Determination of Total Tin and Tributyltin in Biological Tissues

Abstract

Abstract Analytical procedures have been developed for the determinations of total tin and tributyltin in biological tissues using graphite furnace atomic absorption spectrometric (GFAAS) technique. For total tin determination, the acid digested sample solution of the tissues is allowed to pass through an anion exchanger column in the chloride form in order to remove the dissolved solids and residual lipids which interfere with the GFAAS measurements. Tin chloride is recovered in the eluate with 4M HNO3. For the measurements of tributyltin, the acid-homogenised tissue solution is extracted directly with n-pentane. Dibutyl- and monobutyltin and inorganic tin are removed by back-wash with 0.8M NaOH. The extract is further cleaned up by passing through a C18 solid phase extraction (SPE) tube. Tributyltin recovered in a methanol-nitric acid mixture is determined by GFAAS using tungstate-treated graphite tube. The method developed has been applied for the analysis of bivalve samples and a detection limit of 0.4 ng g−1 as TBT-Sn has been achieved. The accuracy of the method has been checked using a certified fish tissue reference material (NIES-11). The levels of total tin and tributyltin obtained are in good agreement with the certified values.