流动注射-氢化物发生-原子荧光光谱法测定牛奶中的铅

建立了流动注射-氢化物发生-原子荧光光谱法测定奶制品中铅含量的分析方法,对仪器条件和反应条件进行了选择、优化。方法的检出限为0.30μg/L,相对标准偏差小于4.7%,回收率为90.0%—114.5%,符合食品中痕量元素的分析要求。     

原子吸收法测定食品中微量硒

原子吸收法测定微量硒被认为是最困难的技术之一，主要因为硒是一种易挥发素。本文在前人工作基础上，以Ｐｄ＋Ｍｇ混合金属为石墨炉原子吸收法测定硒的基体改进剂，提高了灰化和原子化温度，降低了基体干扰，提高了检测灵敏度；同时还对多种金属基体改进剂和复合金属基体改进剂在石墨炉测硒时的行为进行了全面考察，并详细讨论了铁对微量硒石墨炉测定的干扰情况。     

Automatic screening method for the rapid and simple discrimination between synthetic and natural colorants in foods

A simple screening method was developed to discriminate between synthetic and natural colorants present in foods in order to reduce the use of expensive instruments such as a liquid chromatograph with diode array detection. A rapid flow system was proposed in which samples containing natural and synthetic colorants in an acetic acid medium were passed through a wool/cotton column, where only synthetic colorants were retained and were then eluted with dilute ammonia. Yellow, red and green-blue-brown additives can be monitored at 400, 530 and 610 nm, respectively, with a conventional spectrophotometer. Complete discrimination (no false positives) between natural and synthetic colorants can be obtained for molar concentrations of natural colorants (in the absence of synthetic ones) up to 2000 (yellow), 2000 (red) and 10 000 (brown) times that of the detection limit (DL) of synthetic additives. The reliability of the method was established at five concentrations (between 0.5 and 3 DL) of the synthetic colorants tartrazine (yellow), erythrosin B (red) and brilliant black BN (brown). For a cut-off concentration of 2 DL, the percentage of false negatives ranges from 8 to 12%. Finally, the method was applied to screening several fruit drinks and candies for the determination of synthetic colorants with a sampling frequency of 10 h⁻¹.     

Differential-pulse polarography of amino acids in acetaldehyde-borax medium

A differential-pulse polarographic method for the determination of amino acids is reported, based on the formation of Schiff's base compounds in borax buffer solution (pH 10.10) containing acetaldehyde. The compounds are reduced at a mercury electrode with peak potentials of about ?1.5 V (vs. SCE) and well defined polarographic waves are obtained which can be used to determine amino acids in borax medium. The differential-pulse polarographic method was found to be the most sensitive and suitable for the determination of amino acids in the concentration range 1 × 10^?6–8 × 10^?4 M (lysine) and 2.8 × 10^?6–1 × 10^?3 M (arginine). The polarographic characteristics of these waves were studied by differential-pulse polarographic and cyclic voltammetric methods. The waves are ascribed to the reduction of the imido group in the Schiff's base compounds. The procedure was applied to the determination of lysine and arginine in foodstuffs and the total proteins in serum samples.     

食品中甜蜜素的紫外分光光度法测定

采用紫外分光光度法测定食品中的甜蜜素。该法在０．２～１．０ｇ／Ｌ甜蜜素范围内符合比尔定律,回收率为９５．０％～１０２．７％,相对标准偏差（ＲＳＤ）为２．６６％～５．４０％,食品中共存的苯甲酸、山梨酸、糖精钠在０～１０．０ｇ／Ｌ范围内,色 ０～２．０ｇ／Ｌ范围内不影响测定。方法简捷,准确。     

Simultaneous determination of six major ergot alkaloids and their epimers in cereals and foodstuffs by LC–MS–MS

This paper describes a new and rapid method for accurate quantification of the six ergot alkaloids, ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, and ergocornine, by liquid chromatography–tandem mass spectrometry (LC–MS–MS). The six ergot alkaloids studied have been defined by the European Food Safety Authority (EFSA) as among the most common and physiologically active ones. In addition, the method enables the quantification of the corresponding six epimers (ergo-inines) of these ergot alkaloids. This is of considerable importance in terms of the differences in toxicity of the isomeric forms. The method involves extraction under alkaline conditions using a mixture of acetonitrile and ammonium carbonate buffer followed by a rapid clean-up using dispersive solid-phase extraction with PSA (primary secondary amine) and a short chromatographic LC-run (21 min) with subsequent MS–MS detection. The method was developed and validated using ten different cereal and food samples. The major strength of the new method compared with previously published techniques is the simplicity of the clean-up procedure and the short analysis time. The limits of quantification were 0.17 to 2.78 μg kg⁻¹ depending on the analyte and matrix. Recovery values for the 12 ergot alkaloids spiked into ten different matrices at levels of 5, 50, and 100 μg kg⁻¹ were between 69 and 105% for 85 of 90 recovery measurements made over six days. Measurement uncertainty values were highly satisfactory. At a concentration level of 5 μg kg⁻¹ the expanded measurement uncertainty ranged from ±0.56 to ±1.49 μg kg⁻¹, at a concentration level of 100 μg kg⁻¹ the expanded measurement uncertainty ranged from ±8.9 to ±20 μg kg⁻¹. Both LOQs and measurement uncertainties were dependent on the analyte but almost independent of the matrix. The method performance was satisfactory when tested in a mini-intercomparison study between three laboratories from three different countries. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Food allergen detection methods and the challenge to protect food-allergic consumers

The detection of allergenic ingredients in food products has received increased attention from the food industry and legislative and regulatory agencies over recent years. This has resulted in the improvement of measures aimed at the protection of food-allergic consumers. The controlled production of food products and control activities executed by food inspection agencies rely on the availability of methods capable of detecting traces of allergenic ingredients. The development of such methods faces a multitude of analytical challenges. Those challenges will be identified and discussed in this review. Furthermore, future developments and trends in analytical methodology as applied to the detection of food allergens are reported.     

气相色谱-质谱法测定食品中邻苯二甲酸酯

提出了气相色谱-质谱法测定食品中16种邻苯二甲酸酯(PAE′s)含量的方法。详细叙述了不同基质的食品的处理方法,高脂类样品需经凝胶渗透色谱净化。采用HP-5MS石英毛细管柱进行分离和电子轰击离子源质谱检测。16种PAE′s的线性范围为0.50～20.0mg·L-1,检出限(3S/N)在6.03～826μg·kg-1之间。在1,10mg·kg-1两个浓度水平进行加标回收试验,纯油脂和高脂固体样品中16种PAE′s的平均回收率分别在79.2%～101%和77.8%～97.4%之间,测定值的相对标准偏差(n=6)分别在3.4%～6.9%和4.1%～6.0%之间。     

Determination of Melamine and Derivatives in Foods by Liquid Chromatography Coupled to Atmospheric Pressure Chemical Ionization Mass Spectrometry and Diode Array Detection

Two liquid chromatographic methods based on atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) and diode array detection (DAD) are evaluated for the rapid determination of melamine (MEL) and structurally related compounds, including ammeline (AMN), ammelide (AMD), and cyanuric acid (CA) in foods. Both procedures used ion-exchange LC and isocratic elution. Samples were extracted by homogenization with acetonitrile/water/diethylamine. Specificity was demonstrated for LC-MS by the retention characteristics and MS spectra, by comparing with commercial standards. Specificity was only demonstrated in the case of LC-DAD for MEL and AMN, considering the retention characteristics and UV spectra. The recoveries obtained for spiked samples were satisfactory for all the analytes with LC-MS. The proposed procedure, LC-APCI-MS, was successfully applied to the analysis of different baby foods, including infant formula and breakfast cereal, and samples of rice flour, potato starch, soya drink, and coconut drink.     

开放式微波消化-ICP-MS法快速测定食品中多种微量元素

开放式微波消解系统消化食品样品 ,以 45Sc、89Y、1 1 5In、2 0 9Bi作内标元素抑制分析信号的动态漂移 ,加入 1 %异丙醇消除 C元素对 As、Se等元素的干扰 ,建立食品中多种元素同时测定的ICP- MS方法。对 4类食品 (奶粉、鹅肝酱、水果片、燕麦片 )中的 1 2种元素 (Al、Cr、Ni、Ge、As、Se、Ag、Cd、Sn、Sb、Pb、Hg)进行了直接测定 ,绝大部分回收率在 85 %— 1 1 0 %之间 ;线性相关系数均大于 0 .999;精密度 (RSD)值 <1 0 %。对国家标准物质 (SRM)进行了分析 ,测得值与标准参考值相吻合。该法灵敏度、精密度和准确度都能满足有关标准的要求 ,具有多元素同时分析、样品前处理简单、干扰少、测定快速准确 ,省事省力等优点。