5 Aspects To Be Noted For Better Analysis Results With SPE Column

As a sample preparation technique that is usually used by chromatography prior to analysis, solid-phase extraction is the popular way not only to remove interfering compounds from the sample of the solution but to enrich or concentrate desired analytes from the sample. With SPE, the interfering substances will be retained, and the sample will be collected and analyzed when solvents elute.

When you perform SPE and try to get better results, do not let the silica-based sorbent dry before the sample application and between the steps, as it might impact the recovery levels. The right way is to apply each solvent right after the previous one. For polymeric-based materials, drying is not a big issue because it will keep conditioned after an appropriate solvent is applied.

When SPE is performed, don’t forget to dry the cartridge totally before elution by touching the sides of the cartridge at full vacuum. It will ensure optimum analyte recovery. And the SPE cartridge shouldn’t feel cool to the touch at the same time. And we’d better get the solvents ready just before elution, as certain solvents will lose their strength overdue. Hawach provided Normal Phase Silica SPE Cartridges, Ion-Exchange NH2 SPE Cartridges, and Reversed Phase C18 SPE Cartridges for your choice.

solid phase extraction spe cartridges

In addition to the above description, we also need to know how to use it. The SPE column provides fast and effective purification and concentration for the stock before analysis. In order to obtain the best analysis results for these products, the following four aspects need to be paid attention to:

1. The physical and chemical characteristics of the sample: influencing factors such as the polarity of the analyte relative to the medium, charged functional groups, solubility, molecular weight, etc., determine the binding strength of the analyte and the packed bed.

2. Choose an appropriate retention method: there are two possible methods: First, the analyte is not retained in the packed bed, but the interference is retained, thus purifying the sample. Second, the analyte is retained in the packed bed, but the interference is not retained, or the analyte is eluted from the packed bed before the sample is eluted. When the sample needs to be concentrated, the commonly used method is the second method.

3. Choose proper packing material and packed bed size: different packing types provide different selectivity. The type of packing material should make maximum use of the structural difference between the analyte and the interference in the sample. Choosing appropriate selective fillers can obtain samples and extracts with the highest recovery rate and highest purity. When the size of the packed bed is not optimized, there is usually a problem of a low recovery rate. If the packed bed is too large, the elution will be incomplete, while if the packed bed is too small, the retention will be incomplete. In both cases, the recovery rate is lower than expected.

4. Choose appropriate adjustment, rinsing, and elution solvents: It must be noted that various solvents relative to the elution strength of the filler should be a “weak solvent” with no elution effect in the sample conditioning solvent. A buffer must also be used to control the degree of ionization of potentially charged compounds. The rinsing solvent should elute the weakly retained interferences, but the elution strength should not be too strong to cause the analyte to elute. The strength of the elution solvent should be sufficient to completely elute the analyte in a small volume (1-2ml).

The solubility of the compound in the solvent is an important parameter. If a solvent does not dissolve the analyte but dissolves the interfering substances in the sample, it is a washing solvent, but it cannot be used as an elution solvent.