Validated Gas Chromatography – Mass Spectrometry (GC-MS) Method for Simultaneous Quantitation of Tris(4-Chlorophenyl)Methane and Tris(4-Chlorophenyl)Methanol in Rat Plasma and Fetus

Abstract

Tris(4-chlorophenyl)methane (TCPMe) is a byproduct of dichlorodiphenyltrichloroethane synthesis. TCPMe and its metabolite tris(4-chlorophenyl)methanol (TCPMOH) are environmentally prevalent and have been detected in wildlife and humans. Due to inadequate data addressing its toxicity, the National Toxicology Program (NTP) is testing TCPMe in Hsd:Sprague Dawley SD (HSD) rats following perinatal exposure. In support of the toxicology studies, a gas chromatography – mass spectrometry (GC-MS) method was validated to simultaneously quantitate TCPMe and TCPMOH in male Sprague Dawley rat plasma (primary matrix) over calibration standard ranges of 2–200 ng/mL and 1–100 ng/mL, respectively. The method was linear (r2 ≥ 0.9975), accurate (relative error (RE) ≤ ±12.8 (TCPMe) and ±14.5% (TCPMOH), and precise (relative standard deviation (RSD) ≤ 7.6 (TCPMe) and 3.8% (TCPMOH)). The limits of quantitation were 2 and 1 ng/mL and the limits of detection were 0.73 and 0.07 ng/mL for TCPMe and TCPMOH, respectively. Samples, as high as 2000 ng/mL for TCPMe (RSD ≤ 3.9, RE ≤ ±1.0) and 1000 ng/mL for TCPMOH (RSD ≤ 1.0, RE ≤ ±2.9), were successfully diluted with plasma into the validated concentration range. The method was selective and both TCPMe and TCPMOH were quantified in all secondary matrices (HSD male and female plasma, gestation day (GD)18 plasma, amniotic fluid, and fetus, postnatal day (PND)4 dam and pup plasma) using a primary matrix curve (RE ≤ ±14.4% and 11.5; RSD ≤ 7.6 and 11.8%, respectively). These results demonstrate that the method is suitable for simultaneous quantitation of TCPMe and TCPMOH in rodent plasma and fetuses for the evaluation of gestational and lactational transfer following perinatal exposure of TCPMe in NTP studies.