Amperometric detection of heparin, which combines the spontaneous extraction of heparin into the ionic liquid (IL) membrane with its potential-driven stripping, is studied using IL composed of the tetradodecylammonium (TDDA+) cation and tetrakis[3,5-bis(trifluoro-methyl)phenyl]borate (TFPB-). In contrast to the IL membrane composed of tridodecylmethylammonium cation (TDMA+) and TFPB-, no promotion effect of the tetrapentylammonium cation (TPeA+) is observed.
The absence of the effect is ascribed to a much weaker ion association between heparin and TDDA+, which does not support the accumulation of heparin into the IL phase.