异维生素C钠的2.5次微分极谱分析

2.5 TH Order Differential Polarographic Analysis of Sodium D-Isoascorbate

D-异维生素C钠(D-V_cNa)是维生素C钠(L-V_cNa)的一种旋光异构体。它的氧化速度很慢,变化极小,热稳定性比L-V_c高,不影响人体对V_c的吸收,是一种安全无毒的食品抗氧剂和防腐剂,主要应用于鱼类,蔬莱、水果等的保鲜,并能抑制致癌物亚硝胺的形成,亦可代替亚硝酸钠作为肉类的发色剂。关于V_c的极谱学研究已有许多报导,但对D-V_c的极谱学研究却未见到,文献中亦没有V_c(L-V_c)的2.5次微分极谱分析(2.5DPA)

The electrochemistry of D-VcNa has been investigated in B-R buffer solution of pH 6.0, using 2.5 th order differential polarographic analysis (convolution voltammetry). D-VcNa exhibits a fairly good oxidation peak at+0.16 V(vs.Ag/AgCl) on a HMDE with linear range of 5×10^(-6)-4×10^(-4) mol/L and the detection limit 3×10^(-7) mol/L(0.054 ppm). D-Vc and Vc(L-Vc) show the same E_p & i_p as D-VcNa. Thus, stable D-VcNa has been used to replace unstable Vc in the determination of Vc contents in various samples. Cyclic voltammetry etc. confirmed that the electrode process was a semireversible oxidation process controlled by diffusion.