Sub-picogram determination of Vitamin B12 in pharmaceuticals and human serum using flow injection with chemiluminescence detection Original Research Article

A sensitive chemiluminescence (CL) method, based on the enhancive effect of cobalt(II) on the CL reaction between luminol and dissolved oxygen in a flow injection (FI) system, was proposed for determination of Vitamin B12. The increment of the CL intensity was proportional to the concentration of Vitamin B12, giving a calibration graph linear over the concentration from 2.0×10−10 to 1.2×10−6 g l−1 (r2=0.9992) with the detection limit of 5.0×10−11 g l−1 (3σ). At a flow rate of 2.0 ml min−1, a complete determination of Vitamin B12, including sampling and washing, could be accomplished in 0.5 min with the relative standard deviations (R.S.D.) of less than 5.0%. The proposed method was applied successfully to the determination of Vitamin B12 in pharmaceuticals, human serum, egg yolk and fish tissue.