Herbicide biosensor based on photobleacing of the reaction centre of Rhodobacter sphaeroides

A fast and simple measuring device for the detection of photosystem-II herbicides is presented. Herbicides are monitored by absorption changes at 860 nm after photobleacing for 2 s. This system can be easily miniaturized and consists of three components, sample cell, light source and detector for absorption measurements, and a computer data processing unit. Detection ranges and limits were determined for several herbicides. Plans for further miniaturization are discussed.