Copper–Cobalt Nanozyme Mimicking Laccase for Sensitive Colorimetric Determination of Cannabidiol in Food and Cosmetics

In colorimetric analysis, nanozymes are invaluable tools due to their simple production, long-lasting stability, and adaptable enzymatic activity, which enable them to induce changes in substrate color. In this study, a simple nanozyme-based colorimetric sensor was developed to detect cannabidiol (CBD) by using the laccase activity of the self-made MOF with copper and cobalt loading (Cu/Co@MOF) nanozyme, which was synthesized using a one-pot microwave method. The Cu/Co@MOF has the ability to catalyze the coupling reaction between 4-AP and various phenolic substrates, thereby converting colorless phenolic substrates into red substances. Notably, 16 ng/mL was the limit of detection. Based on Y = 0.137X + 0.003 equation, absorbance and CAN concentrations (0.067 to 10 μg/mL with a correlation value [R²] of 0.993) had a significant correlation. The developed colorimetric method was subsequently employed to determine CBD in facial masks and essential oil samples, resulting in relative standard deviations (RSDs) ranging from 1.4% to 4.3%. Therefore, this sensitive, cost-effective, and rapid method ensures an effective determination of CBD in food and cosmetics.