Detection methods for ion chromatography

In this chapter, detection methods are discussed, with emphasis on both the hardware considerations and the chemistry underlying each approach. The discussion will be restricted to separations achieved using ion exchange because this separation mode is the most widespread; moreover, other separation modes such as ion interaction chromatography generally use the same detection procedures after suitable modification to accommodate any special mobile phases employed. It is convenient to subdivide detection methods into three broad categories: (a) electrochemical methods (that is, those using conductivity, amperometry, or potentiometry as the basis of detection); (b) spectroscopic methods [that is, those using ultraviolet / visible (UV /vis) absorbance, refractive index, fluorescence, atomic absorption, or atomic emission for detection] ; and (c) those detection methods based on postcolumn reactions. Each of these approaches will be discussed separately.