USGS-OWQ: NFM 6.2.3-Iodo: Dissolved-oxygen concentrations in water by iodometric (Winkler) method
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Official Method Name
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Dissolved Oxygen, Iodometric Method |
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Current Revision
| Completed 01/24/2006 |
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Media
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WATER |
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Instrumentation
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Colorimeter |
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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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Measurement of dissolved-oxygen concentration in natural waters using the Winkler or iodometric method. This colorometric procedure is used most commonly as an accurate method for calibration of field instruments used for dissolved-oxygen measurement. Reagents are added to the water sample as prescribed in the method and the dissolved-oxygen concentration is determined by visual comparison with a color chart. When used as a field method, sample must be collected in a manner to prevent exposure to the atmosphere. |
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Scope and Application
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This method covers the iodometric measurement of dissolved oxygen concentrations in natural ground-water and surface-water systems. |
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Applicable Concentration Range
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1.0 to 20 |
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Interferences
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Atmospheric exposure. |
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Quality Control Requirements
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Do not expose environmental sample to the atmosphere prior to the measurement process. |
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Sample Handling
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Surface Water field measurement: cap or stopper surface-water sample bottle while submerged, allowing no exposure to the atmosphere. Ground Water field measurement: pump sample from sampling interval directly into the sample bottle, overflowing the bottle at least three times. Cap or stopper the bottle while sample is flowing into the bottle in a manner to prevent contact with the atmosphere. |
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Maximum Holding Time
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zero |
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Relative Cost
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Unknown |
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Sample Preparation Methods
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not applicable |
