Advertisement

Simultaneous determination of 14 urinary biomarkers of exposure to organophosphate flame retardants and plasticizers by LC-MS/MS

  • Michiel Bastiaensen
  • Fuchao Xu
  • Frederic Been
  • Nele Van den Eede
  • Adrian Covaci
Research Paper

Abstract

Organophosphate flame retardants and plasticizers (PFRs) are a group of chemicals widely added to consumer products. PFRs are quickly metabolized in the human body into two types of metabolites, (1) dialkyl and diaryl phosphate esters (DAPs), such as diphenyl phosphate (DPHP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP); and (2) hydroxylated PFRs (HO-PFRs), such as 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) and 2-hydroxyethyl bis(2-butoxyethyl) phosphate (BBOEHEP). Existing analytical methods usually focus on DAPs; therefore, human biomonitoring data on HO-PFRs remain scarce. In this study, an analytical procedure was developed for the simultaneous quantification of multiple PFR metabolites in human urine, covering eight DAPs and six HO-PFRs. Sample preparation was optimized to include all target compounds using Bond-Elut C18 solid-phase extraction cartridges, followed by instrumental analysis based on liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). Method performance was validated according to established guidelines and satisfactory results were obtained for all metabolites in terms of recovery, linearity, limits of quantification, precision, and accuracy. Recoveries ranged from 87 to 112%. Method detection limits from 0.002 ng/mL for 2-ethyl-5-hydroxyhexyl diphenyl phosphate (5-HO-EHDPHP) to 0.66 ng/mL for 4-hydroxyphenyl phenyl phosphate (4-HO-DPHP). Seven PFR metabolites were frequently detected in a small biomonitoring study (n = 14), among them bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), di-n-butyl phosphate (DNBP), 5-HO-EHDPHP, and BBOEHEP. Highest mean concentrations were found for DPHP, 2-ethylhexyl phenyl phosphate (EHPHP), and BCIPHIPP, while 4-HO-DPHP, 5-HO-EHDPHP, and EHPHP were detected in urine for the first time. Overall, the obtained results demonstrate that the developed method can be used for the simultaneous determination of 14 urinary biomarkers of exposure to PFRs.

Graphical abstract

Keywords

Organophosphate flame retardants and plasticizers Biomarkers Urine analysis Validation LC-MS/MS 

Notes

Acknowledgments

Michiel Bastiaensen acknowledges the partial funding of his Ph.D. through the Flemish Environment and Health Study financed by the Ministry of the Flemish Community (Department of Economics, Science and Innovation; Flemish Agency for Care and Health; and Department of Environment, Nature and Energy). Research leading to these results has also received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement #316665 (A-TEAM project). Frederic Been would like to thank the Research Foundation—Flanders (FWO) for his postdoctoral grant (12Y8518N).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

216_2018_1402_MOESM1_ESM.pdf (460 kb)
ESM 1 (PDF 429 kb)

References

  1. 1.
    van der Veen I, de Boer J. Phosphorus flame retardants: properties, production, environmental occurrence, toxicity and analysis. Chemosphere. 2012;88(10):1119–53.CrossRefGoogle Scholar
  2. 2.
    Grand View Research. Global flame retardant market projected to reach US$11.96 billion by 2025. Addit Polym. 2017;2017(1):10–1.Google Scholar
  3. 3.
    Wei G-L, Li D-Q, Zhuo M-N, Liao Y-S, Xie Z-Y, Guo T-L, et al. Organophosphorus flame retardants and plasticizers: sources, occurrence, toxicity and human exposure. Environ Pollut. 2015;196:29–46.CrossRefGoogle Scholar
  4. 4.
    Dodson RE, Perovich LJ, Covaci A, Van den Eede N, Ionas AC, Dirtu AC, et al. After the PBDE phase-out: a broad suite of flame retardants in repeat house dust samples from California. Environ Sci Technol. 2012;46(24):13056–66.CrossRefGoogle Scholar
  5. 5.
    Xu F, Giovanoulis G, Van Waes S, Padilla-Sanchez JA, Papadopoulou E, Magnér J, et al. Comprehensive study of human external exposure to organophosphate flame retardants via air, dust, and hand wipes: the importance of sampling and assessment strategy. Environ Sci Technol. 2016;50(14):7752–60.CrossRefGoogle Scholar
  6. 6.
    He C, English K, Baduel C, Thai P, Jagals P, Ware RS, et al. Concentrations of organophosphate flame retardants and plasticizers in urine from young children in Queensland, Australia and associations with environmental and behavioural factors. Environ Res. 2018;164:262–70.CrossRefGoogle Scholar
  7. 7.
    Araki A, Saito I, Kanazawa A, Morimoto K, Nakayama K, Shibata E, et al. Phosphorus flame retardants in indoor dust and their relation to asthma and allergies of inhabitants. Indoor Air. 2014;24(1):3–15.CrossRefGoogle Scholar
  8. 8.
    Meeker JD, Cooper EM, Stapleton HM, Hauser R. Exploratory analysis of urinary metabolites of phosphorus-containing flame retardants in relation to markers of male reproductive health. Endocr Disruptors. 2013;1(1):e26306.CrossRefGoogle Scholar
  9. 9.
    Preston EV, McClean MD, Henn BC, Stapleton HM, Braverman LE, Pearce EN, et al. Associations between urinary diphenyl phosphate and thyroid function. Environ Int. 2017;101:158–64.CrossRefGoogle Scholar
  10. 10.
    Van den Eede N, Heffernan AL, Aylward LL, Hobson P, Neels H, Mueller JF, et al. Age as a determinant of phosphate flame retardant exposure of the Australian population and identification of novel urinary PFR metabolites. Environ Int. 2015;74:1–8.CrossRefGoogle Scholar
  11. 11.
    Van den Eede N, Maho W, Erratico C, Neels H, Covaci A. First insights in the metabolism of phosphate flame retardants and plasticizers using human liver fractions. Toxicol Lett. 2013;223(1):9–15.CrossRefGoogle Scholar
  12. 12.
    Van den Eede N, Erratico C, Exarchou V, Maho W, Neels H, Covaci A. In vitro biotransformation of tris (2-butoxyethyl) phosphate (TBOEP) in human liver and serum. Toxicol Appl Pharmacol. 2015;284(2):246–53.CrossRefGoogle Scholar
  13. 13.
    Van den Eede N, Meester I, Maho W, Neels H, Covaci A. Biotransformation of three phosphate flame retardants and plasticizers in primary human hepatocytes: untargeted metabolite screening and quantitative assessment. J Appl Toxicol. 2016;36(11):1401–8.CrossRefGoogle Scholar
  14. 14.
    Hoffman K, Daniels JL, Stapleton HM. Urinary metabolites of organophosphate flame retardants and their variability in pregnant women. Environ Int. 2014;63:169–72.CrossRefGoogle Scholar
  15. 15.
    Butt CM, Congleton J, Hoffman K, Fang M, Stapleton HM. Metabolites of organophosphate flame retardants and 2-ethylhexyl tetrabromobenzoate in urine from paired mothers and toddlers. Environ Sci Technol. 2014;48(17):10432–8.CrossRefGoogle Scholar
  16. 16.
    Dodson RE, Van den Eede N, Covaci A, Perovich LJ, Brody JG, Rudel RA. Urinary biomonitoring of phosphate flame retardants: levels in California adults and recommendations for future studies. Environ Sci Technol. 2014;48(23):13625–33.CrossRefGoogle Scholar
  17. 17.
    Hoffman K, Butt CM, Webster TF, Preston EV, Hammel SC, Makey C, et al. Temporal trends in exposure to organophosphate flame retardants in the United States. Environ Sci Technol Lett. 2017;4(3):112–8.CrossRefGoogle Scholar
  18. 18.
    Ospina M, Jayatilaka NK, Wong L-Y, Restrepo P, Calafat AM. Exposure to organophosphate flame retardant chemicals in the US general population: data from the 2013–2014 National Health and nutrition examination survey. Environ Int. 2018;110:32–41.CrossRefGoogle Scholar
  19. 19.
    He C, Toms L-ML, Thai P, Van den Eede N, Wang X, Li Y, et al. Urinary metabolites of organophosphate esters: concentrations and age trends in Australian children. Environ Int. 2018;111:124–30.CrossRefGoogle Scholar
  20. 20.
    Been F, Bastiaensen M, Lai FY, van Nuijs AL, Covaci A. Liquid chromatography–tandem mass spectrometry analysis of biomarkers of exposure to phosphorus flame retardants in wastewater to monitor community-wide exposure. Anal Chem. 2017;89(18):10045–53.CrossRefGoogle Scholar
  21. 21.
    European Medicines Agency. Guideline on bioanalytical method validation. London: European Medicines Agency; 2011.Google Scholar
  22. 22.
    Marchi I, Viette V, Badoud F, Fathi M, Saugy M, Rudaz S, et al. Characterization and classification of matrix effects in biological samples analyses. J Chromatogr A. 2010;1217(25):4071–8.CrossRefGoogle Scholar
  23. 23.
    Su G, Letcher RJ, Yu H, Gooden DM, Stapleton HM. Determination of glucuronide conjugates of hydroxyl triphenyl phosphate (OH-TPHP) metabolites in human urine and its use as a biomarker of TPHP exposure. Chemosphere. 2016;149:314–9.CrossRefGoogle Scholar
  24. 24.
    Petropoulou S-SE, Petreas M, Park J-S. Analytical methodology using ion-pair liquid chromatography–tandem mass spectrometry for the determination of four di-ester metabolites of organophosphate flame retardants in California human urine. J Chromatogr A. 2016;1434:70–80.CrossRefGoogle Scholar
  25. 25.
    Ballesteros-Gómez A, Erratico CA, Van den Eede N, Ionas AC, Leonards PE, Covaci A. In vitro metabolism of 2-ethylhexyldiphenyl phosphate (EHDPHP) by human liver microsomes. Toxicol Lett. 2015;232(1):203–12.CrossRefGoogle Scholar
  26. 26.
    Van den Eede N, Ballesteros-Gómez A, Neels H, Covaci A. Does biotransformation of aryl phosphate flame retardants in blood cast a new perspective on their debated biomarkers? Environ Sci Technol. 2016;50(22):12439–45.CrossRefGoogle Scholar
  27. 27.
    Makiguchi K, Satoh T, Kakuchi T. Diphenyl phosphate as an efficient cationic organocatalyst for controlled/living ring-opening polymerization of Valerolactone and Caprolactone. Macromolecules. 2011;44:1999–2005.CrossRefGoogle Scholar
  28. 28.
    Carignan CC, Butt CM, Stapleton HM, Meeker JD, Minguez-Alarcón L, Williams PL, et al. Influence of storage vial material on measurement of organophosphate flame retardant metabolites in urine. Chemosphere. 2017;181:440–6.CrossRefGoogle Scholar
  29. 29.
    Xu F, Tay J-H, Covaci A, Padilla-Sánchez JA, Papadopoulou E, Haug LS, et al. Assessment of dietary exposure to organohalogen contaminants, legacy and emerging flame retardants in a Norwegian cohort. Environ Int. 2017;102:236–43.CrossRefGoogle Scholar
  30. 30.
    Poma G, Glynn A, Malarvannan G, Covaci A, Darnerud PO. Dietary intake of phosphorus flame retardants (PFRs) using Swedish food market basket estimations. Food Chem Toxicol. 2017;100:1–7.CrossRefGoogle Scholar
  31. 31.
    Van den Eede N, Neels H, Jorens PG, Covaci A. Analysis of organophosphate flame retardant diester metabolites in human urine by liquid chromatography electrospray ionisation tandem mass spectrometry. J Chromatogr A. 2013;1303:48–53.CrossRefGoogle Scholar
  32. 32.
    Hoffman K, Stapleton HM, Lorenzo A, Butt CM, Adair L, Herring AH, et al. Prenatal exposure to organophosphates and associations with birthweight and gestational length. Environ Int. 2018;116:248–54.CrossRefGoogle Scholar
  33. 33.
    Völkel W, Fuchs V, Wöckner M, Fromme H. Toxicokinetic of tris (2-butoxyethyl) phosphate (TBOEP) in humans following single oral administration. Arch Toxicol. 2018;92(2):651–60.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Toxicological Centre, Department of Pharmaceutical SciencesUniversity of AntwerpWilrijkBelgium

Personalised recommendations