EPA-NERL: 375.3: Sulfate by Gravimetric Determination
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Official Method Name
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Sulfate (Gravimetric) |
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Current Revision
| Issued 1974; Editorial Revision 1978 |
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Media
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WATER |
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Instrumentation
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Gravimetry |
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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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Sulfate is precipitated as barium sulfate in a hydrochloric acid medium by the addition of barium chloride. After a period of digestion, the precipitate is filtered, washed with hot water until free of chloride, ignited, and weighed as BaSO4. |
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Scope and Application
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This method is applicable to drinking, surface and saline water; and domestic and industrial wastes. |
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Applicable Concentration Range
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10mg/L - * (* Method does not specify an upper detection limit.) |
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Interferences
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(1) High results may be obtained for samples that contain suspended matter, nitrate, sulfite and silica. (2) Alkali metal sulfates frequently yield low results. This is especially true of alkali hydrogen sulfates. Occlusion of alkali sulfate with barium sulfate causes the substitution of an element of lower atomic weight than barium in the precipitate. Hydrogen sulfate of alkali metal acts similarly and decomposes when heated. Heavy metals such as chromium and iron, cause low results by interfering with complete precipitation and by formation of heavy metal sulfates. |
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Quality Control Requirements
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not included |
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Sample Handling
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Collect 50 mL samples in either glass or plastic bottles. Refrigerate at 4oC until analysis. Analyze within 28 days. |
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Maximum Holding Time
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28 days (MCAWW, Table 1). |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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