Digital image-based quantification of chlorpyrifos in water samples using a lipase embedded paper based device

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Chlorpyrifos pesticide poses risks to health and environment.
• Field-deployable detection methods are needed for pesticide monitoring.
• Existing methods can be complex, time-consuming, or expensive.

Purpose of the Study:

• To develop a cost-effective paper-based device (PBD) for chlorpyrifos pesticide detection.
• To utilize enzyme inhibition and image processing for quantitative analysis.
• To validate the PBD for field applications using smartphone imaging.

Main Methods:

• Fabrication of a PBD using Rhizopus niveus lipase, p-nitrophenol palmitate, and Whatman No.1 paper.
• Lateral flow assay for enzyme inhibition detection.
• Smartphone-based image acquisition and MATLAB analysis using the Cb color coordinate.
• Optimization of paper length and substrate/enzyme ratios.

Main Results:

• The Cb coordinate showed high linearity (R² = 0.988) with chlorpyrifos concentration.
• The PBD demonstrated stability across various pH and temperatures.
• Limit of Detection (LOD) and Limit of Quantitation (LOQ) were 0.065 mgL⁻¹ and 0.198 mgL⁻¹, respectively.
• The method achieved 92.8% accuracy compared to microtiter plate assays.

Conclusions:

• The developed PBD is a precise, cost-effective, and field-deployable biosensor for chlorpyrifos detection.
• Smartphone-based image processing offers a viable alternative for quantitative pesticide analysis.
• The PBD identified higher pesticide residues in wash water from cauliflower, grapes, coriander, brinjal, and bitter guard.