Modified planar sensors for cefepime determination

Abstract

Planar screen-printed potentiometric sensors sensitive to cefepime, cephalosporine antibiotic of the fourth generation, has been developed. Cefepime is an amphoteric antibiotic with carboxyl and aminothiazole groups which exists as a cation in a strongly acidic media, a zwitter-ion in a weakly acidic and neutral media, and as an anion in an alkaline media. The interval of pH = 1.5 - 2.0 is set for obtaining cationic electrode functions for the cefepime determination. Cefepime-tetraphenylborate associates are used as electrode-active components (EAC). The optimal EAC content for planar sensors is 2-3%. The electrode functions are linear in the range of 1 x 10 -5 - 1 x 10 -2 M, angular coefficients 50 ± 2 mV/pC, response time 20 sec for unmodified cefepime sensors. The role of the modifier, ZnO nanoparticles, in improving the electroanalytic properties of sensors is shown. The introduction of a binary mixture of zinc oxide and cetylpyridinium chloride into carbon-containing ink leads to a decrease in the detection limit of cefepime (1 x КГ6 M), an increase in the angular coefficient (58 ± 1 mV/pC) and the interval of linearity of electrode functions (1 x 10 -6 - 1 x 10 -2 mole/liter), sensor response time being 17 sec. The use of a surfactant as an electrode surface comodifier leads to stabilization of the nanoparticle dispersion. The use of modified screen-printed sensors for the cefepime determination in medicinal and biological media, in particular, in saliva, is shown.