SPE Troubleshooting - Extra Peak

Welcome to our new SPE technical tip!

What is the cause when you encounter interferences post-extraction regardless of the analytical or detection method? Possible sources of the mystery peak(s) are outlined below.

Possible Cause/Source   /   Suggested Remedy

• Contaminated reagents: Analyze the purity of reagents and additives or try using these from a different supplier.
• Sample pre-treatment: Compare chromatograms of pre-treated and non-pre-treated sample.
• Mismatched injection solvent: Analytes that are dissolved in a strong injection solvent may retain poorly and thus appear as extra peaks. Using the initial mobile phase as the injection solvent is recommended.
• Incorrect SPE method: The SPE sorbent might not have been properly conditioned and equilibrated. Typically, the strongest solvent used in the method should be used to condition the sorbent. Analyze the conditioning, loading and washing fractions to check if the same interferences appear.
• SPE tube leaching: Before conditioning, clean the tube with elution solvent. If reagents or the nature of the sample are too harsh for the polypropylene SPE tube, a glass tube or PTFE tube could be used instead.
• Degradation/side reaction: Check the reactivity and stability of all components in your sample. Degradation can happen if compounds are sensitive to factors such as heat, light, acids, bases, etc. Sample components may be reacting with each other or with reagents/additives.

We hope this tip was useful. See you soon for another tip!