Cloud point extraction coupled with ultrasound-assisted back-extraction for determination of trace legacy and emerging brominated flame retardants in water using isotopic dilution high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry

Abstract

Isotopic dilution high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry method was developed for determination of seven legacy and emerging brominated flame retardants (BFRs) in water using cloud point extraction coupled with ultrasound-assisted back-extraction. The effects of different experimental conditions on the recovery and matrix effect during cloud point extraction were investigated. Under the optimum conditions (sample volume: 40 mL; Triton X-114 concentration: 1.0 g L−1; equilibration temperature: 40 °C; equilibration time: 10 min; NH4OAc concentration: 0.5 M), the absolute recoveries obtained by cloud point extraction for the seven BFRs ranged from 64.0% to 108.8%, with matrix effect factors ranging between 0.70 and 1.07. Ultrasound-assisted back-extraction combined with isotope dilution mass spectrometry was utilized to enhance the enrichment factor and improve the repeatability. Under the optimized conditions, method limits of detection for BFRs ranged from 0.3 to 3.0 ng L−1. The average recoveries were in the range of 92.9–113.6% and 86.0–99.3% for spiked water samples at 10 and 100 ng L−1 of each BFR. The intra- and inter-day relative standard deviations (n = 6) were less than 5.4% and 8.0%, respectively. The results demonstrated that the proposed method was highly sensitive, efficient and reliable for the determination of trace legacy and emerging BFRs in water samples.