Solid phase microextraction (SPME) and microextraction on packed sorbent (MEPS): a critical review.

Sample preparation is an essential step in analysis, greatly influencing the reliability and accuracy of resulted the time and cost of analysis. It is widely accepted that this analytical step is the most labor-intensive and error-prone part of the analytical process. The recent advances in this field have been focused on the miniaturization and integration of sample preparation online with analytical instrumentation, in order to reduce laboratory workload and increase analytical performance. Solid-Phase Microextraction (SPME) is a very simple and efficient, solventless sample preparation method, invented by Pawliszyn in 1989) . SPME has been widely used in different fields of analytical chemistry since its first applications to environmental and food analysis and is ideally suited for coupling with mass spectrometry (MS). Micro extraction by packed sorbent (MEPS) has emerged in the last few years as a powerful sample preparation approach suitable to be easily automated with liquid and gas chromatographic systems applied in a variety of analytical areas (pharmaceutical, clinical, toxicological, environmental and food research). Both technique allow to integrate in a one-step procedure all steps of the conventional liquid– liquid extraction (LLE) such as extraction, concentration, (derivatization) and transfer to the chromatograph, considerably simplifying the sample preparation procedure. In this presentation, a critical comparison between the two procedures will be carried out, considering also the recent innovation in these fields