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CombiFlash NextGen Systems
Section 3 Operation
Figure 3-10 ELS Detection Options window
3-18
ratio remains steady while the concentration changes from the
beginning to the end of the peak. During the duration of the
peak, this constant value is displayed as a horizontal line.
Now assume that there is a second compound eluting, only
slightly shifted in time from the original compound. It is possible
that the detection absorbance trace alone would indicate a single,
valid chromatographic peak. In reality, it is a combination of two
peaks. By monitoring a second wavelength, it may be possible to
reveal the second compound. Because of the slight shift in time
and the different absorbance properties of the two compounds,
the changing ratio during the detected peak would reveal the
impurity. Therefore, one can assume that if the ratio is not con-
stant for the entire duration of the peak, the compound eluting
may not be pure.
When P
M
URITY
EASURE
opens a D
O
ETECTION
additional settings.
Detection Options (Purity Measure) – A window with options
to customize the purity measurement.
• Show Spectral Purity – When enabled, this measures
purity by using a comparison of UV-spectra measured at
differing time; it is not limited to 2 wavelengths. The
algorithm used is the "similarity index."
• Spectral Purity Detection – When enabled, this
allows fractionation based on spectral purity. If the
spectra within the peak are similar, it is considered 1
peak. If the composition of the peak changes during the
peak, the spectra will not be similar and the purity
index will decrease from the default value of "1"
indicating a change in purity from the early portion of
the peak. This allows the system to advance to the next
fraction as the purity within a detected peak changes.
EAR99 Technology Technology Subject to Restrictions Contained on the Cover Page
is enabled, clicking the D
window on which you can make
PTIONS
button
ETAILS
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