Micromass Quattro Ultima, Руководство пользователя

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Overview
MassLynx NT allows a fully automated mass calibration to be performed, which
covers the instrument for static and scanning modes of acquisition over a variety of
mass ranges and scanning speeds.
A mass spectrum of a reference compound (a calibration file) is acquired and matched
against a table of the expected masses of the peaks in the reference compound which
are stored as a reference file. The mass differences between the reference peaks and
calibration peaks are the calibration points. A calibration curve is fitted through the
calibration points.
The vertical distance of each calibration point from the curve is calculated. This
distance represents the remaining (or residual) mass difference after calibration.
The standard deviation of the residuals is also calculated. This number is the best
single indication of the accuracy of the calibration.
Calibration Types
Each quadrupole analyser requires up to three calibration curves:
•
A static calibration is used to ‘park’ the analyser accurately on a specific mass
of interest (in tuning and SIR for example).
•
A scanning calibration enables peaks acquired in a scanning acquisition to be
mass measured accurately.
•
A scan speed compensation calibration compensates for ‘lag time’ in the system
when the instrument is scanned rapidly.
A separate mass spectrum of the reference compound is acquired for each selected
calibration type.
Quattro Ultima requires these three calibrations for both MS1 and MS2, for a
maximum of six calibration curves. The table below show which types of calibration
are necessary for particular types of experiment.
Experiment
Calibration Required
MS1 MS2
MS All -
SIR Static -
MSMS All All
MRM Static Static
Mass Calibration
Page 102
Quattro Ultima
User's Guide