| 摘 要： | Vitamin D_2 and vitamin D_3 give a clear polarographic oxidation-wave,respectively,by neopolarography,with a 0.25M solution oflithium perehlorate in ethanol-dimethylformamide(1:1)as the supportingelectrolyte.Peak potentials are both+1.27V(vs.pure Ag plate).Thewave-height is proportional to the concentration in the range from 2.6×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(420μg/ml)for vitamin D_3 and from2.5×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(435μg/ml)for vitamin D_2,respe-ctively.The detection limits are both 1.3×10~(-6)M(0.5μg/ml).Themethod can be satisfactorily applied to the determination of vitamin D_3in injcction.Through various experiments,it is shown that the electrodeprocess of vitamin D at glassy carbon electrode is an irreversible oxida-tion process controlled by diffusion.The value of an is 0.84(α is thetransfer coefficient and n is the number of cleclron in the kineticprocess).n=2.The electrode reaction mechanism has been inferred.Besides,the choices of base solution and of experiment conditions aswell as the stability of vitamin D etc.are also discussed.
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