Standard Methods: 3500-MN B: Manganese in Water by Spectrophotometry
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Official Method Name
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Manganese in Water by Persulfate and Spectrophotometry |
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Current Revision
| Standard Methods Online |
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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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If a sample was pretreated by Method 3030-G, transfer a volume containing 0.05 to 2 mg Mn into a flask and bring volume to 90 mL with distilled water. Proceed as follows. Add 5 mL "special reagent" (75 g HgSO4 + 35 mg AgNO3 + 400 mL concentrated HNO3 + 200 mL distilled water + 200 mL 85% phosphoric acid, diluted to 1 liter). Concentrate sample by boiling or dilute sample to 90 mL. Add 1 g (NH4)2S2O8 and boil for 1 minute. Let stand for 1 minute, cool under the tap, then bring up to 100 mL with distilled water. Prepare standards ranging from 0 to 1500 ug Mn by treating like samples above. For visual determination, compare standards made up in nessler tubes to the samples. For spectrophotometric determination, generate an absorbance vs. concentration curve using standards, and compare sample response to curve. When performing analyses of samples and standards use a sample cell which provides an appropriate light path length (method range depends on path length) and measure absorbance at 525 nm against a water blank. Note: The lowest concentration range (0.05-2 mg/L) is obtained using a 15 cm light path. The highest concentration range (0.1-1.5 mg/L) is obtained using a 1 cm path length. |
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Scope and Application
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This method allows for determination of manganese in water by colorimetry. |
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Applicable Concentration Range
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0 - 15.0 mg/L |
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Interferences
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(1) High levels of chloride ion. (2) Organic materials that are not broken down during digestion. (3) Samples exposed to air may give low results due to the precipitation of manganese dioxide, unless they are treated with hydrogen peroxide prior to analysis (to re-dissolve precipitate). |
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Quality Control Requirements
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not included |
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Sample Handling
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Collect samples in plastic or glass containers that have been rinsed with 1+1 HNO3. Acidify samples to a pH < 2 with HNO3. For dissolved metals, filter samples immediately. Analyze within 6 months. |
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Maximum Holding Time
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6 months |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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3030 |
