Distribution of dimethoate in the body after a fatal organophosphate intoxication.

Many organophosphate pesticides (OPs) such as dimethoate are used to eradicate household pests, and those occurring in agriculture and forestry sectors. Combinations of two or more different insecticides have been manufactured to increase their effectiveness. A case of death is presented as suspected organophosphates intoxication. Autopsy was unremarkable except for grayish fluid in the stomach, with garlicky odor. A systematic toxicological analysis on post-mortem specimens revealed high concentrations of dimethoate in blood 38 microg/mL, urine 0.47 microg/mL, brain 2.2 microg/g, myocardial muscle 7.6 microg/g, liver 4.6 microg/g, lung 7.6 microg/g, skeletal muscle 21 microg/g, kidney 55 microg/g and gall bladder 31 microg/g. Blood alcohol was 2.85 g/L, cyclohexanone and cyclohexanol were also detected in the blood but not quantified. The cause of death was determined as organophosphate intoxication.

Acute poisoning with phosphamidon: determination of dimethyl phosphate (DMP) as a stable metabolite in a case of organophosphate insecticide intoxication.

Many organophosphate pesticides (OP) such as phosphamidon are unstable in aqueous solutions and especially in blood in the presence of esterases. In a case of intoxication, the phosphamidon concentration in serum decreased from 10 mg/L to 4.4 mg/L after storage at -20 degrees C for six months; nearly complete degradation was observed after three years. Dimethyl phosphate (DMP) is a metabolite of phosphamidon, mevinphos, dicrotophos, monocrotophos, dichlorvos, and trichlorfon. A gas chromatographic-mass spectrometric method with deuterated DMP-d6 as internal standard for the determination of DMP in biological material was validated. DMP was found in all of the patient's samples (3.9 and 4.9 mg/L in blood, 33.5 and 50.4 mg/L in urine, and 8.1 mg/L in gastric fluid), even after storage at -20 degrees C for up to 3 years. No hints for a degradation of DMP when spiked in fresh blood and stored at 4 degrees C for 1 week and stored in water over a time period of 10 months. Looking for the stable metabolites like DMP in cases of suspected OP intoxication is recommended.

An analytical method for the rapid screening of organophosphate pesticides in human biological samples and foodstuffs.

Gas chromatography with nitrogen/phosphorus sensitive detection (GC/PND) and electron impact mass spectrometry (GC/MS) with selected ion monitoring provides a simple, rapid and sensitive method for the determination of organophosphate pesticides (OPs). A selective single-step extraction of 23 different OPs in urine, blood, serum and food samples (baby food, soft drinks and instant soups suspected of contamination from a blackmailing scare) is described. The OPs were extracted with 1ml toluene (with and without addition of mevinphos as internal standard), using a 0.7ml aliquot of urine, blood or serum sample. Food samples (0.2g) were homogenised with water (0.5ml) before extraction. An amount of 1microl of the toluene phase (extraction supernatant) was analysed directly by GC/PND and GC/MS.The method was validated using spiked human serum. The OPs were mixed with serum containing 10mg/ml disodium ethane diamine tetraacetic acid disodium salt (EDTA disodium salt) and stored up to 10 days at 4 and -20 degrees C, respectively. The recovery rates of OPs in freshly spiked human plasma ranged between 50% (dimethoate) and 133% (dialifos). OPs in plasma proved to be stable at -20 degrees C. Their levels decreased only slightly after storage at 4 degrees C.