钯(Ⅱ)对显色体系DAoVMPM-V(V)-H3PO4-Mn(Ⅱ)-Tween60阻抑作用的研究

On Inhibition of Palladium(Ⅱ) in Colour System of DAoVMPM-V(V)-H3PO4-Mn(Ⅱ)-Tween60

关键词:  二安替比林邻烯丙氧基苯基甲烷(DAoVMPM)  动力学分光光度法  阻抑作用  钯(Ⅱ)  钒(V)

Key words:  Diantipyryl-(-o-vinyl methoxy-)-phenyl methane (DAoVMPM)|kinetic spectrophotometry|inhibition|palladium (Ⅱ)|vanadium (V)

摘要:

研究在酸性介质中钯(Ⅱ)阻抑试剂DAoVMPM与V(V)显色反应的动力学参数,反应的表观速率常数K₀=2.285×10^-2 min^-1,表观活化能E_a=67.51kJ/mol。基于这种阻抑作用建立了一种测定钯的动力学光度分析法,Pd(Ⅱ)含量在0.5μg/25mL~10.0μg/25mL能被准确检出,检出限为5.0×10^-9 g/mL。该方法灵敏度高,稳定性好,用于石钯渣和钯催化剂中钯的测定,本法的相对标准差RSD为1.0‰~1.5‰,回收率为96%~103%。

Abstract:

In acidic medium the palladium (Ⅱ) inhibits the rate of colour reaction system in DAoVMPM-V (V) -H₃PO₄-Mn (Ⅱ) -Tween20. The kinetic parameters of the inhibited reaction are studied. Rate of reaction apparent constant (Ko) is 2.285×10^-2 min^-1 and energy of activation (Ea) is 67.51 kJ/mol. On the bases of such inhibition, a kinetic spectrophotometry determining trace palladium (Ⅱ) is established. The limit of detection is 5.0×10^-9 g/mL. Palladium (Ⅱ) can be determinated accurately in the range of 0.5 μg/25m L~10.0 μg/25m L. This method has high sensitivity and g ood stability. It is applied to the determination of palladium (Ⅱ) in samples of palladium catalyst and litho-palladium dross, the relative standard deviation is 1.0‰~1.5‰, and the recovery is 96%~103%.