Semiquantitative Nontargeted Screening of Organophosphorus Plastic Additives in Consumer Products Using 31P NMR.

Mass spectrometry (MS) is typically employed for the nontargeted identification of unknown organophosphorus compounds (OPCs). However, quantitative analysis remains a major challenge due to the lack of authentic standards for most of the OPCs. A phosphorus NMR (31P NMR) method for semiquantitative nontargeted analysis was developed and applied to 37 different plastic products, where OPCs were detected in nine at high concentrations (86.9-7206 nmol/g). Three classes of compounds were detected with clearly separated chemical shifts, including organophosphites (δ = 125-140 ppm) and organophosphates (δ = (-20)-5 ppm), as well as an unexpected "unannotated" class (δ = 5-20 ppm). The "unannotated" class was subsequently identified as organophosphite diesters and confirmed through in-lab hydrolysis trials. In this work, we demonstrate how a 31P NMR method may serve as a powerful analytical tool when combined with mass spectrometry for the nontargeted analysis of OPCs. We highlight organophosphite diesters as a novel class of compounds which represent a potential source of organophosphate diesters in the environment.