Capillary electrophoresis apparatus equipped with a bioluminescence detector using a batch- or flow-type detection cell

We developed a capillary electrophoresis (CE) apparatus equipped with a batch- or flow-type bioluminescence (BL) detection cell. Firefly luciferin–luciferase BL reaction was used to analyze samples of nucleotides, such as ATP, dATP, ADP, GTP, UTP, CTP, ITP, and TTP. In the CE apparatus with the batch-type cell, ATP was detected at concentrations of 5–100 μM, while the other nucleotides were not detected at concentrations less than 500 μM. The electropherogram of ATP included two BL peaks; the latter peak showed peculiar broadening, which continued up to ca. 2.5 h. In the CE apparatus with the flow-type cell, ATP, dATP, and ADP were detected with single peaks with detection limits of 1, 75, and 100 μM, respectively. The other nucleotides, GTP, UTP, CTP, ITP, and TTP, were not detected at concentrations less than 0.5 mM. A mixture of 10 μM ATP and 100 μM dATP was examined using the CE apparatus with the flow-type BL detection cell. ATP and dATP were separated using running buffer at pH 10 containing 1 mM phenylboronic acid. The interaction between ATP and phenylboronic acid delayed the migration time of ATP.