Study on the cocolouration effect in the β-complex formation reactions of rare earths with p-chloro-chlorophosphonazo (CPApC)

Terbium- and yttrium-group rare earths form β-complexes with CPApC in acidic medium. The sensitivities for determination of these rare earths by this reaction depend on their ionic radii. Cerium- or terbium-group rare earth in the presence of yttrium-group element produces the cocolouration effect which remarkably sensitizes the reaction. Yb-CPApC-Eu complex has a molar composition of 1:4:2 and gives a molar absorptivity of 2. 02 ×10~5 L·mol^(-1)·cm^(-1) at 746 nm for Eu. It is found that the closer the lengths of ionic radii of the rare earths are, the greater will be the cocolouration effect.

对氯偶氮氯膦作退色剂测定低合金钢中铬

<正>光度法测铬通常采用二苯基碳酰二肼法。近年也有偶氮氯膦类试剂作退色剂测定铬的报道,但灵敏度都不太高。用对氯偶氮氯膦(CPAPC)作退色剂测定铬尚未见有报道。本文研究了在Triton X-100存在下,CPAPC与Cr(Ⅵ)的退色反应,拟定出测定Cr(Ⅵ)的新方法。该方法反应酸度高,操作简便、快速,重现性好。在550nm处,其摩尔吸光系数为1.21×10~5,Cr(Ⅵ)含量在0～6μg/20ml范围符合比耳定律。该方法测定结果与标准值相吻合,而且在测定Cr(Ⅵ)方面有实际应用价值。

对氯偶氮氯膦分光光度法测定钴基合金中微量钇

在pH4.5的弱酸介质中,钇与对氯偶氮氯膦形成1:1的β型络合物,其最大吸收波长和表观摩尔吸光系数分别为746nm和1.56×10~5。方法用于钴基合金中微量钇的测定,结果满意。