Paraquat dichloride detection from forensic blowfly samples

Abstract

Accidental ingestion of paraquat dichloride contributed for a high number of pesticide-related deaths. It is a major suicide agent in many developing countries because of its easy accessibility. Based on the escalated death events related to misuse of paraquat, a study was conducted to observe its effect on decomposition process of New Zealand white rabbits, hence, biological and entomological samples were obtained for analysis. Entomological samples especially blowflies which are the main processor of dead remains applied in forensic investigations to obtain time and cause of death. In this research, high performance liquid chromatography (HPLC) was introduced in toxicological analysis to determine the presence of paraquat dichloride from biological specimens, and exploring the potential of blowfly samples as an alternate sample when biological specimen had decomposed. Paraquat dichloride was extracted using C18 solid phase extraction (SPE) to retain the interferences. Mobile phases used were acidified water (pH 3) and acetonitrile with ratio of 85:15. Limit of detection (LOD) and limit of quantitation (LOQ) were 0.03 mg/L and 0.09 mg/L, respectively with a linear curve (R2 = 0.9982). From the analysis, concentration of paraquat dichloride found out to be the highest in liver as well as in the third instar of blowfly larvae. The isolation and analytical method proposed in this present study were able to be applied in detection of paraquat dichloride in post-mortem specimens. In conclusion, blowfly samples were suitable to be applied in forensic toxicological analysis to replace decomposed biological samples.