Resolving Power and Resolution in Mass Spectrometry

1 Resolving Power and Resolution In Mass Spectrometry The resolving power of a mass spectrometer describes the smallest mass differences which can be separated by the mass analyser (Webb, 2004b). Resolution and resolving power in MS today are defined differently depending on the analyser or instrument type, and is often stated without the indication of the definition employed. The new fUPAC definitions of terms used in MS provide a precise definition. 

The smallest mass difference Am between two equal magnitude peaks so that the valley between them is a specified fraction of the peak height. 

In a mass spectrum, the observed mass divided by the difference between two masses that can be separated ml Am. 

The procedure by which Am was obtained and the mass at which the measurement was made shall be reported as full width at half maximum (FWHM) or 10% valley of two adjacent peaks of similar height (equals 5% peak height of a single isolated mass peak). 

The mass resolving power R can be calculated by the comparison of two adjacent mass peaks m and m of about equal height. R is defined as 

---

Webb, K. (2004b) Resolving Power and Resolution in Mass Spectrometry, Best Practice Guide, VlMMMS/2004/01, LGC Ltd., Teddington, November 2004, www.lgc.co.uk (accessed 14 May 2014). 

---