EPA-NERL: 420.1: Phenols by Spectrophotometry
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Official Method Name
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Phenolics, Total Recoverable (Spectrophotometric, Manual 4-AAP with Distillation) |
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Current Revision
| Issued 1971; Editorial Revision 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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Organic |
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Method Source
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Citation
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Brief Method Summary
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Phenolic materials react with 4-aminoantipyrine in the presence of potassium ferricyanide at high pH to form a stable reddish-brown colored antipyrine dye. The amount of color produced is proportional to the concentration of phenolic materials. However the color response of all phenolic compounds is not equivalent, and the results (which are compared against pure phenol standards) represent the minimum concentration of phenolic compounds in the sample. |
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Scope and Application
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This 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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Above 5 ug/L (with extraction and concentration). Above 50 ug/L (with no extraction). |
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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. |
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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. |
