Development and validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of 17 traditional and emerging aryl organophosphate esters in indoor dust

Aryl organophosphate esters (aryl-OPEs) have gained increasing interest over the past few years since a growing number of emerging aryl-OPEs were identified in the environmental media. The currently available analytical methods for aryl-OPEs are usually tailored to detect a very limited number of aryl-OPEs and have inadequate sensitivity for several emerging aryl-OPEs. In this work, a comprehensive and sensitive method for the quantitative analysis of 17 aryl-OPEs in indoor dust samples by liquid chromatography-tandem mass spectrometry (LC–MS/MS) was developed and validated. The method allows for the determination of four traditional and thirteen emerging aryl-OPEs, which compose almost all the environmentally relevant aryl-OPEs that have been identified. For the first time, 2-isopropylphenyl diphenyl phosphate (2IPPDPP), 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP), bis(2-isopropylphenyl) phenyl phosphate (B2IPPPP), bis(4-tert-butylphenyl) phenyl phosphate (B4tBPPP), and 2-naphthalenyl phosphate (NDPHP) were analyzed using LC–MS/MS. With a systematic optimization of the MS/MS parameters, chromatographic separation conditions, and sample preparation procedures, the target aryl-OPEs in the indoor dust were well separated within 13 min in one analytical run, with limits of quantification ranging from 0.09 to 3.2 ng g−1. Compared with the previously published methods, this method obtained a better sensitivity for most aryl-OPEs. The validated method was applied to 12 indoor dust samples that were collected from residential houses in Guangzhou, China. Both the traditional and emerging aryl-OPEs were frequently detected in the samples, except for NDPHP, with ∑aryl-OPEs ranging from 90 to 33,800 ng g−1. In particular, elevated concentrations of the newly identified tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) were observed in all the indoor dust samples. To our knowledge, these are the first reported data of AO168 = O levels in the environment media from China. These data indicate that AO168 = O is a ubiquitous pollutant that was previously overlooked and merits further investigation in the environment.