EPA-NERL: 375.1: Sulfate by Colorimetry
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Official Method Name
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Sulfate (Colorimetric, Automated, Chloranilate) |
|---|---|
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Current Revision
| Issued 1971 |
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Media
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WATER |
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Instrumentation
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Spectroscopy (Colorimetry; Photometry) |
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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 in a sample is treated with barium chloranilate to precipitate barium sulfate and release a highly colored chloranilate ion. The absorbance of the chloranilic acid is measured with a colorimeter and is proportional to sulfate concentration. |
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Scope and Application
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This automated method determines sulfate in drinking and surface waters; domestic and industrial wastes. |
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Applicable Concentration Range
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10 to 400 mg sulfate/L |
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Interferences
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Cations: Cations such as calcium, aluminum, and iron interfere by precipitating the chloranilate. These cations can be removed by passing the sample through a ion exchange column. |
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Quality Control Requirements
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None. |
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Sample Handling
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Refrigerate samples at 4oC. |
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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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None. |
