POTENTIOMETRIC DETECTION OF METAL-IONS SEPARATED BY LIQUID-CHROMATOGRAPHY USING A TUNGSTEN-OXIDE ELECTRODE

The use of a tungsten oxide sensor for the potentiometric detection of metal ions separated by liquid chromatography is described. Separatio n of metal ions such as Fe3+, Fe2+. Cu2+ and Pb2+ was performed by ion chromatography using a mobile phase containing 25 mM sodium tartrate/ 2 mM ethylenediamine at pH 3.8. Calibration plots were linear in the r ange 0.5 to 3.5 mM. Potentiometric detection was also applied to ion-i nteraction chromatography. The results showed that separation of metal ions was improved and the detection limits for the test metals in the range of 0.5-5 nmol were obtained in the presence of sodium citrate/1 -octanesulfonic acid at pH 3.0. The potentiometric detection described in this article is shown to base advantages in terms of low cost, sim plicity and sensitivity.