乙醇替代丙酮测定水中叶绿素a的优化实验研究
Experimental Optimization Study on the Determination of Chlorophyll a in Water by Substituting Acetone with Ethanol

叶绿素a是评价水体富营养化的重要指标，多所高校的环境类专业开设了“丙酮–分光光度法测定水中叶绿素a含量”的本科教学实验。丙酮具有较强挥发性和一定毒性，具有特殊气味，在使用中可能对实验人员造成危害，增加了实验成本和风险性。为了倡导绿色化学，针对这一问题本文探讨了现有国内外测定方法，并实验研究了乙醇法替代丙酮法的可行性，优化了实验参数。实验结果表明：乙醇和丙酮的提取时间对测定结果均有显著性影响，酸化时间对乙醇–分光光度法的测定结果没有显著性影响；乙醇–分光光度法在提取时间为15 h、酸化时间为5 min时，与丙酮法结果最接近。乙醇法替代丙酮法作为大学本科教学实验《水中叶绿素a含量的测定》的教学方法是可行的。本文提供了可用于高校本科实验教学的减排优化实验方案，也可为其它研究院所、工矿企业，环保部门进行叶绿素a测定技能培训教学提供服务。
Chlorophyll a is an important indicator to evaluate the eutrophication of water bodies, and the undergraduate teaching experiment of “acetone-spectrophotometric determination of chlorophyll a content in water” has been introduced in the environmental majors of many universities. Acetone has strong volatility and toxicity, and has a special odor, which may cause harm to the ex-perimenters and increase the cost and risk of the experiment. In order to advocate green chemistry, this paper discusses the existing domestic and international determination methods, and ex-perimentally investigates the feasibility of the ethanol method instead of acetone method, and op-timizes the experimental parameters. The experimental results showed that the extraction time of both ethanol and acetone had a significant effect on the determination results, and the acidification time had no significant effect on the determination results of the ethanol-spectrophotometric method; the results of the ethanol-spectrophotometric method were closest to those of the acetone method when the extraction time was 15 h and the acidification time was 5 min. The ethanol method is feasible to replace the acetone method as a teaching method for the undergraduate teaching experiment “Determination of chlorophyll a content in water”. This paper provides an optimized experimental scheme for emission reduction that can be used for undergraduate ex-perimental teaching in universities, and can also be used for training and teaching of chlorophyll a determination skills in other research institutes, industrial and mining enterprises, and environ-mental protection departments.