摘要
采用微乳液为介质,以4-(2-吡啶偶氮)–间苯二酚(PAR)为显色剂,在乙酸–乙酸钠缓冲体系中,利用分光光度法测定油样中的微量Co2+。Co2+与PAR形成稳定的橙红色络合物,其最大吸收峰位于518 nm处,Co2+含量c在0～25μg/(25 mL)范围内服从比耳定律,线性回归方程为A=0.042 02c+0.004 46,相关系数为0.999 5。以该方法测定辽河重油和辽河渣油中钴Co2+的含量,其相对标准偏差分别为1.73%和2.22%(n=6),回收率分别为102.60%和97.67%,检出限为0.13μg/(25 mL)。研究结果表明,该方法不需分离可以直接测定油样中的Co2+,具有经济适用,简单易行,灵敏度、准确度高,选择性好等特点。
The direct determination of trace Co^2＋in oil samples by spectrophotometry was established,using the micro-emulsion （cetylpyridinium bromide-n-butanol-n-heptane-water volume ratio was 1∶1∶1∶97） as the medium, and 4-（2-pyridylazo）-resorcinol （PAR） as chromogenic reagent in acetic acid-sodium acetate buffer system. Co^2＋formed a stable orange-red complex with PAR,which had maximum absorption peak at 518 nm. Beer’s law was obeyed as the Co^2＋content c in the range of 0-25μg/（25 mL）. Linear regression equation was A=0.042 02c＋0.004 46 with correlation coefficient of r=0.999 5. The Co^2＋contents of Liaohe heavy oil and Liaohe residue oil were determined by this method, their relative standard deviations were 1.73%and 2.22%（n=6）, respectively,the recovery rates were 102.60%and 97.67%, respectively,and the detection limit was 0.13μg/（25 mL）. This method can directly determine Co2＋in oil samp without separation. The method is simple and has high sensitive and accuracy,good selectivity of characteristic.
出处
《化学分析计量》
CAS
2014年第3期76-78,共3页
Chemical Analysis And Meterage
