Determination Co2+ in vitamin B12 based on enhancement of 2-(4-substituted-phenyl)-4,5-di(2-furyl) imidazole and H2O2 chemiluminescence reaction

In this paper, three kinds of imidazole derivatives, 2-(4-methylphenyl)-4.5-di(2-furyl) imidazole (MDFI), 2-(4-nitrophenyl)-4,5-di(2-furyl) imidazole (NDFI), and 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole (t-BDFI) were synthesized. In an alkaline medium, the chemiluminescence (CL) reaction of imidazole derivatives with H2O2 has been investigated. It was also found that MDFI/H2O2 and t-BDFI/H2O2 systems gave strong CL When Co2+ was added into the two CL systems, the CL intensity was remarkably enhanced. In the optimum conditions, the CL intensity is linearly related to the logarithm of concentration of Con. The linear ranges are 5 x 10(-9)-2.5 x 10(-7) mol/L for MDFI/H2O2 system and 5 x 10(-9)-2.5 X 10(-7) mol/L for t-BDFI/H2O2 system, and the corresponding detection limits are 1.2 X 10(-9) mol/L and 1.1 X 10(-9) mol/L, respectively. The method was applied to the determination of Co2+ in vitamin B-12 injection. Furthermore, the CL mechanism was also discussed. (C) 2011 Elsevier B.V. All rights reserved.