I am trying to extract features, but the outputted table shows that various peaks had the same m/z but different retention times. What could this mean? How do I move forward with the analysis?
Hi,
m/z is really just a measure of a mass divided by the charge. Hence, several different molecules can have the exact same m/z. If you look at glucose, C6H12O6, there are many different oses that have exactly the same raw formula - plus enantiomers. Being different molecules, your LC should ideally be able to separate them, leading to different retention times - but the m/z will be identical. Combining retention time and m/z can help pinpointing which peak is what. When doing your statistical analysis, the softwares will thus consider each combination of [m/z + RT] as being different molecules. You should let the soft work that way. If you’re interested in knowing which peak is what, you probably need to dig using e.g. MSMS or other techniques - or compare with standards
Hope this can help