Synthesis of a novel fluorescent probe and investigation on its interaction with nucleic acid and analytical application

A novel fluorescent probe N-(N-(2-(4-morpholinyl)ethyl)-4-acridinecarboxamide)-α-alanine (N-(N-(ME)-4-ACA)-α-ALA) was synthesized. The structure was characterized by 1H NMR, MS, elemental analysis, fluorescent and ultraviolet spectra. This new compound exhibited high binding affinity to DNA, intense fluorescence and high water solubility. Experiment indicated that the fluorescent intensity was quenched when DNA was added. A method for DNA determination based on the quenching fluorescence (λex = 258 nm, λem = 451 nm) of N-(N-(ME)-4-ACA)-α-ALA was established. Under optimal conditions (pH 7.2, CN-(N-(ME)-4-ACA)-α-ALA = 3 × 10−6 mol L−1), the linear range is 0.1-4.0 μg mL−1 for both fish semen (fsDNA) and calf thymus DNA (ct-DNA). The corresponding determination limits are 4.6 ng mL−1 for fsDNA and 5.1 ng mL−1 for ct-DNA, respectively. The relative standard deviation is 1.0%. Thus this compound can be used as a DNA fluorescent probe. The experiments proved that the interaction mode between N-(N-(ME)-4-ACA)-α-ALA and DNA was groove binding. The modified Rosenthal's graphical method gave the binding constant of 1.0 × 106 L mol−1 and a binding size of 0.31 base pairs per bound drug molecule.