General Procedure for Solid Phase Extraction
The simplest solid-phase extraction device is an SPE column with a diameter of several millimeters. The SPE column( Normal Phase PR Grade Florisil SPE Cartridge, Reversed Phase C8 SPE Cartridge) can be used, or it can be plastic such as polypropylene, polyethylene Teflon, or stainless steel.
Materials Needed:
SPE cartridge with the appropriate sorbent material
Vacuum manifold or positive pressure manifold
Sample syringe or pipettes
Collection tubes or vials
Solvents (e.g., elution solvent, washing solvent)
Vacuum pump or positive pressure source (if using a manifold)
Sample vials for collecting eluates
Waste container
Procedure:
Conditioning of the SPE Cartridge:
Connect the SPE cartridge to the manifold or holder.
Condition the cartridge by passing a specified volume of a suitable conditioning solvent through it. The volume and type of solvent depend on the cartridge and sorbent material used. Common choices include methanol, acetonitrile, or water.
Apply vacuum or positive pressure to facilitate solvent flow through the cartridge.
Loading the Sample:
Prepare the sample by filtering it if necessary to remove particulate matter.
Use a sample syringe or pipette to load the sample onto the conditioned SPE cartridge. Ensure that the sample is evenly distributed across the sorbent bed.
Slowly load the sample to avoid channeling or bypassing the sorbent.
Washing the Cartridge:
After sample loading, wash the cartridge with one or more portions of a suitable washing solvent. The washing solvent helps remove interfering substances while retaining the analytes on the sorbent.
Apply vacuum or positive pressure to facilitate solvent flow through the cartridge. Adjust the flow rate as needed.
Drying the Cartridge (Optional):
In some cases, it may be necessary to dry the cartridge by applying a gentle flow of air or nitrogen to remove residual moisture.
Elution of the Analytes:
Elute the analytes of interest from the cartridge by passing an elution solvent through it. The elution solvent should be chosen based on the analytes’ properties and the separation method.
Collect the eluate in a clean collection tube or vial. You may need to use multiple fractions if analytes elute at different times.
Apply vacuum or positive pressure to facilitate elution.
Concentration (if necessary):
If the eluate is too dilute, you can evaporate the solvent under reduced pressure or using a gentle stream of nitrogen to concentrate the analytes.
Reconstitution and Analysis:
After concentration, reconstitute the analytes in a suitable solvent for analysis (e.g., the mobile phase for chromatography).
Transfer the reconstituted sample to an appropriate vial for injection into the chromatographic system.
Dispose of Waste:
Dispose of the waste from the SPE process properly, following laboratory safety and environmental regulations.
Cleanup and Maintenance:
Clean and regenerate the SPE cartridge according to the manufacturer’s recommendations to prolong its lifespan and maintain consistent performance.
Remember to always refer to the manufacturer’s instructions and method-specific guidelines for the best results. Adjustments to this procedure may be necessary based on the specific cartridge, sorbent, and analytes being used.
The general operating procedure for SPE:
(1) Activating the adsorbent;
(2) Sample through the column
(3) Rinsing
(4) Analyte elution
In order to keep the adsorbent in the solid phase extraction cartridge moisturized after activation until the sample is added, about 1 ml of the solvent for the activation treatment should be maintained on the adsorbent after the activation treatment.
In the detection of drug residues in aquatic products, the application of SPE has been extensive, and the solid phase extraction columns such as the C18 column, cation exchange column, and alumina column are often used to purify and concentrate the sample.
In the detection of diethylstilbestrol residues in fish, the C18 SPE cartridge used is an application case using solid phase extraction. The adsorption of C is used to remove excess fat and other macromolecular substances in the extraction to achieve the purification of the extract and to concentrate at the same time to improve the sensitivity of the detection.
