原子吸收硫化锌法间接测定精氨酸络合反应的机理研究

通过编程计算精氨酸和锌离子在不同pH条件下的各种存在形式,通过分析拟合分布图,研究了在硫化锌法原子吸收间接测定精氨酸时的pH对原子吸收响应的影响及络合反应的机理.经对不同形态的精氨酸与金属锌离子的共存区域的各种组合探讨,指出在pH 9.0左右最佳测定条件下的pH响应峰是由于精氨酸和锌离子的两种不同存在形式的变化所引起的左右峰边缘,精氨酸是以正一价荷电形态的精氨酸基Arg -与Zn(OH)2形成了可溶性络合离子HN=CH(NH 3)-NH-(CH2)3-CH(NH 3)-COO]2Zn(OH)2.结果表明,理论分析计算的结果与实验数据得到了基本吻合,确定了硫化锌法原子吸收间接测定精氨酸时的络合物反应机理及络合物的组成结构.

Studies of Complexing Action Mechanism in the Indirect Determination of Arginine by FAAS with ZnS

Each state of arginine and zinc ion in aqueous solution under different pH conditions was calculated by computer, giving out the scattergram. After the investigation, the mechanism of complexing action in indirectly determining arginine by flame atomic absorption spectrometry with ZnS was studied in terms of the influence of solution pH. It is with different state of arginine and zinc ion in aqueous solution in differential pH that the response peak with pH in given conditions is obtained. The reason for forming the left peak is different from the reason for forming the right peak. The soluble complexing ion is composed of 1 valence arginine Arg - and Zn(OH)_2. The theoretical analysis from computing and scattergram dovetails very well the data determined from the experiments. The structure of complexing ion is HN CH(NH _3) NH (CH_2)_3 CH(NH _3) COO]_2Zn(OH)_2.