Simultaneous determination method of 10 organophosphate esters in oyster, an environmental indicator organism

Oyster is a common indicator organism of environment pollution. A method was built to simultaneously determine ten common commercial organophosphate ester flame retardants in oysters. After the careful optimization of conditions, the organophosphate esters (OPEs) in oyster sample were extracted with hexane assisted by ultrasound, purified with NH2 solid-phase extraction column, eluted with the mixture solution of dichloromethane and ethyl acetate at the ratio of 1:1 (v/v), and finally detected by gas chromatography coupled with tandem triple quadrupole mass spectrometry (GC–MS/MS). All the ten compounds in the concentrations ranging from 0.5 ng·mL-1 to 100 ng·mL-1 showed good linearity with their R2 higher than 0.9991. The limits of detection and limits of quantification for the organophosphate esters were from 0.03 ng·g-1 to 0.47 ng·g-1 (dry weight) and from 0.1 ng·g-1 to 1.56 ng·g-1 (dry weight), respectively. At the three spiking levels with five replicates, recoveries of organophosphate esters ranged from 82% to 108% with the relative standard deviation ranging from 0.9% to 6.4%. In the samples collected from mariculture farms, nine OPE compounds were detected in oysters with the concentration ranging from 6.52 ng·g-1 to 22 ng·g-1 (dry weight). It indicated the method was suitable for OPEs determination in oysters.