Abraxis: 550051: Organophosphate and Carbamate Pesticides by Cholinesterase Inhibition, Tube

Summary
Analytes
Revision
Data and Sites

Official Method Name

Abraxis OP/Carbamate Assay Kit (20T) PN 550051

Current Revision

2008

Media

WATER

Instrumentation

Spectroscopy (Colorimetry; Photometry)

Method Subcategory

Organic

Method Source

Abraxis

Citation

Abraxis User Guides and Flowcharts

Brief Method Summary

The test is a qualitative, colorimetric assay (modification of the Ellman method) for the detection of organophosphates and carbamates, based on a modification of their inhibition of the enzyme Acetyl Cholinesterase (Ach-E). Ach-E hydrolyzes acetylthiocholine (ATC) which reacts with 5,5?-Dithio-bis(2-Nitrobenzoic Acid) [DTNB] to produce a yellow color which is read at 405 nm. If OP or Carbamate pesticides are present in a sample, they will inhibit ACh-E and therefore the color formation will be reduced or absent depending on their concentration.

Scope and Application

This method determines Organophosphate and Carbamate pesticides in water (groundwater, surface water, well water).

Applicable Concentration Range

Interferences

Quality Control Requirements

(A) Calibration with 3 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.

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 4 degrees C, longer if held frozen

Relative Cost

Less than $50

Sample Preparation Methods

This method has 2 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Carbamate pesticides(E-12895) Carbamate pesticides Carbamate pesticides, N-methyl- N-methyl carbamate pesticides	N/A	N/A	N/A
Organophosphate pesticides(E-12873) Organophosphate pesticides Organophosphorus pesticides Pesticides, organophosphate	N/A	N/A	N/A

Precision Descriptor Notes:
Detection Level Note:	Detection limits of the various OP/C pesticides differ depending on their ability to inhibit the enzyme. If it has been established that only a single OP/C is present, the test can be used in conjunction with appropriate standards for quantitative testing.

Revision	PDF/Link
2008

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Abraxis: 550051: Organophosphate and Carbamate Pesticides by Cholinesterase Inhibition, Tube

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