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Purity Measure
EAR99 Technology Technology Subject to Restrictions Contained on the Cover Page
solvents such as heptane, or reverse phase solvents
such as water, methanol, or acetonitrile.
• Spray Chamber Temperature – The default settings
are 30 °C (normal phase default methods) and 15 °C
(reverse phase).
· This setting may be adjusted from 10 to 60 °C so that
detection can be optimized for the solvent system in
use. However, the lower limit is 5 °C below the
ambient temperature.
• Drift Tube Temperature – The default settings are
60 °C (normal phase default methods) and 60 °C
(reverse phase).
· This setting may be adjusted from 30 to 90 °C, but is
limited to a range of 5 °C below and 60 °C above the
ambient temperature.
• Mass Spectrometer – Enable this option to monitor or
detect compounds with a PurIon mass spectrometer
system (PurIon systems only).
• Threshold – Sets the signal level used to detect a peak.
This is based on the baseline noise. The baseline noise is
measured during the first column volume; this is multi-
plied by the value entered in the T
generate a trigger value. A peak is collected if the signal
is greater than this trigger value.
· For the PurIon mass detector, only threshold peak
detection is allowed. In this case the threshold is set
as a factor of the measured noise signal. The noise for
the first few seconds of the chromatogram is used to
determine average noise level. Any mass signal that
exceeds this level by the selected factor will be
collected as a peak.
• Monitor – Prevents fractionation on the basis of the
mass spectrometer signal.
• Terminate On Target – Stops the run after all mass
spectrometer detection ions have been detected.
• Detection Ions – Sets ions for detection or to be
monitored. Up to 4 single ions may be chosen, or a range
of ions and up to 3 single ions may be chosen. Detected
ions may be a mixture of positive and negative ions.
Purity Measure – When using two wavelength detection
options, a ratio of the two wavelengths can be displayed which
can provide an indication of compound purity.
For example, if a pure compound is eluting, the absorbance is lin-
early related to the concentration of the compound in the solvent
regardless of wavelength. If the compound absorbs differently at
different wavelengths, the absorbance at each wavelength may
be different, but is still linearly related to the concentration. If
the concentration doubles, the absorbance at each wavelength
doubles (at least within the limitations for Beer's Law). Since the
relationship of absorbance to concentration is not variable, the
CombiFlash NextGen Systems
Section 3 Operation
control to
HRESHOLD
3-17
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