USGS-NWQL: I-3631: Potassium, total recoverable, FLAA
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Official Method Name
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Potassium, atomic absorption spectrometric, direct-EPA |
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Current Revision
| 1977 |
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Media
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WATER |
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Instrumentation
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Flame Atomic Absorption |
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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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Methods for the Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the United States Geological Survey, Book 5, Chapter A1 Edited by Marvin J. Fishman and Linda C. Friedman |
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Brief Method Summary
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Potassium is determined by atomic absorption spectrometry by direct aspiration of the filtered or digested and filtered sample into an air-acetylene flame (Fishman and Downs, 1966). Effluent samples must undergo a preliminary nitric acid digestion followed by a hydrochloric acid solubilization. |
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Scope and Application
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This method may be used to analyze water-suspended sediment. Sample solutions containing from 0.1 to 100 mg/L of potassium may be analyzed without dilution, but those containing more than 100 mg/L need to be diluted. For ambient water, analysis may be made on a portion of the acidified water-suspended sediment sample. For all other water, including domestic and industrial effluent, the atomic absorption procedure must be preceded by a digestion-solubilization as specified below. In cases where the analyst is uncertain about the type of sample, the digestion-solubilization procedure must be used. |
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Applicable Concentration Range
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0.1 to 100 mg/L |
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Interferences
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Of the substances commonly occurring in water, only sodium has been found to interfere, and its interference is greatly minimized if a reducing flame is used and the burner is raised to approximately 0.05 cm below the optical light path. Data are indicative of the magnitude of sodium interference under these conditions are provided in the method. Alternatively, an excess of sodium or cesium may be added to all samples and standards. Such additions essentially eliminate the effects of the then comparatively minor contributions of sodium present in the samples. |
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Quality Control Requirements
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Calibrate instrument using calibration standards (CAL); quality control samples (QCS); and laboratory blanks (LB) analyzed at a minimum of 1 for every 10 samples. |
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Sample Handling
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Container Description: 250 mL polyethylene bottle, nitric acid rinsed Treatment and handling: Use unfiltered sample to rinse container, acidify sample with nitric acid to pH <2 Hot acid solubilization with nitric and HCl acids is required. |
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Maximum Holding Time
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180 days |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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