On‐Line Preconcentration System by Coprecipitation with Lanthanum Hydroxide Using Packed‐Bed Filter for the Determination of Tellurium in Water by ICP‐OES with USN

Abstract

A sensitive procedure for the determination of total tellurium traces in water samples is described, which combines an on‐line analyte preconcentration system coupled to inductively coupled plasma optical emission spectrometry (ICP‐OES) associated with flow injection (FI) and ultrasonic nebulization (USN). Tellurium was preconcentrated by co‐precipitation at pH 9.1 with lanthanum hydroxide precipitate. The precipitate was quantitatively collected on a packed‐bed filter with Amberlite XAD‐4 resin and subsequently eluted with 5% (v/v) nitric acid. A total enhancement factor of 140‐fold was obtained with respect to ICP‐OES using pneumatic nebulization. The detection limit (3σ) for the preconcentration of 10 mL of aqueous solution (3σ) was 0.15 µg L⁻¹. The precision for 10 replicate determination at the 10 µg L⁻¹ tellurium level was 2.6%, relative standard deviation (RSD), calculated with the peak heights obtained. The calibration graph using the preconcentration system for tellurium was linear with a correlation coefficient of 0.9995 at levels near the detection limit up to at least 100 µg L⁻¹. Satisfactory results were obtained for the analysis of tellurium in the standard reference material NIST 1643d “Trace Elements in Water” and tap water.

Keywords:

• On‐line coprecipitation
• Tellurium determination
• ICP‐OES
• Te in water

Acknowledgments

This work was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Agencia Nacional de Promoción Científica y Tecnológica (FONCYT) (PICT‐BID); and Universidad Nacional de San Luis (Argentina).