Liquid-liquid extraction (LLE) separates an analyte through partitioning between two immiscible solvents. How does SPE compare to liquid-liquid extraction? Next, the analyte is eluted (c) and removal/trapping strategy (B) where the analyte is not retained and elutes, while the interferents are retained on the sorbent. SPE bind and elute strategy (A) where the analyte is selectively retained on the adsorbent, while interferents pass through (a-b). concentrate analytes present at low levels.įigure 2.fractionate complex mixtures for analysis by classification.reduce the ion suppression in mass spectrometry applications. The captured analyte elution solvent can be further reduced in volume to concentrate the analyte prior to analysis. Removal/trapping strategy : The analyte(s) are not retained and elutes, while the matrix components are retained.The analyte subsequently is washed and eluted with a strong solvent. Bind and elute strategy : The analyte(s) are retained and matrix components do not retain.The following different scenarios can be utilized to achieve this goal. The ultimate goal is to remove interferents present in the matrix from the analyte, producing a solution containing primarily analyte. Depending on the properties of the analyte and the SPE sorbent, a wash solvent can be chosen to selectively remove ( elute) components from the SPE sorbent while retaining others. Photograph of an SPE cartridge (top).Īs the sample is slowly passed through the SPE cartridge or disk, the analyte and some of the sample matrix compounds may be retained on the SPE material. SPE is used to isolate a species in a sample or to clean-up a sample before analysis.įigure 1. Solid phase extraction 1 (SPE) is a sample preparation technique using a solid adsorbent contained most commonly in a cartridge device (Figure 1), or on a disk to adsorb select species from solution.
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