EPA-NERL: 110.1: Color by Spectrophotometry
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Official Method Name
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Colorimetric, ADMI |
|---|---|
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Current Revision
| Issued 1978 |
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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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This method is an extension of the Tristimulus Filter Method 1. Tristimulus values are converted to an ADMI single number color difference, of the same magnitude assigned to platinum-cobalt standards, using the Adams Nickerson Color Difference (DE). |
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Scope and Application
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This method is applicable to colored waters and waste that have color characteristics significantly different from the yellow platinum-cobalt standard. |
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Applicable Concentration Range
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25 to 250 color units is recommended. Sample values above 250 units may be determined by quantitative dilution. |
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Interferences
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Turbidity: Since very slight amounts of turbidity interfere with the determination, turbid samples must be filtered prior to analysis. The optimum filter media to remove turbidity without removing color has not been found. Membrane and glass fiber filters with functional pore sizes of approximately 0.45 micron are convenient to use. Other techniques such as centrifuging and/or filter aids may be used. |
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Quality Control Requirements
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None. |
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Sample Handling
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Refrigerate at 4oC. |
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Maximum Holding Time
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48 hours (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. |
