Study on the interaction among molecules and the determination of DNA by light scattering with a new type rhodanine derivative

In this paper the resonance Rayleigh scattering (RRS) and second-order scattering (SOS) spectrums of interaction between deoxyribonucleic acid (DNA) and 3-(4′-methylphenyl)-5-(2′-sulfophenylazo) rhodanine (4MRASP) in the environment of surface active substance sodium dodecyl sulfate (SDS) were reported. The light scattering intensity of 4MRASP was enhanced obviously and directly proportional to the concentrations of DNA when DNA was present. Based on this, two new determination methods of DNA were established with high sensitivity and selectivity, and the limits of detection were 8.00 and 1.07 ng mL⁻¹. They were applied to the determination of trace amounts of nucleic acid in synthetic and practical samples with satisfactory results. At last, the active mechanism among molecules was studied by ultraviolet spectrum, scattering spectrum and thermodynamics, which showed that the active force was changed from hydrophobic force to electrostatic force before and after SDS was added, and the mechanism of sensitization effect of SDS was proposed.