EPA-NERL: 420.2: Phenolics by Automated Colorimetry
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Official Method Name
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Phenolics, Total Recoverable (Colorimetric, Automated 4-AAP with Distillation) |
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Current Revision
| Issued 1974 |
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Media
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WATER |
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Instrumentation
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Automated Spectrophotometer |
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Method Subcategory
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Organic |
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Method Source
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Citation
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Brief Method Summary
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This automated method is based on the distillation of phenols and subsequent reaction of the distillate with alkaline ferricyanide and 4-aminoantipyrine to form a red complex which is measured with an on-line colorimeter. |
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Scope and Application
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This automated method determines phenolic compounds in drinking, surface and saline waters; domestic and industrial wastes. |
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Applicable Concentration Range
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There are two working ranges: 2-200 ug/L and 10-500 ug/L. |
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Interferences
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(A) Sulfur compounds: Interferences from sulfur compounds are eliminated by acidifying the sample to pH < 4 with phosphoric acid and aerating briefly by stirring and adding copper sulfate. (B) Oxidizing agents: Oxidizing agents can oxidize phenolics, causing results to be low. Test for the presence of oxidizing agents with potassium iodide strips. If present, remove them when sampling by adding ferrous ammonium sulfate in excess. (C) Contamination: Contamination from plastic tubing and sample containers is eliminated by using glass and Kel-F tubing. |
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Quality Control Requirements
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None. |
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Sample Handling
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Add copper sulfate (1 gram/L) and acidity to pH < 4 to inhibit biodegradation. The sample should be refrigerated at 4oC. |
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Maximum Holding Time
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24 hours. |
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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. |
