Immunovoltammetric Determination of Hepatitis B Surface Antigen with PPy/HBsAb/MWCNT Electrode

PPy/HBsAb/MWCNT electrode was prepared by immobilizing HBsAb (dissolved in PBS of pH 7.2 containing 0.05 mol·L-1 of pyrrole) onto the surface of MWCNT carbon paste electrode,which was further sealed with BSA (1+99) solution.The sealed PPy/HBsAb/MWCNT electrode was reacted with HBsAg and horeadish peroxidase labelled antibody to form a sandwish-like complex,which will react with 2-aminohydroxybenzene in the presence of H2O2 to give 2-hydroxy-3-aminophenoxazine (HAPXZ in short).A pair of significant redox peaks of the electroactive compound,HAPXZ,were observed at the potentials of -0.270 V and -0.320 V (vs.Ag/AgCl).Values of peak current were found to keep linear relationship with mass concentration of HBsAg in the range of 0.2-200 μg·L-1.Detection limit (3S/N) of the method found was 0.06 μg·L-1.