The Reason of Poor Sample Recovery When Using SPE

Solid-phase extraction (SPE) is a useful method of sample preparation. By sorting onto a disposable solid-phase cartridge, it can concentrate and purify analytes from solution. But sometimes, the results are unsatisfied with the poor and non-repeatable sample recovery. To avoid it, we’d better find out the reason.

Poor sample recovery in Solid Phase Extraction (SPE) can be caused by various factors, and troubleshooting the issue involves identifying and addressing these factors. Here are some common reasons for poor sample recovery in SPE:

  1. Incomplete Wetting of the SPE Sorbent:
    • If the sorbent bed is not properly wetted before sample loading, it can result in incomplete binding of the analytes. Ensure that the sorbent is wetted evenly with the appropriate solvent before loading the sample.
  2. Sample pH and Ionization:
    • Some analytes may be poorly retained on the SPE sorbent if the pH of the sample is not adjusted appropriately. Ionizable compounds may require pH adjustment to ensure optimal retention and recovery.
  3. Sample Matrix Interference:
    • Complex sample matrices can lead to analyte loss or poor recovery. Matrix components may compete with analytes for binding sites on the sorbent or interfere with elution. Sample cleanup techniques or alternative SPE sorbents may be necessary to address matrix effects.
  4. Incorrect Sorbent Selection:
    • Choosing the wrong type of sorbent for your analytes can result in poor recovery. Ensure that the SPE sorbent is specifically designed to retain the target analytes of interest. Different sorbents have varying affinities for different compounds.
  5. Sample Loading Volume:
    • Overloading the SPE cartridge with too much sample can lead to poor recovery. Follow the manufacturer’s recommendations for maximum sample loading capacity.
  6. Flow Rate and Dwell Time:
    • Inadequate flow rates or dwell times during sample loading can result in incomplete analyte binding to the sorbent. Ensure that the sample is loaded at an appropriate flow rate and that it dwells on the sorbent for the recommended time.
  7. Wash Solvent Selection and Volume:
    • Insufficient washing of the sorbent bed or using a wash solvent that is too polar can result in incomplete removal of interfering substances. Use an appropriate wash solvent and ensure sufficient washing steps. The past experience has fully proved that, only if the wash solvent is strong enough, the most interference can be removed without eluting any sample.
  8. Elution Solvent:
    • The elution solvent must be chosen carefully to ensure efficient recovery of analytes. Using a solvent that is too polar or too weak can lead to poor recovery. Optimize the elution solvent composition and volume. We must make sure that the eluting solvent we choose is strong enough to elute 100% of the sample, as while as weak enough to leave more interfering contaminants on the SPE column.
  9. Drying the Sorbent:
    • Over-drying the sorbent bed after washing can cause the sorbent to become excessively hydrophobic, leading to poor elution of analytes. Use proper drying techniques as recommended by the manufacturer.
  10. Column Conditioning:
    • Ensure that the SPE column is conditioned with the appropriate solvent before sample loading to ensure consistent and efficient analyte recovery.
  11. Sample Volume Reduction:
    • In some cases, concentrating the sample volume before SPE may be necessary to improve recovery, especially when dealing with trace analytes.
  12. Check for Sorbent Contamination:
    • Contamination of the sorbent bed can occur from previous use or inadequate column storage. Proper column cleaning and conditioning are essential.
  13. Column Damage:
    • Physical damage to the SPE column or sorbent bed can affect recovery. Inspect the column for any signs of damage.
  14. Sorbent Bed:
    • According to the working principle of SPE, we must choose the sorbent bed fully retained with the analyte of interest. Poor recoveries will be found when the sample is leaching during load and wash.

To address poor sample recovery in SPE, it’s essential to systematically evaluate these factors and optimize the SPE protocol for your specific analytes and sample matrix. Adjustments to sample preparation, sorbent selection, and method parameters can often improve recovery rates.

Perfect balance of the three parameters: the sorbent, the wash solvent, and the elution solvent, will help us achieve the best sample recovery from solution.
You also can choose Mixed Mode Octyl(C8)/SCX SPE Cartridge, Normal Phase Cyanopropyl (CN) SPE Cartridge, Ion-Exchange PRS SPE Cartridge, Normal Phase PR Grade Florisil SPE Cartridges and other SPE Cartridges using.