Jenway 6305 - Manual (Page 19)

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SECTION 5 – CONCENTRATION MEASUREMENTS
The concentration measurement mode enables simple measurements of concentration to be
performed. In this measurement mode it is possible to calibrate against a standard of a known
concentration or use a known factor. The sample is measured at one wavelength at one point in
time.
To select concentration use the LEFT or RIGHT arrow keys to move the cursor to the CONC
indicator on the menu bar (refer to figure 2.3.1). The primary display will show the concentration
with the selected units. To adjust the wavelength use the UP and DOWN arrow keys.
To select the units use the LEFT or RIGHT arrow keys to move the cursor to the UNITS indicator
on the menu bar (refer to figure 2.3.1). Use the UP and DOWN arrow keys to select ppm, mg/l,
g/l, M, % or blank units. Once the required units have been selected press the RETURN or CAL
key to store the units and return to the concentration measurement mode.
5.1 USING A KNOWN STANDARD
The calibration must be performed at the same wavelength at which the sample will be measured.
Insert a cuvette containing the known concentration standard into the sample chamber and close
the instrument lid. Press the CAL key; the CAL annunciator will flash continuously. Use the arrow
keys to change the concentration to the required value for the standard. Press the CAL or
RETURN key to calibrate the instrument to the standard concentration. The instrument will
calculate the factor for subsequent measurements. If the factor calculated is out of range, then the
instrument will display Err 3 for 2 seconds after the calibration. To view the factor use the LEFT
or RIGHT arrow keys to move the cursor to the xF indicator on the menu bar (refer to figure
2.3.1).
Once the calibration has been performed a sample of unknown concentration can be measured.
Remove the cuvette containing the standard solution and place a cuvette containing the sample
to be measured in the sample holder. Close the instrument lid and the concentration result will be
shown on the screen.
Subsequent samples can be measured in the same way. If the wavelength is adjusted between
sample measurements then the instrument must be calibrated again before more samples can be
measured.
5.2 USING A KNOWN FACTOR
If the factor is known there is no need to calibrate against a known standard. To enter the factor
use the LEFT or RIGHT arrow keys to move the cursor to the xF indicator on the menu bar (refer
to figure 2.3.1). Use the UP and DOWN arrow keys to enter the required factor. Once the required
factor has been entered press the RETURN or CAL key to store the factor and return to the
concentration measurement mode.