Hoefer SP-2001 Vision Life Spectrophotometer - Manual (Page 12)

Version 1.0
Page 12
2: Concentration
This makes simple concentration measurements on samples, by measuring the amount of light that has passed
through a sample relative to a reference (this can be air). Concentration is obtained by multiplying the measured
Absorbance at a specific wavelength by a factor. The factor may be known in advance, or may be calculated by the
instrument by measuring a standard of known concentration.
The procedure is as follows:
Step 1
Set wavelength by using keypad numbers or left and right
arrows.
Press the down arrow key.
Step 2
Select the mode, Factor (user entered) or Standard (factor is
calculated from a calibration sample), using the left and right
arrows.
Press the down arrow key.
Step 3 (if Factor is selected)
Enter the Factor using the keypad numbers. Range 0.001 to
9999. Use the C button to delete the last digit entered.
Press the down arrow key.
Step 3 (if Standard is selected)
Enter the concentration using keypad numbers. Range 0.01-
9999. Use the C button to delete the last digit entered.
Press the down arrow key.
Step 4
Units: The user can enter a text string up to 8 characters long.
To access a list of pre-defined units press the Options key ::;
and then use the left/right arrows (μg/ml, μg/μl, pmol/μl, mg/dl,
mmol/l, μmol/l, g/l, mg/l, μg/l, U/l, %, ppm, ppb, conc or none).
These units can also be edited once OK is pressed.
This screen also allows the number of displayed decimal points
(DP) to be selected, from 0 to 2 Note that the result will always
be fixed to 5 significant figures regardless of how many decimal
points are selected (so 98768.2 will display as 98768 even with 1
decimal point selected). Press OK
to store the chosen
parameters or Cancel .
Step 5
To enter the results screen with the selected parameters press
OK
OR
Cancel the selections and return to the Applications Folder by
pressing Cancel
.
Step 6 (if using a Factor)
Insert the reference. Press 0A/100% key. This will be used for all
subsequent samples until changed.
Step 7
Insert sample and press
.