电子元器件引脚的前处理及Cr^6＋的测定

Pretreatment of electronic components/ devices lead frame and determination of Cr^(6+)

采用湿消解法,即用氧化性的混酸(3 mL质量分数为15%硝酸、1 mL浓盐酸)溶解电子元器件引脚,以保证样品中铬的价态不变。此样品处理方法简单、分解速度快、不引入其它阳离子且多余的酸易于除去。消除基体干扰后,用分光光度法测定了样品中的六价铬,加标回收率为98.7%~102%。

Wet nitration method which include 3 mL of 15% HNO3 （mass fraction） and 1 mL of concentrated HC1 was chosen to dissolve the electronic components/devices lead flame to guarantee the valence unchange of Cr^6＋ in the sample, This pretreating method of the sample is simple, rapid and other cations are not introduced and remained acids are removed easily. After eliminating the matrix interferences, the Cr^6＋ in the sample was determined by spectrophotometry. Rates of recovery test obtained by standard addition method were in the range of 98.7%-102%.