Flow injection analysis of benzene using an amperometric bacterial biosensor

A bacterial biosensor integrated within a flow injection analysis (FIA) system has been developed for the detection of benzene, based on its aerobic catabolism by Pseudomonas putida ML2. P. putida ML2 cells were immobilised between two cellulose acetate membranes and fixed onto a Clark dissolved oxygen electrode. Biosensor responses were investigated with the FIA system, resulting in a linear detection range between 0.01 - 0.1 mM benzene. A response and baseline recovery time of 6 and 10 - 15 min, respectively, was obtained. A stable and reproducible sensor response has been found up to 28 days of use based on the same bacterial membrane, and the sensor has shown a high specificity to benzene, with a negligible response to other benzene-related compounds. Its ease of operation, rapid and sensitive response, and cost-effective production, demonstrate that the P. putida ML2 biosensor has potential applications for the analysis of samples containing benzene. The optimisation of the biosensor-flow injection system is described.