IDENTIFICATION OF VITAMIN-B-12 ANALOGS BY LIQUID-CHROMATOGRAPHY WITH ELECTROTHERMAL ATOMIC-ABSORPTION DETECTION

The coupling of liquid chromatography and electrothermal atomic absorp tion spectrometry (LC-ETAAS) lowers the detection limit for identifica tion of vitamin B-12 analogues. Cobalamins and aqueous cobalt (II) wer e separated by reversed-phase liquid chromatography using a linear gra dient: 26:74 (v/v) methanol:0.05 M phosphate buffer (pH 4.2) to 50:50 mixture over 8 min. The vitamins were quantitatively determined in the column effluent by measuring total cobalt by ETAAS. The analysis of m eat and liver extracts by LC-ETAAS showed that the matrix did not inte rfere with the determination of cobalt. Hence, recoveries of cobalt in spiked meat and liver samples were satisfactory.