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Issue 02 - 07/2001
English
7
Basic Modes
In the basic modes it is possible to change cell position by pressing the required
number on the keypad.
Absorbance
Absorbance mode measures the amount of light that has passed through a sample
relative to a blank (this can be air). The procedure is as follows:
•
Enter appropriate wavelength and press
enter
•
Enter appropriate sample number and press
enter
•
Insert reference and press
set ref
. The cell changer, if fitted, automatically
moves to position 2 and displays the result for the reference measurement (0.000)
•
This is a “press to read” instrument, whereas other deuterium / tungsten
lamp instruments measure continuously. Thus to monitor sample
stabilisation, the simple kinetics mode must be used
•
This reference value is used for subsequent samples until changed
•
Insert samples as required and press
run
(repeat as necessary)
•
To go back and change the wavelength press
mode
% Transmission
Transmission mode measures the amount of light that has passed through a sample
relative to a blank (this can be air), but displays the result as a percentage. The
relationship between the concentration of the sample and its transmittance at any
given wavelength is not linear, and hence transmission mode is rarely used
experimentally except for samples having very high absorbances (low
transmittances). The procedure is as follows:
•
Enter appropriate wavelength and press
enter
•
Enter appropriate sample number and press
enter
•
Insert reference and press
set ref
. The cell changer, if fitted, automatically
moves to position 2 and displays the result for the reference measurement
(100%)
•
This reference value is used for subsequent samples until changed
•
Insert samples as required and press
run
(repeat as necessary)
•
To go back and change the wavelength press
mode
