Inline electrochemical detection for capillary electrophoresis

Abstract

This paper presents for the first time fabrication and initial measurements of an electrophoresis stage integrated with a novel inline electrochemical detection system. This detector system can be easily incorporated into plastic substrates and has less complex fabrication procedure compared to fluorescent detection systems. Potentiostatic and Open potential modes of detection are demonstrated. Techniques used to eliminate gas evolution at the detection electrodes and to reduce noise are discussed. Noise levels of 0.7 pA on a signal of 5 nA and drift in signal of 1.18 pA/s were measured for the potentiostatic mode of detection for the field and buffer concentration mentioned. Open potential mode had noise levels of 9.1 mV on a signal of 800 mV and a drift in signal of 0.22 mV/s. The potentiostatic mode was determined to be more stable based on the S/N ratios. Separation and detection of few biologically important compounds along with few electrochemical tags are demonstrated. Detection limits of 14.5 amol were measured for the potentiostatic mode of detection.