DIRECT DETERMINATION OF TIN IN RIGID POLY(VINYL CHLORIDE) BY HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY IN ORGANIC MEDIA

A procedure is described for the determination of tin in rigid poly(vi nylchloride) (PVC) by hydride generation-atomic absorption spectrometr y (HG-AAS) in organic media and direct atomization in an electrically heated quartz tube. A rigid PVC sample was dissolved in hot N,N'-dimet hylformamide (DMF). An aliquot of this solution was treated with bromi ne solution in CC14 to separate organic radicals linked to Sn in the o rganotin compounds used to stabilize rigid PVC. Tin hydride was genera ted from a DMF solution of the sample, containing 1.0% H2SO4 and 40% ( v/v) formamide, by injecting 3% (m/v) NaBH4/DMF through the septum mem brane of the hydride generator. A detection limit of 8.1 mg/L was obta ined for tin and the precision was 3.2%. The method was applied to the determination of tin in two PVC samples.