高频燃烧红外吸收法测定锡铅焊料中痕量硫

Determination of trace sulfur in tin-lead solder by high frequency combustion infrared absorption method

以硫酸钾基准试剂绘制校准曲线,将试样置于铺有0.50g纯铁的瓷坩埚中,再覆盖3.0g纯钨,建立了高频燃烧红外线吸收法测定锡铅焊料中痕量硫的方法。确定最佳实验条件如下：硫质量分数不大于0.001 0%时,试样量为1.0g;硫质量分数为0.001 0%-0.010%时,试样量为0.50g;硫质量分数为0.010%-0.025%时,试样量为0.20g。结果表明,硫量在0.001 0-0.050mg之间与其吸光度呈良好的线性关系,相关系数r=0.999 7。方法检出限为0.000 021%,测定下限为0.000 084%。对选定的4个不同硫含量水平的锡铅焊料内控样品进行11次平行测定,测定结果与参考值基本一致,相对标准偏差（RSD）在7.3%-15.0%之间,回收率在96%-115%之间。硫质量分数在0.000 10%-0.025%之间,方法的重复性标准偏差为Sr=0.064 6 x＋0.000 01、重复性限为r=0.181 2 x＋0.000 03,再现性标准偏差为SR=0.081 9 x-0.000 002、再现性限为R=0.229 7 x-0.000 006。

The calibration curve was prepared by standard reagent of potassium sulfate.The sample was placed onto porcelain crucible containing 0.50 g of pure iron followed by covering 3.0g of pure tungsten.The determination method of trace sulfur in tin-lead solder by high frequency combustion infrared absorption method was established.The optimal experimental conditions obtained were listed as below：the sample mass was 1.0g when S≤0.001 0%;the sample mass was 0.50 g when 0.001 0〈%S≤0.010%;the sample mass was 0.20 g when 0.010%〈 S≤ 0.025%.The results indicated that the sulfur content in range of 0.001 0-0.050 mg showed good linearity to the absorbance.The correlation coefficient was r=0.999 7.The detection limit of method was 0.000 021%,and the low limit of determination was 0.000 084%.Four internal control samples of tin-lead solder with different content of sulfur were determined for 11 times.The found results were basically consistent with the reference values.The relative standard deviation（RSD）was between 7.3% and 15.0%.The recoveries were between 96% and 115%.When the mass fraction of sulfur was in range of 0.000 10%-0.025%,the repeatability standard deviation was Sr =0.064 6 x＋0.000 01,the repeatability limit was r=0.181 2 x＋0.00 003,the reproducibility standard deviation was SR =0.081 9 x-0.000 002,and the reproducibility limit was R =0.229 7x-0.000 006.