DETERMINATION OF IRON IN REAL SAMPLES BY HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS IN COMBINATION WITH THERMAL LENSING

Natural iron concentrations in real water samples have been determined by thermal lensing as a high performance capillary electrophoresis de tector. 1,10-Phenanthroline was used as a chromogenic reagent, which f orms a stable complex with Fe(II) but not with Fe(III). The interferen ces by other cations can be neglected by a combination of this photome tric technique with high performance capillary electrophoresis. Laser induced thermal lens spectroscopy is demonstrated as a new technique f or the measurement of small absorbances in the picoliter detection vol ume of a capillary. A limit of detection of 36 nmol/L with a signal to noise ratio of 7:1 was achieved using a 75 mu m fused silica capillar y.