Revue générale Extraction en phase solide (SPE) : théorie et applications

Solid phase extraction (SPE) has become, in recent years, a technique for sample preparation increasingly used in analytical toxicology. Its basic principle is similar to that of partition chromatography. Since its appearance, many stationary phases have been developed by industry for more targeted extractions or adapted for the extraction of a large number of chemical substances of various kinds for a wide search for xenobiotics in hospital for patients admitted to the emergency ward, or forensic research into the causes of death. Because of the variety of stationary phases it allows the extraction of polar compounds from previously difficult to extract organic phases. The extraction is generally conducted in four steps: conditioning of the stationary phase, loading of the sample, washing(s) of the cartridge and finally, elution. Control of this pre-analytical stage allows factors of pre-concentration of the analyte(s) to search for or to be determined which can lower the limit of detection of a method. The wide ranges marketed by the industry are suitable for specific extraction of very varied volumes (a few tens of microliters up to several mL or liters) but also for extraction of large sets with plates of 96 wells. It is also a technique which has the advantage of being automated. Many analytical methods have been developed on biological matrices: serum, plasma and urine, but also in more complex matrices such as hair and meconium.