自动样品前处理在乳品中二恶英和共平面多氯联苯同时测定中的应用

Application of Automatic Clean-Up System to Simultaneous Analysis of Polychlorinated Dibenzo-p-Dioxins and-Furans and Planar Polychlorobiphenyls in Milk

采用索氏提取及自动净化处理系统对乳品进行提取和净化，在高分辨气相色谱-高分辨双聚焦质谱仪（HRGC／HRMS）上进行定性和定量检测。在3种不同残留水平的奶粉样品中，17种多氯代二苯并-对二恶英和多氯代二苯并呋喃（PCDD／Fs）的测定结果与给定值具有很好的一致性，且所有具有保证值的二恶英同系物测定结果的相对标准偏差（RSD）均小于20％；12种共平面多氯联苯（PCBs）测定结果的RSD均在1596以内，内标物的回收率为44％～133％，完全符合国际标准方法的要求。母乳样品的国际考核结果表明本方法在不同实验室间具有良好的准确度和精密度。本方法定量准确可靠，适用于乳品中二恶英及共平面PCBs的同时检测。

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.