Recent Advances in the Recognition Elements of Sensors to Detect Pyrethroids in Food: A Review

Broad-spectrum portable magnetic relaxation switching immunosensor with gold-functionalized magnetic nanoprobes for the sensitive detection of multiple pyrethroids

At present, the most available pyrethroid (PYR) detection methods still suffer from a narrow detection spectrum, low sensitivity, and less portability. Herein, a novel magnetic relaxation switching (MRS) sensor was elaboratively designed to detect multiple PYRs, combining a novel broad-spectrum antibody CL-CN/1D2 and synthesized immune gold-functionalized magnetic nanoparticles, with the inherent response of the sensor. A series of antibodies and the immune gold-functionalized magnetic nanoparticles were designed and synthesized. The broad-spectrum antibody CL-CN/1D2 and high-performance gold-functionalized magnetic nanoprobe were further selected. The target analytes were effectively captured by the gold-functionalized magnetic nanoparticles in 20% (v/v) ethanol, resulting in the number increase of the signaling probes in the supernatant after magnetic separation. This sensor can detect multiple PYRs with a detection limit of 2.72 μg/L for cypermethrin, 3.58 μg/L for β-cypermethrin, 4.07 μg/L for cyfluthrin, 3.66 μg/L for λ-cyhalothrin, 4.42 μg/L for β-cyhalothrin, 3.51 μg/L for fenpropathrin, 4.41 μg/L for fenvalerate, and 4.12 μg/L for deltamethrin in lake water and milk within 35 min. This study not only achieves broad-spectrum PYRs detection at a trace amount but also provides an effective and universal strategy for enhancing the sensitivity and stability of the portable MRS sensor when detecting hydrophobic analytes in the environment.

Assessment of developed paper strip based sensor with pesticide residues in different dairy environmental samples

According to the results of this study, the paper strip biosensor can detect pesticide at very low concentration like fungicide, organochlorine, organophosphate, carbamate, and herbicide group ranges from 1 to 10, 1-50, 250-500, 1-50, and 1 μg/L, respectively in animal feed, water, milk and soil. This is a significant improvement from the previous study, which found that the paper strip biosensor could only detect pesticide levels of up to 500 or 1000 μg/L. A total of 436 samples were collected from the dairy farm, including 58 samples of green feed, 54 samples of dry feed, 45 samples of concentrated feed, 41 samples of fermented feed, 49 samples of manure, 54 samples of soil, and 86 samples of milk. PSA (Primary Secondary Amine) and MgSO₄ (1:2 ratio) were used to remove pigments from dairy farm samples to prevent the enzyme-pesticide interaction leading to colour development on the strip, which was successfully achieved. Using a strip-based test and an optimized extraction protocol, pesticides were detected in 38.49% in the samples. Limit of Detection of 15 pesticides from the organochlorine, organophosphate, carbamate, neonicotinoid, pyrethroid, ryanoid, strobilurins, and triazole groups recommended for use in dairy farms were evaluated in feed/fodder. Pesticides were being detected in various dairy farm matrices using the newly developed test. The developed technology can be used as a semi-quantitative test for pesticides monitoring in the dairy farm as well as for screening of primary produce under field condition for organic certification of various food/feed commodities.

Development of a time-resolved fluorescence microsphere Eu lateral flow test strip based on a molecularly imprinted electrospun nanofiber membrane for determination of fenvalerate in vegetables

Fenvalerate residues in fruits and vegetables may result in biological immune system disorders. Current sensor detection methods are harsh due to the shortcomings of antibody preparation and preservation conditions. Therefore, developing a recognition material with strong specificity, good stability, and low cost is of practical significance in designing a sensitive, simple, and rapid method. This study used precipitation polymerization to synthesize molecularly imprinted polymers (MIPs). The MIP was prepared into a fiber membrane using the electrostatic spinning method. After that, the fenvalerate hapten-mouse IgG-Eu fluorescent probe was synthesized, and the side flow chromatography strip was constructed to determine fenvalerate in vegetables using the immunocompetition method. The results showed that the adsorption capacity of MIP to fenvalerate was 3.65, and the adsorption capacity on MIPFM (an electrospinning membrane containing the fenvalerate MIPs) was five times that of free MIP. The test strip showed good linearity with R² = 0.9761 within the range of 50 μg/L-1,000 μg/L. In conclusion, substituting fenvalerate monoclonal antibodies with a molecularly imprinted electrospinning membrane is ideal for rapid onsite detection of pyrethroids.