ABSTRACT
In 1998, Regnier et al. first introduced pillar array columns. Branched-chain amino acids (valine, isoleucine, and leucine), other amino acids (phenylalanine and tyrosine), and keto acids in human plasma samples could be quantified, demonstrating for the first time that pillar array columns can be applied to the analysis of biological samples. Furthermore, an automated sample injection system for pillar array columns was developed to maintain a constant sample injection volume. The turn structure described has a high flow resistance due to the narrow channel width of the turn, making it difficult to achieve high-speed separation at high flow rates. Upon introducing the PDC turn structure into the pillar array columns, separation at high flow rates became possible, and five fluorescently derivatized amino acids, could be separated within 24 s. The PDC turn structure offers the advantages of longer pillar array columns for the fast analysis of complex samples. Hence, a gradient elution system with pillar array columns was developed.
