Lovibond Maxi Direct - Sample Dilution Techniques; Correcting for Volume Additions

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MaxiDirect_2c 03/2010
1.2.4 Sample dilution techniques
Proceed as follows for accurate dilutions:
Pipette the water sample (see table) into a 100 ml volumetric flask and fill up to 100 ml mark
with deionised water. Swirl to mix the contents.
Water sample
[ml]
Multiplication
factor
1 100
2 50
5 20
10 10
25 4
50 2
Pipette the required volume of the diluted sample into the vial and proceed as described in
the test methods.
Caution:
1. Dilution decreases accuracy.
2. Do not dilute water samples for measurement of pH-values. This will lead to incorrect
test results. If “Overrange” is displayed use another instrument (e.g. pH-meter).
1.2.5 Correcting for volume additions
If a larger volume of acid or base is used to pre-adjust the pH-value, a volume correction of
the displayed result is necessary.
Example:
For adjusting the pH-value of a 100 ml water sample 5 ml of acid had to be added. The
corresponding displayed result is 10 mg/l.
Total volume = 100 ml + 5 ml = 105 ml
Correction factor = 105 ml / 100 ml = 1.05
Corrected result = 10 mg/l x 1.05 = 10.5 mg/l