Liofilchem® Microplate Acetylcholinesterase Inhibition Assay (MAIA) Pesticide MultiTest

The Liofilchem® MAIA Pesticide MultiTest is a colorimetric assay designed for the detection of organophosphate, organochloride, and carbamate pesticide residues in water, food, and beverages. Using the Acetylcholinesterase (AChE) Inhibition Assay (MAIA), this test system provides a semi-quantitative screening method for identifying pesticide contamination, making it an essential tool for food safety and environmental monitoring.

Key Features:

1. Comprehensive Detection:
   • Targets three major pesticide families: organophosphate, organochloride, and carbamate residues.
   • Effective for hydro-acetonitrilic extracts of solid and liquid food matrices.
2. Colorimetric Assay:
   • Based on the inhibition of acetylcholinesterase (AChE) activity by pesticide molecules.
   • Utilizes acetylthiocholine as a substrate and a chromogenic detector for thiocoline, enabling visual or absorbance-based detection.
3. Dual Analysis Options:
   • Visual Evaluation: Compare the yellow intensity in sample wells to control wells.
   • Quantitative Analysis: Use a microplate reader to measure absorbance and calculate pesticide titers.
4. Convenient and Ready-to-Use:
   • Includes all necessary reagents and tools for the test:
     • MAIA microplate.
     • MAIA STARTER and MEDIUM solutions.
     • MAIA salts.
   • Designed for ease of use with minimal preparation time.
5. Accurate and Reliable:
   • Provides precise screening results with an easy-to-follow workflow.
   • Detects pesticide concentrations through a biological mechanism, ensuring specificity and relevance.

Test Procedure:

1. Sample Preparation:
   • Mix 4 mL of milk or homogenized food sample with 4 mL of acetonitrile.
   • Add 2 g of MAIA salts, shake vigorously, and centrifuge at 3,000 rpm for 10 minutes.
   • Use the post-centrifugation supernatant as the sample extract.
2. Microplate Setup:
   • Dispense 100 μL of each sample extract into the designated wells of the MAIA microplate.
   • Desiccate the extracts under direct airflow at room temperature.
3. Enzyme Preincubation:
   • Add MEDIUM solution (prepared by reconstituting a MEDIUM vial with ultrapure water) to all wells.
   • Cover the plate with the sealing film and preincubate for 50 minutes on a microplate shaker.
4. Reaction Start:
   • Add STARTER solution (prepared from the STARTER vial) to all wells except matrix blanks.
   • Incubate for 8 minutes, then stop the reaction by adding STOPPER solution.
5. Result Interpretation:
   • Visual Analysis: Compare the color intensity in sample wells to control wells (yellow intensity inversely proportional to pesticide concentration).
   • Microplate Reader: Measure absorbance values to calculate quantitative pesticide titers.

Principle of the Test:

The test uses the AChE inhibition mechanism, wherein pesticides inhibit enzyme activity, reducing the conversion of acetylthiocholine into yellow-colored thiocoline. The intensity of the yellow color is inversely proportional to the pesticide concentration in the sample.

Kit Components:

Applications:

1. Food Safety Testing:
   • Detects pesticide residues in milk, vegetables, fruits, and processed foods.
2. Water Quality Analysis:
   • Screens for pesticide contamination in drinking and environmental water samples.
3. Beverage Testing:
   • Evaluates pesticide levels in juices, wines, and other liquid samples.
4. Research:
   • Used in studies of pesticide impact on food and environmental systems.

Advantages:

1. Versatile Detection:
   • Applicable to a wide range of food and beverage samples.
   • Suitable for both solid and liquid matrices.
2. Fast and Efficient:
   • Simple workflow with results available within a few hours.
3. Dual Evaluation:
   • Allows for both visual and quantitative analysis, accommodating varying resource levels.
4. Portable and Convenient:
   • Ideal for both laboratory and field-based pesticide screening.

Storage and Handling:

• Store kit components at 2–8°C in their original packaging.
• Avoid exposure to direct light or moisture.
• Ensure reagents are used before the expiration date.

Specifications:

References:

1. ISO 15214: Horizontal methods for food and feed microbiology testing.
2. Briggs, M. (1953). J. Dairy Res. 20:36.

The Liofilchem MAIA Pesticide MultiTest offers a comprehensive, reliable, and efficient solution for pesticide residue detection in food, water, and beverages. Its colorimetric assay provides flexible analysis options, making it an invaluable tool for laboratories and quality control teams.