Lithium sensor based on the laser scanning semiconductor transducer Original Research Article

A lithium-selective polymeric membrane has been immobilised on the surface of a semiconductor transducer. This light-addressable potentiometric sensor (LAPS) with the induced lithium selectivity has been prepared with the aim at further development of a Li+ assay in liquid media, including biological fluids. The sensor developed exhibits Nernstian response interval of 10−5 to 10−1 mol l−1 with an ionic sensitivity of (58±1) mV/pLi. The detection limit was found to be (3±1)×10−6 mol l−1 Li+. The sensor has high selectivity for lithium over sodium and potassium ions with selectivity coefficients of KLi/NaPOT=(7±2)×10−3 and KLi/KPOT=(5±1)×10−3, respectively, and a response time of less than 30 s.