Amperometric dimetridazole sensor using glycosylated metalloporphyrin as a recognition element

An amperometric dimetridazole (DNZ) sensor based on the supermolecular recognition by glycosylated metalloporphyrin, which was immobilized on a glassy carbon electrode by chitosan, is reported. For the preparation of a DNZ-sensitive active material, 5,10,15,20-tetrakis[2-(2,3,4,6-tetraacetyl-β-d-glucopyranosyl)-1-O-phenyl]porphyrin (T(o-glu)PPH2) and its Mn(III) complex MnT(o-glu)PPCl were synthesized from the reaction of pyrrole with ortho-acetylglycosylated benzaldehyde by Lindsay's method. The MnT(o-glu)PPCl-modified electrode showed excellent selectivity toward DNZ with respect to a number of interferents and exhibited stable response. The calibration graph obtained with the proposed sensor was linear over the range of 1.5 × 10−3 to 2.7 × 10−9 M/L, with a detection limit of 2.7 × 10−9 M/L for DNZ. Cyclic voltammetric measurements indicated that MnT(o-glu)PPCl entrapped in chitosan matrices could decrease the reduction potential for DNZ detection. The sensor could be regenerated by washing in an alcohol solution, with an excellent reproducibility (R.S.D. = 2.6%). The experimental conditions such as pH and applied working potential were optimized. The prepared sensor is applied for the determination of DNZ in pharmaceutical preparations and the results agreed with the values obtained by the pharmacopoeia method.