Shima Karimi, Mohammad Amjadi, Tooba Hallaj
Synthesis and study of nanomaterials with enzyme-like properties and their application in the sensing is a growing field of research. In this work, Cu-impregnated Ti 3 C 2 MXene quantum dots (Cu-Ti 3 C 2 MQDs) are introduced as a novel nanozyme with remarkable peroxidase-mimicking activity. To clarify their properties, we characterized them through UV-Vis absorption, energy dispersive X-ray analysis, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Additionally, the catalytic mechanism and steady-state kinetics of these QDs were studied using the Michaelis-Menten model, yielding values for K m and V max of 0.60 mM and 3.47 10 -8 M.s -1 for TMB, and H 2 O 2, respectively. The synthesized nanozyme was then applied to design a colorimetric probe for malathion determination in the concentration range of 15-150 nM. Evidence from FTIR spectroscopy and radical scavenger study show that malathion inhibits the catalytic action of nanozyme likely via Cu-S interaction and hydroxyl radical consumption leading to a decrease in the absorbance intensity at 652 nm. The proposed sensor effectively detects malathion in agricultural products such as apples and cucumbers, and water, achieving recoveries of 95.5%–101.6% with a relative standard deviation (RSD) of 0.62%–4.06%.