Development of Rapid and High-Precision Colorimetric Device for Organophosphorus Pesticide Detection Based on Microfluidic Mixer Chip

Abstract

The excessive pesticide residues in cereals, fruit and vegetables is a big threat to human health, and it is necessary to develop a portable, low-cost and high-precision pesticide residue detection scheme to replace the large-scale laboratory testing equipment for rapid detection of pesticide residues. In this study, a colorimetric device for rapid detection of organophosphorus pesticide residues with high precision based on a microfluidic mixer chip was proposed. The microchannel structure with high mixing efficiency was determined by fluid dynamics simulation, while the corresponding microfluidic mixer chip was designed. The microfluidic mixer chip was prepared by a self-developed liquid crystal display (LCD) mask photo-curing machine. The influence of printing parameters on the accuracy of the prepared chip was investigated. The light source with the optimal wavelength of the device was determined by absorption spectrum measurement, and the relationship between the liquid reservoir depth and detection limit was studied by experiments. The correspondence between pesticide concentration and induced voltage was derived. The minimum detection concentration of the device could reach 0.045 mg·L−1 and the average detection time was reduced to 60 s. The results provide a theoretical and experimental basis for portable and high-precision detection of pesticide residues.

Research on multiwalled carbon nanotubes spray method for preparing flexible piezoresistive tactile sensor

“…The method can fabricate microstructures with a surface roughness of 0.17 μm, which has been discussed in our previous research. 25 The conductive mixture prepared before was sprayed onto the surface of a photosensitive resin mold with a microstructure array using a selfdeveloped high-pressure spray equipment. The high spray pressure ensures that the sprayed particles have a sufficiently small size, thereby improving the consistency of the prepared conductive film.…”

Research progress on pesticide residue detection based on microfluidic technology

“…With the development of 3D printing technology, an increasing number of researchers are applying it to biochemical analysis. 3D printing significantly reduces the cost of microfluidic chip fabrication [77] and simplifies the manufacturing process. For example, Wu researched and developed a smartphone-based portable sensing system by 3D printing to manufacture a flower-shaped design chip, simplifying the manufacturing process.…”

Rapid fabrication of microfluidic mixer chip by non-isothermal molding method based on resistance heating principle and its application in pesticide residue detection

“…The microfluidic mixer chip includes two inlets, mixing channel, liquid storage tank and outlet. The color reaction was based on the Ellman method [25][26][27][28]. Under the catalysis of acetylcholinesterase (AChE), the thioacetylcholine iodide was hydrolyzed into thiocholine and acetic acid.…”