Ru-MOFs Modified Microelectrode for Trace Mercury Detection

Mercury ions (Hg
²⁺
) pollution in water environment can cause serious harm to human health. Trace Hg
²⁺
detection is of vital importance for environment monitoring. This paper reports a novel approach for rapid detection of trace mercury by microelectrode with the immobilization of Ru-based metal-organic frameworks (Ru-MOFs). Ru-MOFs are synthesized by cathodic electrochemical method on the gold microelectrode, which significantly enlarges electrochemical active surface area. This method offers the advantages of short synthesis time and needless for high temperature and high pressure that required by solvothermal synthesis. Differential pulse stripping voltammetry is used to determine mercury ions (Hg
²⁺
). The results show a good linearity (R
²
=0.996) from 0.1ppb to 5ppb, with a high sensitivity of 0.583μA ppb
^-1
mm
^-2
. The limit of detection is found to be 0.08ppb and the test process is within 6min. This miniature electrochemical sensor has the potential for on-site rapid detection of trace mercury.