Anion Exchange Chromatography and Integrated Amperometric Detection of Amino Acids

During the 1980s and 1990s, electrochemical detection has gained acceptance as a method of choice for some important biomolecules. Initially, the technique was utilized with glassy carbon electrodes and in the mode of constant potential amperometry. The first widely used applications were for catecholamines and their derivatives (1 ). Today, most laboratories around the world still rely on electrochemical detection when it comes to analyzing catecholamines in biological fluids. Although that approach has been highly successful, the next important advance came in the form of pulsed amperometric detection (PAD). The introduction of voltage pulses broadens the scope of electrochemical detection by regenerating the electrode in time for each new detection measurement. Gradual or sudden fouling of the electrode surface by the products of electrode reaction and the corresponding decreased detection response is eliminated with properly designed PAD techniques. The first important application of PAD was for carbohydrates following their separation by anion exchange (2 ,3 ).