How to Solve Solid Phase Extraction Cartridge Common Problems?
Regarding the common problems in the use of extraction columns, there are generally low recovery rates, poor reproducibility, poor purification effects, and flow rates that are too fast or too slow. HAWACH has summarized the possible reasons and solutions for your reference. Also, welcome to contact us for further discussion.
- Low recovery rate
Cause Analysis:
①Insufficient retention of the target on the packing
| Possible Causes | Solution |
| SPE column selection is inappropriate | Choose a stronger retention SPE column |
| The elution strength of the sample loading solution or eluent is too strong | Reduce the elution intensity of the sample loading solution or eluent |
| Overload caused by too high sample volume/concentration | Increase the amount of filler or reduce sample volume/concentration |
| During the operation, the small column “dries up” | Reactivate/equilibrate to ensure that the cartridge does not “dry up” before the end of the elution |
②Incomplete target elution
| Possible Causes | Solution |
| Small column retention is too strong | Choose a slightly weaker SPE column |
| The elution capacity is too strong | Enhanced elution intensity |
| The elution volume is too small | Enhanced elution volume |
③Other reasons
| Possible Causes | Solution |
| Insufficient extraction of pre-processing | Change the extraction solvent |
| Unstable, volatilized or decomposed target substance | Reduce heating temperature, change the extraction and transfer mode, and add buffer salt to adjust PH of the compound which is greatly affected by PH |
| Complex pretreatment process | Simplify the pretreatment process |
| Combination of target and impurities | Change the appropriate method to remove impurities |
| Impurity interference effect is too strong | Change the pre-processing method or compare with the matrix spike material |
| Too much impurity, exceeding the maximum retention of the small column | Change the pretreatment method, reduce the amount of sample loading or increase the amount of small column packing |
- Reasons and solutions for poor reproducibility
| Possible Causes | Solution |
| The operation steps are cumbersome and caused by human error | Change the pre-processing method or formulate SOP method |
| Poor impurity removal effect for complex sample matrix | Change the whole pre-processing method, add internal standard or compare with matrix spiked data |
| Dry up during sample loading | Reactivate balance |
| Column clogging occurs or the flow rate is too fast | The former changes the pretreatment method, the latter uses a check valve to control the flow rate |
- Solutions for poor purification effect
①Change the pretreatment method
②Change the intensity of eluent and eluent
③Choose the appropriate role column
④Carry out SPE operation correctly
- Reasons and solutions for too fast or too slow flow rate
| Reason for the slow flow rate | Solution |
| SPE selected particle size is too small | Choose large particle size SPE |
| Suspended insoluble matter remains after sample pretreatment | Freeze centrifugation before loading |
| Sample viscosity is too high | Sample dilution |
| SPE resistance is too large, and the liquid cannot drop by gravity | Use a manual solid phase extraction column device to adjust the flow rate by adjusting the check valve, the valve, and the negative pressure |
| Reasons for too fast flow rate | Countermeasure |
| SPE selected particle size is too large | Choose a small particle size SPE |
| The flow velocity is still very fast under the action of gravity | Use manual SPE device to adjust check valve |
| The flow rate is too fast when pumping negative pressure | Adjust the check valve and valve to control the pressure of the vacuum gauge to be constant within a certain range |