基于乙醇-正己烷的水中石油类测定改进方法研究

Study of an improved determiation methord for petroleum in water based on ethanol-hexane mixture

针对《水质石油类的测定紫外分光度法(试行)》(HJ 970—2018)测定水中石油类时实验器皿污染导致的检测质量问题和正己烷漂洗导致的环境问题,提出了基于乙醇—正己烷的水中石油类测定改进方法,研究了乙醇—正己烷混合溶液的紫外比色规律。结果表明不同体积比(质量比)的乙醇—正己烷混合溶液与紫外吸光度呈高度正相关,乙醇占比较小时对石油类测定结果的影响小于方法检出限,随着乙醇占比的增加,乙醇成为了石油类测定的目标物质,因此,乙醇替代正己烷作为器皿漂洗液是可行的。为了有效保障石油类测定的质量和减少正己烷对检测人员的危害及对环境的污染,建议将器皿洗净晾干后采用乙醇作为漂洗液,并将此改进方法作为HJ 970—2018修订时的重要内容。

In view of the environmental problems while using n-hexane and testing quality problems of contamination of experimental vessels,the colorimetric rules of ethanol—hexane mixture by ultraviolet spectroscopy was studied.An improved method based on ethanol-hexane mixture was presented in this paper to optimize Watew quality-Detemination of petroleum-ulltraviolet spectrophotometric method(HJ 970—2018).The study showed that the ethanol-hexane mixture in various volume ratio(mass ratio)had high positively correlated with absorbance.When the proportion of ethanol in the ethanol—hexane mixtur was low,the influence on the detection result was less than the detection limit of the method.With the increase of the proportion of ethanol,ethanol became the target substance for detection.Therefore it was feasible to use ethanol instead of nhexane as rinsing solution for experimental vessels.In order to effectively guarantee the quality of determination and to reduce harm to human body and to environment,it was suggested to use ethanol insteading of n-hexane as rinsing solution to rinse experimental vessels which had already been cleaned up and dried.And the improved method could be an important part of the revision in HJ 970—2018.