EPA-NERL: 305.1: Acidity by Titration
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Official Method Name
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Acidity (Titrimetric) |
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Current Revision
| Issued 1971; Technical Revision 1974 |
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Media
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WATER |
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Instrumentation
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Titration |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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Brief Method Summary
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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. |
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Scope and Application
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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. |
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Applicable Concentration Range
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Approximately 10 mg/L acidity to approximately 1000 mg/L as CaCO3, using a 50 mL sample. |
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Interferences
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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. |
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Quality Control Requirements
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None. |
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Sample Handling
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Refrigeration at 4oC is recommended. |
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Maximum Holding Time
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14 days. |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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