Simple analytical methods for pesticides, fungicides and herbicides in soil and water
Various methods can be used to analyze pesticides, fungicides, and herbicides in soil and water samples. Especially for laboratories working with commercially available chemicals, the following relatively simple methods are suitable:
1. Thin layer chromatography (TLC)
Thin-layer chromatography is a cost-effective and relatively simple method for separating and qualitatively identifying different classes of pesticides.
Advantages:
- Simple equipment (TLC plates, solvent, UV lamp, spray reagents)
- Fast pre-screening method
- Low costs
After developing the plate, the spots can be visualized under UV light or by special spray reagents to assess the presence of pesticide residues.
2. Enzyme inhibition tests
Enzyme inhibition tests, such as the acetylcholinesterase inhibition test, are particularly suitable for organophosphate pesticides.
Advantages:
- Easy to perform in microtiter plates
- Semi-quantitative assessment of pesticide contamination
- High sensitivity for certain pesticide classes
3. Colorimetric tests
Some pesticides, fungicides, and herbicides react with specific chemical reagents and cause a color change.
Benefits:
- Visual recognition by color change
- No expensive instruments required
- Relatively quick results
4. Immunoassays (e.g. ELISA)
ELISA kits are available for specific pesticides and offer high specificity.
Advantages:
- High specificity and sensitivity
- Fast analysis, often automatable
Note: While these kits are relatively easy to use, they are often expensive and may be less "chemical" in the traditional sense, as they are based on pre-prepared reagents.
Conclusion
Titration methods are generally suitable for determining nutrients present in relatively high concentrations (macronutrients). However, for pesticides, fungicides, and herbicides, which often occur in very low concentrations (trace elements), classic titration reaches its limits.
Recommendations:
- Use thin-layer chromatography (TLC) as a screening method to obtain a qualitative statement about the presence of various active ingredients.
- Complement the detection with enzyme inhibition tests or colorimetric tests for specific pesticide classes.
- If necessary, immunoassays (ELISA) can also be used to refine the results.
Overall, laboratories working with commercially available chemicals, especially TLC, can use simple enzymatic and colorimetric methods to obtain initial indications of the presence of pesticides, fungicides and herbicides in soil and water.
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