Simple electrochemical sensing for mercury ions in dairy product using optimal Cu2+-based metal-organic frameworks as signal reporting.

A convenient sensor is developed for electrochemical assay of Hg2+ in dairy product using the optimal Cu2+-based metal-organic frameworks (Cu-MOFs) as signal reporting. Benefiting from specific recognition between Hg2+ and thymine (T)-rich DNA strands, the interferences of milk matrices are effectively eliminated, thereby greatly improving the accuracy of test results. Moreover, the suitable Cu-MOFs offer an efficient carrier for probe design, and the contained Cu2+ ions could be directly detected to output electrochemical signal of Hg2+ presence without labor- or time-intensive operations. Compared with previous methods, this sensor substantially simplifies the process of electrochemical measurement and facilitates highly sensitive, selective and rapid analysis of Hg2+ with detection limit of 4.8 fM, offering a valuable means for monitoring dairy product contamination with Hg2+.