基于纳米SiO_(2)的分散微固相萃取环境水样中的无机硒

Dispersed micro-solid phase extraction of inorganic Se in environmental water samples based on nano-silica

通过建立一种基于分散微固相萃取(D-μ-SPE)技术的高灵敏度和高特异性方法,用于测定环境水样中的无机硒。采用非常简单且快速的预富集方法,即利用纯纳米二氧化硅萃取与吡咯烷二硫代氨基甲酸铵(APDC)络合的Se(Ⅳ)。用乙酸乙酯洗脱纳米SiO_(2)中的Se(Ⅳ),然后通过电热原子吸收光谱法(ETAAS)进行测定。在形态分析方面,预还原步骤后基于总无机Se和Se(Ⅳ)之间的浓度差异,选择性地对于Se(Ⅳ)进行定量。并对pH值、离子强度、螯合剂种类等因素进行优化,最终得到92%的保留率,最佳优化条件为pH=2.0、4.8μmol/L的APDC和使用1 mg纳米SiO_(2)为吸附剂。基于10 mL样品的研究结果得出:LOD为1.2 ng/L,LOQ为4.2 ng/L,相对标准偏差为3.6%。本研究方法最终可用于不同来源和成分的环境水样,包括自来水、雨水、地下水和江水。

A highly sensitive and specific method based on dispersed micro-solid phase extraction(D-μ-SPE)was established for determination of inorganic selenium in environmental water samples.A very simple and fast preconcentration method was used,that is,using pure nano-silica to extract Se(Ⅳ)complexed with ammonium pyrrolidine dithiocarbamate(APDC).The retained Se(Ⅳ)was eluted from nano-silica with ethyl acetate,and determined by electrothermal atomic absorption spectrometry(ETAAS).For speciation analysis,Se(Ⅵ)was selectively quantified based on the concentration difference between total inorganic Se and Se(Ⅳ)after a prereduction step.The pH value,ion strength and chelating agent type were optimized,the retention rate of 92% was obtained,the optimum conditions were as follows:APDC of pH=2.0,4.8μmol/L and 1mg of nano-SiO_(2)as adsorbents.The results of the study based on the 10 mL sample yielded the LOD of 1.2 ng/L,the LOQ of 4.2 ng/L and the relative standard deviation of 3.6%.The method can be used for determination of environmental water samples of different sources and components,including tapwater,rainwater,groundwater and riverwater.