Determination of aromatic and sulfur-containing amino acids, peptides, and proteins using high-performance liquid chromatography with photolytic electrochemical detection.

Aromatic amino acids, sulfur-containing amino acids, peptides containing such constituents, and proteins can now be detected in high-performance liquid chromatography by the use of on-line, postcolumn, continuous photolytic derivatization with electrochemical (HPLC-hv-EC) detection. The overall approach is a very simple, reproducible, rapid, and fully automatable approach for the determination of certain amino acids, peptides, and proteins with excellent selectivity, sensitivity, and linearities of response. Dual-electrode response ratios, lamp-on/lamp-off behavior, and chromatographic capacity factors all contribute to the enhanced selectivity of the overall HPLC-hv-EC determination for these particular classes of bioorganics and biopolymers. The analytical figures of merit, chromatography detection, and method validation approaches have all been optimally derived and demonstrated reproducible. Applications of the basic methodology to real-world samples are demonstrated and validated.