A new polymeric adsorbent for screening and pre-concentration of organotin compounds in sediments and seawater samples

A new adsorbent based on the imprinting technique with high retention capacity and pre-concentration factor has been synthesized and tested for retention of inorganic and organotin compounds [tributyltinchloride (TBT), dibutyltindichloride (DBT), monobutylytintrichloride (MBT) and triphenyltinchoride (TPhT)]. The polymerization has been carried out in the presence of TBT, the target organotin compound of this work. These compounds can be quantitatively retained on this adsorbent over a wide pH range and after elution these compounds are determined by graphite furnace atomic absorption spectrometry (GFAAS). Only organotin compounds are eluted from the adsorbent with 0.1 M hydrochloric acid (HCl) in methanol (MeOH) solution whereas inorganic tin is eluted later on with a suitable complexing agent such as citric acid. Linearity is obtained in the concentration range 0.1-4 ng (5-200 mug l(-1)) for each organotin compound with a correlation coefficient not less than 0.994 and relative standard deviation <5% even for complex samples such as sediments and seawater samples. The detection limit has been found to be 30 ng l(-1). Various parameters related to determination, pre-concentration and GFAAS conditions have been optimized. The screening method proposed has been applied to the determination of organotin in natural sediments and seawater samples. The recovery is between 82 and 90% for TBT, DBT and TPhT and 50-55% for MBT in the case of sediment samples, while it is 97-103% for all the organotin compounds in seawater samples. The method has been conveniently validated using a standard sediment reference material. (C) 2003 Elsevier B.V. All rights reserved.