Abstract
The preconcentration of trace cadmium from water samples for a flame atomic absorption spectrometry (FAAS) determination was studied using alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN). A sample solution up to 1000 ml containing μg Cd at pH 10.2 was passed through a microcolumn packed with 1.5 g sorbent at a flow rate of 5 mL min−1. The cadmium collected on the column was eluted with 10 ml of 2 M nitric acid, and then determinated by FAAS. Recovery was greater than 97%. A concentration factor of 100 can be achieved by passing 1000 ml of sample through the microcolumn. The relative standard deviation (10 replicate analyses) at the 20 ng ml−1 level for cadmium was 1.6% and the corresponding limit of detection (based on 3σ) was 24.3 ng L−1. The method was applied to the determination of Cd in waste, tap and mineral waters.
ACKNOWLEDGMENT
Support of this investigation by the Research Council at the University of Tehran through Grant No. 514/1/427 is gratefully acknowledged.