A cysteine self-assembled monolayer was formed on a gold electrode. Cu 2+ + 2 electrons - Cu0

If 1 mol of Cu2+ has been reduced how much change in Columbus must have been transferred to convert Cu2+ to Cu0?

The electrochemical signals were detected before and after introducing the carnitine sample to the sensor. 2 mol of electrons were detected by the electrode initially. After introducing sample carnitine only 1 mol of electrons were detected by the electrode. How many moles of carnitine interacted with cysteine on the sensor surface?