Octadecyl silica membrane disks modified with a new Schiff's base for the preconcentration of lead and copper before their determination in water samples

A simple and fast method for the extraction and determination of ppt level of Pb2+ and Cu2+ ions using octadecyl-bonded silica membrane disks modified by a new tetradentates Schiffs base [Bis(2,4-dimethoxy benzaldehyde) ethylen diimine](TDSB) and inductively coupled plasma atomic emission spectrometry is described. Extraction efficiency, and influence of flow rate, pH, type and the least amount of acid for stripping of Cu2+ and Pb2+ from the modified disks and break through volume were evaluated. The maximum capacity of the membrane disks modified by 5 mg of TDSB used was found to be 347 +/- 7 and 470 +/- 6 microg of copper and lead, respectively. The concentration factor is 500 (for 2500 mL water sample and flow rate of 20 mL min(-1)) and detection limit of the proposed method is 12.5 and 150.5 pg/ml for Cu2+ and Pb2+, respectively. The method was applied to the determination of Cu2+ and Pb2+ ions from various water, wastewater, black tea, and hot pepper samples.