Hello,

Split peaks in mass spectrometry data can have a variety of causes, including problems with the instrument, sample preparation, or data analysis. Some potential causes of split peaks specifically in the context of oligonucleotide analysis on a RapidFire mass spectrometer include:

• Insufficient mass resolving power of the instrument: If the mass resolving power of the instrument is not high enough to separate closely eluting peaks, they will appear as split peaks.
• Incomplete sample preparation: If not all the salts, buffer, or other contaminants were removed from the sample, they can interfere with the ionization process and lead to split peaks.
• Poorly designed mass spectrometry method: if the method is not optimized for the kind of sample you are analyzing, this can lead to split peaks.
• Ion suppression: The presence of certain species of ions in the sample can suppress the signal of other ions, leading to split peaks.

here are some more specific steps you can take to troubleshoot split peaks in oligonucleotide analysis on a RapidFire mass spectrometer:

It's worth mentioning that split peaks can also be due to the presence of multiple species of ions that have the same mass but different charge states, which can be resolved by using a mass spectrometer with high resolution and mass accuracy.