Operation steps of solid-phase extraction

A complete solid-phase extraction step involves four steps: pre-treatment of the solid-phase extraction column, sample loading, washing away interfering impurities, and collecting analytes. The operation steps are shown in Figure 2-1.

(1) Preparation of Solid Phase Extraction Column
Before extracting the sample, the adsorbent must be pre processed in a satisfactory manner to wet and activate the solid-phase extraction filler, so that the target extract can come into urgent contact with the surface of the solid phase and facilitate intermolecular interactions; The second is to eliminate possible impurities in the filler and reduce pollution. The method adopted is to rinse the extraction column with a certain amount of solvent.
Reverse phase solid-phase extraction of silica gel and non-polar adsorbent media is usually pre treated with water-soluble organic solvents such as xylenol. xylenol wets the surface of the adsorbent and the alkyl phase of the permeable bond, making it easier for water to effectively wet the surface of the silica gel. Then replace the lignin retained in the column with water or buffer solution to ensure excellent contact between the sample aqueous solution and the adsorbent surface, thereby increasing the extraction rate. Solid phase extraction using silica gel and polar adsorbent media is usually pre processed with the organic solvent in which the sample is located. Ionic exchange fillers are typically prepared with 3-5ml of deionized water or low concentration ion buffer solution.
Solid phase extraction fillers should be kept moist from pre-treatment to sample intervention. If the fillers in the extraction column are present before sample intervention, the pre-treatment process needs to be repeated. And before introducing new organic solvents, rinse the buffer solution inside the column with water to remove salt.
(2) Sample above
Pour the sample into the activated SPE column, and then use pressure, vacuum or centrifugation to immerse the sample into the adsorbent (as shown in Figure 2-2). The liquid sample is passed through the solid phase extraction column at a comfortable flow rate by manual or pump push or negative pressure suction. At this time, the daily standard extract in the sample is adsorbed on the packing of the solid phase extraction column.
(3) Wash and disturb impurities
The goal of scrubbing is to remove the small amount of matrix components adsorbed on the solid-phase extraction column for r. Ordinary Choice

Medium strength mixed solvents are used to eliminate interfering components in the matrix as much as possible without causing loss of the target extraction stream. In reverse phase extraction systems, a certain proportion of organic solvent water mixture is often used, and the proportion of organic solvent should be greater than that of the sample solution and less than that of the eluent solution.
(4. Elution and collection of analytes
Choose appropriate elution solvents to elute the analyte, collect the elution solution, evaporate the solvent for later use or directly perform online analysis. In order to elute the analyte as much as possible and retain impurities with stronger adsorption than the analyte on the SPE column, it is necessary to choose an elution solvent with appropriate strength.