Functional Group-Dependent Screening of Organophosphate Esters (OPEs) and Discovery of an Abundant OPE Bis-(2-ethylhexyl)-phenyl Phosphate in Indoor Dust

Abstract

There is increasing scientific interest in environmental pollution and the effect on public health caused by organophosphate esters (OPEs). Using liquid chromatography coupled to a hybrid quadrupole Orbitrap high-resolution mass spectrometer, a novel, robust, and untargeted screening strategy for the identification of novel OPEs in indoor dust samples was presently developed based on the characteristic molecular fragmentation pathways, and 12 previously reported OPEs and six previously unrecognized OPEs were detected in the combined extracts of indoor dust samples, collected in Nanjing, eastern China. One of the six detected OPEs, bis-(2-ethylhexyl)-phenyl phosphate (BEHPP), was identified by comparison of unique LC and MS characteristics with a synthesized pure standard. Accurate concentrations of BEHPP were determined in n = 50 individual indoor dust samples with 100% detection frequency with a median concentration range of 50−1530 ng/g dry weight, which were generally greater or at least comparable to traditional OPEs, that is, triphenyl phosphate and 2-ethylhexyl diphenyl phosphate (EHDPP), in the same dust samples. Statistically significant, positive correlations were found for log-transformed concentrations of BEHPP versus EHDPP (r 2 = 0.7884, p < 0.0001), and BEHPP versus tris(2-ethylhexyl)phosphate (r 2 = 0.4054, p < 0.0001), suggesting their similar commercial applications and sources in the environment.

Establishment of a Target, Suspect, and Functional Group-Dependent Screening Strategy for Organophosphate Esters (OPEs): “Into the Unknown” of OPEs in the Sediment of Taihu Lake, China

“…Previously, our group first reported the occurrence of BEHPP in environmental samples. 22 Specifically, early this year, we analyzed n = 50 indoor dust samples from Nanjing city (Eastern China) and found that BEHPP was detectable in 100% of the analyzed samples with concentrations ranging from 50 to 1530 ng/g dw. For the first time, our present study reported its ubiquity in sediment samples, implying that further studies should be encouraged to elucidate the possible contamination source of BEHPP in the environment.…”

“…Details of the synthesis method are provided in our previous study. 22 Hydroxylated triphenyl phosphates (para-and meta-OH-TPHPs) were synthesized, and the synthesis methods are provided in the SI. The deuterated internal standards (IS), d 12 -TEP, d 15 -TPHP, d 15 -TDCIPP, d 12 -TCEP, and d 27 -TNBP, were purchased from TCI America (Portland, OR).…”

“…Functional group-dependent screening was based on nine feature fragment ions of OPEs reported in previous studies. 22,23 The structures of these nine fragment ions are supplied in Table S5.…”

“…20,21 For instance, a novel functional groupdependent screening method has been developed for the identification of potential OPEs in indoor dust, 22,23 and this method provided opportunities to identify novel OPEs or OPE-like chemicals, i.e., bis-(2-ethylhexyl)-phenyl phosphate (BEHPP). 22 However, there are no integrated strategies that could provide the potential to screen out all OPEs in the environment.…”

Enhanced Nontarget Screening Algorithm Reveals Highly Abundant Chlorinated Azo Dye Compounds in House Dust

“…Recent improvements in high-resolution mass spectrometry have made it possible to screen for previously unrecognized compounds using nontarget analysis (NTA) . Several recent studies have applied characteristic fragment-based NTA to successfully identify previously unrecognized per- and polyfluoroalkyl substances (PFAS, e.g., [C n F 2 n +1 ] − ), − brominated pollutants (Br – ), and organophosphate flame retardants ([H 4 PO 4 ] + ) in house dusts. However, these NTA methods were limited to a constrained class of pollutants with known diagnostic fragments.…”