A nanozyme cascade sensor for profenofos based on one nanozyme with dual enzyme-like activities

The dual enzyme-like activities (phosphatase-like activity and laccase-like activity) of one nanozyme (Ce-MOF-808) were employed to develop a nanozyme cascade sensor for the facile and selective detection of profenofos. It was found that the nanozyme Ce-MOF-808 had phosphatase-like activity (V max  = 0.31 μM/min and K m  = 0.014 mM) and laccase-like activity (V max  = 6.27 μM/min and K m  = 0.033 mM). In the cascade sensor process, profenofos was first hydrolyzed by Ce-MOF-808. The P O bond was cleaved to produce 4-bromo-2-chlorophenol containing phenol through the phosphatase-like activity of nanozyme. The colorless product was efficiently oxidized because of the laccase-like activity of nanozyme, and then reacted with the color rendering agent 4-aminoantipyrine to produce the red quinone imine. The absorbance peak at 510 nm fitted a linear curve. The limit of detection (LOD) was determined to be 3.33 μg/mL in this method. The quantitative detection of profenofos was conducted on a variety of different real samples. Nanozymes could be stored at 4 ℃ for a long time and the detection method was simple and direct. The nanozyme cascade sensor was convenient and rapid for the detection of pesticides and had promising application prospects in the conventional rapid detection of pesticides in the field.