Pbs‐field‐effect‐transistor for heavy metal concentration monitoring

A simple and inexpensive Pbs-FET with high sensitivity and short response time was developed which consists of a PbS layer on a pH-sensitive gate of a field effect transistor. The PbS-layer was prepared with simple wet precipitations technique. The PbS-FET has about the same selectivities for Pb 2+ - and for Cu 2+ -ions, but only slight sensitivity for Cd 2+ - and Zn 2+ -ions. The sensor was integrated in a FIA system. By variing the injection time the measuring range varied between 10 -1 - 10 -6 and 10 -2 - 10 -8 mol Pb 2+ /l. The PbS-FET-FIA system is suitable for monitoring of Pb 2+ concentrations in drinking water.