Thermo Scientific TSQ Altis, Руководство по оборудованию

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G
Thermo Scientific TSQ Altis, Quantis, and Fortis Hardware Manual 151
P
peak threshold The minimum number of intensity counts per sampling interval that is
required before a signal is recorded.
peak width The distance across a peak measured at a selected peak-height level, in minutes
or mass units. The peak-height level is usually specified as a percentage of the maximum
peak height.
peak width at half height The full width of a peak at half its maximum height, sometimes
abbreviated FWHM.
precursor ion An electrically charged molecular species that can dissociate to form
fragments. The fragments can be electrically charged or neutral species. A precursor ion can
be a molecular ion or an electrically charged fragment of a molecular ion.
precursor mass The mass-to-charge ratio of a precursor ion. The location of the center of a
target precursor-ion peak in mass-to-charge ratio ( m/z ) units.
product ion An electrically charged fragment of an isolated precursor ion.
product mass The mass-to-charge ratio of a product ion. The location of the center of a
target production peak in mass-to-charge ratio ( m/z ) units.
profile data Data representing mass spectral peaks as point-to-point plots, with each point
having an associated intensity value.
Q
qualitative analysis Chemical analysis designed to determine the identity of the components
of a substance.
quantitative analysis Chemical analysis designed to determine the quantity or concentration
of a specific substance in a sample.
R
relative standard deviation (RSD) A measure of the dispersion of a group of measurements
relative to the mean of the group. Related standard deviation is expressed as a percentage of
the average value. The percent standard deviation is calculated as:
where S is the standard deviation and is the sample mean.
retention time (RT) The time after injection at which a compound elutes. The total time
that the compound is retained on the chromatograph column.
%RSD 100 S X
⁄ ( ) ×
=
X