Determination of l- and d-fucose using amperometric electrodes based on diamond paste

Abstract

Monocrystalline diamond (natural diamond, synthetic-1 and synthetic-2) based electrochemical electrodes were designed for the analysis of L- and D-fucose. Response characteristics of the electrochemical electrodes were determined using cyclic voltammetry and differential pulse voltammetry (DPV). L-Fucose was determined using DPV with electrodes based on natural diamond, synthetic-1 and synthetic-2, respectively, at 240 mV using NaCl as the electrolyte (pH 3.0); at 160 mV using KNO₃ (pH 10.0) and at 80 mV using KCl as the electrolyte (pH 10.0) while D-fucose was analyzed at 120 mV using KCl as the electrolyte (pH 1.0); at 140 mV using KNO₃ as the electrolyte (pH 1.0) and at 160 mV using NaNO₃ as the electrolyte (pH 3.0). The linear concentration ranges for L-fucose were between 10⁻¹³ and 10⁻⁹ mol L⁻¹ (natural diamond), 10⁻¹¹ and 10⁻⁸ mol L⁻¹ (synthetic-1) and 10⁻⁶ and 10⁻³ mol L⁻¹ (synthetic-2) with detection limits of 10⁻¹⁴, 10⁻¹² and 10⁻⁸ mol L⁻¹ magnitude order, respectively. For D-fucose, the linear concentration ranges were 10⁻⁶ to 10⁻³ mol L⁻¹ (natural diamond), 10⁻⁵ to 10⁻³ mol L⁻¹ (synthetic-1) and 10⁻⁹ to 10⁻³ mol L⁻¹ (synthetic-2) with detection limits of 10⁻⁷, 10⁻⁷ and 10⁻¹⁰ mol L⁻¹ magnitude order, respectively. The sensors were used for the assay of L-fucose in serum and urine samples.