动力学光度法测定环境样品中微量钒

Determination of Trace Amount of Vanadium in Environmental Samples with a Kinetic Spectro-photometric Method.

本文研究了V(Ⅳ)对Cr_2O_7^(2-)-I^--淀粉氧化还原反应体系的诱导作用,以此为基础提出了一种测定微量钒的动力学新方法,并建立了测定最佳条件:[Cr_2O_7^(2-)]=8.4×10^(-5)mol·L^(-1),[I^-]=2.1×10^(-3)mol·L^(-1),pH=2.1,585nm。在此条件下,钒(Ⅳ)含量在0—6.6μg·ml^(-1)范围内符合比尔定律,方法检测限为0.02μgV(IV)·ml^(-1)。除Fe^(3+),Fe^(2+),Sn^(2+),Ti^(3+)外,其它共存离子不影响测定。用本方法测定了几种环境样品中的微量钒,结果满意,标准加入回收率为95.1—98.3％。

A novel kinetic spectrophotometric method for the determination of trace amount of vanadium was proposed based on the inductive effect of Ⅴ(Ⅳ) on Cr2O2 7--I--starch redox reaction. The optimal conditions for the determination were established as: 8.4×10-5mol L-1I-, pH = 2.1 and the determination shoulp be carried out at a wavelenth of 585nm. The calibration graph was linear for vanadium (Ⅳ) concentration ranging from 0 to 6.6 μg·mL-1 under optimal conditions mentioned above, and the detection limit was determined to be 0.02 μgⅤ(Ⅳ)·mL-(?) The procedure is highly selective for Ⅴ(Ⅳ) since most coexisted foreign ions have no interference on the determination except for Fe3+, Fe2+, Sn2+ and Ti3+. Trace amount of vanadium waste in water and soil was determined and satisfactory were obtained, the recovery was observed to be 95.1-98.3%.