“Determination of Scandium in River Water by ICP-OES with Flow Injection On-line Preconcentration Using Knotted Reactor and Ultrasonic Nebulization”

S. CERUTTI, J. A. SALONIA, J. A. GÁSQUEZ, R. A. OLSINA AND L. D. MARTINEZ.

JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY

The Royal Society of Chemistry

Año: 2003 vol. 18 p. 1198 - 1201

0267-9477

An on-line scandium preconcentration and determination system implemented with inductively coupled plasma optical emission spectrometry (ICP-OES) associated with flow injection (FI) with an ultrasonic nebulization system (USN) was studied. The scandium was retained as the scandium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, Sc-(5-Br-PADAP), complex, at pH 9.5. The 5-Br-PADAP solution concentration was 1x10-4 mol l-1 and it was dissolved in a 17% (v/v) ethanol–water solution. The scandium complex was removed from the knotted reactor (KR) with 30% (v/v) nitric acid. A total enhancement factor of 1120 was obtained with respect to ICP-OES using pneumatic nebulization –Meinhard, Pneumatic Nebulizer– (25 for USN and 45 for KR) with a preconcentration time of 300 s. The value of the detection limit for the preconcentration of 30 ml of sample solution was 0.45 ng l-1. The precision for 10 replicate determinations at 10 ng l-1 Sc level was 3.5% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for scandium was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 50 ug l-1. The method was successfully applied to the determination of scandium in river water samples.