2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚分光光度法测定原油及环烷酸钴中钴

Spectrophotometric determination of cobalt in crude oil and cobalt naphthenate with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

采用Co^2＋-2-（5-溴-2-吡啶偶氮）-5-二乙氨基苯酚（5-Br-PADAP）-OP显色体系测定钴。在硫磷混合酸介质中共存元素与5-Br-PADAP形成的有色络合物被分解破坏，从而达到消除干扰的目的。建立了分光光度法测定原油及环烷酸钴中钴的分析方法。对测定条件、灰化条件进行了考察。样品测定结果的相对标准偏差：原油小于3．1％，环烷酸钴小于0．2％。合成样品回收率为99．6％～104．5％；样品加标回收率：原油96．7％～103．1％，环烷酸钴97．9％～101．9％。

In the medium of mixed acid of H2SO4 - H3PO4, the complex formed by coexistence elements with 2-（5-bromo-2-pyridylazo）-5-diethylaminophenol （5-Br-PADAP） were decomposed, thus attaining the goal for elimination of interference. A spectrophotometry for determination of cobalt in crude oils and cobalt naphthenate was reported based on the color system of Co^2＋ - 5-Br-PADAP- emulsifier OP. The deter mining and ashing conditions were studied. The relative standard deviations of determination results were less than 3.1% for crude oils and 0.2% for cobalt naphthenate. The recoveries of synthetic sample were 99.6 % - 104.5 %. The recoveries of standard addition of samples were 96.7 % - 103.1% for crude oils and 97.9% -101.9% for cobalt naphthenate.