分辨质谱技术的进步以及液相色谱-质谱联用技术的发展,促进了蛋白质组学技术在药物靶蛋白筛选领域的广泛应用.化学蛋白质组学技术在药物-蛋白相互作用研究领域已取得巨大突破,因其需要在药物小分...     

Analytical method for fast screening and confirmation of multi-class veterinary drug residues in fish and shrimp by LC-MS/MS

A multi-class, multi-residue analytical method based on LC-MS/MS detection was developed for the screening and confirmation of 28 veterinary drug and metabolite residues in flatfish, shrimp and eel. The chosen veterinary drugs are prohibited or unauthorised compounds in Korea, which were categorised into various chemical classes including nitroimidazoles, benzimidazoles, sulfones, quinolones, macrolides, phenothiazines, pyrethroids and others. To achieve fast and simultaneous extraction of various analytes, a simple and generic liquid extraction procedure using EDTA-ammonium acetate buffer and acetonitrile, without further clean-up steps, was applied to sample preparation. The final extracts were analysed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The method was validated for each compound in each matrix at three different concentrations (5, 10 and 20 ng g^–1) in accordance with Codex guidelines (CAC/GL 71-2009). For most compounds, the recoveries were in the range of 60–110%, and precision, expressed as the relative standard deviation (RSD), was in the range of 5–15%. The detection capabilities (CCβs) were below or equal to 5 ng g^–1, which indicates that the developed method is sufficient to detect illegal fishery products containing the target compounds above the residue limit (10 ng g^–1) of the new regulatory system (Positive List System – PLS).     

Identification of Human UDP-Glucuronosyltransferase 1A4 as the Major Isozyme Responsible for the Glucuronidation of 20(S)-Protopanaxadiol in Human Liver Microsomes

20(S)-protopanaxadiol (PPD), one of the representative aglycones of ginsenosides, has a broad spectrum of pharmacological activities. Although phase I metabolism has been investigated extensively, information regarding phase II metabolism of this compound remains to be elucidated. Here, a glucuronidated metabolite of PPD in human liver microsomes (HLMs) and rat liver microsomes (RLMs) was unambiguously identified as PPD-3-O-β-d-glucuronide by nuclear magnetic resonance spectroscopy and high resolution mass spectrometry. The chemical inhibition and recombinant human UDP-Glucuronosyltransferase (UGT) isoforms assay showed that the PPD glucuronidation was mainly catalyzed by UGT1A4 in HLM, whereas UGT1A3 showed weak catalytic activity. In conclusion, PPD-3-O-β-d-glucuronide was first identified as the principal glucuronidation metabolite of PPD in HLMs, which was catalyzed by UGT1A4.     

基于非靶向代谢组技术研究不同发酵温度酱油中代谢产物差异

目的 基于非靶向代谢组学研究不同发酵温度(25、30、35、40℃)酱油中代谢产物差异。方法 采用超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)检测不同发酵温度的酱油样品的代谢物,通过主成分分析(principal component analysis,PCA)、正交偏最小二乘判别分析法(orthogonal partial least square-discriminant analysis,OPLS-DA)等统计学分析,筛选不同温度发酵酱油的差异代谢物。结果 4种不同发酵温度酱油样品共鉴定出14类266个代谢物。其中,25℃下发酵酱油中氨基酸和有机酸类化合物的含量最高,而35℃发酵酱油的中氨基酸、脂肪酸类和生物碱化合物的相对含量最高。通过OPLS-DA分析研究,鉴定出了37种显著差异代谢物质(变量投影重要性>1),包括有氨基酸9种,糖类和有机酸各5种,生物碱和脂肪酸各4种,芳香类化合物3种,香豆素类、胺类和酚类各2种,黄酮类1种。结论 该研究明...     

液相色谱串联质谱法测定食品中红曲色素

采用液相色谱串联质谱法测定了食品中红曲红胺、红曲红素、红曲素、红曲黄素的含量,并选择离子检测进行阳性确证。液体试样用水超声提取,离心定容后,固体和半固体样品采用水溶解定容,提取液再经固相萃取柱净化,样液经洗脱定容后,供液相色谱-质谱/质谱仪测定和确证,外标法定量。该方法的最低检出限、线性范围和方法回收率分别为:1.0 mg/kg、1.0～100.0 mg/kg和89.3%～94.3%。     

Acrylamide in daily food in the metropolitan area of Hanoi,Vietnam

ABSTRACT

Acrylamide, a colourless and odourless crystalline solid, formed via the Maillard reaction in food, has been reported with harmful properties for humans, such as toxicity and carcinogenicity. Three hundred and four processed food samples from 17 product types, collected in Hanoi, Vietnam, were analyzed by LC-MS/MS to measure the acrylamide concentration. The limit of detection (LOD) and the limit of quantification (LOQ) of acrylamide were 1 µg Kg^?1 and 3 µg Kg^?1, respectively. Effectively, the highest acrylamide content is usually found in processed food, which is one of the primary reasons of increased acrylamide content in food. All French fried samples contained acrylamide above 500 µg kg^?1. Acrylamide concentration in non-fried noodle, vermicelli, rice noodle, ph?, dried vegetable, and rice cracker is lower than in potato chips, fried potatoes, fried cake, and fried noodles. The results could be helpful to estimate exposure and risk assessment of acrylamide in Vietnam.     

液质联用快速鉴定减肥类保健食品中4种违禁添加药物

目的建立快速鉴定减肥类保健食品中咖啡因、盐酸麻黄碱、盐酸芬氟拉明和盐酸西布曲明的液质联用方法。方法使用Agilent 1100液相色谱和离子阱质谱联用,ESI源,C18柱梯度洗脱。结果使用本方法对12种市售减肥保健食品中的4种违禁添加药物进行了快速筛查鉴定,其中2种检出西布曲明。结论方法简便快速,专属性好。     

车前子总黄酮的纯化及其成分的液相质谱联用分析

采用DPPH自由基清除法和邻苯三酚自氧化抑制法对车前子黄酮初提液的不同溶剂萃取液的体外抗氧化能力进行了比较,发现正丁醇萃取液具有与初提液相近的抗氧化能力,说明用正丁醇能萃取出大部分有效成分.并比较了AB-8、D101、NKA-2、NKA-9四种大孔吸附树脂对车前子黄酮的吸附及解吸性能,以选择合适的车前子黄酮纯化工艺.将纯化液进行液质联用分析其组成.结果表明,AB-8型树脂吸附和解吸率最高,适合萃取后的车前子黄酮的纯化,纯化后黄酮含量可从4%提高到30%以上.采用液质联用技术分析纯化液,确定其主要成分为苯乙醇苷类毛蕊花苷、异毛蕊花苷、大车前苷和黄酮类物质野漆树苷.