Stable and user-friendly paper-based test strip for pesticide detection in dried seafood products

This work introduces a simple, user-friendly paper-based test strip for the rapid detection of carbamate (CBs) and organophosphate (OPs) pesticides, designed to work similarly to a pH test strip. The strip includes a control area (C) and a test area (T), enabling easy comparison of color changes. The assay is based on acetylcholinesterase (AChE) inhibition assay, that produces a yellow color when no pesticides are present. If pesticides are detected, the yellow color fades, indicating contamination. To enhance stability, the test strip uses biopolymers including chitosan and sodium carboxymethylcellulose (NaCMC), which protect the reagents and allow the strip to remain effective for over two months under ambient or refrigerated storage. With a total analysis time of only 10 min, this device is ideal for on-site pesticide testing without requiring specialized laboratory equipment. The method achieved excellent limits of detection (LOD) as low as 1.36 mu g/mL, 1.48 ng/mL, 1.34 mu g/mL and 1.21 ng/mL for carbaryl (CAR), carbofuran (CBF), malathion (MAL) and dichlorvos (DDVP), respectively. Validation with dried seafood samples showed strong agreement between the test strip results and LC-MS/MS, confirming its accuracy and reliability for detecting pesticides in complex food samples. This paper-based test strip offers a portable, costeffective, and efficient solution for pesticide detection. Its stability, ease of use, and validated performance make it a promising tool for widespread on-site applications and potential commercialization.