A simple, accurate, and sustainable electrocatalytic conversion strategy has been used for the speciation analysis of trace mercury. An Au-or Ag-modified nickel foam electrode (Au/NFE or Ag/NFE) prepared by cyclic voltammetry was used first as a cathode for the gaseous conversion of organomercury. The mechanism of improving the electrochemical inertness of methylmercury is considered to be the migration of charge centers and the weakening of C−Hg bonds caused by the formation of Au−Hg amalgam. A large specific surface area, high catalytic activity, and low transport resistance allow an effective conversion of 0.1 μg L −1 level organomercury on the Au/NFE surface. The difference of gaseous conversion behavior under current control also provides a green way for the analysis of mercury speciation. A lower limit of detection (4.9 pg g −1 for Hg 2+ and 5.5 pg g −1 for CH 3 Hg + ), stronger anti-interference ability, more than 180 sample analysis capacities, and less than 8% signal fluctuation, importantly, confirmed that the electrocatalytic conversion technology based on the gold/silver-modified NFE is very suitable for the analysis of ultratrace methylmercury in complex matrix samples, such as animal and plant samples.

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