Sample preparation is a considerable step before modern instrumental analysis (High Performance Liquid Chromatography, Gas Chromatography, Radioimmun Assay, Spectrometric techniques etc.). For many years, sample dissolution followed by liquid-liquid extraction has been a popular sample preparation procedure. But, traditional liquid-liquid extractions are high solvent consumption, time consuming and costly. Furthermore, these methods present the following problems: phase emulsions, impure and wet extracts, nonquantative extractions. Other classical sample preparation techniques include centrifugation, filtration, distillation, lyophilization have same problems.

In the mid 1970's, an alternative approach, solid phase extraction (SPE) was introduced. This concept is basis for the design of a practical sample preparation technique consisting of small, disposable extraction columns filled with a variety of sorbents. Today, solid phase extraction is a powerful method for sample preparation and is used by most laboratories. Compared to classical liquid-liquid extraction, SPE is faster, uses less solvent, eliminates emulsions, and saves money. In addition, solid phase extraction provides clean extracts and high recoveries.

In this article, solid phase extraction and other sample preparation methods; principles, procedures, and advantages of solid phase extraction; solid phase extraction columns, adsorbents and solvents and solid phase extraction application areas are evaluated.