Flow injection online solid phase extraction system using Amberlite XAD-16 functionalized with 8-hydroxyquinoline for copper and zinc determination by flame atomic absorption spectrometry

Abstract

A newly functionalized resin has been applied in an on-line preconcentration system for copper and zinc determination. Amberlite XAD-16 functionalized with 8-hydroxyquinoline packed in a minicolumn was used as sorbent material. The retained metals can be quickly eluted from the sorbent material, with the eluent stream consisting of nitric acid solution, directly in the nebulizer burner system of the FAAS. The sample acidity was adjusted over a pH 4.0 and 8.0 for effective retention of copper and zinc ions on the resin. The linearity was maintained between 0–180 and 0–90 μg L⁻¹ for copper and zinc respectively. The sample throughputs of analytes were 30 h⁻¹ for 5 mL of sample. The enrichment factors obtained were 80 for copper and 147 for zinc, while the limits of detection were estimated as 0.16 and 0.2 μg L⁻¹ for copper and zinc respectively using a preconcentration time of 180 s. The precision (RSD %) obtained was 1.2% (50 μg L⁻¹) and 2.2% (40 μg L⁻¹) for copper and zinc respectively. The effects of foreign ions on the adsorption of these metal ions were reported. To test the accuracy of the developed on-line FI-FAAS procedure, Standard Reference Material (SRM 1643e, trace elements in water) supplied by the National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA, was analyzed. Spike recovery studies in water samples were performed using a NIST certified copper and zinc nitrate solution to confirm the accuracy of the proposed preconcentration procedure.