Instruction manual

5.5 Measuring in the Spectrum Scanning Mode
5-61
RF-20A/20Axs
5
5.5 Measuring in the Spectrum Scanning
Mode
This instrument features a spectrum scanning function to find the optimum excitation wavelength and
emission wavelength. Two sample spectra and one background spectrum can be read. Executing spectrum
scanning also makes it possible to ascertain the overall characteristics of a sample.
NOTE
In order to reduce the effects of fluctuations in excitation light intensity, this instrument outputs signals where
the emission light intensity has been divided by the excitation light intensity (division correction), but this
division correction is not applied on measurement of the excitation wavelength spectrum. This is because the
excitation wavelength spectrum that has not been subjected to division correction shows excitation
wavelengths with a higher detection limit.
5.5.1 Flow Line for Spectrum Scanning
In order to ensure that the liquid inside the cell doesn't move during spectrum scanning, a high-pressure 6-
port valve is used as shown in the figure below.
Fig. 5.1
The 6-port valve normally takes the positions indicated with solid lines as the flow line. Before starting
spectrum scanning the flow line is switched to the positions shown with dotted lines, stopping flow (pumping).
The method described in "Stopping the pump on reaching the peak" can also be used as a simple method for
stopping the flow (pumping), but since the flow (pumping) doesn't stop immediately on stopping the pump, this
time lapse has to be factored in.
NOTE
During pumping set the drain valve to the "open" position and don't stop the flow. This could shorten the life of
the column as a result of pressure shock.
Follow the procedure from the next section onward to set the parameters required for spectrum scanning.
Reservoir
Manual
injector
Stop plug
Drain
LC-20AD
Column
Drain
FCV-12AH, etc.
(high-pressure 6-port valve)
RF-20A/20Axs