[Determination of hexabromocyclododecanes in ambient air by high performance liquid chromatography- electrospray...

A high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method was developed for the determination of hexabromocyclododecanes (HBCDs) in ambient air samples. The samples were extracted by Soxhlet extractor with hexane, then purified on the composite gel column. At first, the interfering substances were rinsed with 50 mL hexane and 100 mL hexane-dichloromethane (9:1, v/v), then 180 mL hexane -dichloromethane (4:1, v/v) was used to elute the targets. The compounds were separated by gradient elution with acetonitrile-methanol-water as mobile phases on a UF-ODS column (150 mm×2.1 mm, 3.0 μm). Electrospray ionization negative ion source and selective ion monitoring (SIM) mode were adopted in MS detection. The results showed that α -HBCD, β -HBCD and γ -HBCD could be well separated, and the chromatographic peak area ratio of α -HBCD, β -HBCD and γ -HBCD to internal standard D₁₈- γ -HBCD with their concentrations had a good linear relationship, with the correlation coefficients (R) ≥ 0.9988. The limits of detection (LODs, S/N=3) of α -HBCD, β -HBCD and γ -HBCD were 0.4, 0.5 and 0.4 μg/L, respectively. The limits of quantification (LOQs, S/N=10) were 1.4, 1.6 and 1.3 μg/L, respectively. The method detection limits (MDL) were 0.13, 0.17 and 0.13 pg/m³ (n=5), respectively. The recoveries of HBCDs spiked in the actual air samples were in the range of 74.8%-95.8%. It is demonstrated that the method has high sensitivity and good selectivity, and can meet the requirement of monitoring and analyzing HBCDs in air samples.