ABSTRACT
This chapter provides a few examples of the newer online analyzers and discusses analyzer selection and application. It deals with a description of the most common categories of analyzers: the radiant energy, the electrochemical, and the inferential property types. The new generation of on-stream analyzers are similar in appearance and ruggedness to everyday pressure and temperature transmitters and are of the probe form, requiring no sampling for their operation. Probe-type analyzers have been used for a long time to measure pH, conductivity, selective ion, dissolved oxygen, relative humidity, residual chlorine, oxidation-reduction potential, differential vapor pressure, corrosion, and many other variables. In-line, probe-type analyzers are also used in stack gas composition measurement. The ability to calibrate an analyzer properly usually depends on the availability of a reliable reference sample, or on the ability to perform reliable laboratory analysis on the actual sample that is entering the analyzer.
