Separation and preconcentration of trace amounts of lead on octadecyl silica membrane disks modified with a new S-containing Schiff's base and its determination by flame atomic absorption spectrometry

A synthetic procedure was developed for the preparation of a new S-containing Schiff's base [ethane amine, N,N'-bis(2-thienyl methylene)]. The resulting compound (L) was used as a modifier in octadecyl silica membrane disks for solid phase extraction and flame absorption spectrometric determination of lead in water samples. Extraction efficiency and influence of flow rates, pH, type and minimum amount of stripping acid were investigated. The maximum capacity of the membrane disks modified by 5 mg of the (L) used was found to be 700 mug Pb2+. The limit of detection of the proposed method is 16.7 ng ml(-1). The method was applied to the recovery of Pb2+ ions from different synthetic samples and spring water samples. (C) 2001 Elsevier Science B.V. All rights reserved.