球墨铸铁中稀土元素的测定,目前常采用偶氮肿Ⅲ光度法、偶氮氯磷Ⅲ光度法和偶氮氯磷—mA光度法。偶氮肿Ⅲ与稀土元素的显色反应,使选择性较差,一般均需分离操作。偶氮氯磷Ⅲ比偶氮肿Ⅲ选择性好,可以不经分离直接测定,但灵敏度较低,络合物溶液色泽稳定时间短。偶氮氯磷—mA具 Determination of rare earth elements in nodular cast iron, the current use of azo swollen Ⅲ spectrophotometry, chlorophosphate Ⅲ arsenic and chlorophosphate-mA spectrophotometry. Azole swollen Ⅲ and rare earth color reaction, so that the selectivity is poor, generally require separation. Azo chlorophosphate Ⅲ azo nitrogen selectivity than good, can be directly measured without isolation, but the sensitivity is low, the color stability of complex solution time is short. Azo chlorine phosphorus-mA with