Method Development and Validation for the Rapid Detection of Organophosphates in Blood Plasma from Obese, Obese-Diabetic, and Lean Patients from Eastern North Carolina

Abstract

The incidence of diabetes and rate of obesity is on the rise, along with the use of organophosphorus insecticides in the United States. Organophosphates (OP), a specific class of pesticide that is biodegradable and readily available for purchase, represent 50% of all insecticides used worldwide. OPs are toxic and can cause numerous acute effects, but the health effects from low dose chronic exposure have not been thoroughly investigated. Interestingly, there have been few studies showing a correlation between the rise in organophosphate pesticide use and the elevated rates of diabetes and obesity. These correlations should be more thoroughly investigated however the current methods of detection for OPs in human plasma use a time- and cost-consuming sample preparation method, which do not always yield accurate results. Thus, the need to develop and validate a sensitive, selective, and high-throughput analytical method for the accurate and precise determination of organophosphate levels in human plasma. A simple "dilute and shoot" sample preparation has been developed along with an ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) method for detection and quantification of OPs in blood plasma. The method was validated and standard curves have been generated revealing the limits of detection and quantification to range from 0.0660 ng/mL to 19.1 ng/mL and 0.200 ng/mL to 58.0 ng/mL respectively. The percent accuracies ranged from 0 to 262% for all organophosphates. Several patients showed detectable levels of diazinon, malathion, and terbufos. Interestingly, these patients were either obese or obese/diabetic. One obese and diabetic patient displayed both a detectable and quantifiable levels of diazinon (0.237 ng/mL), which had a limit of detection and quantification of 0.0660 and 0.200 ng/mL respectively. These results suggest that more intensive studies should be conducted on larger population of patients.