EPA-NERL: 305.1: Acidity by Titration
Official Method Name
|
Acidity (Titrimetric) |
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Current Revision
| Issued 1971; Technical Revision 1974 |
Media
|
WATER |
Instrumentation
|
Titration |
Method Subcategory
|
Inorganic |
Method Source
|
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Citation
|
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Brief Method Summary
|
The pH of the sample is determined and a measured amount of standard acid is added, as needed, to lower the pH to 4 or less. Hydrogen peroxide is added, the solution boiled for several minutes, cooled, and titrated electrometrically with standard alkali to pH 8.2. |
Scope and Application
|
This method is applicable to surface waters, sewages and industrial wastes, particularly mine drainage and receiving streams, and other waters containing ferrous iron or other polyvalent cations in a reduced state. |
Applicable Concentration Range
|
Approximately 10 mg/L acidity to approximately 1000 mg/L as CaCO3, using a 50 mL sample. |
Interferences
|
Suspended matter present in the sample, or precipitates formed during the titration may cause a sluggish electrode response. This may be offset by allowing a 15-20 second pause between additions of titrant or by slow dropwise addition of titrant as the endpoint pH is approached. |
Quality Control Requirements
|
None. |
Sample Handling
|
Refrigeration at 4oC is recommended. |
Maximum Holding Time
|
14 days. |
Relative Cost
|
Less than $50 |
Sample Preparation Methods
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