Capillary injection device for in situ pre-concentration of trace elements in graphite furnace-atomic absorption spectrometry

Abstract

A device for in situ pre-concentration of trace elements in graphite furnace-atomic absorption spectrometry (GF-AAS), which is based on the direct introduction of the sample solution into the furnace by a fused silica capillary, is described. Experimental conditions have been optimized for the determination of several elements at the sub pg/g level with a CV always better than 15%. A deposition yield of approximately 95% was estimated by depositing a solution containing NaCl 0.002 M. A very simple and effective device for handling a sample under contamination-free conditions is also described which allowed a CV less than 10% to be obtained for replicate determinations of Cd in blank samples at 0.4 pg/g. The overall analytical system was validated by recovery studies carried out on standard solutions and spiked snow samples. Measurements were performed at 1, 5 and 50 pg/g, and the error was always lower than 20, 10 and 5%, respectively. The evaluation of the experimental detection limits which ranged in the interval 0.1–4 pg/g is finally discussed.