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研究报告

Geochemical characteristics of amino acids in surface sediments of Haihe basin

基金项目：国家水体污染控制与治理重大专项(No.2012ZX07203-002,2012ZX07203-003);国家自然科学基金青年科学基金项目(No.21107126)

摘要：为探明子牙河水系沉积物氮的主要形态,采用柱前衍生反相高效液相色谱-同位素内标法研究了表层沉积物中20种氨基酸的形态及组成特征.结果表明:子牙河水系沉积物中有机氮是氮的主要存在形态,沉积物有机氮(SON)平均浓度为3114 mg·kg^-1,总水解氨基酸氮(THAAs-N)占SON的45.53%;蛋白类氨基酸氮是THAAs-N的主体,占THAAs-N的90.24%,为沉积物潜在释放氮及矿化氮的主体;子牙河水系表层沉积物氨基酸以甘氨酸(Gly)、脯氨酸(Pro)摩尔含量最高,分别占THAAs的14.70%、10.00 %;根据官能团类型分类,蛋白类氨基酸为主要类别,占THAAs的89.50%;蛋白类氨基酸以中性氨基酸为主,平均含量为THAAs的40.69%;亚氨基酸及非蛋白类氨基酸的含量差异性从侧面反映出水系河流污染物来源;采用Glu/γ-Aba及DI指数判断有机质的降解程度,结果显示子牙河水系大部分区域沉积物有机质降解程度较低.

Abstract：In order to examine the main form of nitrogen in sediments of Ziya River basin, 20 amino acids were analyzed by methods of reversed phase high performance liquid chromatography with precolumn derivation and isotope internal standard. The results showed that sediment organic nitrogen (SON) was the main form of nitrogen, with the average concentration of 3114 mg·kg^-1. 45.53% of SON was identified as nitrogen from total hydrolyzable amino acids (THAAs), accounting for 90.24% of THAAs-N. Protein amino acids as the main fraction of THAAs-N were the potential sources of the mineralized nitrogen and nitrogen released from sediments. Glycine and l-proline were the highest mole percent compositions of amino acids in surface sediments of the Ziya River basin, accounting for 14.70 and 10.00% of THAAs, respectively. Amino acids were classified by the type of functional groups, protein amino acids as the main categories, accounted for 89.50 % of THAAs. Neutral amino acids were the main kinds of protein amino acids with the average content of 40.69% of THAAs. Amino acids and nonprotein amino acids could be indicators of pollutant sources in river system. The ratio of l-glutamic acid to γ-aminobutyric acid (Glu/γ-Aba) and degradation index were used to determine the degradation status of organic matter, which showed that most of sediments were in lower degradation state.