Determination of Hexabromocyclododecanes in Fish Using Modified QuEChERS Method with Efficient Extract Clean-Up Prior to Liquid Chromatography–Tandem Mass Spectrometry

Linda Okšová,Peter Tölgyessy

doi:10.3390/separations7030044

Abstract

A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation method coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS) was proposed for the determination of α-, β-, and γ-hexabromocyclododecane (HBCD) diastereomers in whole-fish homogenate samples. The main modification of the QuEChERS method concerned a clean-up step in which the combination of pH-tuned dispersive liquid–liquid microextraction (DLLME) with 18.4 M H2SO4 digestion allowed to successfully eliminate the matrix substances from the final extract. For the target HBCDs, good response linearity was obtained with coefficients of determination (R2) >0.998 for the concentration range corresponding to 0.1–50 ng of analyte per g of sample. Limits of quantifications (LOQs) were 0.15–0.25 ng g−1 ww (wet weight), and the recoveries from samples spiked at levels of 0.5 and 5 ng g−1 ranged from 89% to 102% with relative standard deviations <7.5%. The accuracy of the method was verified by analysis of the NIST standard reference material SRM 1947, and a good agreement (90%) was obtained with the certified value for the α-HBCD present in the sample. Finally, the method was applied to the analysis of 293 fish samples collected in water bodies from all over Slovakia, in which the highest concentrations were determined for α-HBCD with the maximum value of 31 ng g−1 ww.

Highlights

Hexabromocyclododecane (HBCD) is a group of synthetic organobromines, which is generally used as flame retardant [1]
The method was applied to the analysis of 293 fish samples collected in water bodies from all over Slovakia, in which the highest concentrations were determined for α-HBCD with the maximum value of 31 ng g−1 ww
(primary-secondary amine) sorbents, according to this study, was tested, but the resulting extract purity was insufficient for subsequent LC–MS/MS analysis

Summary

Introduction

Hexabromocyclododecane (HBCD) is a group of synthetic organobromines, which is generally used as flame retardant [1]. HBCD belongs to very hydrophobic substances (log Kow >5) with low solubility in water, which tends to accumulate in biota. Directive 2013/39/EU of the European Parliament and of the Council [3], amending the European Water Framework Directive (WFD) [4], classifies HBCD as a priority substance and requires its monitoring in biota (fish) samples for which environmental quality standard (EQS) was set at 167 ng g−1 ww (wet weight). The HBCD concentrations determined are one of the indicators, indicating the long-term status of water quality as well as the suitability of fish for human consumption. HBCD analysis involves the determination of three major diastereomers forming technical mixtures: α-HBCD (10–13%), β-HBCD (1–12%), and γ-HBCD (75–89%) [1]. Because of the Separations 2020, 7, 44; doi:10.3390/separations7030044 www.mdpi.com/journal/separations

Objectives

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Conclusion