Capillary electrophoresis with laser-induced fluorescence detection for chiral analysis and DNA binding studies of ruthenium(II) Tris-diimine complexes

The separation of Ru(II)) tris-diimine enantiomers was performed by chiral capillary electrophoresis (CE). A highly sensitive laser-induced fluorescence (LIF) detection system was employed for detection of transition metal complexes present in solution at the low micromolar range. An argon ion laser (457.9nm, 0.15mW) was used as an excitation source. The enantiomers of the [Ru(diimine)3]2+ complexes were separated using either potassium antimonyl-D-tartrate or dibenzoyl-L-tartrate (L-DBT) as chiral resolving agents. The concentration limit of detection (LOD) for the tris(1,10-phenanthroline) Ru(II) complex was 12.5µM and the LOD for the tris(2,2´-bipyridine) ruthenium(II) complex was 1.0µM. These limits represent an improvement in the overall LOD by three-orders of magnitude relative to that obtained via UV-VIS detection. The CE-LIF system was also used to assess the stereoselective interactions between tris(1,10-phenanthroline) Ru(II) complexes and B-form deoxyribonucleic acid (B-DNA).