A highly sensitive acetylcholinesterase electrochemical biosensor based on Au-Tb alloy nanospheres for determining organophosphate pesticides

Rapid and sensitive detection of methyl parathion in rice based on carbon quantum dots nano-fluorescence probe and inner filter effect

A highly sensitive fluorescent sensing system of novel carbon quantum dots nano-fluorescent probe based on corn stalks was established for the determination of methyl parathion by alkaline catalytic hydrolysis and inner filter effect mechanism. The carbon quantum dots nano-fluorescent probe was prepared from corn stalks using an optimized one-step hydrothermal method. The detection mechanism of methyl parathion was revealed. The reaction conditions were optimized. The linear range, sensitivity and selectivity of the method were evaluated. Under the optimal conditions, the carbon quantum dots nano-fluorescent probe exhibited high selectivity and sensitivity to methyl parathion, achieving a linear range of 0.005-14 µg/mL. The fluorescence sensing platform was applied to the detection of methyl parathion in rice samples, and the results showed that the recoveries range from 91.64 to 104.28 %, and the relative standard deviations were less than 4.17 %. The detection limit for methyl parathion in rice samples was 1.22 µg/kg, and the limit of quantitation (LOQ) was 4.07 µg/kg, which was very satisfactory.

One-dimensional bimetallic PdRh alloy mesoporous nanotubes constructed for ultra-sensitive detection of carbamate pesticide

Bimetallic nanomaterials with various dimensions have been successfully explored in electrochemical biosensor to detect the carbamate pesticide. One-dimensional bimetallic nanomaterials with mesoporous, which possess bigger electrochemical active area, more catalytic active sites and faster electron transmission efficiency, may have excellent performance in electrochemical biosensor, but have been rarely reported. In order to confirm this hypothesis, one-dimensional PdRh alloy mesoporous nanotubes were prepared and applied as a platform for carbamate pesticide electrochemical detection. Upon optimum conditions, the constructed AChE sensor showed an ultrahigh sensitivity (0.279 μA/nM), a wide linear range (9.44 × 10^-8 - 0.944 mg/L) and a low detection limit (9.44 × 10^-8 mg/L) for carbaryl. And the biosensor exhibited outstanding anti-interference ability, precision and stability. Moreover, the actual sample detection of the biosensor has been demonstrated with a satisfactory recovery (94.01%-102.80%). The remarkable property may attribute to the integrated advantages of one-dimensional mesoporous structure and bimetallic alloy.