Tin and Zirconium Based Ion Exchangers as Sensors for Rare Earth Metal Ions

Abstract

The growing area of sensors has permeated virtually all professional science and engineering branches. There are three types of sensors, i.e., physical, chemical and biosensors. Physical sensors are concerned with measuring physical quantities such as temperature and pressure where as, chemical sensors respond to a particular analyte in a selective way through a chemical reaction and can be used for the qualitative or quantitative determination of the analyte. Biosensors are really a subset of chemical sensors, but are often treated as a topic in their own right. A biosensor is a device incorporating a biological sensing element connected to a transducer. All chemical sensors consist of a transducer, which transforms the response into a detectable signal on modern instrumentation, and a chemically-selective layer, which isolates the response of the analyte from its immediate environment. Chemical sensors have been widely used in such applications as critical care, safety, industrial hygiene, process control, product quality control, human comfort control, emission monitoring, automotive clinical diagnostics, home safety alarms and more recently, homeland security. In these applications, chemical sensors have resulted in both economic and social benefits. They can be classified according to the property to be determined as: electrical, optical, mass or thermal sensors and are designed to detect and respond to an analyte in the gaseous, liquid or solid state [1]. Compared to optical, mass and thermal sensors, electrochemical sensors are especially attractive, because of their remarkable detectability, experimental simplicity and low cost.