Standard Methods: 3030 J: Dry Ashing of Metals Samples
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Official Method Name
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Dry Ashing of Samples |
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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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Preparatory Procedure |
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Method Subcategory
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Sampling/Preparation |
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Method Source
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Citation
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Brief Method Summary
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When using more than 100 mL of sample during digestion, determine recovery for each matrix to verify method validity. Transfer well-mixed sample onto a platinum or high-silica evaporating dish. Evaporate to dryness on a steam bath. Place dish in a muffle furnace and heat sample to a white ash. If determining volatiles, maintain heat at 400 to 450 degrees C. If determining only sodium, ash sample at 600 degrees C. Dissolve ash in a small amount of concentrated HNO3 and warm water. Filter diluted sample and adjust to a volume so that the final HNO3 concentration is 1 percent. Dry ashing yields are highly variable and should be used only on samples that have been shown to yield acceptable precision and bias. |
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Scope and Application
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This method is applicable to the dry ashing of waste and wastewater samples. |
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Applicable Concentration Range
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Interferences
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Metals introduced during preliminary treatment from equipment common to environmental labs. |
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Quality Control Requirements
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Check reagent grade acids for purity. Process blanks through all digestion and filtration steps. |
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Sample Handling
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Collect sample in plastic or glass container which has been rinsed with 1+1 HNO3. Adjust the pH of the sample to < 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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