ASTM: D4454: Respiring Bacteria in Water
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Official Method Name
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Standard Test Method for Simultaneous Enumeration of Total and Respiring Bacteria in Aquatic Systems by Microscopy |
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Current Revision
| 1985 |
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Media
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WATER |
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Instrumentation
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Direct Optical Microscopy |
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Method Subcategory
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Microbiological |
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Method Source
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Citation
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Brief Method Summary
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A water sample is treated with an aqueous solution of INT-dye (2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride) for 20 min. The reaction then is stopped by adding a 37 % solution of formaldehyde. Sample is filtered through a 0.1-mm pore size polycarbonate membrane filter (presoaked in sudan black solution or equivalent), and stained with acridine orange for 3 min. The filter is then air-dried and examined under oil immersion for total bacteria under epifluorescence illumination and for respiring bacteria under transmitted bright light illumination. |
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Scope and Application
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This test method covers the detection and enumeration of aquatic bacteria by the use of an acridine-orange epifluorescence direct-microscopic counting procedure. This test method is applicable to environmental waters and potable waters. |
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Applicable Concentration Range
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10,000 cells/mL |
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Interferences
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None indicated. |
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Quality Control Requirements
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Sample Handling
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Maximum Holding Time
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Relative Cost
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$51 to $200 |
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Sample Preparation Methods
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