Liquid Chromatography−Tandem Mass Spectrometry Determination of Nonionic Organophosphorus Flame Retardants and Plasticizers in Wastewater Samples

A comprehensive method for the determination of nonionic organophosphorus flame retardants/plasticizers in wastewater samples by solid-phase extraction (SPE) with liquid chromatography−electrospray ionization−tandem mass spectrometry (LC−ESI−MS/MS) is presented. It allows the determination of 11 organophosphorus compounds, trialkyl and trichloralkyl phosphates, triaryl phosphate, and biphosphates together with triphenylphosphine oxide (TPPO). Limits of quantification after SPE of 100 mL of water are between 3 and 80 ng/L, which are adequate for most aqueous samples. The sensitivity of the LC−ESI−MS approach allows direct injection of aqueous sample without preceding extraction for concentrations in the low μg/L range. The method was finally applied to municipal wastewater samples, showing the occurrence of six phosphoric acid triesters and TPPO in both raw and treated municipal wastewaters.