论文部分内容阅读
用流动注射 -氢化物发生 -非色散原子荧光光谱法对海水中 As( )和As( )的直接测定进行了研究。氢化物发生的最佳条件为 :KBH4 溶液浓度为 5g·L-1(含 KOH5g· L-1) ,流速 1 0 .0 m L·min-1;样品酸度为 1 .3mol· L-1HCl,流速 4.2 m L· min-1。对基体 Na Cl,Mg Cl2 ,Ca Cl2 ,Na2 SO4 以及微量共存金属离子 (Cd,Zn,Pb,Cu)的干扰实验结果表明 ,基体和微量共存金属离子对 As( )的测定没有干扰。样品中 As( )的测定用硫脲进行预还原 ,通过总量和As( )含量的差减得到 As( )含量。在优化实验条件下测得方法的检出限(3σ)为 0 .0 8ng· m L-1;7次测定的相对标准偏差为 0 .48%～ 1 .30 % (8.0ng· m L-1标准溶液 )。标准曲线和标准加入法对海水样品测定的对照结果表明 ,两种方法测定结果吻合较好。该方法已应用于近岸海水和大洋海水中 As( )和As( )的直接测定。
The direct determination of As () and As () in seawater was studied by flow injection-hydride generation-non-dispersive atomic fluorescence spectrometry. The optimum condition for the hydride generation is as follows: the concentration of KBH4 solution is 5 g · L-1 (containing KOH5g · L-1) and the flow rate is 10 · 0 m L · min-1; the sample acidity is 1.3mol · L-1HCl, Flow rate 4.2 m L · min-1. The experimental results on interferences of Na Cl, Mg Cl2, Ca Cl2, Na2 SO4 and trace coexisting metal ions (Cd, Zn, Pb, Cu) showed that there was no interference of As (subscript A) with the matrix and trace coexisting metal ions. Determination of As () in the sample was prereduced with thiourea and the As () content was obtained as the difference between the total and As () contents. The detection limit (3σ) of the method was 0.08 ng · m L-1 under the optimized experimental conditions. The relative standard deviations of the seven determinations were 0.48% -130% (8.0 ng · m L- 1 standard solution). Comparison of standard curve and standard addition method for the determination of seawater samples showed that the two methods were in good agreement with each other. This method has been applied to the direct determination of As () and As () in coastal seawater and oceanic seawater.