Comparison of Glassy Carbon and Copper Microparticles as a Renewable Working Electrode Material for Amperometric Determination of Amino Acids Using Flow Through Detector

Flow-through detector with renewable working material based on glassy carbon or copper microparticles was used for flow injection determination of tyrosine by direct oxidation and phenylalanine via the complexation reaction with copper ions, respectively. Copper-based detector allows the determination of electrochemically inactive amino acid, but the detection conditions are limited and fabrication and handling of the detector are more demanding. Low working potential, applied for the detection on copper microparticles, makes the determination very selective. Moreover, low baseline noise compensates lower sensitivity of copper-based detector, enabling to reach quantification limit 4.7×10 ⁻⁶ mol L ⁻¹ , in comparison with quantification limit 1.6×10 ⁻⁶ mol L ⁻¹ obtained for tyrosine on carbon-based detector.