Thermo Scientific ISQ EC, Руководство по эксплуатации

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6

Operation
Page 154 ISQ EC and ISQ EM Mass Spectrometer Operating Manual
Table 15: Scan mode parameters: Scans Pane
Table 16: Scan mode parameters: Groups Pane
Table 17: Scan mode parameters: Fraction Collection Channels Pane
6.6.7 Method Development
Often, a method needs to be optimized for enhanced sensitivity or
improved qualitative detection. Whether starting from a fresh method or
transferring a protocol from a different system, it is important to take a
diligent approach to obtaining the proper source and scan parameters.
Some things to consider: mass-to-charge ratio, polarity, adduct formation,
mobile phase composition, mobile phase flow rate, etc. It is always
important to verify the m/z being detected versus assuming an [M+H]
+
or
[M-H]
-
ion as there are many possible adduct formations. Polarity is another
important consideration as some molecules favor protonation or de-
Source CID voltage
Accelerates ions into the background gas to aid in desolvation. Can
increase sensitivity or reduce noise for some analytes. Range: 0-100
V, default: 0 V (no source CID)
Tube lens voltage
Voltage applied to tube lens after the ion transfer tube. 0 V – 300 V.
Higher values can aid in desolvation. Lower values can reduce
fragmentation. Can increase sensitivity or reduce noise for some
analytes.
Note: Use 0 to 300 V for positive ions. Use 0 to -300 V for negative
ions. Use higher values for higher masses. If Last Tune is input, the
tube lens will be run with the values stored in the tune file. Last
Tune is the standard way to run the tube lens.
Parameter Description
Time (min) Time that the MS begins to acquire this particular group of scans
Total scan time (sec) Sum of all the scans in each segment
Chrom. filter peak width
(sec) Sets the peak width to match the width of the HPLC or IC peak
Detector gain
Sets the detector gain to the one in the previous tune file or may be
set manually
Parameter Description
Name The name of the channel for fraction collection
Scan Filter Based on the scan information entered into the Scans pane
Target mass (min) The minimum mass scanned within the scans range
Target mass (max) The maximum mass scanned within the scans range