The application of conducting polymer nanoparticle electrodes to the sensing of ascorbic acid.

An ascorbic acid sensor was fabricated via the drop-casting of dodecylbenzene sulphonic acid (DBSA)-doped polyaniline nanoparticles onto a screen-printed carbon-paste electrode. The modified electrode was characterised with respect to the numbers of drop cast layers, optimum potential and operating pH. The sensor was found to be optimal at neutral pH and at 0V vs. Ag/AgCl. Under these conditions, the sensor showed good selectivity and sensitivity in that it did not respond to a range of common interferents such as dopamine, acetaminophen, uric acid and citric acid, but was capable of the detection of ascorbic acid at a sensitivity of 0.76 microA mM(-1) or 10.75 microA mM(-1) cm(-2) across a range from 0.5 to 8mM (r2=0.996, n=6), and a limit of detection of 8.3 microM (S/N=3). The sensor was compared to a range of other conducting polymer-based ascorbate sensors and found to be comparable or superior in terms of analytical performance.