Analytical human biomonitoring method for the identification and quantification of the metabolite BDCPP originated from the organophosphate flame retardant TDCPP in urine

Abstract Tris(1,3-dichloropropyl) phosphate (TDCPP, CAS 13674-87-8) is one of the most commonly used organophosphate flame retardants (OPFRs) in cars, residential furniture and other products containing polyurethane foam to meet the required flammability standards. For the tasks of the working group Analyses in Biological Material from the German Research Foundation (DFG), a human biomonitoring process for TDCPP is developed. The metabolism of TDCPP is described in different in vivo studies and it is already shown that Bis (1,3-dichloropropyl) phosphate (BDCPP, CAS 72236-72-7) is the primary compound specific metabolite of TDCPP which is often detectable in urine samples. BDCPP is also the most appropriate metabolite because it is unique to TDCPP since no other OPFR known today is transformed or hydrolyzed to BDCPP. A combined method by liquid chromatography-tandem mass spectrometry (LC–MS/MS) is implemented by optimizing atmospheric pressure chemical ionization (APCI) and Electron Spray Ionization (ESI) operating in negative ionization mode. Simultaneous, multiple reaction monitoring is studied to achieve the best performance with respect to selectivity, detectability and robustness of BDCPP. During an expanded validation assessment, the methodological performance characteristics are determined in details and the method is applied in a specific human biomonitoring study among non-occupationally exposed humans of randomly chosen volunteers from the Netherlands.