Why PSA is Used as a Purification Adsorbent in D-SPE?
Purified and dispersed asparagus extracting solution by different adsorbents and then detected by GC, the chromatograms showed that NH2 and PSA among all had the best purification effect.
In the analysis of agricultural products, the main interfering substances in the matrix are polar interferences such as fatty acids, organic acids, carbohydrates, and sterols, while NH2 and PSA act as normal phase and weak anion exchange adsorbents for the adsorption of the above-mentioned polar interferences, can provide the best purification effect.
Both NH2 and PSA have both polar adsorption and weak anion exchange, which can achieve retention by weak anion exchange or polar adsorption. When used in a non-polar solution for pretreatment. It can form hydrogen bonds with molecules bearing -OH, -NH, or -SH functional groups.
The amino group pKa = 9.8, which is weaker than SAX in the action of the anion and can be exchanged as a weak anion in an aqueous solution of pH < 7.8. In the pesticide residue analysis, it is used to remove polar compounds (such as carbohydrates, and pigments), organic acids, phenols, strong anions in the matrix, and the like in the extract.