What is the purpose of dilution?

Document ID

Document ID TE1595

Published Date

Published Date 25/01/2018
Question
What is the purpose of dilution?
Summary
Dilution explanation
Answer
Dilutions can be important when dealing with an unknown substance.
A dilution can be performed not only to lower the concentration of the analyte that is being tested, so that it is in range, but also to help eliminate interferences from other substances that may be present in the sample that can artificially alter the analysis.
An analyte is the compound in the sample that is desired to be tested.  An example is if performing a chlorine test, chlorine would be the analyte.
An interference is a compound that can add to, or subtract from the result of the analysis. For example, oxidized manganese (Mn+6) acts as an interference to the chlorine test. If the Mn+6 is present in the sample it will add to the value of the chlorine test due to the way the it reacts to the chlorine test reagents. By performing a dilution on a sample it may reduce the interfering substance to a point where it no longer interferes with the test.
When performing a dilution there is a equation that can be used to determine the final concentration. 
C1V1 = C2V2
C1 is the initial concentration
V1 is the inital sample volume before diluton 
C2 is the final concentration after dilution
V2 is the final volume after dilution
For more information as well as examples, please see Chemical Analysis the section of the Water Analysis Handbook