燃烧-微库仑法汽油中有机氯含量测定方法的优化

Optimization of determination of organochlorine content in gasoline by combustion-microcoulometry method

为了提高汽油中有机氯含量测定的准确度和精密度,基于燃烧-微库仑法,采用0.02 mol/L乙酸钠的水溶液作汽油无机氯萃取剂,优化了直接测定和总氯含量差减无机氯含量(差减法)测定汽油中有机氯含量的方法。结果表明:采用0.02 mol/L乙酸钠的水溶液取代水-乙醇(异丙醇)溶液作无机氯萃取剂,可取上层油相直接测定汽油有机氯含量;采用萃取剂内含0.10~0.20 mg/L无机氯盐的空白加标方法,解决现行差减法部分汽油中有机氯含量偏差大的问题;2种方法的测定结果相对偏差均不大于10%。

In order to improve the accuracy and precision of the determination of organochlorine content in gasoline,basing on combustion-microcoulometry method,the direct determination method and the difference of total chlorine content minus inorganic chlorine content(difference subtraction method)were optimized by using 0.02 mol/L sodium acetate solution as the inorganic chlorine extractant.The results showed that aqueous solution of 0.02 mol/L sodium acetate was used as inorganic chlorine extractant instead of aqueous solution of water-ethanol(isopropyl alcohol),and the content of organic chlorine in gasoline could be directly determined by the upper oil phase.The extractant containing 0.10-0.20 mg/L inorganic chloride was used to solve the problem of large deviation of organic chlorine content in some gasoline in the current differential subtraction method.The relative deviation of the above two methods was less than 10%.