Supercritical Fluid Chromatography: A Green Approach for Separation and Purification of Organic and Inorganic Analytes

Abstract

'Supercritical fluid' describes a gas or liquid at conditions above its critical point. A greater range of solvent properties can be achieved with Supercritical fluid as a single solvent by careful manipulation of temperature and pressure at the supercritical state. Supercritical fluids are attractive media for several chemical reactions having better control over the reaction rates in different areas of biochemistry, polymer chemistry and environmental science. Supercritical fluid extraction (SFE), a rapid, convenient, efficient, and selective method has been used successfully for the separation of analytes prior to supercritical fluid chromatography (SFC), which is a relatively recent chromatographic technique and is commercially available since 1982. SFC significantly reduces the usage of organic solvents and wastes by using supercritical CO 2 as the mobile phase. The important principles of green chemistry that are applicable to green chromatography includes prevention of waste, use of safer solvents and increasing energy efficiency. All these factors are taken care of in SFC which combines some of the best features of HPLC as well as GC. Analytes that cannot be vaporized for analysis by gas chromatography or have no functional groups for detection by the usual liquid chromatography techniques, can be separated and detected using SFC. By now SFC has been applied to wide variety of materials including natural products, pharmaceuticals, foods, pesticides, herbicides, surfactants, polymers and polymer additives, heavy metals, fossils fuels, petroleum, explosives and propellants. SFC has now become an attractive alternative for chiral drug separation.

Enhancing Sustainable Analytical Chemistry in Liquid Chromatography: Guideline for Transferring Classical HPLC and UHPLC Methods into Greener, Bluer, and Whiter Methods

“…Twelve principles of green analytical chemistry (GAC) were later proposed and published by Galuszka et al [3] adapted for analytical chemistry and represented a basic guideline for going green in analysis as shown in Figure 2. Unlike techniques such as capillary electrophoresis [4,5], supercritical fluid chromatography [6] and sensor-based analytical techniques [7] that are quite green from a sustainable point of view, liquid chromatography utilizes larger amounts of organic solvent in the mobile phase [8] and generating huge amounts of toxic wastes and emitting relatively large amounts of carbon dioxide that affect global warming through slowing the production of ozone in the lower stratosphere. Moreover, the extensive use of volatile organic compounds (VOC) acts also as ozone-depleting chemical to further contribute to the global warming potential [9].…”