Properties of poly-beta-aminoanthraquinone modified carbon fiber electrode as a basis for hemoglobin biosensors

An amperometric microsensor for hemoglobin (HE) has been constructed using a carbon fiber electrode modified with poly-beta-aminoanthraquinone (pAAQ). Scanning electron microscopic studies showed that the potential range and time of electrochemical polymerization had strong effects on the morphology of the polymer film at the microelectrode. The stability and the electrochemical properties of the modified electrode were studied using cyclic voltammetry. The pAAQ modified microelectrode showed an excellent electrocatalytic activity for the reduction of HE in a weakly acidic solution. The catalytic current in cyclic voltammetry increased linearly with the HE concentration between 1.0-400 mu M. The amperometric response to HE had a linear range of 0.5 mu M to 340 mu M with a correlation coefficient of 0.990(n=18). The biosensor was stable for at least one month when it was stored in a phosphate buffer (pH 7.4) below 20 degrees C. The obtained HE concentration in the whole blood agreed well with the one obtained with the reference instrument.