Caffeine Electrochemical Sensor Using Imprinted Film As Recognition Element Based on Polypyrrole, Sol-Gel, And Gold Nanoparticles Hybrid Nanocomposite Modified Pencil Graphite Electrode, B. Rezaei, A.A. Ensafi, Malihe Ka, Biosens. Bioelectron 2014, 60, 77

In the present study,a novel sensitive and selective nanocomposite imprinted electrochemical sensor for
the indirect determination of caffeine has been prepared.The imprinted sensor was fabricated on the
surface of pencil graphite electrode (PGE) via one-step electropolymerization of the imprinted polymer
composed of conductive polymer, sol-gel, gold nanoparticles (AuNPs), and caffeine. Duetosuch
combination likethethin film ofmolecularlyimprintedpolymer(MIP)withspecific bindingsites,the
sensor respondedquicklytocaffeine.AuNPswereintroducedfortheenhancementofelectricalresponse
by facilitatingchargetransferprocessesof[Fe(CN)6]3
/[Fe(CN)6]4
which wasusedasanelectro-
chemical activeprobe.Thefabricationprocessofthesensorwascharacterizedbycyclicvoltammetry
(CV) andelectrochemicalimpedancespectroscopy(EIS).Severalimportantparameterscontrollingthe
performance ofthesensorwereinvestigatedandoptimized.Theimprintedsensorhastheadvantagesof
high poroussurfacestructure,inexpensive,disposable,excellentstability,goodreproducibilityand
repeatability.ThelinearrangesoftheMIPsensorwereintherangefrom 2.0 to 50.0 and 50.0 to
1000.0 nmol/L
, with the limitofdetection(LOD)of 0.9 nmol/L (S/N=3). Furthermore,theproposed
method wassuccessfullyintendedforthedeterminationofcaffeineinrealsamples(urine,plasma,
tablet, greentea,energyandsodadrink).