钢中微量锶的测定,资料采用偶氮胂Ⅲ光度法,操作手续较为麻烦。我们在此基础上进一步研究,采用偶氮氯膦Ⅲ光度法测定钢中微量锶。该法是用甲基异丁基酮萃取分离大量铁后,在掩蔽剂三乙醇胺、酒石酸钾钠存在下,用偶氮氧化偶氦BN-磷酸三丁酯-环己烷在碱性溶液中萃取锶。以0.12mol/L盐酸反萃取锶于水相,以pH6.65DCTA掩蔽一定量钙、镁及其它金属离子,用偶氮氯膦Ⅲ作显色剂。锶-偶氮氯膦Ⅲ络合物很稳定,最大吸收波长660nm,摩尔吸光系数为3.83×10~4,较偶氮胂Ⅲ法灵敏度提高一倍多,锶量从0—25μg/50mL符合比尔定律,该法测定钢中0.005—0.5％含量的锶,方法准确,操作简便,结果重现性好。一、主要试剂及仪器 Determination of trace amounts of strontium in steel, the data using arsenazo Ⅲ luminosity method, the operating procedures are more troublesome. On this basis, we further study, using chlorophosphonazo Ⅲ spectrophotometric determination of trace strontium in steel. The method is to use methyl isobutyl ketone extraction and separation of large amounts of iron, the masking agent triethanolamine, sodium potassium tartrate in the presence of azo oxidized helium BN-tributyl phosphate - cyclohexane in alkaline solution extraction strontium. Strontium was stripped with 0.12mol / L hydrochloric acid in aqueous phase, masking a certain amount of calcium, magnesium and other metal ions with pH6.65DCTA, and using chlorophosphonazo Ⅲ as chromogenic agent. The strontium-chlorophosphonazo complex was stable with a maximum absorption wavelength of 660 nm and a molar absorptivity of 3.83 × 10 -4. The sensitivity of the strontium-chlorophosphonazo complex was more than double that of the arsenazo Ⅲ method. The strontium content was from 0 to 25 μg / Law, the method for the determination of steel content of 0.005-0.5% strontium, accurate, easy to operate, the results reproducible. First, the main reagents and equipment