The　flotation　of　copper　bearing　minerals　is　always　a　hot　topic　in　the　field　of　minerals　processing.　In　this　paper,　the　adsorption　of　a　flotation　collector,　2-mercaptobenzothiazole(MBT),　onto　a　typical　secondary　copper　sulfide　mineral,　chalcocite,　depending　on　electrochemical　potential　was　investigated　with　the　help　of　shell-isolated　nanoparticle　enhanced　Raman　spectroscopy　(SHINERS).　The　MBT　adsorbs　through　its　exocyclic　sulfur,　in　addition　to　its　endocyclic　nitrogen　at　negative　potentials.　This　is　because　negative　potentials　are　thermodynamically　unfavorable　for　the　adsorption　to　occur.　Especially,　chalcocite　electrode　that　has　been　exposed　to　deep　negative　potential　(-600　mV　versus　SCE)　can　be　totally　inhibited　from　MBT　adsorption.　A　＂cathodic　passivating　＂　process　is　proposed　possibly　accompanied　by　the　formation　of　a　passivation　layer,　kinetically　preventing　adsorption,　even　after　potentials　switch　back　to　positive.　Cyclic　voltammetry　(CV)　and　X-ray　photoelectron　spectroscopy　(XPS)　were　also　used　to　explain　this　phenomenon.　The　present　work　implicates　enhanced　separation　efficiency　of　chalcocite　by　using　electrochemical　controlled　flotation.