Preconcentration and determination of tellurium in garlic samples by hydride generation atomic absorption spectrometry

A procedure for the determination of traces of total tellurium (Te) in garlic (Allium sativa) is described that combines hydride generation atomic absorption spectrometry with preconcentration of the analyte by coprecipitation. The samples, each spiked with lanthanum nitrate (20 mg/L), are introduced into an Amberlite XAD-4 resin and mixed with ammonium buffer (pH 9.1). Te is preconcentrated by coprecipitation with the generated lanthanum hydroxide precipitate. The precipitate is quantitatively collected in the resin, eluted with hydrochloric acid, and then transferred into the atomizer device. Considering a sample consumption of 25 mL, an enrichment factor of 10 was obtained. The detection limit (3sigma) was 0.03 microgram/L, and the precision (relative standard deviation) was 3.5% (n = 10) at the 10 microgram/L level. The calibration graph using the preconcentration system for Te was linear with a correlation coefficient of 0.9993. Satisfactory results were obtained for the analysis of Te in garlic samples.