Analysis of ochratoxin A in pig kidney and rye flour using liquid chromatography tandem mass spectrometry (LC/MS/MS)

A liquid chromatography electrospray tandem mass spectrometric (LC/MS/MS) method is described for analysis and confirmation of ochratoxin A in pig kidney and rye flour using derivatization of ochratoxin A to the methyl ester. Ochratoxin A methyl(d₃)ester is used as internal standard. The method works well, the detection limit is 0.02 μ g/kg and the repeatability (coefficient of variation) is between 6% and 16% in the contamination range 0.5 to 8 μ g/kg.     

牙刷刷毛中邻苯二甲酸酯类增塑剂的测定

建立了牙刷刷毛中16种邻苯二甲酸酯的气相色谱-质谱(GC-MS)检测方法.样品经超声提取后,采用外标法选择离子扫描模式(SIM)进行定量分析.16种邻苯二甲酸酯在0.1～20 mg/L范围内呈现良好的线性关系,相关系数均大于0.999.检出限为0.05 mg/kg,平均回收率为74.5％～109.1％,相对标准偏差(RSD,n=6)为2.3％～9.1％.该方法样品处理简单,分析时间短,定量准确,适用于牙刷刷毛中邻苯二甲酸酯的分析检测.     

Direct Determination of Saccharin and Acesulfame-K in Sweeteners and Fruit Juices Powders

A simple and rapid analytical procedure for determination of saccharin (SAC) and acesulfame-K (AC-K) based on UV-vis measurements and partial least squares (PLS) was proposed. Thus, an experimental design at levels 2 and 15 mg l⁻¹ for SAC and 2 and 20 mg l⁻¹ for AC-K was applied. Because real samples usually contain SAC and AC-K combined with aspartame (ASP), this interference was also included in the model. The procedure was successfully applied for SAC and AC-K simultaneous determination in sweeteners and fruit juice powders, without any separation step to remove ASP. The results were validated by using spiked samples, and the obtained recoveries were satisfactory.     

电感耦合等离子体发射光谱法测定岩土浸出液中硫酸根

一些岩土中硫酸盐的大量存在是影响其工程性质的重要因素之一,SO42-是混凝土结晶腐蚀中最活跃也是最主要的阴离子,而且含SO42-和Cl-的盐类都对钢铁具有电化学腐蚀的作用。硫酸盐的腐蚀是盐类腐蚀中最普遍而具有代表性的。鉴于此,本文提出了等离子发射光谱法对岩土浸出液中硫酸根的测定方法,从而实现利用等离子发射光谱间接测定硫酸根的含量。方法的精密度小于2%,加标回收率在96～104%。与其它测试技术之间无显著性差异。方法可以快速、准确有效地反映岩土中硫酸盐的含量,更加及时地反映对建筑的腐蚀情况。     

MEMS质谱仪研究综述

近年来,小体积、低功耗、价格低廉、使用方便的MEMS质谱仪成为了质谱领域的研究重点和热点。目前国外对MEMS质谱仪及其相关技术的研究已取得了一些成果,甚至研发出了较为完整MEMS质谱仪。但是整体而言,MEMS质谱仪的性能还很低,其研究主要还处于对其元件分别进行微型化的阶段。其中,MEMS离子源以对电喷雾离子源的研究为主;MEMS质量分析器以对离子阱的研究为主;MEMS离子检测器以对法拉第筒的研究为主。本文总结了MEMS质谱仪的最新成果,同时分析了可能面临的问题。     

Level and source of 129I of environmental samples in Xi'an region, China

Iodine-129 is widely used as a tracer in various environmental practices such as monitoring of nuclear environmental safety, seawater exchange and transport, geochemical cycle of stable iodine and dating of geological events. The spatial distribution of ¹²⁹I concentration varies significantly on global scale because of anthropogenic input from nuclear activities coupled with scarcity of data on environmental ¹²⁹I variability in many parts of the world including Asia. Here we report new data on ¹²⁹I and ¹²⁷I concentrations in soil, vegetation, river water and precipitation collected from Xi'an area, China. The results indicate values for environmental ¹²⁹I/¹²⁷I ratios in the investigated area range from 1.1 × 10^− 10 to 43.5 × 10^− 10 with a mean of 20.6 × 10^− 10, which is 1-3 orders of magnitude lower than the ratios observed in Europe, but comparable with those observed in the locations far from direct effect of point release sources and at similar latitude. The main source of ¹²⁹I in the investigated area is attributed to the global fallout of both atmospheric nuclear weapons testing and long distance dispersion of fuel reprocessing releases.     

Triacylglycerol Species of Less Common Edible Vegetable Oils

Chromatographic and spectroscopic methods used for the detection and quantification of triacylglycerol (TAG) species present in less common edible vegetable oils (almond, hazelnut, pumpkin seed, safflower, sesame, walnut, and wheatgerm oils) are reviewed. For these oils, as well as for thistle oil and high-oleic sunflower oil, for which no data exist on their TAG composition, both high-performance liquid chromatography (HPLC) and gas chromatography (GC) chromatographic plus spectrometric techniques have also been performed. Triacylglycerol comparison of the data found in the literature is also presented. Five fatty acyl moieties (palmitoyl-, stearoyl-, oleoyl-, linoleoyl-, and linolenoyl-) are found to mainly contribute to the formation of TAG species of the aforementioned edible vegetable oils, whereas six more (palmitoleoyl-, arachidoyl-, gadoleoyl-, heptadecenoyl-, margaroyl-, and erucoyl-) are reported as minors. Only 19 to 33 TAG make up the mass of these oils. These TAG are also found in most common edible oils, thus indicating a “uniformity” in the minor and main TAG composition of edible vegetable oils. Trioleoyl-glycerol predominates in almond (13.3-48.6%), hazelnut (35.3-57.9%), and high oleic sunflower (44.2% and 52.9%) oils, trilinoleoyl-glycerol in safflower (40.1-49.7%), thistle (36.9% and 46.0%), walnut (25.9-38.1%), and wheatgerm (15.7-33.0%) oils. Sesame and pumpkin seed oils are rich in dioleoyl-linoleoyl-glycerol (5.9-17.5%, 9.5% and 18.6%, respectively) and oleoyl-dilinoleoyl-glycerol (8.0-18.7% and 12.8-21.1%, respectively).     

时间延迟谱技术及测量系统

时间延迟谱技术(TDS)是一项较新的测量技术,它可以用于测量电声系统的复频响应和复时域响应。本文讨论了TDS的一些基本概念和一种简化的实现方法并给出了一个具体的测量系统。该系统由本文作者设计,它以一台IBMPC-AT为核心,软件为主体,具有丰富的测量功能。最后,本文给出了一些测量实例以演示和验证这套系统的功能。     

砷化镓、锑化铟中痕量碲的无火焰原子吸收分光光度法测定

本工作系统地探索了各种腐蚀剂对砷化镓及锑化铟的腐蚀速度,建立了无火焰原子吸收法直接测定砷化镓体材料、砷化镓和锑化铟外延层中的碲.方法准确、快速,满足于材料工艺的要求.     

Extensive Ozonation of C60: Degradation or Polymerization?

The impact of the oxidizing agent ozone (O₃) on the structure of the most common spherical allotrope of carbon, buckminsterfullerene (C₆₀) is studied. Past studies measured ozonation of C₆₀ over short periods of time. In this study, we establish that C₆₀ is completely degraded, not polymerized, during ozonation. The techniques, laser desorption time-of-flight mass spectrometry, UV/Vis absorbance spectroscopy, and FT-Raman are used to study the molecular degradation of the spherical allotrope C₆₀ by O₃.