Triazine herbicides determination in water with an optical biosensor

The alternating deposition on quartz of a cationic polymer and the integral bacterial membrane protein called Reaction Centre led to the formation of the polyelectrolyte multilayer called PEM. The PEM revealed to be a valuable tool for the determination of the presence of herbicides in water through the measurement of its optical properties. Among the most striking features of the PEM is the long time stability of the embedded protein that allowed the use of the same specimen for several months without any loss in sensitivity or reproducibility of the determinations. Here further details on the PEM structure and properties will be presented together with a first attempt to overcome the major drawback of the proposed biosensor, i.e.: its poor sensitivity.