Abstract:

Since the chemical nature and toxicity of planar polychlorobiphenyls (PCBs) are similar to those of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs). Dioxin-like PCBs and PCDD/Fs are often surveyed together in their exposure assessments. The analysis of PCBs and PCDD/Fs in breast milk is specially emphasized by World Health Organization (WHO) due to their severe toxicity. The development of a method for the simultaneous analysis of PCBs and PCDD/Fs in milk samples is invaluable. In this work, three certified milk powder materials with different PCDD/Fs levels were Soxhlet-extracted and then cleaned up using Power-Prep system automatically. PCDD/Fs and planar PCBs were determined using isotope dilution and high resolution gas chromatography-high resolution mass spectrometry. The determined values of 17 PCDD/Fs were consistent with the certified values and the relative standard deviations (RSDs) of the determined values were less than 20%. The recoveries of 13C labeled PCDD/Fs and planar PCBs, and their RSDs were within the ranges specified in EPA1613 and 1668a methods, respectively. Meanwhile, the analytical results of breast milk in an interlaboratory comparison showed that this method has good reproducibility between different laboratories. An accurate and reliable method was successfully developed and can be used in the simultaneous analysis of PCDD/Fs and planar PCBs in milk.

Key words: dioxin, isotope dilution, polychlorinated biphenyls , high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS)