流动注射氢化物发生-原子荧光光谱法测定土壤中有效态As(Ⅲ)和As(Ⅴ)

Determination of Available As(Ⅲ) and As(Ⅴ) in Soils by Flow Injection Hydride Generation Atomic Fluorescence Spectrometry

提出了一种流动注射氢化物发生 原子荧光光谱法测定土壤中有效态As(Ⅲ )和As(Ⅴ )的方法。在0 1mol·L-1柠檬酸介质 (pH =3 1)中选择性测定As(Ⅲ ) ,然后用L 半胱氨酸流动注射在线还原As(Ⅴ )后测定总砷 ,由二者之差求得As(Ⅴ )。设计了在线还原及氢化物发生流路和操作程序 ,选择了各项化学条件和流路参数。As(Ⅲ )和As(Ⅴ )的检出限 (3σ)分别为 0 11和 0 0 7ng·mL-1。对于 10ng·mL-1As(Ⅲ )溶液 ,连续7次测定得精密度 (RSD)为 1 43% ,应用于实际土壤样品的测定 ,加标回收率在 82 %～ 10

A method for the determination of available As(Ⅲ) and As(Ⅴ) in soils by flow injection hydride generation atomic fluorescence spectrometry (FI-HG-AFS) was presented. As the concentration of As(Ⅲ) in extract was determined by HG-AFS in the medium of 0.1 mol·L -1 citric acid solution and the total arsenic was determined after FI on-line reduction of As(Ⅴ) by L-cysteine , the concentration of As(Ⅴ) was calculated by the difference. The manifolds for FI on-line reduction of As(Ⅴ) were designed. The chemical conditions and the operating parameters were optimized. The detection limits (3σ) of As(Ⅲ) and As(Ⅴ) are 0.11 and 0.07 ng·mL -1,respectively, and the relative standard deviation is 1.43 for 7 determinations of 10 ng·mL -1 As(Ⅲ) solution. The developed method was applied to the determination of available As(Ⅲ) and As(Ⅴ) in real soils and the recovery was 82%-104%.