分光光度法测定原油中的钙含量

Determination of Calcium Content in Crude Oil by Spectrophotometric Method

摘要: 分别采用酸性铬蓝K(ACBK)双波长法和三溴偶氮胂(TB-ASA)法测定原油中的钙含量。结果表明：镁离子的干扰影响了用TB-ASA法测定钙含量的精度，而ACBK法采用双波长原理消除了镁离子的干扰，其最佳条件为：组合波长528、541 nm，缓冲溶液的pH为10.5，显色时间30 min，显色剂为3 mL w=0.000 5的ACBK溶液。在此条件下，钙离子的标准曲线为c=446.07ΔA+0.123 9，R2=0.999。ACBK双波长测试方法与电感耦合等离子体发射光谱法(ICP-AES)比较，其测定结果与ICP-AES的结果一致，ACBK双波长法具有操作简单及准确度好的特点。

Abstract: Two spectrophotometric methods ACBK and TB-ASA were developed for the determination of calcium content in crude oil. The results show that the existence of magnesium ion decreases the precision of measurements for TB-ASA method, while the disturbance of magnesium ion can be eliminated by ACBK method due to the dualwavelength spectrophotometery. The optimal conditions include the dual wave length of 528 nm and 541 nm, pH of buffer solution of 10.5, color time of 30 min, and a color agent of 3 mL ACBK solution (w = 0.000 5). The regression equation is c = 446.07ΔA + 0.123 9 with R2 = 0.999 for ACBK spectrophotometery. Compared with the inductively coupled plasma atomic emission spectrometry (ICPAES) method, the ACBK dualwavelength method is more simple and precise while similar results are obtained.