Negative Ion Chemical Ionization Mass Spectrometry for the Analysis of 3,5,6‐Trichloro‐2‐pyridinol in Saliva of Rats Exposed to Chlorpyrifos

Abstract

Organophosphorus (OP) insecticides (e.g. chlorpyrifos) are widely used in a variety of applications, and the potential exists for significant occupational and environmental exposures. They have been associated with more occupational poisoning cases than any other class of insecticides. One of the best approaches for accurately assessing human dosimetry and determining risk from both occupational and environmental exposure is biomonitoring. Biological matrices such as blood and urine have been routinely used for biomonitoring; however, other matrices such as saliva represent a simple and readily obtainable fluid. As a result, saliva has been suggested as an alternative biological matrix for the evaluation of a broad range of biomarkers such as environmental contaminants, drugs of abuse, hormones, chemotherapeutics, heavy metals, and pesticides. Chlorpyrifos (CPF), and its major metabolite, 3,5,6‐trichloro‐2‐pyridinol (TCP), have been quantified in urine and blood as a biomarker for exposure to OP insecticides. The purpose of this study was to develop an analytical approach for detecting and quantitating the levels of TCP in saliva obtained from rats exposed to CPF and to evaluate the potential of saliva as a noninvasive biomonitoring matrix for the determination of exposure to OP insecticides. Adult male rats were administered CPF, and blood and saliva were humanely collected for analysis of TCP and CPF. The TCP was detected and quantitated in saliva using negative ion chemical ionization mass spectrometry with selected ion monitoring. Initial results indicate that saliva potentially may be utilized as a noninvasive biomonitoring matrix to determine exposure to organophosphate insecticides. The authors would like to thank Ms. K. Brzak and Dr. M. Bartels of Dow Chemical Company for their helpful input. This work was partially supported by the U.S. Environmental Protection Agency's STAR program through grant R828608. It has not been subject to any EPA review and, therefore, does not necessarily reflect the views of the agency, and no public endorsement should be inferred. This publication was also partially supported by grant 1 R01 OH03629‐01A2 from the Centers for Disease Control and Prevention (CDC). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the CDC.