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冰川冻土 ›› 2000, Vol. 22 ›› Issue (1): 36-42.doi: 10.7522/j.issn.1000-0240.2000.0011

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超纯水中甲酸、乙酸污染的实验研究及其对雪冰有机酸测定的意义

李心清, 秦大河, 任贾文, 周会   

  1. 中国科学院, 寒区旱区环境与工程研究所冰芯与寒区环境开放研究实验室, 甘肃兰州730000
  • 收稿日期:1999-03-04 修回日期:1999-09-20 出版日期:2000-02-25 发布日期:2012-04-26
  • 基金资助:
    中国科学院“九五”重大项目 (KZ951-A1-402-03) ;国家自然科学基金 (49871022) ;中国科学院大山冰川观测试验站站长基

Contamination of Acetic and Formic Acids in Water and its Implications for the Study of Carboxylic Acids in Show and Ice

LI Xin-qing, QIN Da-he, REN Jia-wen, ZHOU Hui   

  1. Laboratory of Ice Core and Cold Regions Environment, Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou Gansu 730000, China
  • Received:1999-03-04 Revised:1999-09-20 Online:2000-02-25 Published:2012-04-26

摘要: 塑料容器是降水中生物有机酸研究的常用样品储集器.极地冰芯和粒雪样品钻取中也常用聚乙烯塑料袋盛装,且常常采用双封口方式保存这种样品保存方式和样品暴露于大气一样,都会造成样品中有机酸含量的污染.定量研究上述污染是准确分析降水中有机酸含量的前提和基础.以超纯水为主要实验样品,对聚乙烯塑料容器和空气的甲酸、乙酸污染的研究表明,甲酸、乙酸的污染主要来自聚乙烯塑料袋的热塑封口过程,而聚乙烯塑料桶的影响不明显.塑料袋热塑封口造成的乙酸污染在相同条件下是甲酸的18倍左右.空气对甲酸、乙酸也存在着污染,但其影响远低于聚乙烯塑料袋.因此,在雪冰甲酸、乙酸的研究中,其融样过程必须避开塑料制品,尤其是聚乙烯塑料袋.此外,加大待测样品量 (体积或重量) 也可以一定程度地减小雪冰融化样品的甲酸、乙酸的污染.

关键词: 甲酸, 乙酸, 雪冰

Abstract: Plastics are widely used as containers for storing precipitation samples for the analysis of organic acids. Polyethylene bags are also employed to contain ice and firn samples extracted from the polar regions and double sealed for transportation. The utilization of the containers leads to the contamination of organic acids as atmosphere does with the samples exposed. Making sense quantitatively of the contamination is basically the prerequisite for studies of the organic acids in precipitation. An experimental study of acetic and formic contamination to double deionized water from plastic container and air was performed in laboratory. The result shows that the plastic container, especially the polyethylene bag is a significant source of the contamination. which occurred mainly in the process of the thermal plastic seal. While the solid polyethylene flask, of which no thermal scal is needed to keep the water inside tree of the air outside, remains an undetectable source of the carboxylic acids. The acetic acid contamination due to thermal plastic seal is about 18 times higher than that of formic acid under the same conditions. Additionally, the air is another contributor of formic acid and acetic acid to water samples, the contamination of which are much less than of the plastic bag. Consequently, the study of the carboxylic acids in snow and ice must avoid the plastic containers, especially the polyethylene bags, in the processes of sample preparations.

Key words: formic acid, acetic acid, snow and ice

中图分类号: 

  • P343.6