ABSTRACT
Various estimation conditions concerned with a europium chelate labeling agent, 4-(1,1,1,2,2-pentafluoro-3,5-dioxo-pentyl)-[1,11′-biphenyl]-sulfonyl chloride (PDB-SCl), was studied, by using reversed-phase HPLC-time-resolved fluorescence detector system. Samples dissolved in acetonitrile were introduced to a TMS column; the eluent was monitored with absorbance at 280 nm, and then collected. To the fractions was added europium (Eu) solution containing tri-n-octylphosphine oxide (TOPO) and Triton X-100, and the time-resolved fluorescence intensity of the PDB-Eu chelate was measured with an off-line time-resolved fluorometer. In time-resolved fluorescence measurement, one major peak of PDB-SCl was observed, but in absorbance measurement, many peaks were observed. The fractions having time-resolved fluorescence were hydrolyzed, and the reaction solutions were analyzed by an HPLC system connected to an on-line time-resolved fluorescence detector (TRFD). There were little byproduct peaks, which were produced by reacting PDB-SCl with contaminants in the synthesized PDB-SCl powder. The stability of chlorosulfonyl group of PDB-SCl in aqueous acetonitrile solutions was also studied, and 80% of chlorosulfonyl group of PDB-SCl dissolved in 90% aqueous acetonitrile solution was hydrolyzed to sulfonic acid. However, PDB-SCl dissolved in 100% acetonitrile was stable at ambient temperature for at least 96 hours in the dark.
ACKNOWLEDGMENT
Authors express their acknowledgment for the various suggestions to professor emeritus T. Okuyama of Tokyo metropolitan university.