Abraxis: 500086:  Glyphosate by Immunoassay, Microtiter Plate

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Abraxis Glyphosate Plate Assay Kit (96T) PN 500086
Current Revision
2005
Media
WATER
Instrumentation
Immunoassay
Method Subcategory
Organic
Method Source
  Abraxis
Citation
  Abraxis User Guides and Flowcharts
Brief Method Summary
Glyphosate is detected using a colorimetric immunoassay (ELISA) procedure. A sample (0.05 mL) and an enzyme conjugate (enzyme-labeled Glyphosate) are added to a microtiter plate well pre-coated with Glyphosate-specific antibodies. Both the Glyphosate in the sample and the enzyme conjugate compete for antibody binding sites on the wells in proportion to their concentrations. At the end of an incubation period, the wells are washed and 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 Glyphosate in the sample is determined by measuring its absorbance at a specific wavelength (450 nm) using a plate photometer, and comparing its absorbance to the absorbance of the calibrators.
Scope and Application
This method determines Glyphosate in water (groundwater, surface water, well water).
Applicable Concentration Range
0.15 - 5.0 ppb
Interferences
Quality Control Requirements
(A) Calibration with 4 standards and 1 blank, all analyzed in duplicate.
(B) Precision: 4 matrix samples with different levels in the range for quantitative analysis analyzed daily for 3 days with 5 replicates in each of 3 days.
(C) Accuracy: 5 matrix samples are 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.
Sample Handling
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.
Maximum Holding Time
14 days at 4oC, longer if held frozen
Relative Cost
Less than $50
Sample Preparation Methods