Micro-band Boron-doped Diamond Electrode in Capillary Electrophoresis for Simultaneous Detection of AMP, ADP, and ATP

Abstract

A micro-band boron-doped diamond (BDD) electrode was prepared by sealing a piece of BDD film with an area of 1.11×10-7 m2 between two insulating plates, one Teflon and one silicon rubber, to form sandwich-like layers, so the surface area could be investigated. The micro-band BDD was combined with capillary zone electrophoresis as an electrode for the simultaneous detection of adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) in a solution. These adenosine phosphates can be separated with a 0.3 m-long fused silica capillary using Britton–Robinson buffers at pH 2.0. Current in the concentration range of 0.1 to 2.0 mM were linear with the limits of detection of 0.004 μM, 0.006 μM, and 0.011 μM for AMP, ADP, and ATP, respectively. A comparison with an unmodified BDD as the detector in the same electrophoresis system showed that the micro-band generated better limits of detection (LODs) than the macroelectrode. This method was successfully applied to human urine samples injected with three adenosine phosphates, as well as adenine and guanine, which can be well-separated with recovery percentages of adenine, guanine, AMP, ADP, and ATP of 99.2%, 102.5%, 107.4%, 107.7%, and 105.4%, respectively.