偶氮胂Ⅲ褪色光度法测定锡铈合金镀液中的铈

Determination of cerium amount in the tin-cerium alloy plating bath by discoloring spectrophotometry of arsenazo Ⅲ

为了抑制锡的水解而干扰铈的测定,采用偶氮胂Ⅲ褪色光度法测定新型酸性光亮镀锡铈、锡铜合金镀液中的铈;优选出的最佳测定波长为538 nm.研究了硫酸﹑甘油、显色剂的用量以及共存离子对测定的影响,有色溶液吸光度的减少值与铈的含量在0.4～10μg/mL范围内服从朗伯比耳定律,摩耳吸光系数为1.2×104L/(mol·cm);样品加标回收率达98%以上.该方法简便、快速、准确度高,不经分离可直接对锡铈合金镀液中的铈进行测定.

This paper studies the chromogenic reaction of Ce4~ and Arsenazo II1 to inhibit tin hydrolysis which may interference the determination of cerium in the new tin-cerium or tin-copper alloy plating bath. A new-style of speetrophotometry determination the concentration of Ce4＋ was set up. The result indicates that the maximum absorption wavelength is 538 nm. The relationship between the decrease of absorbanee and Ce4＋ content follows Lambert＇s law when the Ce4~ content is among 0.4 and 10 Ixg /mL. The molar absorptivity is 1.2~104 L.mol-t .cm-l. The effects of sulfuric acid, glycerin, developer and interfering ions were studied. The determination technology is fast, simple and accurate. When the sample was added standard cerium, the recovery was higher than 98 %. This method can be used in determining cerium amount in the new tin-cerium or tin-copper alloy plating bath.