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All Wavelength Detection
EAR99 Technology Technology Subject to Restrictions Contained on the Cover Page
· Select the average peak width for your chromatog-
raphy. Peak widths are measured at the baseline.
The slope detector will detect peak widths ranging
from about 0.2 to 2 times the peak width setting for a
moderately sized peak.
· For example, if you entered a peak width of 1 minute,
the range would be 12 seconds to 2 minutes.
· For best operation, the peak width should be set to
just over the average peak width being separated.
For instance, if the average peak width is 45 seconds,
you should enter a peak width of 1 minute. For most
flash chromatography, 1 minute is a good starting
point for a peak width.
• Threshold – Identifies a peak if the absorbance exceeds
the selected value.
· It will continue to identify a peak until the
absorbance drops 0.01 AU below the programmed
threshold to minimize false peaks due to a noisy
signal.
· If both S
LOPE
peak is collected if either criteria is met.
• Monitor – Displays the detector signal for reference but
won't trigger fraction collection based on the signal.
• Baseline Correction – Allows compensation of absor-
bance due to solvent UV absorbance.
· Selecting this option enables a pre-run gradient to
provide a 'blank' run that can be used to adjust for
absorbance changes due to changing concentration of
UV-absorbing solvents throughout the run. This
requires ~1 minute.
· Baseline correction may impact peak intensity.
Additionally, this setting may effect peak shape
because the software distinguishes between sample
and solvent.
· Selecting baseline correction for any wavelength will
apply the correction to all wavelengths and may
impact peak height even in areas where the solvent
absorbance is low.
All Wavelength Detection – Enable this option to detect peaks
within a user-selected range of wavelengths.
· This algorithm compares the current total spectrum
of absorbance and compares it to the solvent
spectrum. The more that the spectrum deviates from
the solvent spectrum, the higher the signal. It is
useful to limit the range of wavelengths used in this
algorithm to better differentiate the compound
spectrum from the solvent background spectrum.
When enabled, clicking the D
O
window on which you can make additional settings.
PTIONS
CombiFlash NextGen Systems
Section 3 Operation
B
and T
ASED
HRESHOLD
button opens a D
ETAILS
are selected, a
ETECTION
3-15
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