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CHAPTER 25

Analytical Methods in Toxicology

ROSS B. LEIDY

25.1INTRODUCTION

Some 200,000 chemicals are synthesized annually worldwide, and the toxicity of most of them is unknown. Few of these chemicals reach the stage of further development and use, but those that do usually find their way into the environment. Some are persistent and remain adsorbed to soil particles or soil organic matter, some find their way into water through soil movement or aerial deposition, others are metabolized by microorganisms into compounds of greater toxicity that move up the food chain. Over time, their accumulation in higher life forms could result in debilitating alterations in metabolism, leading to illness. It might be years before such illness could be attributed to specific compounds because of the difficulty involved in identifying and quantitating them. The concern over the role of persistent organochlorines in the food chain and their possible role as human xenoestrogens is an example. The identification and quantitation of chemicals in both the environment and in living beings relies on the development of analytical techniques and instruments.

Advances in analytical techniques continue to multiply in all fields of toxicology, and as mentioned, many of these focus on the environmental area. Whether looking for new techniques to sample water or for an automated instrument to determine quantities of sulfur-containingcompounds in air, such devices are available. In many instances, developments in environmental analyses are adaptable to experimental work related to drug toxicity, or in forensic medicine, to determine the cause of poisoning.

Although new techniques and instruments continue to enter the commercial market, the basic analytical process has not changed: define the research goal(s), develop a sampling scheme to obtain representative samples, isolate the compound(s) of interest, remove potential interfering components, and quantitate and evaluate the data in relation to the initial hypothesis. Based on the data generated, many options are available. For example, was the sampling scheme complete? Would further refinement of the analytical procedure be required? Should other sample types be analyzed? Thus it is obvious that within these general categories particular methods vary considerably depending on the chemical characteristics of the toxicant (Table 25.1).

A Textbook of Modern Toxicology, Third Edition, edited by Ernest Hodgson

ISBN 0-471-26508-XCopyright 2004 John Wiley & Sons, Inc.

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