Huckins J N, Stalling D L, Johnson J L
J Assoc Off Anal Chem. 1976 Sep;59(5):975-81.
The Armour and Burke method for separating polychlorinated biphenyls (PCBs) from pesticides involves the use of silicic acid. However, we detected di-2-ethylhexyl phthalate, PCBs, and other impurities as interfering contaminants in several batches of silicic acid. The presence of H2SO4 in some batches of silicic acid is inferred. The acid may be responsible for the production of contaminants which interfere in gas-liquid chromatographic analyses. Contaminants in silicic acid are reduced by extracting the adsorbent with solvent, and/or partitioning the concentrated pesticide fraction with 1N NaOH. These purification procedures provide separations relatively free of impurities, but result in reduced adsorbent activity. PCB-pesticide separations are reproducible only within a given batch lot of silicic acid because of the varying adsorbent characteristics of each lot. Alternative adsorbents should be explored for most PCB-pesticide separations.
阿默尔和伯克从农药中分离多氯联苯（PCBs）的方法涉及使用硅酸。然而，我们在几批硅酸中检测到邻苯二甲酸二（2-乙基己基）酯、多氯联苯和其他杂质作为干扰污染物。推测某些批次的硅酸中存在硫酸。这种酸可能是产生干扰气液色谱分析的污染物的原因。通过用溶剂萃取吸附剂和/或用1N氢氧化钠对浓缩的农药馏分进行分配，可以减少硅酸中的污染物。这些纯化程序提供了相对不含杂质的分离，但会导致吸附剂活性降低。由于每批硅酸的吸附剂特性不同，多氯联苯-农药的分离仅在给定批次的硅酸内可重现。对于大多数多氯联苯-农药的分离，应探索替代吸附剂。
