Solid phase micro extraction: an alternative technique for the determination of volatile orgnanic compounds in groundwater

Abstract

Standard methods for sample preparation use toxic organic solvents and can be replaced by utilizing a new sample preparation and concentration technique. One such technique, compatible with capillary gas chromatography was developed in this study that shows promise of increased speed, cost-efficiency and ease of automation: The solid phase micro extraction (SPME) process has two steps: partitioning of analytes between the coating of a SPME fibre and the sample matrix, followed by desorption of concentrated extracts directly into an analytical instrument. In the first step, the coated fibre is exposed to the sample or its headspace which causes the target analytes to partition from the sample matrix into the coating. The fibre bearing concentrated analytes is then transferred to an instrument for desorption, whereupon separation and quantitation of extracts can take place. SPME can be used as a sample preparation technique for liquid, gas and solid samples. Results show that SPME, when fully optimized can successfully be used for the determination of volatile organic compounds in groundwater at a fraction of the equipment cost. The technique can also be used as a screening tool before the validated purge and trap methods are employed.