Determination of vitamin B12 by flow analysis with chemiluminiscent detection

This thesis reports determination of vitamin B12 by flow techniques of analysis. This method is based on luminol-peroxide chemiluminiscence assay for the detection of cobalt (II) ions in vitamin B12 molecules. The method includes releasing of Co2+ from the vitamin B12 using different types of its decomposition; these are mentioned in this thesis. The efficiency of the decomposition of real samples of vitamin B12 in this study reached 74.43 %. The high efficiency was achieved with 1.5 mmol.l-1 K2S2O8 and irradiation time 1 minute. In the FIA mode, the linear range obtained was between 1.0 to 500 mg.l-1 with a relative standard deviation (RSD) 2.59% (n = 10), limit of detection (LOD) 55 µg.l-1 . The minimum sample volume required and the time of analysis were 60 µl and 140.2 s. In the SIA mode, the linear range obtained was between 0.01 to 50 mg.l-1 with an RSD = 4.5% (n = 10), LOD = 25 µg.l-1 . The minimum sample volume required and the time of analysis were 250 µl and 80.1 s. Interference study showed that from wide range of interfering ions were selected only Ni2+ , Zn2+ and NO2 - , that from concentration level 50 mg.l-1 they significantly affect the determination of the Co2+ in solution. The intensity of chemiluminiscence most suppress ion Zn2+ . The solution with the concentration ratio of Co2+..