Quantity of Cu(II) ions in a copper pot by a DNAzyme-based fluorescent sensor

Copper deficiency can adversely impact health, and using copper cookware can help supplement copper ions. In this study, we have developed a fluorescent Cu(II) sensor using an efficient DNAzyme, a novel cofactor 2-mercaptoethanol and an optimized fluorophore. This sensor has demonstrated high sensitivity, with a linear detection range of 30 nM-50 μM and a detection limit of 3.4 nM. Furthermore, it has shown high selectivity for Cu(II) ions and possesses excellent anti-interference ability against 10,000-fold excess of Ca(II) and Mg(II), etc. These features allow the sensor suitable for quantitatively detecting Cu(II) in a copper pot, where a maximum Cu(II) concentration of 40.0 μM was achieved upon the addition of pickled cucumber. Our findings suggest that acidic conditions are beneficial for increasing Cu(II) content in the cooking medium. This provides a scientific basis for using copper cookware as a means to increase dietary copper intake.