Hach Co.: 8203: Alkalinity of Water By Digital Titration
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Official Method Name
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Phenolphthalein and Total Alkalinity Using Sulfuric Acid By Digital Titration |
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Current Revision
| 2003 |
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Media
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WATER |
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Instrumentation
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Titration |
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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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Alkalinity is expressed as P (phenolphthalein) alkalinity or as T (total) alkalinity. Both types are determined by titration with a sulfuric acid standard solution to an end point evidenced by the color change of an indicator solution or determined with a pH meter. The P alkalinity is determined by titration to a pH of 8.3 and registers the total hydroxide and one half the carbonate present. The T alkalinity is determined by titration to a pH of 4.5. The total alkalinity includes all carbonate, bicarbonate and hydroxide alkalinity. Alternatively, total alkalinity end points may be determined by using a pH meter and titrating to the specific pH required for the sample composition. |
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Scope and Application
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For water, wastewater, and seawater |
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Applicable Concentration Range
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10-4000 mg/L |
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Interferences
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Chlorine at levels above 3.5 mg/L cause a yellow-brown color upon the addition of the Bromcresol Green-Methyl red indicator. Highly colored or turbid samples may mask the color change at the end point. |
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Quality Control Requirements
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Sample Handling
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Collect samples in clean plastic or glass bottles. Fill completely and cap tightly. Avoid agitation and prolonged exposure to air. Samples should be analyzed as soon as possible after collection but can |
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Maximum Holding Time
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24 hours @ 4deg. C. |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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