嵌段分子筛聚合材料P123-SH萃取分离-石墨炉原子吸收光谱法分析痕量铬的形态

研究了嵌段分子筛聚合材料P123-SH萃取分离-石墨炉原子吸收光谱法对尿中痕量铬的形态分析方法,探讨了嵌段分子筛聚合材料P123-SH吸附铬的原理和最佳条件。在pH 7.0、常温下,Cr3+和Cr(Ⅵ)被很好的分离,且Cr3+可被该材料定量吸附,其吸附容量为6.15 mg/g。吸附的Cr3+可用2 mol/L的HCl洗脱,用石墨炉原子吸收法测定洗脱下来的Cr3+,往溶液中加入0.1%抗坏血酸将Cr(Ⅵ)还原为Cr3+测总铬,Cr(Ⅵ)含量为总铬减去Cr3+,方法测定Cr3+的检出限为0.011μg/L(3σ,n=11),线性范围为0.1～10μg/L,加标回收率在94%～106%之间,对0.50μg/L的Cr3+溶液平行测定7次,RSD为3.6%。方法可应用于生物样品和环境样品中痕量铬的形态分析。

Study on triblock copolymer mesoporous P123-SH material for the separation/extraction and determination of trace speciation of chromium by graphite furnace atomic absorption spectrometry

A sensitive and selective method has been developed for the speciation analysis of Cr3+ and Cr(Ⅵ) in urine using triblock copolymer mesoporous P123-SH material and graphite furnace atomic absorption spectrometry(GFAAS).Under the optimized conditions(pH 7.0) Cr3+ was retained on the triblock copolymer mesoporous material,then eluted with 2.0 mol/L HCl and determined by graphite furnace atomic absorption spectrometry(GFAAS).Total chromium was determined after the reduction of Cr(Ⅵ) to Cr3+ by ascorbic acid as a reducing reagent.The absorption capacity was 6.15 mg/g.The detection limit was 0.011 μg/L(3σ,n=11).The linear range was 0.1~10 μg/L.The recoveries of Cr3+ and Cr(Ⅵ) were 94.0%~106.0%.The RSD was 3.6%(n=7,c=0.50 μg/L).The proposed method has been applied to the determination of speciation of chromium in urine samples and environmental water.