Standard Methods: 2540 B: Total Solids in water dried at 103-105 C to constant weight
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Official Method Name
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2540 B. Total Solids Dried from 103 to 105 C |
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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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Gravimetry |
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Method Subcategory
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Physical |
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Method Source
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Citation
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Brief Method Summary
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Well-mixed water samples are dried at 103-105 C to a constant weight in pre-weighed dishes. This method is included in NEMI for informational purposes as it is approved by EPA for regulatory use. Detailed information on this method is not currently available in NEMI; refer to Standard Methods (www.standardmethods.org) for the most current method information. |
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Scope and Application
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This method is suitable for determining solids in potable, surface, and saline waters as well as domestic and industrial waters. |
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Applicable Concentration Range
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2.5 to 200 mg/L for a 1,000-mL sample. Upper end can be extended using a smaller sample volume. |
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Interferences
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(A) Highly mineralized water with a significant concentration of calcium, magnesium, chloride, or sulfate may be hygroscopic and require prolonged drying, proper desiccation, and rapid weighing. (B) Visible floating oil and grease can be dispersed with a blender or homogenizer before withdrawing a sample portion for analysis. (C) Retention of water of crystallization and some mechanically occluded water. No remedy. (D) Loss of CO2 when bicarbonate converts to carbonate during drying. Usually, very little organic matter will volatilize. It may take a long time to attain constant weight because occluded-water removal is marginal at this temperature. (E) Formation of a water-trapping crust at high solids concentrations. Limit sample to 200 mg or less of residue. |
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Quality Control Requirements
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Sample duplicates, Method blank (MB), Laboratory-fortified blank (LFB) |
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Sample Handling
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Use borosilicate glass, plastic, or fluoropolymer [e.g., polytetrafluoroethylene (PTFE)] bottles, so long as suspended solids in sample do not adhere to container walls. Begin analysis as soon as possible and refrigerated at 6 °C or less without freezing to minimize microbiological decomposition of solids. Bring samples to ambient temperature before beginning the analysis. |
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Maximum Holding Time
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7 d from the time of collection (168 hrs); refrigerate at 6 °C or less without freezing |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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