Pyridylazo) 2 naphthol(PAN) can cause a sensitive incision on the oscillogram in NaOH solution, and the incision depth would decrease linearly with the increase of the concentration of Co 2+ . Based on this oscillogra...Pyridylazo) 2 naphthol(PAN) can cause a sensitive incision on the oscillogram in NaOH solution, and the incision depth would decrease linearly with the increase of the concentration of Co 2+ . Based on this oscillographic characteristic, second order differential oscillographic voltammety is developed for Co 2+ determination. The linear range of the determination of Co 2+ is 2 00×10 -7 ～ 8 20×10 -6 mol/L and the detection limit is 1 00×10 -7 mol/L. RSD is 1 8% for eight successful determinations of 4 20×10 -6 mol/L Co 2+ . Satisfactory results were obtained by this method in determination of VB 12 content in VB 12 injection liquid.展开更多
Vitamin B 12 model molecule, dicyano cobyric mono acid hexamethylester 2f was synthesized from Vitamin B 12 by alcoholysis and acidic hydrolysis. Dicyano-a,b,c,d,e,g-α-f-N-(3-imidazoly) propylamido cobyrinate 3f was ...Vitamin B 12 model molecule, dicyano cobyric mono acid hexamethylester 2f was synthesized from Vitamin B 12 by alcoholysis and acidic hydrolysis. Dicyano-a,b,c,d,e,g-α-f-N-(3-imidazoly) propylamido cobyrinate 3f was synthesized by the reaction between 2f and 3-imidazolylpropylamine hydrochloride. Compound 3f was treated with trifluoroacetic acid to give dimer-vitamin B 12 model molecule 5f. Compound 5f was treated with acidic buffers in methanol and the ring of 5f was opened to give compounds 6f. UV-Vis spectra were determined in buffers with different pH values. The equilibrium constants of Co-N bonds were calculated. K-value of 5f was 552×10 3, which is much greater than that of monomer vitamin B 12 4f. The strength of coordination bonds between the N atom in the side chain of cobyrinate and the Co atom in 5f was much weaker than that in monomer-vitamin B 12 4f.展开更多
文摘Pyridylazo) 2 naphthol(PAN) can cause a sensitive incision on the oscillogram in NaOH solution, and the incision depth would decrease linearly with the increase of the concentration of Co 2+ . Based on this oscillographic characteristic, second order differential oscillographic voltammety is developed for Co 2+ determination. The linear range of the determination of Co 2+ is 2 00×10 -7 ～ 8 20×10 -6 mol/L and the detection limit is 1 00×10 -7 mol/L. RSD is 1 8% for eight successful determinations of 4 20×10 -6 mol/L Co 2+ . Satisfactory results were obtained by this method in determination of VB 12 content in VB 12 injection liquid.
文摘Vitamin B 12 model molecule, dicyano cobyric mono acid hexamethylester 2f was synthesized from Vitamin B 12 by alcoholysis and acidic hydrolysis. Dicyano-a,b,c,d,e,g-α-f-N-(3-imidazoly) propylamido cobyrinate 3f was synthesized by the reaction between 2f and 3-imidazolylpropylamine hydrochloride. Compound 3f was treated with trifluoroacetic acid to give dimer-vitamin B 12 model molecule 5f. Compound 5f was treated with acidic buffers in methanol and the ring of 5f was opened to give compounds 6f. UV-Vis spectra were determined in buffers with different pH values. The equilibrium constants of Co-N bonds were calculated. K-value of 5f was 552×10 3, which is much greater than that of monomer vitamin B 12 4f. The strength of coordination bonds between the N atom in the side chain of cobyrinate and the Co atom in 5f was much weaker than that in monomer-vitamin B 12 4f.
