Development of an electrochemical DNA biosensor for the detection of vitamin B12 (cyanocobalamin) at a carbon paste modified electrode with a manganese(II) complex

摘要

A simple, fast, sensitive and selective electrochemical detection of vitamin B12 (cyanocobalamin) has been developed using a DNA electrochemical biosensor and a modified carbon paste electrode. Carbon paste electrode was modified with electrochemically produced polymer of [Mn(thiophenyl-2-carboxylic acid)2(triethylonamine)] using cyclic voltammetry with a scan rate of 0.01 V/s and three number of scans. Vitamin B12 was immobilized onto the modified electrode. Measurements were carried out using adsorptive transfer square wave voltammetry. Detection was achieved from 3.667 μg/L to 236.0 μg/L, presenting sufficiently low detection (i.e. 1.210 μg/L) and quantification (i.e. 3.667 μg/L) limits. The precision was tested showing excellent results (i.e. from 5.50 % and 5.35 %). The selectivity towards certain interferences was also investigated and revealed that none of them had significant effect on the detection of vitamin B12. The electrode has been applied in the determination of Vitamin B12 in human urine sample.