微乳液介质-PAR显色体系光度法测定油中的Co2+
邓秀琴,吴丽香
辽宁石油化工大学顺华能源学院化学工程系,辽宁抚顺 113001
Determination of Co2+ in the Oil by Microemulsion Medium-PAR Chromogenic System Spectrophotometry
邓秀琴,吴丽香
Shunhua Energy College of Liaoning Petrochemical University, Fushun 113001, China
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0~25 μg/(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0.13 μg/(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。
Abstract:The direct determination of trace Co2+ 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. Co2+ formed a stable orange-red complex with PAR, which had maximum absorption peak at 518 nm. Beer's law was obeyed as the Co2+ content c in the range of 0-25 μg/(25 mL). Linear regression equation was A=0.042 02c+0.004 46 with correlation coefficient of r=0.999 5. The Co2+ 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 0.13 μg/(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.
关键词:微乳液;PAR显色剂;分光光度法;油样;Co2+
Keywords:microemulsion; PAR chromogenic reagent; spectrophotometry; oil sample; Co2+
本文引用格式:
邓秀琴,吴丽香.微乳液介质-PAR显色体系光度法测定油中的Co2+[J].化学分析计量,2014,23(3):76-78.
DENG X Q,WU L X.Determination of Co2+ in the Oil by Microemulsion Medium-PAR Chromogenic System Spectrophotometry[J]. Chemical analysis and meterage,2014,23(3):76-78.
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