Tài liệu Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 58) pdf

7.1

© Springer-Verlag Berlin Heidelberg 2005

II.7.1 Simultaneous analysis

of pesticides by GC/MS

by Shinji Kageyama and Makoto Ueki

Introduction

Agricultual chemicals include not only pesticides for protecting plants, such as insecticides,

germicides, herbicides and rodenticides, but also fertilizers and growth regulating substances

being used in agricultural production and horticulture. In poisoning cases with agricultural

chemicals, the causative poisons are largely the pesticides. Th ere are many cases, in which the

poisoning due to exposure to an organophosphorus pesticide is obvious with clinical symp￾toms [1]. However, there are more than 5,000 agricultural chemicals registered and commer￾cially available in Japanese markets [2]; it is essential to identify a causative chemical to make

the fi nal clinical diagnosis in a poisoning-suspected case.

Since sensitive and simultaneous analysis of multiple compounds is possible using GC/MS,

the method is being widely used for analysis of pesticides for environmental specimens, such

as water and soil [3–6]. In this chapter, among main pesticides which had been reported caus￾ative for poisoning cases [7], more than 30 kinds of pesticides have been picked up from or￾ganophosphorus, organochlorine, carbamate and triazine pesticides, and a method for simul￾taneous analysis of many pesticides by GC/MS is presented. For alkylpyridinium and amino

acid type herbicides, their analyses are described in other chapters.

Reagents and their preparation

i. Reagents

• Pure n-hexane for organic trace analysis (Merck, Darmstadt, Germany and other manu￾facturers) is directly used or redistilled befor use according to need.

• Many of the authentic standards of pesticides can be purchased from Supelco, Bellefonte,

PA, USA; but fenobucarb, salithion, thiometon, ethylthiomethon, propanil, cyanofenphos

and isoxathion cannot be obtained from the above manufacturer, but can be obtained from

Wako Pure Chemical Industries, Ltd., Osaka, Japan. As internal standard (IS), fenitrothion￾d6 was obtained from (Hayashi Pure Chemical Ind., Ltd, Osaka, Japan). Other common

chemicals used were of the highest purity commercially abailable.

ii. Preparation

• Standard solutions for each pesticide are prepared by dissolving each compound in ethanol

(1 mg/mL); each retention times were determined by GC. Th e 35 compounds were divided

into 3 groups, where each peak did not overlap or interfere with each other as shown

in > Figure 1.1. Such 3 mixture standard solutions with known compounds at 1 mg/mL

each are also prepared.