The General Usage of SPE Cartridge

Solid-Phase Extraction (SPE) cartridges are widely used in analytical chemistry for the extraction, purification, and concentration of specific compounds from complex sample matrices. The general usage of SPE cartridges involves several key steps:

  1. Sample Preparation:
    • Prepare your sample by filtering it to remove particulates and ensuring it is compatible with the SPE cartridge and the chosen elution solvent.
  2. Conditioning:
    • Prior to sample loading, condition the SPE cartridge by passing a specific volume of a compatible solvent through it. This step helps activate the sorbent and remove any impurities.
  3. Sample Loading:
    • Load your prepared sample onto the SPE cartridge. The sample is adsorbed onto the solid-phase sorbent in the cartridge. Ensure that the flow is controlled to prevent overloading.
  4. Activation
    • Activation is also called solvation. We can add an appropriate solvent to spread the functional group on the adsorbent, and also remove possible chaff interference. As for reverse-phase adsorbent, we often use a solvent with medium polarities, such as methyl alcohol. When referring to the normal-phase adsorbent, a solvent with weak polarity or a nonpolar solvent, such as hexane, is always applied.
  5. Equilibrium
    • To remove the activated solvent and make a suitable solvent environment for loading the sample, we often use a solvent that is the same as the solvent in the solution sample. As for the ion exchange SPE column, if the sample is an alkali compound, normally we need to add acid into the equilibrium liquid. On the contrary, we need to add alkali.
  6. Retention
    • When the solution sample goes through the adsorbent, the effort between the adsorbent and certain compounds surpasses the effort between compounds and the solvent, these compounds will be fixed by the adsorbent. This process is called Retention.
  7. Washing:
    • After sample loading, wash the cartridge with one or more suitable solvents to remove interfering compounds while retaining the target analytes on the sorbent. After the sample is loaded, some chaff interferent and target compounds will be retained at the same time. We need to add the appropriate solvent to remove the chaff interferent to the maximum possible extent, and also not to affect the retention of the target compounds.
  8. Elution:
    • Elution is the process of recovering the target analytes from the sorbent. Use an elution solvent or a combination of solvents that are selective for your analytes. The eluted compounds are collected in an appropriate vial or container.
  9. Evaporation or Concentration:
    • In some cases, you may need to evaporate the eluate to concentrate the analytes before analysis. This step depends on the analytical method being used.
  10. Analysis:
    • Analyze the eluate, which now contains the purified and concentrated analytes, using the appropriate analytical technique, such as chromatography or spectroscopy.
  11. Column Cleanup:
    • After elution, perform a cleanup step to remove residual analytes and impurities from the SPE column to prepare it for the next use. This typically involves washing the column with a solvent to remove any remaining contaminants.
  12. Column Storage:
    • Store the conditioned and cleaned SPE column properly to protect it from contamination and maintain its performance. Follow the manufacturer’s guidelines for storage conditions.

SPE cartridges are versatile and can be used for a wide range of applications, including environmental analysis, pharmaceutical testing, food and beverage analysis, clinical diagnostics, and more. The specific sorbent material, cartridge size, and elution conditions may vary depending on the target analytes and the nature of the sample matrix.

It’s important to follow the manufacturer’s instructions for the specific SPE cartridge you are using, as different cartridges may have varying requirements and recommendations for sample loading, washing, and elution. Properly executed SPE can significantly improve the quality and accuracy of analytical results by removing interfering substances and concentrating target compounds.