Abstract
The UHPLC belongs to the group of fast chromatography techniques, therefore the specific demands of UHPLC/MS coupling on parameters of selected mass analyzer are related to the fact that peaks are narrower compared to the conventional HPLC. The minimum acquisition speed of mass spectrometer in the UHPLC detection should be at least 4-12 Hz, which fits with TOF, Q, IT and LIT mass analyzers, because all of them can reach at least 10 Hz.
The fastest mass analyzer is obviously the TOF with common acquisition speeds 40-50 Hz and recently the fastest QqTOF instrument on the market has reached 100 Hz, which allows numerous parallel SRM scans even in ultrafast UHPLC/MS analysis. Additional advantage of modern TOF-based instruments is rather high resolving power (40-60 thousands) and mass accuracy (typically, better than 3 ppm with the external calibration and better than 1 ppm with the internal calibration).
Another parameter important for the quantitation is the linear dynamic range, which is at least 5 orders of magnitude for all latest Q, linear IT, TOF and their combinations, therefore these analyzers are the most common instrumental configurations in UHPLC/MS coupling, but the top class Fourier transform mass analyzers provide additional benefits for the structural elucidation.