Solid phase extraction column is a key tool for laboratory sample pretreatment, but it often faces various troubleshooting challenges during its operation. The following are common fault classifications and targeted solutions:
1、 Low recycling rate issue
Insufficient retention of the target object
Phenomenon: Blank labeling experiment shows that the residual target substance in the sample solution/eluent exceeds 5%.
Reason: Improper selection of SPE column (such as polarity mismatch), uneven packing or aging of fillers, and unadjusted pH of sample solution leading to abnormal dissociation of target substances.
Solution: Replace the adsorbent with a more selective one; Optimize the pH value of the sample; Ensure that the activation process is standardized.
Incomplete elution
Phenomenon: The concentration of the target substance in the eluent is lower than the theoretical value, and there is still no improvement after increasing the elution volume.
Reason: Insufficient solvent strength, small elution volume, or irreversible adsorption between the target substance and the filler.
Solution: Use a more polar eluent instead; Fractional elution improves efficiency; Replace the packing with weak hydrophobicity.
2、 Poor reproducibility and decreased precision
Operational factors
Flow rate out of control: Flow rate>1mL/min will result in insufficient mass transfer, and it is necessary to strictly control the flow rate during activation and sample loading stages to ≤ 2mL/min.
Column drying: Failure to sample in a timely manner after pretreatment may expose the filling material to air. It is necessary to reactivate and avoid draining.
Matrix interference
Ionic strength/pH fluctuation: Complex samples require the addition of buffer salts to maintain system stability and suppress impurity competition adsorption.
Co outflow interference: gradient elution is used to establish a elution curve, accurately separating the target substance from impurities.
3、 Poor purification effect
Low impurity removal rate
Mode selection error: Prioritize the purification mode that retains the target substance, as its exclusive selectivity is superior to the mode that retains impurities.
Filler deactivation: Failure to activate the column with strong eluent resulted in residual impurities. Pure methanol is required to rinse the reverse phase column during activation.
Silicon alcohol based effect
Performance: The combination of alkaline compounds and residual silanol groups causes tailing.
Countermeasure: Adjust the pH of the eluent to acidic or add competitive amine reagents to block hydrogen bonding.
4、 Abnormal flow velocity and column blockage
Physical blockage
Particle contamination: The sample contains insoluble particles and requires centrifugation or filtration pretreatment.
Excessive viscosity: Dilute the sample to reduce flow resistance.
Loading defects
Bubbles/Cracks: The height of the packing bed is abnormal and the packing needs to be reinstalled.
5、 Equipment operation failure
Abnormal pressure
High pressure alarm: Due to pipeline blockage or scaling of the outlet filter screen, the machine should be shut down for cleaning.
Low pressure leakage: Check the wear of the sealing ring and replace the sealing components in a timely manner.
Control system malfunction
Software error: Restart the device and update the firmware; If it is ineffective, contact the manufacturer to repair the circuit board.
The fault diagnosis of solid-phase extraction column needs to be combined with experimental phenomena and systematic troubleshooting. Regular maintenance (such as gasket replacement and liner cleaning) can significantly reduce the failure rate. For complex problems, it is recommended to refer to the error code guidelines in the equipment manual or use a dual column series connection strategy to verify separation efficiency.