Microwave accelerated sample preparation for speciation analysis of organotin compounds in biomaterials
Résumé
One- and two-step protocols for microwave-assisted preparation of biomaterials in a low-power focused microwave field were developed for speciation analysis of organotin. The two-step procedure was based on the alkaline hydrolysis of the biomaterial using 25% tetramethylammonium hydroxide, followed by the adjustment to pH 5, ethylation of ionic organotin compounds with sodium tetraethylborate (NaBEt4) and extraction into iso-octane. The one-step procedure involved the simultaneous dissolution of biomaterial in acetic acid, ethylation with NaBEt4 and extraction with nonane. Both procedures gave good agreement with the certified values for TBT in the NIES11 reference fish tissue. The content of TPhT determined in the NIES11 sample was close to the indicated value using the one-and two-step procedures. The procedure based on the simultaneous sample dissolution-derivatization-extraction was found to be the fastest ever reported but suffers from the elevated consumption of NaBEt4.