Two factors will be considered generally when choosing the SPE cartridges, which are the selection of adsorbents and the selection of cartridge specification. The proper adsorbents will separate the interfering materials and the target substances better and satisfy the retrieving demands at the same time. And there exists upper limits of the quality of compounds adsorbed by adsorbents. Once the quality of adsorbed compounds exceeds, the target substances will pass over the SPE cartridge straightly instead of remaining in it.
The selection of adsorbents
Adsorbents should be selected according to the properties of target compounds and substrates. As to the examples, we can choose the adsorbents based on the principle that distinguishes target substances and the major interfering materials.
Maximum sample size
Minimum elution volume
Major Interfering Materials
hydrophobic organic pollutants
Fruits, vegetables, Chinese medicine, fruits syrup
Carbohydrates, pigments, organic acids, phenols
Pesticide residues with weak polarity
Liposoluble vitamins, phospholipids, aflatoxins
The selection of cartridge specification
After choosing the proper adsorbent, we should choose the proper SPE cartridges with the best specification according to the volume of samples. And if the quality of the compounds to be measured is beyond the limit, the target substance will not be remained effectively, and the result of the elution is not good. Therefore, it is necessary to choose the proper specification.