June 11, 2015, 715004752 Rev. A
Page 26
1.3.4 Cuvette operations
Note:
This section pertains only to flow cells that require a cuvette.
Detector cuvette option is used to measure the absorbance spectrum of a sample in a
cuvette.
To generate and store a spectrum:
1. Acquire a zero scan, which measures the absorbance of the contents of the
cuvette and flow cell over the desired wavelength range.
2. Acquire a sample (absorbance) scan, which measures the absorbance of the
analyte dissolved in mobile phase.
The detector subtracts the zero scan from the sample scan to create a sample
spectrum.
Since the cuvette scan is acquired by measuring the absorbance from a light path that
includes both the flow cell and the cuvette, the solvent conditions in the flow cell must
be identical for both scans. (See
“Scanning using the cuvette” on page 88
1.3.5 RatioPlot
The detector allows ratio plotting: comparing the absorbances of a compound or
analyte at two wavelengths. The RatioPlot divides absorbances at two selected
wavelengths and plots the resulting ratio on a data system over one output channel
(channel A). Use the RatioPlot when detecting hidden components within individual
peaks.
The RatioPlot of a spectrally homogeneous peak appears as a rectangular wave. The
RatioPlot of an impure peak appears as a distorted wave. When obtaining a RatioPlot,
you must be operating the detector in dual-wavelength mode; the RatioPlot is output
on the selected channel. (See
“Obtaining a RatioPlot” on page 71
.)
1.3.6 MaxPlot
The MaxPlot function monitors absorbance at two selected wavelengths and plots the
maximum absorbance value for each sample component. To obtain a MaxPlot, you
must operate the detector in dual-wavelength mode. The MaxPlot outputs the greater
of the two absorbance values on the selected channel.
For an explanation of the MaxPlot procedure, see the discussion
1.3.7 Thermal-wander management
The detector's insulation, fans, and baffling are designed to mitigate thermal
instability caused by ambient temperature changes.
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