Common Trouble-Shooting About SPE Cartridge

1. Low recovery rate
Possible reasons and solutions
1)Cartridge activation conditions are not appropriate – correct activation of SPE cartridges depending on the stationary phase.
2)The solvent of the sample has a stronger force on the target component than the stationary phase-select the SPE cartridge with more selectivity to the target component; adjusting the pH of the sample solvent to increase the force of the target component on the stationary phase; changing the polarity of the sample solvent, reducing the force of the target ingredient in the solvent.
3)Improper cleaning solvent selection, too strong elution ability – use the correct cleaning solvent, choose the solvent with weaker elution ability.
4)The flow rate is too fast when loading – gravity natural load or control sample flow rate ≤ 1 ml/min.
5)SPE cartridge is too small – replace the larger size SPE cartridge; use a more selective SPE cartridge; use a larger sample of SPE cartridge.
6)SPE cartridge cleaning solvent is not sufficiently dried before elution – fully drain the rinse solvent.
7)The flow rate is too fast or too slow when eluting – control flow rate 1-2ml / min.

2. The target component cannot be eluted from the SPE cartridge.
Possible reasons and solutions
1)The selectivity relative to the target component is too strong-select the cartridge that retains the weaker analyte; select the elution solvent with stronger elution ability.
2) SPE cartridge size is too large – increase the amount of eluent; replace it with a smaller specification SPE cartridge.
3) Insufficient amount of eluent – increase eluent.
4) The flow rate is too fast or too slow when eluting – control flow rate 1-2ml / min.
5) The elution ability is too weak – adjust the pH of the eluent or change the polarity of the eluent to increase the elution ability of the solvent to the target component.

3. Poor reproducibility
Possible reasons and solutions
1)The bed dried before loading–Reactivate the cartridge
2)Exceeding the load capacity of the cartridge – reducing the amount of load, or using a larger SPE cartridge
3)The flow rate during the loading process is too high – the flow rate is reduced, the gravity is naturally loaded or the flow rate of the controlled sample is ≤ 1 ml/min.
4)The elution flow rate is too fast – the eluent is added twice
5)Insufficient amount of eluent – increase the amount of eluent, or use a smaller size SPE cartridge

4. Interfering substances are not cleaned
Possible reasons and solutions
1)The selectivity of the fixed relative interferer is too strong – select the appropriate cleaning solution to selectively wash away the interference; select the SPE cartridge that is more specific to the target component.
2)Interstitial residual interference – select a more specific SPE cartridge for the target component

5. Interfering substances are not cleaned
Possible reasons and solutions
1) Excessive particulate matter in the sample – filter or centrifuge the sample solution before loading, or switch to a more solvent solvent
2) The viscosity of the sample solution is too high – check the tightness of the extraction device, check if the pump is working properly, increase the vacuum
3) Insufficient vacuum – check the tightness of the extraction unit, check that the pump is working properly, increase the vacuum

6. The sample size is too large
Possible reasons and solutions
The sample volume is larger than the loading amount of the extraction cartridge – using a larger SPE cartridge

7. Poor extraction efficiency
Possible reasons and solutions
The wrong method – select stationary phases with different extraction modes, or use other analytical methods