Envirologix: EP 010: Chlordane (cyclodiene) immunoassay
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Official Method Name
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Cyclodienes (chlordane) Microwell Plate Assay EP010 (EL 1999) http://www.envirologix.com/ |
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Current Revision
| 1999 |
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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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Inhibition immunoassay, with a colorimetric indicator for competitive binding of analyte and an enzyme-labeled conjugate to surface-immobilized antibodies. Colorimetric response is inversely related to the concentration (log) of analyte in the sample or standard. Calibrated using chlordane. Sensitivity to chlordane less than to dieldrin, endosulfan and endrin. Reagents are purchased in kits with manufacturers' instructions for sample preparation and analysis. Requirements: a supply of clean water and methanol, to extract soil and sediment samples, to dilute sample extracts, and to prepare standards; filtration equipment to remove particulates from water samples and soil extracts; an analytical balance, to accurately determine the weights of soil and sediment samples after drying and extraction; a spectrometer, which accepts plate-kits (96-well) for analyses at visible wavelengths (450 nm); equipment to automate sample preparation for large numbers of samples (prefiltration, measurement of uL volumes, plate washing, agitation), so that contact times with reagents are controlled as required; computerized data acquisition and processing. Expendable supplies - approximately $6 per determination |
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Scope and Application
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Ambient and compliance monitoring. Can be adapted for analysis of soils by Method 4041. Soil screening for chlordane by immunoassay (EPA 1995). |
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Applicable Concentration Range
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1 - 100 ug/L as chlordane |
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Interferences
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Sensitivity > chlordane: aldrin; dieldrin; endosulfan; endrin; heptachlor. Sensitivity < chlordane: lindane; toxaphene |
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Quality Control Requirements
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Recommended for a kit allowing 96 quantitative determinations: a. calibration with 3 standards and 1 blank, all analyzed in duplicate b. precision: all 44 samples analyzed in duplicate (repeats) c. accuracy: 3 matrix samples, spiked with the target analyte at 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 typically collected in glass containers with Teflon-lined caps. Drinking water samples are typically dechlorinated with 0.008% sodium thiosulfate, but the choice of reagents needs to be validated for the kit being used. Samples are held in a refrigerator at 4 oC. Immunoassay reagents and kits are stored in the dark at 4 to 8 oC until use. Soil and sediment samples need to be dried, weighed, and extracted (methanol; clean water). Water samples and soil extracts generally need to be centrifuged or prefiltered to 0.2 um. Quantitative analysis requires dilution of highly concentrated samples, until they are bracketed by standards in the linear response range. Aliquots of samples and reagents are accurately measured (uL) and mixed for required times, following manufacturer's instructions for use of the materials purchased. |
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Maximum Holding Time
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5 days at 4oC until extraction and analysis |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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