2.21 - Solid-Phase Microextraction

Abstract

Solid-phase microextraction (SPME) is often seen as a radical departure from conventional sample preparation strategies, due to the fact that the goal is to extract only a portion of the target analyte according to sorbent partitioning, as opposed to the exhaustive extraction of many other techniques. Due to this, many potential practitioners have avoided the technique due to the differences in method optimization between exhaustive and nonexhaustive extraction. This is particularly true among those who expect the technique to be an extension of solid-phase extraction. However, SPME is more closely aligned to techniques such as headspace extraction and several of the membrane extraction techniques so strategies for method development may be more easily understood from those points of view. A careful study of the principles of extraction presented reveals that the processes are in fact universal among all extraction methods, with emphasis needing to be placed on different aspects depending on the specific strategy at hand. In this chapter, the various fundamental aspects of extraction are reviewed with reference to their relationships to SPME method development. It is intended to provide a general strategy for SPME method development. Selected examples further illustrate how the principles are applied to different matrix types and analyte classes.