*Correspondence should be addressed: Sanganalmath, Toxicology Division, Forensic Science Laboratory, Madivala, Bangalore – 560 068, Karnataka. E-mail: praveen_usp@rediff.com.
Quinalphos is a heterocyclic organothiophosphate insecticide, which inhibits acetylcholinestarase resulting in cholinergic signs. A fatal case of poisoning due to ingestion of insecticide containing quinalphos formulation in a suicidal attempt was reported. In this paper a simple, specific and accurate high-performance thin-layer chromatographic (HPTLC) method for the quantitative determination of quinalphos in postmortem blood is described. The method involves the extraction of quinalphos from blood using diethyl ether followed by separation on precoated silica gel using a mixture of hexane-acetone (8:2), as eluent. Densitometric analysis of quinalphos was carried out at 322 nm with quinalphos being detected at Rf of 0.63. The concentration of quinalphos detected in blood extract was 0.062 mg/ml. The relationship between peak area/height with concentration was linear over a range of 2.5–10mg/spot. The method is validated in terms of stability, specificity, accuracy, linearity and limits of detection. The developed HPTLC method has specific advantages of simplicity, speed, reproducibility and the separation achieved is free from interferences from postmortem blood matrix and can thus become affordable and reliable alternative to other chromatographic techniques.
HPTLC, Quinalphos, Densitometry, Validation
