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

A sensitive chemiluminescence (CL) method, based on the enhancive effect of cobalt(H) on the CL reaction between luminol and dissolved oxygen in a flow injection (FI) system, was proposed for determination of Vitamin B-12. The increment of the CL intensity was proportional to the concentration of Vitamin B-12, giving a calibration graph linear over the concentration from 2.0 x 10(-10) to 1.2 x 10(-6) g l(-1) (r(2) = 0.9992) with the detection limit of 5.0 x 10(-11) g l(-1) (3sigma). At a flow rate of 2.0 ml min(-1), a complete determination of Vitamin B-12, 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 B-12 in pharmaceuticals, human serum, egg yolk and fish tissue. (C) 2003 Elsevier B.V. All rights reserved.