LaMotte SMART 3 Electronic Soil Lab - Manual (Page 12)

12 SMART3 Soil 1.11
SAMPLE DILUTION TECHNIQUES & VOLUMETRIC 
MEASUREMENTS
If a test result using the SMART3 Colorimeter gives an over range message
then the the sample must be diluted. The test should be repeated on the diluted
sample to obtain a reading which is in the concentration range for the test.
(Note: This is not true for colorimetric determination of pH.)
Example:
Measure 5 mL of the water sample into a graduated cylinder. Add
demineralized water until the cylinder is filled to the 10 mL line. The sample
has been diluted by one-half, and the dilution factor is therefore 2. Perform
the test procedure, then multiply the resulting concentration by 2 to obtain
the test result.
The following table gives quick reference guidelines on dilutions of various
proportions. All dilutions are based on a 10 mL volume, so several dilutions will
require small volumes of the water sample. Graduated pipets should be used for
all dilutions.
Size of Sample
Deionized Water to
Bring Volume to 10 mL Multiplication Factor
10 mL 0 mL 1
5 mL 5 mL 2
2.5 mL 7.5 mL 4
1 mL 9 mL 10
0.5 mL 9.5 mL 20
If the above glassware is not available, dilutions can be made with the
colorimeter tube. Fill the tube to the 10 mL line with the sample then transfer
it to another container. Add 10 mL volumes of demineralized water to the
container and mix. Transfer back 10 mL of the diluted sample to the tube and
follow the test procedure. Continue diluting and testing until a reading, which
is in the concentration range for the test, is obtained. Be sure to multiply the
concentration found by the dilution factor (the number of total 10 mL volumes
used).
Example:
10 mL of sample is diluted with three 10 mL volumes of demineralized water;
the dilution factor is four.