Alachlor
Alachlor
ALA_None_Other_IMM_Eng_Ody.fm Page 7 of 8
Diluting Water Samples
Other levels of Alachlor can be tested by diluting the sample and comparing the
results to the 0.1 ppb Calibrator. Select the appropriate sample volume from the
table below, place it in a graduated mixing cylinder, and dilute it to 50 mL with
deionized water.
Example:
Dilute 2.5 mL of sample to 50 mL with deionized water. Run the diluted sample
in the procedure along with the 0.1 ppb calibrator. If the absorbance of the
diluted sample is less than the 0.1 ppb calibrator, the concentration of the
original sample is greater than 2 ppb.
Summary of Method
Hach immunoassay tests use antigen/antibody reactions to test for specific
organic compounds in water and soil. Alachlor-specific antibodies, attached to
the walls of plastic cuvettes, selectively bind and remove Alachlor from complex
sample matrices. A prepared sample and a reagent containing enzyme-conjugate
molecules (analyte molecules attached to molecules of an enzyme) are added to
the Antibody Cuvettes. During incubation, enzyme-conjugate molecules and
Alachlor compete for binding sites on the antibodies. Samples with higher levels
of analyte will have more antibody sites occupied by Alachlor and fewer
antibody sites occupied by the enzyme-conjugate molecules.
After incubation, the sample and unbound enzyme conjugate are washed from
the cuvette and a color-development reagent is added. The enzyme in the
conjugate catalyzes the development of color. Therefore, there is an inverse
relationship between color intensity and the amount of Alachlor in the sample.
The resulting color is then compared with a calibrator to determine whether the
Alachlor concentration in the sample is greater or less than the threshold levels.
Test results are measured at 450 nm.
mL Sample
Representative Concentration using
0.1 ppb Calibrator
0.5 10 ppb
1.0 5 ppb
2.5 2 ppb
5.0 1 ppb
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