Abstract:

Organic phosphate esters （OPEs） and phthalate esters （PAEs） are two classes of synthetic compounds widely incorporated into various industrial and consumer products as flame retardants and plasticizers. Both exhibit multi-organ cumulative toxicity. In this study， an ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method was developed for the determination of 22 OPEs and their diester metabolites （mOPEs） and 11 phthalate ester metabolites （mPAEs） in whole blood. The whole blood samples were extracted with 0.1% formic acid-acetonitrile by liquid-liquid extraction for protein precipitation， and then purified by HMR S-micro BIO 96-well solid phase extraction column. The filtrate was blown to near dryness with nitrogen， and reconstituted with 0.1% formic acid-acetonitrile solution. The target compounds were detected by UPLC-MS/MS. A Ghost Trap DS-HP chromatographic column （30 mm×2.1 mm） was used as the background ghost peak trap column， and an ACQUITY UPLC^® BEH C18 chromatographic column （150 mm×2.1 mm， 1.7 μm） was used as the analytical column. Methanol and 0.5 mmol/L ammonium acetate were used as mobile phase for gradient elution. Electrospray ionization （ESI） was used for MS detection， with both positive and negative ion scanning in the multiple reaction monitoring （MRM） mode. Isotope internal standard method was used for quantification. The results showed that 33 target compounds could be separated within 15 min， and good linear relationships were observed for all target compounds across their respective mass concentration ranges （r=0.993 3-0.999 8）. The limits of detection were 0.003-0.31 ng/mL and the limits of quantification were 0.01-1.02 ng/mL. The spiked recoveries of 33 targets in whole blood samples ranged from 60.5% to 138.3%， with relative standard deviations （RSDs） from 1.6% to 11.0%. The detection rates of tris-（2-chloroisopropyl）phosphate （TCiPP）， triphenyl phosphate （TPHP）， 2-ethylhexyl diphenyl （EHDPP）， mono（2-ethyl-5-hydroxyhexyl） phthalate （MEHHP）， mono-n-butyl phthalate （MNBP） and mono-n-octyl phthalate （MOP） were 100% in 14 whole blood samples， and the highest detection amount of TPHP was 10.04 ng/mL. The developed method is simple to operate， sensitive， accurate， requires small sample volumes， and is cost-effective on reagents. It is suitable for human biomonitoring， and provides a theoretical basis for monitoring organic phosphate and phthalic ester substances in the population.

Key words: organic phosphate esters, phthalate ester metabolites, whole blood, ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）