| This dynamic scan provides UV spectra
in only 200mS, previously only possible using the static optical
system of a PDA detector.
Powerful signal processing software has been developed which enables
very high quality “on-the-fly” scans to be triggered
by eluting peaks without the peaks being degraded.
Spectral data is transferred by Cecil’s DataStream software
to a PC workstation where the same software offers spectral manipulation
and processing, library facilities and the export of data to applications
such as Excel, word etc. All data may be stored on disk.
Eluting peaks may be integrated at the same time as purity and
peak identification is carried out. Quantitative evaluation and
reporting is carried out by Cecil’s CE4900 PowerStream software,
which is combined with DataStream software.
One Detector Covers All UV Applications
A single beam Photodiode Array Detector (PDA), used for method
development and R & D, will often be replaced by a dual beam
UV variable wavelength detector for routine monitoring, when the
developed method is adopted, because of the poor drift performance
of single beam PDA detectors. Their performance can be as much as
20 times worse. The Dynamic Absorbance Detector has a double beam
optical system with very high all round performance and the lowest
drift available.
The CE4300 may therefore be used for method development, purity
determination, etc. and also as a high performance UV detector for
variable wavelength monitoring (VWM).
WaveQuest, which is less expensive than a PDA detector, therefore
has a double cost advantage.
Universal UV/Visible Detector
WaveQuest the ultra fast scanning Dynamic Absorbance Detector (DAD)
is a major advance in UV-visible detector design, offering the capabilities
of a Photo Diode Array (PDA) detector with greatly improved performance
when used for chromatogram monitoring.
Very high speed scanning of eluting peaks, “on the fly”,
makes purity checks, the determination of optimum monitoring wavelengths
for unfamiliar peaks (lambda max scans), and compound identification
of peaks using library spectra all possible with considerable cost
saving.
CE4300 Dynamic Absorbance Detector
WaveQuest the new CE4300 Dynamic Absorbance Detector (DAD) for
ultra fast scanning, part of the Adept HPLC range from Cecil Instruments,
offers all the spectral facilities of Photo Diode Array detectors,
with better noise and drift performance, particularly important
when used to monitor and quantify chromatograms.
The CE4300 has a double beam optical system in which the dispersed
radiation is dynamically scanned across the detectors in the manner
of a UV-Visible double beam spectrophotometer at ultra fast speeds
– up to 1000nm/second.
All components of the detector – monochromator, optical system,
lamp optics, detector optics and signal processing software have
been carefully optimised to provide unprecedented performance in
both wavelength scanning and single or multi-wavelength monitoring.
The lower noise level when monitoring a chromatogram makes accurate
measurements at the highest sensitivities possible when measuring
very low concentrations.
The lower drift, as much as 20 times lower, gives flat chromatogram
baselines making integration of peaks more accurate, particularly
at high sensitivities.
Taper Beam Optics
Taper beam optical imaging at the flowcell, with all transmitted
energy reaching the detector, provides maximum energy collection.
The result is minimal baseline wander due to changes in the solvent
refractive index during gradient formation.
Performance Validation
Validation of detector performance is carried out conveniently,
using the instruments standard software. A Holmium Oxide filter
is automatically inserted in the optical path when the calibration
routine is selected.
Bandwidth validation is automatic, using the Deuterium emission
line at 656.1nm. Absorbance accuracy is checked using filters traceable
to NPL standards.
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