Beacon: 20-0098: Microcystin in water by immunoassay, Coated Tube
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Official Method Name
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Microcystin Tube Kit |
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Current Revision
| 2012 |
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Media
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WATER |
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Instrumentation
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Immunoassay |
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Method Subcategory
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Biotoxin |
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Method Source
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Citation
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Brief Method Summary
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Microcystins in the sample compete with the Microcystin-enzyme conjugate for a limited number of antibody binding sites. In the assay procedure you will: • Add Microcystin-enzyme conjugate and a sample containing Microcystins to a test tube, followed by antibody solution. The conjugate competes with any Microcystins in the sample for the same antibody binding sites. The test tube is coated with anti-rabbit IgG to capture the rabbit anti-microcystin added. • Wash away any unbound molecules, after you incubate this mixture for 20 minutes. • Add clear substrate solution to each tube. In the presence of bound Microcystin-enzyme conjugate, the substrate is converted to a blue compound. One enzyme molecule can convert many substrate molecules. Since the same number of antibody binding sites are available in every tube, and each tube receives the same number of Microcystin-enzyme conjugate molecules, a sample containing a low concentration of Microcystins allows the antibody to bind many Microcystin-enzyme conjugate molecules. The result is a dark blue solution. Conversely, a high concentration of Microcystins allows fewer Microcystin-enzyme conjugate molecules to be bound by the antibodies, resulting in a lighter blue solution. The color is analyzed using a colorimeter to obtain optical density (OD) values at 450 nm. A spreadsheet is used to generate a standard curve and interpolate the sample values off that curve. |
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Scope and Application
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This method determines Microcystin in water. |
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Applicable Concentration Range
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0.3 - 5.0 |
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Interferences
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Cross reactivity: Microcystin-RR (73%), Microcystin-YR (58%), Microcystin-LA (2%), Microcystin-LF (3%), Microcystin-LW (4%) and Nodularin (126%). |
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Quality Control Requirements
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The value of the provided control (1.0 ppb) should fall within the range from 0.80 to 1.30 ppb. |
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Sample Handling
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Samples are collected in glass volumetric flasks and stored in amber glass vials at 4 degrees Celsius until testing. |
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Maximum Holding Time
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Relative Cost
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Unknown |
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Sample Preparation Methods
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If required, samples containing live algae can be lysed before analysis to release the toxins in the cells. A simple freeze/thaw cycle will accomplish this. Be sure the sample temperature is ambient before running in the assay. |
