Ozone Monitoring Based on a Biosensor Concept Utilizing a Reagentless Alcohol Oxidase Electrode

摘要

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 flow-through 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 H_(2)O_(2) 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(centre dot)mL~(-1) ozone was constructed. The detection limit (S/N velence 3) was calculated at 1.1 (mu)g(centre dot)mL~(-1) ozone. The proposed method is interference-free from other gases such as O_(2), Ar, N_(2), N_(2)O, NOCl, SO_(2), NH_(3), and CO_(2), which were tested at concentrations >200-fold higher than that of 100 (mu)g(centre dot)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.