Caldas E D, Conceição M H, Miranda M C, de Souza L C, Lima J F
College of Health Sciences and Chemistry Institute, University of Brasília, 70919-970 Brasília, DF, Brazil.
J Agric Food Chem. 2001 Oct;49(10):4521-5. doi: 10.1021/jf010124a.
Dithiocarbamates are a class of fungicides extensively used in many crops worldwide. The current residue definition of dithiocarbamates in food for compliance with maximum residue limits, at national and international levels, is total residues arising from the use of any or each dithiocarbamate fungicide, determined as CS(2). The analytical method most frequently used to analyze dithiocarbamate residues in food for monitoring purposes was proposed more than 30 years ago. In this method, total dithiocarbamates are decomposed to CS(2), which is purified and reacted with a cupric reagent. The yellow complex formed is quantified by spectrophotometry. In this paper, a new reaction system for the purification and complexation of CS(2) is proposed. The new system is less fragile than the traditional design, is easier to assemble, and allows for a higher sample throughput, in addition to being of low cost. Recovery of added mancozeb, thiram, or ziram (0.15-8.0 mg/kg) in rice, beans, apple, banana, orange, papaya, tomato, cucumber, and potato ranged from 82 to 120%, with relative standard deviations from 0 to 10% (n = 3 or 5). Analysis of apple, tomato, and papaya samples with field-incurred dithiocarbamate residues showed comparable results using both the traditional and the new reaction systems.
二硫代氨基甲酸盐是一类在全球许多农作物中广泛使用的杀菌剂。目前，在国家和国际层面，食品中二硫代氨基甲酸盐的残留定义是指使用任何一种或每种二硫代氨基甲酸盐杀菌剂产生的总残留量，以CS(2)来测定。用于监测食品中二硫代氨基甲酸盐残留量的最常用分析方法是30多年前提出的。在该方法中，总二硫代氨基甲酸盐被分解为CS(2)，CS(2)经过纯化后与铜试剂反应。形成的黄色络合物通过分光光度法进行定量。本文提出了一种用于CS(2)纯化和络合的新反应体系。除了成本低之外，新体系比传统设计更不易损坏，更易于组装，并且具有更高的样品通量。在大米、豆类、苹果、香蕉、橙子、木瓜、番茄、黄瓜和土豆中添加代森锰锌、福美双或福美锌（0.15 - 8. mg/kg）后的回收率在82%至120%之间，相对标准偏差为0%至10%（n = 3或5）。使用传统和新反应体系对含有田间产生的二硫代氨基甲酸盐残留的苹果、番茄和木瓜样品进行分析，结果相当。
