NOVEL SENSORS FOR METAL-ION DETECTION AND QUANTIFICATION

METALS AND METAL COMPLEXES PLAY AN IMPORTANT ROLE IN MANY INDUSTRIAL PROCESSES. DUE TO THE WIDESPREAD AND LARGE-SCALEUSE OF METALS, MONITORING THEIR PRESENCE IN WASTE STREAMS AND CONTROLLING THEIR LEVELS OF DISCHARGE INTO THE ENVIRON-MENT ARE DIFFICULT AND COSTLY TASKS--TASKS THAT ARE ALL THE MORE IMPORTANT GIVEN THE TOXICITY OF MANY COMMONLY USED METALS. CURRENTLY AVAILABLE SENSOR TECHNOLOGY FOR ON-SITE METAL -ION DETECTION IS LIMITED TO ION-SELECTIVE ELECTRODES (ISE) --FRAGILE, SLOW, HIGH-MAINTENANCE DEVICES THAT ARE SUSCEPTIBLE TO INTERFERENCE AND FOULING. THE ALTERNATIVE IS EXPENSIVE AND TIME-CONSUMING OFF-SITE LABORATORY ANALYSIS. THE TECHNIQUES AT HAND ARE CLEARLY NOT ADEQUATE FOR ADDRESS-ING THE PROBLEM. AS A NEW MEANS OF MEETING THIS CHALLENGE, THIS RESEARCH WILLATTEMPT TO DEVELOP THIN-FILM SENSORS THAT CAN BE CHEMICALLY "TUNED" SELECTIVELY FOR EACH OF THE FOLLOWING TOXIC-METAL IONS: CR3+, CR6=, CD2+ AND BA2+. SINCE THERE ARE NO COMMERCIALLY AVAILABLE SENSORS FOR CR3+, CR6+, AND BA2+, AND SINCETHE CURRENT TECHNOLOGY FOR REMOTE DETETION OF CD2+ IS INADE-QUATE, THE SENSORS TO DEVELOPED IN THIS PROGRAM SHOULD FIND WIDE APPLICATION IN POLLUTION MONITORING AND CONTROL. PRELIMINARY INDICATIONS ARE THAT ANALYTE-SENSITIVE THIN-FILMSENSORS CAN BE MADE TO BE VERY SENSITIVE AND SELECTIVE FOR CR3+, CR6+, CD2+ AND BA2+. THESE SENSORS, ONCE DEVELOPED, WILL FIND APPLICATION IN FEEDBACK CONTROL LOOPS FOR THE PRE-VENTION OF EXCESSIVE DISCHARGE OF TOXIC METAL IONS INTO THE ENVIRONMENT AND IN MONITORING THE METAL-ION CONCENTRATION ININDUSTRIAL PROCESSES TO AID IN RECYCLING AND RESOURCE-RECOV-ERY EFFORTS. THESE SENSORS CAN ALSON PROVIDE EARLY WARNING OF GROUNDWATER CONTAMINATION.