Comparison of shaking extraction and reflux extraction for the determination of PCDDs, PCDFs and coplanar PCBs in vegetables

Abstract

Two different extraction methods involving shaking extraction and reflux extraction were examined for the determination of PCDD/Fs and Co-PCBs in vegetables. The two sets of vegetables were extracted by shaking with acetone/hexane and reflux with toluene, followed by a cleanup step. Then, determination of PCDD/Fs and Co-PCBs was carried out by HRGC/HRMS. From three individual experiments, total concentrations of PCDDs, PCDFs and Co-PCBs in a spinach sample were 0.48±0.04, 0.80±0.06 and 7.7±0.1 pg/g by shaking extraction, and 0.43±0.08, 0.72±0.05 and 7.3±0.7 pg/g by reflux extraction. In a chingentsuai sample, total concentrations of PCDDs, PCDFs and Co-PCBs were 0.67±0.19, 0.50±s0.08 and 2.6±0.6 pg/g by shaking extraction, and 0.81±0.17, 0.64±0.13 and 2.6±0.6 pg/g by reflux extraction. No significant difference in total concentrations was observed between the two extraction methods. Moreover, total TEQ concentrations in the two vegetables showed almost the same values. Our results indicate that these extraction methods are equally efficient for extracting PCDD/Fs and Co-PCBs from vegetables.