摘要:
多氯联苯(PCBs)是环境中一类强致癌性持久性有机污染物,而其在环境中含量极低(10-9~10-8 mg/kg级),选择合适的前处理方法,以实现对环境复杂背景中痕量PCBs的分离富集,这对于PCBs的环境毒理学研究具有重要意义。使用绿色环保的前处理技术,减少有机试剂用量,并能简化实验步骤,提高富集和分离效率,且最大程度上减少背景干扰是当前PCBs前处理方法发展的方向。近年来PCBs的前处理方法取得了较快发展,开发新型的萃取材料是发展高效快捷前处理方法的关键因素。文章综述了国内外PCBs的前处理方法,包括液液萃取、超临界流体萃取、微波萃取、加速溶剂萃取、固相萃取。固相萃取已经成为富集PCBs的最佳提取方法之一,固相萃取方法使用的材料(键合硅胶、有机物聚合树脂、活性炭、纳米材料、分子印迹材料)对PCBs富集原理和富集效率、操作过程等各有优缺点。新型的磁性固相纳米萃取材料由于其极高的比表面积和强吸附性能,较常规的固相萃取方法大大缩短了前处理时间;分子印迹萃取纳米材料对PCBs兼具高富集性和高选择性的突出优点,可以大大降低背景干扰,非常适合于痕量PCBs的无干扰萃取。这两种材料是今后主要的发展方向。
Abstract:
Polychlorinated biphenyls (PCBs) are importantly strong carcinogenic persistent organic pollutants, and their concentrations are very low (10-9-10-8 mg/kg) in environmental samples, such as in water or sediment samples. It is very important to select appropriate pre-treatment methods to achieve the separation and enrichment of trace PCBs in complex environmental samples, which is important for the speciation and toxicity study of PCBs. The development direction of the pretreated method for PCBs includes application of green pre-treatment technology, reduction of organic reagents usage, simplification of the chemical procedure, improvement the enrichment and separation effect, and decreasing the background interference. In recent years, substantial progress has been made in pre-treated methods for PCBs and the new developed extraction material is the key for pretreated methods. This paper demonstrates an overview of the main pre-treated methods for PCBs such as liquid-liquid extraction, supercritical fluid extraction, microwave extraction, accelerated fluid extraction and solid-phase extraction. Solid-phase extraction is one of the best methods to enrich PCBs. The different materials for solid-phase extraction have the advantages and defects for the effects of PCBs enrichment and operation. The application of newly developing magnetic solid extraction nanometre materials, which has extremely high specific surface area and better absorbability, reduces the pre-treatment time compared with the traditional solid-phase extraction method. The molecularly imprinted extraction nanometre material has high enrichment and selectivity which reduce the background interference and is better suited to extract low level PCBs. The magnetic solid extraction nanometre material and molecularly imprinted extraction nanometre material are the main research direction for the future.
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