Abraxis: 50020B: Spinosyn in water by Immunoassay, Coated Tube
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Official Method Name
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Abraxis Spinosyn ELISA Tube Kit PN 50020B |
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Current Revision
| 2007 |
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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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Organic |
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Method Source
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Citation
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Brief Method Summary
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Spinosyn is detected using a colorimetric immunoassay (ELISA) procedure. A sample (0.50 mL) and an antibody solution (anti-Spinosyn) are added to tubes pre-coated with anti-rabbit IgG. After incubation, an enzyme-labeled Spinosyn conjugate is added to the tubes. Both the Spinosyn (if present) in the sample and enzyme conjugate compete to bind to the limited number of antibody binding sites in proportion to their concentrations. The antibodies then bind to the anti-rabbit IgC binding sites. After a second incubation, the unbound molecules are washed and decanted. A substrate is then added which is catalyzed by the enzyme and converted from a colorless to a blue solution. The reaction is terminated with the addition of a dilute acid. The concentration of Spinosyn in the sample is determined by measuring its absorbance at a specific wavelength (450nm) using a photometer and comparing its absorbance to the absorbance of the calibrators. |
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Scope and Application
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This method determines Spinosyn in water (groundwater, surface water, well water). It is capable of detecting Spinosyn J, A, D, and L. |
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Applicable Concentration Range
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0.014 - 0.5 |
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Interferences
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Cross-reactivity: Spinosyn A, D, and L; XDE-175-J, XDE-175-L; 2?-demethyl XDE-175-L, 2?-demethyl XDE-175-J; and 6,6-dihydro-Spinosyn J produce false positive responses for Spinosyn J. |
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Quality Control Requirements
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(A) Calibration with 4 standards and 1 blank, all analyzed in duplicate. (B) Precision: 3 matrix samples with different levels in the range for quantitative analysis analyzed daily for 5 days with 5 replicates in each of 5 assays. (C) Accuracy: 5 matrix samples spiked with the target analyte at 4 different levels in the range for quantitative analysis. (D) Validation: Analysis of 4 positive and 4 negative samples by an independent method, for confirmation. |
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Sample Handling
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Samples are collected in glass containers with Teflon-lined caps; for compliance monitoring, samples should be held no longer than 14 days. If samples are held frozen, they can be held for longer periods of time. Immunoassay reagents are stored refrigerated until use. Samples containing gross particulate matter should be filtered using a 1 micron filter or centrifuged before use. Drinking water samples are typically dechlorinated with 0.008% sodium thiosulfate. |
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Maximum Holding Time
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14 days at 4 degrees C, longer if held frozen. |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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