Given the many advantages of solid phase extraction over traditional solution extraction, this technology is being increasingly used in various fields, including environmental analysis, food, pharmaceuticals, clinical research, and industrial production. The United States Environmental Protection Agency has also included it in many methods of pollutant analysis. In recent years, the use of automated solid phase extraction equipment in environmental analysis has also been increasing, with involvement in the analysis of environmental samples such as water, air, soil, and sediments.
Automated solid phase extraction technology is widely used for the enrichment of trace organic pollutants in environmental water samples. In the 1980s, solid phase extraction technology was already widely used in water quality monitoring in the Songhua River, Huangpu River, Taihu Lake, and other regions to test for halogenated hydrocarbons, chlorinated pesticides, chlorobenzene, chlorophenol, aniline, nitro compounds, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and phthalic esters, among others. To extract organic compounds from water samples, it is necessary to make the desorption capacity of water to be weak, therefore, reverse-phase extraction is generally used for the processing of environmental water samples.
In environmental air pollutants, volatile substances account for 90%, while the rest are particulate pollutants, which can be captured by filtration membranes. Volatile and semi-volatile substances are generally extracted using automated solid-phase extraction or solution absorption or low-temperature condensation sampling. Air is made to pass through the solid phase extraction column at room temperature or low temperature, and the target organic compounds are retained on the column while normal components of air, such as nitrogen and oxygen, flow out of the small column, thus, the target substances are directly extracted from the air and then separated and quantitatively analyzed through gas chromatography after thermal desorption. Using solid phase extraction sampling can achieve integrated sampling, separation, and enrichment of pollutants in the air, which is convenient and fast.
The solid-phase extraction (SPE) technology is mainly used for purification and enrichment in solid samples. Solid samples are usually dissolved and extracted, and the extracted solution is purified through a solid phase extraction column to further remove interfering substances and to enrich target analytes.
Researchers have used accelerated solvent extraction and SPE purification combined with gas chromatography to measure polycyclic aromatic hydrocarbons and organochlorine pesticides in soil. The method has shortened the processing time, improved purification efficiency and has higher accuracy and sensitivity, and is simple to apply for batch soil sample analysis.