Stripping voltammetric determination of cerium in food using an electropolymerized poly-catechol and ion-imprinted membrane modified electrode

For the aim to detect Ce(III) in food with selectivity, sensitivity and speediness, a electrochemical sensor (Ce(III)-IIM/PC/GCE) was constructed by electropolymerization of a poly-catechol (PC) film on glassy carbon electrode (GCE) followed by modifying a Ce(III) ion-imprinted membrane (IIM) formed with electropolymerization using o -phenylenediamine as monomer . After that, a differential pulse adsorptive stripping voltammetry (DPASV) was developed for determination of Ce(III) by the obtained sensor. Under the optimal conditions, the sensor possesses good reproducibility and storage stability. Furthermore, it can be used directly for determination of Ce(III) in the concentration range of 3.0   ×   10 −   12 –1.0   ×   10 −   4   mol   L −   1 with the limit of detection of 1.0   ×   10 −   12   mol   L −   1 . Since over 50-fold excess concentration of Fe 3   + , Cu 2   + and Ni 2   + will produce some interferences in the direct determination of Ce(III), an extraction method was adopted when it be used in food. After extraction of the samples with 1-phenyl-3-methyl-4-benzoyl-5-benzopyrazolone (PMBP), Ce(III) can be determined by Ce(III)-IIM/PC/GCE in the presence of >   500-fold excess concentration of Fe 3   + , Cu 2   + and Ni 2   + with the limit of detection of 4.7   ×   10 −   9   mol   L −   1 . The sensor was successfully applied to determine cerium in food after extracted by PMBP with a relative standard deviation (RSD) of <   3.3% (n   =   4) and recoveries in the range of 94.9–102.2%.