天然磁铁矿吸附-电感耦合等离子体质谱测定砷

Natural Magnetite Solid Phase Extraction-Inductively Coupled Plasma Mass Spectrometry for Determination of Arsenic in Water

基于天然磁铁矿对砷的选择性吸附作用,建立了以天然磁铁矿为除砷吸附剂、电感耦合等离子体质谱法(ICP-MS)测定饮用水中砷的方法。考察了吸附剂用量、溶液酸度、吸附时间、竞争共存离子等因素对As(Ⅲ)和As(Ⅴ)吸附效率的影响。结果表明,在pH5时,选取0.5g天然磁铁矿,振荡48h后,吸附反应基本达到平衡,此时可定量分析吸附样品中的砷含量。本方法检出限为0.039μg/L,对样品检测的相对标准偏差为0.738%(n=8)。用本方法对已知砷浓度的模拟天然水成分分析标准物质(GBW08605)进行测定,结果在标准范围之内,加标回收率为100.7%～103.2%。本方法简便快速且易于操作,可用于天然饮用水体中砷的富集分离与测定。

The performance of natural magnetite used as extractant for solid phase extraction and its application for the determination of arsenic in water were studied.The parameter affecting the extraction and adsorption process was optimized.Under the optimized conditions（extraction time was 48 h,pH was 5,magnetite was 5 g）,the limit of detection of this method was 0.039 μg/L,RSD（n = 8） was 0.7%.This method is simple,and can be successfully applied to determine As in water sample with good accuracy and precision.The results were evaluated by comparing with a CRM（GBW08605） standard sample.