1995 McBryde Medal Award Lecture - Solid phase microextraction - A unique tool for chemical measurements

The paper presents recent advances in solid phase microextraction (SPME). The method utilizes a small fused silica fibre coated with a suitable polymeric stationary phase for analyte extraction from various matrices. The fibre is mounted in a syringe-like holder for protection. SPME has been used for the characterization of polymeric coating properties. Infinite-dilution weight-fraction activity coefficients have been determined for five solutes in two different stationary phases. Their values correlate well with the structure of the analytes and the coating. Other SPME uses include simultaneous determination of 60 pesticides in liquid matrices. A comparison between SPME, liquid extraction, and Soxhlet extraction for the analysis of Atrazine, Simazine, and Metolachlor in well water, as well as Metolachlor in soil samples, produced similar results for all three methods. The solvent-free character of SPME enables its use as sample introduction technique for fast GC analysis. Separations of BTEX in less than 9 s, and of volatile compounds described in EPA method 624 in 2.5 min, are described. SPME has also been used for the analysis of tetraethyllead and Pb(II) in water. Before the analysis, lead is derivatized with sodium tetraethylborate, and the tetraethyllead formed is extracted from sample headspace. Sub-ppb detection limits have been achieved with FID. Finally, SPME has been coupled to HPLC with the use of a specially designed interface. The combination has been tested on samples of polyaromatic hydrocarbons and surfactants in water. Very good precision of retention times and peak areas has been achieved.