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Toxicological screening , Tests for specific compounds and groups of compounds

المؤلف: 

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  230

2026-10-17

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Toxicological screening

Tests for specific compounds and groups of compounds

Alcohols, acetone, acetaldehyde and glycols Ethanol is frequently taken at the same time as other drugs and can intensify the action of depressant drugs. A blood-ethanol determination helps to distinguish this from normal alcoholic intoxication; it is also useful in the clinical assessment of unconscious patients admitted with head injuries and smelling of drink. Children are particularly at risk from hypoglycaemia which may follow the ingestion of alcohol. Methanol is available in a variety of commercial products (antifreeze preparations, windscreen washer additives, duplicating fluids). Acetone is sometimes consumed by alcoholics as a substitute for ethanol; children may take nail cleaner fluid; diabetics may be comatose from high endogenous acetone levels. Acetone is also a metabolite of propan-2-ol. It can be useful to measure acetaldehyde as a toxic metabolite of ethanol, since some patients are unable to metabolise this compound for genetic reasons or because of an interaction with disulfiram, metronidazole, tolbutamide, watercress and other substances. Acetaldehyde is also a major metabolite of paraldehyde. Ethylene glycol is a principal component of automotive antifreeze products. Poisoning by either methanol or ethylene glycol is often associated with severe metabolic acidosis and electrolyte imbalance; therapy with ethanol infusions or other anti-dotes must be instituted without delay. Enzymatic assays based on ADH and breath analysers are applicable only to ethanol; a qualitative and quantitative GLC method is required for the other alcohols.