A portable detection method for organophosphorus and carbamates pesticide residues based on multilayer paper chip

Organophosphorus and carbamates pesticide residues detection is one of significance in vegetables and fruits production. However, an effective directly detection method without any auxiliary has not been reported yet. Herein, we proposed a multilayer paper chip, including injection layer, heating layer, conduction layer, fixed enzyme layer, fixed indophenol acetate layer, and color layer, for pesticide residue of organophosphorus and carbamates detection based on the principles of enzyme inhibition reaction and heat generation inside. It's the first time for paper‐based chip to include an inside built‐in heating layer, which can ensure the reaction process with enzyme is always at the optimum temperature. Without any external instrument, we can determine whether the pesticide exceeds the standard according to the reaction color. Besides, we can also make quantitative detection of pesticide with external spectrometer detection system. The overall detection process runs automatically, then relatively accurate test results can be acquired. Under the optimum condition, a good linear correlation for dipterex concentrations over the range from 0.05 to 0.5 mg/L was obtained by quantitative detection, which can reach a detection limit (LOD) of 0.0406 mg/L. Besides, it also showed satisfactory reproducibility, specificity, and stability. Therefore, it is suitable for the instant detection technique. Practical applications This article provides a method which is used to detect organophosphorus and carbamates pesticide residues existing in vegetables and fruits production. The detection limit is 0.0406 mg/L and it is lower than national standards. The detection reproducibility is acceptable. This method is energy‐saving and environment friendly. In this article, multilayer paper chip that includes enzyme inhibition reaction, color reaction and exothermic reaction was proposed. The heating layer in multilayer paper chip relies on the principle of chemical heat production and needs only a little water, which is very simple and easy. Under the whole process of detection without manual intervention, the testing result from the paper chip not only can be distinguished by eyes, but also can be detected precisely by simple detection device, which provide a basis for development of portable pesticide detector.