Abstract:

Herein a novel colorimetric method based upon copper nanoclusters for detection of cholesterol in milk was
developed. Copper nanoclusters (CuNCs) that possess the catalytic activity of horseradish peroxidase (HRP) which catalyzes
the oxidation of colorless guaiacol to amber tetraguaiacol by H2O2, were produced by the reaction of cholesterol and oxygen
catalyzed by cholesterol oxidase. Therefore, the oxidation of cholesterol could be transduced into the color change of
guaiacol by combining these two reactions. Under the optimum conditions, the absorbance was found to be proportional
to the concentrations of cholesterol within the range of 40–320 μg/mL, with a limit of detection (LOD) of 5 μg/mL and
recovery rates of 99.8%–101.2%. Moreover, the practicability of this assay in the detection of cholesterol in milk was studied
as well, and the results showed good precision, reproducibility, stability and accurateness of this assay method. Thus, this
method could be used for quick detection of cholesterol in milk.

Key words: copper nanoclusters, colorimetric detection, cholesterol, milk