Amperometric carbon paste enzyme electrodes with Fe(3)O(4) nanoparticles and 1,4-benzoquinone for glucose determination.

Two new amperometric carbon paste enzyme electrodes including Fe(3)O(4) nanoparticles with and without 1,4-benzoquinone were developed for glucose determination. Electron transfer properties of unmodified and Fe(3)O(4) nanoparticles and/or 1,4-benzoquinone modified carbon paste electrodes were investigated in 0.1 M KCl support electrolyte containing Fe(CN)6(3-/4-) as redox probe by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. Fe(3)O(4) nanoparticles increased electron transfer at solution/electrode interface. The parameters affecting the analytical performance of the enzyme electrode have been investigated in detail and optimized for Fe(3)O(4) nanoparticle modified enzyme electrode (Fe(3)O(4)-CPEE). Fe(3)O(4) nanoparticles and 1,4-benzoquinone modified enzyme electrode (BQ-Fe(3)O(4)-CPEE) exhibited linear response from 1.9 × 10(-7) M to 3.7 × 10(-6) M, from 7.2 × 10(-6) M to 1.5 × 10(-4) M and from 1.3 × 10(-3) M to 1.2 × 10(-2) M with an excellent detection limit of 1.9 × 10(-8) M. BQ-Fe(3)O(4)-CPEE was used for determination of glucose in serum samples and results were in good agreement with those obtained by spectrophotometric method.