Enhancement of chemiluminescence for vitamin B12 analysis

In the current article, chemiluminescence (CL) from the vitamin B-12 and luminol reaction was studied under alkaline conditions to develop a sensitive analytical method for vitamin B-12 using the carbonate enhancement effect. The method was successfully applied to the determination of vitamin B-12 in vitamin B-12 tablets, multivitamin Capsules, and vitamin B-12 injections. Experimental parameters were optimized, including luminol concentration, urea-hydrogen peroxide (urea-H2O2) concentration, effect of pH, and sequence of addition of reactants for obtaining maximum CL, which was not explored previously. The limit of detection was 5 pg/ml, and the linear range was 10 pg/ml to 1 pg/ml with a regression coefficient of R-2 = 0.9998. The importance of these experimental parameters and the carbonate enhancement effect is discussed based on the knowledge of the mechanism of oxidation of luminol and decomposition of urea-H2O2 in the presence of vitamin B-12. Extraction of vitamin B12 Was carried Out, and the observed recovery was 97-99.2% with a relative standard deviation in the range of 0.30-1.09%. The results obtained were compared with those of the name atomic absorption spectrometry method. (c) 2009 Elsevier Inc. All rights reserved.