Study of interference of pharmaceuticals with complexing characteristics in solid phase microextraction of lead on chelating celluloses

Trace lead impurities of drugs in 1-5% solutions can be preconcentrated on imino diacetic acid-ethyl cellulose (IDAEC). The buffered sample was loaded onto a chelating cellulose minicolumn by flow injection followed by the nitric acid elution and graphite furnace atomic absorption spectrometry (GFAAS) determination. The detection limit of the procedure depending on the concentration of drug solution is in the range 210 ng g(-1). The bonding of lead to various pharmaceutical compounds appeared in reduced rate during preconcentration according to the competition between ligands. The first step was focused on the determination of the stability constants of the lead-chelating cellulose species. In the second step, the sorption was estimated from different pharmaceutical matrices considering the lead-drug interaction. In the third experimental step estimated sorption was compared with the determined values for some medicines like aspartic acid, penicillamine, captopril, N-acetyl-cysteine and its pharmaceutical product, ACC 200. (c) 2006 Elsevier B.V All rights reserved.