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• CN 62-1072/P
• ISSN 1000-0240
• 创刊于1979年
• 主管单位：中国科学院
• 主办单位：中国科学院寒区旱区
•                  环境与工程研究所
•                  中国地理学会

• 研究论文 •

### 雪冰中生物有机酸的测试分析方法研究

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:2000-03-12 修回日期:2000-05-08 出版日期:2001-02-25 发布日期:2012-04-26
• 基金资助:
中国科学院“九五”重大项目(KZ951-Al-402-03);国家自然科学基金项目(49871022;40073035);中国科学院寒区旱区环境与工程研究所天山冰川观测试验站站长基金,中国博士后基金会博士后基金项目资助

### Determination of Organic Acids in Snow and Ice from Mountain Glaciers

LI Xin-qing(LEE Xin-qing), QIN Da-he, ZHOU Hui

1. Laboratory of Ice Core and Cold Regions Environment, CAREERI, CAS, Lanzhou Gansu 730000, China
• Received:2000-03-12 Revised:2000-05-08 Online:2001-02-25 Published:2012-04-26

Abstract: Organic acids are major chemical species in acidic precipitation. This is especially true for light carboxylic acids in precipitation in remote areas. Thus, they play a significant part in acidification of environment. Because organic acids are closely related to the biosphere in terms of their sources, their records in snow and ice provide ways for learning changes of paleoenvironment and paleoecosystem, as well as biogeochemical cycles of C, H, O or S. However, they are very difficult to determine for their trace concentration and susceptibility to contamination. For samples from a specific place and with a specific Ion Chromatography (IC), use of the conventional instrument must take into consideration the following aspect: 1) The IC used should have advanced pump system that enables gradient elution; 2) Pre concentrator columns and anion trap columns should be added to the system; 3) The gradient elution should eluent and separate both organic and inorganic anions present in a sample in a single run; 4) Weak chemical reagent should be used for separation of monovalent analyses with similar affinity. Accordingly, a method for determining organic acids together with inorganic anions in snow and ice from mountain glaciers is provided in this paper. Based on a DX-300 Ion chromatography, the method uses AS4A-SC and AG4A-SC as separator and guard column, respectively, TAC-2 as a concentrator column, which is installed in place of sample loop, and ATC-1 as a contaminant trap column that is installed before injection valve. ASRS-Ⅱ suppressor column and chemical suppression mode is employed. The suppression solution is 25 mM H2SO4 with a flow rate of 5 mL·min-1. The eluent is prepared from Na2B4O7·10H2O in 18.2 MΩ water. In order to analyze like species Fluoride, Acetate, Formate, Pyruvate and Methanefulfonate that are closely related in affinity thus prone to be co eluented, and to separate and quantitate in the same run all anions present in samples, gradient elution is adopted with a constant eluent rate of 2 00 mL·min-1. In the first 6 min, the eluent is kept in 2.0 mM for elution of F-, monovalent organic acids and Pyruvate; in the next 5 min, the concentration increases from2 mm to 31.5 mm for elution and separation of Cl-, NO2-, Br-, NO3- and PO43-; and in the last 3 min, the eluent is hold at 31.5 mM until SO42- and (CO)22- is eluented. The method resolves and quantitates in a single run over 10 analyses both organic and inorganic species from Fluoride, Acetate to Phosphate, Sulfide and finally Oxalate. The relative standard errors for some anions are: 2.0% for Fluoride, 4.5% for Acetate, 2.0% for Formate, 16.9% for Methanesulfonate, 3.1% for Chloride, 3.9% for Nitrite, 2.2% for Nitrate, 4.9% for Bromide and 2.4% for Sulfate.

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