Combination of solid phase extraction with supercritical fluid extraction for the determination of contaminants in water

The applicability of supercritical fluid extraction was studied for the determination of mineral oil contaminants in the presence of non-ionic surfactants in water after a prior preconcentration on a solid sorbent. The species representative of the two types of contaminants were retained first on a solid sorbent Separon SGX Cls. Under optimized conditions supercritical fluid extraction (SFE) with carbon dioxide was used in the first step to extract selectively mineral oil, to be determined by FTIR in a carbon tetrachloride solution. In the second step, SFE with carbon dioxide modified with 5 % (v/v) of methanol yielded a-selective and quantitative separation of a non-ionic surfactant into methanol with UV spectrometric finish. A new design of column for retention of species from SFE with the use of a solid sorbent was also developed and tested.