Direct use of superparamagnetic nanoparticles as electrode modifiers for the analysis of mercury ions from aqueous solution and crude petroleum samples

► Superparamagnetic carbon powder allows to capture and transport mercury to the electrode. ► The magnetic carbon substrate is highly conducting and has a large surface area. ► By preconcentrating the elements at the electrode a large signal enhancement is achieved. ► The superparamagnetic carbon powder allows to perform direct electrochemistry analysis. ► A magnetic alternative for mercury stripping analysis is proposed.