Hydroxyapatite-modified carbon ionic liquid electrode (HAPCILE)
was prepared according to the following procedure. The modified carbon ionic liquid electrode was prepared by mixing the graphite powder with the HAP to give an appropriate ratio HAP/CP.
The mixture and OPPF6 with a ratio of 50/50 (w/w) were ground in a mortar and then a portion of the resulting paste was packed firmly into the cavity (1.8mmin diameter) of a Teflon holder. The electrode was then heated either in an oven to a temperature higher than the
melting point of OPPF6 (m.p. 65 ◦C) or simply by using a hair drier
for 2 min. It was then left to cool to room temperature. The electric
contact was established via a stainless steel handle. A new surface
was obtained by smoothing the electrode onto a weighing paper.