Abstract:
Liquid and graphite coated electrodes of polymers imprinted with dextromethorphan hydrobromide
(DM) were constructed using precipitation polymerization. The molecularly imprinted (MIP) and
nonimprinted (NIP) polymers were synthesized using DM as a template, acrylic acid (AA) and 2-vinyl
pyridine (VPY) as monomers, ethylene dimethacrylate (EDMA) as a cross-linker and benzoyl peroxide
(BPO) as an initiator. The molecularly imprinted membranes and the non-imprinted membranes were
prepared using dioctyl phthalate (DOP) and bis (2-ethylhexyl) sebacate (BEHS) as plasticizers in PVC
matrix. The slopes and detection limits of the liquid electrodes ranged from 55.9 ? 58.3 mV/decade
and 3.0 x 10-6
? 6.0 x 10-5 M, respectively and their response time was about 1 minute. The Liquid
electrodes were filled with 0.01 M DM solution and their response was stable in a pH range from 2.0
to 9.0 and with good selectivity for DM over several species. Graphite electrodes coated with MIP
membrane of AA and DOP and AA and BEHS were prepared for DM determination. Graphite
electrodes coated with MIP membrane of AA and DOP showed a near Nernstian response with slope
of 52.4 mV/decade and a linear response for a concentration range of 5.0x 10-7 to 1.0 x 10-2 M and a
response time of around 1 minute. The most effective electrodes were used to determine the
concentration of DM in cough syrups.