Application Advantages, Mechanism, and Adsorbent of Solid Phase Extraction Cartridge
What kind of project pretreatment is suitable to use solid phase extraction technology, that is, SPE cartridge is more ideal than ordinary solvent extraction cartridge. There are the following situations:
(1) Pretreatment of organic matter in water
This kind of conventional treatment is basically the extraction with an organic solvent that is incompatible with water. The advantage of solid phase extraction is that:
Firstly, the pre-treatment process can be repeated quantitatively. Generally speaking, the operation of solvent oscillation can only be required to control the time, but cannot control the oscillation frequency, intensity, and action. You know that everyone’s oscillation action is different, and it is difficult for the same person to guarantee a consistent action.
In the application of solid phase extraction cartridge , it is easier to maintain the uniformity and stability of the column and elution rate. Therefore, the extraction process of solid phase extraction can be repeated and quantified.
(2) On-site treatment
The analysis of organic matter in water has a bottleneck that has plagued us for a long time. So organic matter and other samples can keep stable condition, but once it enters the small environment of the sampling bottle, it will change rapidly.
Therefore, many water organic matter analysis methods require immediate analysis, which cannot exceed 4 hours, or the reactive effect will decrease to some extent. The situation is that the time from the water collection to the laboratory is far more than 4 hours, the sample has changed, and the reliability of the analysis results can be imagined.
If the solid phase extraction technology is introduced, due to its simple equipment, small size, and ease to carry, it can be done on-site pre-processing. This will ensure that water samples that are truly stable in composition. In terms of practical application, there is still considerable work to be explored to replace traditional liquid-liquid extraction with solid-phase extraction technology in water detection. It cannot be completely replaced at present, but its development prospects are worth looking forward to.
(3) Reduction in consumption of organic reagents
When processing water samples, if solid phase extraction cartridge is used, only organic solvents need to be used for elution, and the amount is ten times more than traditional liquid-liquid extraction. It has positive significance for the personal protection and environmental protection of experimenters. Therefore, it is better to add proper amount of organic reagents according to actual needs.
Mechanism of SPE Method
The SPE method has three modes: solid phase extraction, normal phase extraction, and ion exchange extraction. The adsorbent for reverse phase extraction is non-polar or weakly polar. Its mechanism of action is non-polar-non-polar interaction van der Waals force or dispersion force. Reverse phase extraction can adsorb non-polar to medium-polar compounds from strong polar solvents. Other reverse adsorbents such as C8, similar to C18, are suitable for non-polar to moderately polar compounds, and their retention of non-polar compounds is slightly weaker than that of C18.
The adsorbent of SPE Method
The adsorbent for normal phase extraction is a polar bonded phase, and its mechanism of action lies in the polarity-polarity interaction. The interactions between the polar functional groups of polar compounds, dipole-dipole interactions, and dipole-induced dipole are interactions.
The adsorbent for normal phase extraction silica gel column is an acidic adsorbent that can adsorb acidic or neutral polar compounds. Because of the silanol group on the surface, it can release weakly acidic hydrogen ions, and it also acts as a weakly acidic cation exchanger. Adsorption of basic compounds. The ion exchange separation method relies on the interaction between the target compound and the adsorbent is electrostatic attraction.