Solid‐Phase Extraction and Preconcentration of Copper in Mineral Waters with 4‐(2‐Pyridyl‐Azo) Resorcinol‐Loaded Amberlite XAD‐7 and Flame Atomic Absorption Spectrometry

A simple, sensitive, accurate, and selective method for determination of ultratrace levels of copper is modified. The method is based on preconcentration of copper on the 4‐(2‐pyridyl‐azo) resorcinol‐loaded amberlite XAD‐7 (non‐ionic copoly[styrene‐acrylic compound]) at pH 5.0 to 6.5 for contact time as low as 45 minutes. The adsorbed copper was eluted with concentrated nitric acid and measured by flame atomic absorption spectrometry. Recoveries of up to 90% were achieved. The optimized preconcentration method was applied to copper determination in various water samples. The detection limit was found to be 0.09 ng mL −1 . The relative standard deviation was found to be 9% using 300 mL of 5.0 ng mL −1 for 10 replicate preconcentration procedures. Copper concentrations in the studied water samples were found to be in the ranges of 0.4 to 18.0 ng mL −1 .