Resolution and Accuracy

One common mistake made by scientist dealing with mass spectrometry is confusing resolution and accuracy.   Basically, resolution is the ability to separate ions with a specific m/z, while accuracy is how well the mass spectrometer measures the mass of the peak.   Resolution helps accuracy in two ways, one is that it eliminates possible contaminating peaks at the same nominal mass, while the second is that it makes it easier to define the peak position consistently. 

While traditionally chemist have requested "high resolution", that terminology is technically wrong for what they need.  The correct request is for "accurate mass".  A high resolution spectra may not have very good accuracy, which is what is needed.   An example of this is the high resolution obtained on an electrostatic ion trap (called zoom scans), that show ability to seperate closely space peaks, but the mass accuracy is the same as the normal scans.  However, some researchers have shown the ability to measure accurate masses on low resolution instruments when measuring clean samples.