O
PERATION
ProStar 340 UV/Vis Detector
19
Range
Rotate the Range Selector Switch to an appropriate full scale
absorbance for your sample. Full scale ranges of 2.0, 1.0, 0.5,
0.2, 0.1, 0.05, 0.02, 0.01, 0.005, 0.002, 0.001, and 0.005 AUFS
are provided. This switch does not affect the fixed 1 V/AU output
of the rear panel located integrator output.
Rise Time
As a general rule a rise time equivalent to 1/10 of the fastest
peak base-width should be used. Too short a rise time results in
an unnecessarily noisy baseline, while too long a rise time may
distort the shape of the peak. For most LC applications, a rise
time value of 1.0 second is sufficient.
The Second Order Bessel filter provides user selectable rise
times of 0.1, 0.3, 1.0, and 3.0 seconds. For extremely fast peaks,
a filter by-pass switch is provided on the rear panel (Figure 7,
Switch #6).
NOTE:
Although the filter may distort peak shape at long rise times, peak area is
always maintained. Integration can be safely performed for the purpose
of quantitative analysis from the recorder output.
Pressing the top portion of this switch turns the circuit on,
disables the rise time selector, and results in an effective rise
time of 0.1 seconds.
Performing a Test Run
After setting the detector parameters, the instrument should be
zeroed. As a general rule, it is a good idea to autozero the
detector prior to each injection.
Zero the detector, inject your sample, and activate the event
mark. You should note an approximate 20% deflection on the
recorder. Note the peaks as they appear on the strip chart
recorder. Readjust the parameters of wavelength, range, and
rise time to optimize the chromatography.
Summary of Contents for ProStar 340
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