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displayed. In this case, divide the concentration by 10, re-select the C mode by
successive presses on the Mode button, cycling through the F, %T, and A modes, and
follow step 2 above to set the concentration of the standard to the reduced value.
8. With the standard concentration set, determine the concentration values of samples
with unknown concentration by inserting the sample cuvette into the sample
compartment and reading the value direct from the display.
9. To read the value of the multiplier used to convert Abs to Concentration, after
measuring all the samples, change the Mode to Factor (F) and read the multiplier
from the display. Keep a record of this value for future use.
Operational Note: if the mode switch is changed to read Factor or Absorbance, the
Concentration (C) reading is “frozen”, and cannot be changed. This requires the
operator to re-start at step 1.
Factor (F) Mode
This is a special mode for measuring concentration values of unknown samples using a
previously determined factor to convert Absorbance readings to concentration.
1. After setting the wavelength, and setting zero Abs on the blank solution, using
the MODE button, select factor (F) mode.
2. Insert a cuvette containing a sample.
3. Using the ∧and ∨arrows, set the digital read-out window to the desired value of
the multiplier.
4. Press the ENT button. The spectrophotometer switches to the Concentration (C)
MODE.
Operational Note: If the Concentration of the sample is too high to be displayed, the
instrument will not switch to Concentration Mode when the ENT button is pressed.
Dilute the sample and multiply the concentration reading by the dilution factor to obtain
the original sample concentration.
5. Read the concentration value of the sample direct from the display.
6. Insert a cuvette containing the next sample and read the result. Repeat until all
samples have been measured.
Operational Note: If the MODE switch is changed to A or T, then the concentration
reading is “frozen”. This requires the operator to re-start at step 1.