Photometric ion chromatography.

Abstract

Ion chromatography (IC) with conductivity detection, which was introduced in 1975, has become widely used for the simultaneous determination of inorganic and organic ions. On the other hand, photometric ion chromatography (PIC) based on the difference of absorbances of sample and eluent (mobile phase) species has attracted much attention in the recent field of IC, since this technique has potential advantages over IC methods with conductivity detection. This technique which allows IC on a conventional single column HPLC system with an absorbance detector gives compatible sensitivity to conductivity detection. This paper deals mainly with indirect PIC methods performed by both ion exchange and reversedphase modes, where non-UV-absorbing ions are detected as positive and negative peaks by using UV-absorbing ions in the eluent (mobile phase). The features of PIC have been reasonably well known, but it is necessary to understand principles and conditions of PIC for the effective use of this technique. This paper reviews a number of significant reports which deal with the optimisations of separating column, eluent (mobile phase), detection wavelength, sensitivity and restrictions of PIC with its applications. It is also the purpose of this paper to discuss alternative methods and innovations of PIC.