Development and validation of a method for determinion of organophosphorus flame retardant di-ester and hydroxylated metabolites in human urine.

BACKGROUND

As biomarkers for assessing human exposure to organophosphate flame retardants (OPFRs), the accurate measurement of urinary metabolites of OPFRs (mOPFRs) is critical for evaluating their health impacts.

RESULTS

We established a high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique for the concurrent quantification of 14 mOPFRs in human urine, including diesters and hydroxylated metabolites. Urine samples were processed via solid-phase extraction, eluted with 2% ammoniated methanol solution, concentrated by nitrogen stream, and finally reconstituted in the original mobile phase before analysis using LC-MS/MS, executed in electrospray ionization and multiple reaction monitoring modes. High-sensitivity mass spectrometry signal acquisition was achieved based on ion fragmentation patterns. Baseline separation of isomeric compounds was accomplished by adjusting the mobile phase elution strength. Enhanced extraction efficiency and purification were based on quasi-molecular properties. The methodology exhibited method detection limits ranging from 0.018 to 0.16 μg/L. Spiked recovery rates varied between 72.2% and 109.6%, while relative standard deviations fluctuated from 5.1% to 14.7%, and matrix effects were noted to be within the range of 77.2%-112.3%. The reliability of method was validated through the analysis of certified reference materials and participation in proficiency evaluations conducted in various laboratories. This approach has been effectively utilized for analyzing urinary mOPFRs within framework of Chinese National Human Biomonitoring Program by conducting environmentally sustainable and applicable green assessment.

SIGNIFICANCE: This method thoroughly optimized essential elements concerning mass spectrometry settings, chromatographic parameters, and sample preparation procedures, providing reliable technical support for assessing population exposure to OPFRs and conducting risk evaluations.