MassQC Help > Troubleshooting > Signal & Ionization > Degraded Sample          
Sample Degradation and Semi-Tryptic Peptides

Sometimes a sample can degrade over time. Perhaps the technician left the sample out on the bench top at room temperature for an extended period of time. Maybe the freezer broke down and the sample defrosted over night. Whatever the reason, MassQC can help find these errors from looking at the mass spectra.

In this example, we notice an increase abundance of +1H charged ions, and a high number of Semi-Tryptic Peptides:

+1H Ions and Semi-Tryptic Peptides

From the Dashboard view in MassQC, you can clearly see that the Percent Semi-Tryptic Peptides is far out of range. This may spark some interest to dig deeper into your historical data. You would then click the Control Charts tab and take a closer look:

High Percent Semi-Tryptic Peptides

In just a few minutes, you can track down what metrics are out of range and make some kind of conclusion about your sample. By combining the knowledge that you have a high percentage of +1H ions and that the number of Semi-Tryptic Peptides has increased, it is reasonable to conclude that there has been some sample degradation. This information can be of great assistance tracking down exactly what caused your sample to degrade in the first place.

Metrics discussed this section:
Forum

If you have questions, comments and/or insights about MassQC, you can share them on the MassQC Users Forum.

Search the MassQC Site and the Help Center