阻抑-褪色光度法测定痕量硅

基于NH3 NH4 Cl缓冲溶液介质中 ,Si 对H2 O2 氧化十六烷基三甲基溴化铵 姜黄素离子缔合物的褪色反应的抑制作用 ,提出了测定痕量硅新的高灵敏的褪色光度法。该方法的表观摩尔吸光系数ε50 0=5 .70× 10 5L·mol-1·cm-1;线性范围为 0 .4～ 3.6 μg/L ;线性回归方程ΔA =2 .2 3× 10 -4 + 0 .0 2 0 17CSi (μg/L) ;相关系数r =0 .9999;测定下限为 2 0× 10 -8g/L。本法用于人发样和水样中痕量硅的测定 ,结果满意。

Determination of Trace Silicon by Inhibition Discoloring Spectrophotometry

A new spectrophotometric method for the determination of trace amount of silicon was developed. It is based on the fact that Si(Ⅳ) inhibits discoloration of the ion-association complex of cetyltrimethylammonium-curcumin by H2O2 in the NH3-NH4Cl buffer medium. The apparent molar absorption coefficient ε500=5.70×105 L*mol－1*cm－1. The Beer′s law is obeyed in the range of 0.4～3.6 μg/L with a　linear regression equation ΔA=2.23×10－4＋0.02017CSi(μg/L),r=0.9999. The determination limit is 2.0×10－8 g/L. The method has been used for the determination of silicon in water and hair samples with satisfactory results.