Ozone monitoring based on a biosensor concept utilizing a reagentless alcohol oxidase electrode

An electrochemical method based on the concept of a biosensor for the monitoring of ozone is described for first time. The proposed method includes two parts: a selective sorbent for ozone, that is, eugenol, and a formaldehyde amperometric biosensor mounted into a flowthrough cell. Ozone adds rapidly to the double bond of the allyl group of eugenol, which has been immobilized onto a hydrophobic C-18 reactor and the so produced formaldehyde is collected into the working buffer solution ( sampler) and pumped to the detector. A multimembrane assembly consisting of an alcohol oxidase-modified nylon membrane sandwiched between an outer polycarbonate and an inner cellulose acetate membrane was fitted onto a Pt electrode and the enzymatically produced H2O2 was monitored at + 0.65 V ( vs Ag/AgCl/ KCl 3 M). Under optimum conditions, a linear calibration curve over the concentration range 3-200 mu g.mL(-1) ozone was constructed. The detection limit (S/N = 3) was calculated at 1.1 mu g.mL(-1) ozone. The proposed method is interferencefree from other gases such as O-2, Ar, N-2, N2O, NOCl, SO2, NH3, and CO2, which were tested at concentrations > 200-fold higher than that of 100 mu g.mL(-1) ozone used for comparison. Besides selectivity, the method is easy to perform and reproducible; its applicability in synthetic gaseous samples is also demonstrated.