甲基紫分光光度法测定痕量钒

A Spectrophotometric Method for the Determination of Trace Vanadium Based on the Vanadium-Methyl Violet Reaction

摘要: 在碱性条件下,甲基紫(MV)与钒(Ⅴ)反应形成紫色缔合物,吸收峰位于580nm,缔合物组成摩尔比为V(Ⅴ):MV=1:3,表观摩尔吸光系数ε₅₈₀=2.5×10⁷L/(mol·cm),钒(Ⅴ)浓度在0～6.4μg/L范围内遵守比耳定律.方法操作简便,用于水、粮食和矿物样品中痕量钒(Ⅴ)的测定,结果令人满意.

Abstract: Vanadium reacts with methyl violet in the presence of NH₃ to form a violet a complex. The ion association complex exhibits maximum absorption at 580 nm with an apparent molar absorptivity of 2.5×10⁷ L/(mol·cm). The molar ratio of the components of V(Ⅴ):MV=1:3. Beer's law is obeyed in the range of 0～6.4 μg/L for vanadium. It has been applied easily for the determination of V(Ⅴ) in water, flour, rice and mineral samples with satisfactory results.