Study on the interaction between torasemide and 12-tungstophosphoric acid by resonance Rayleigh scattering and resonance nonlinear scattering spectra and its analytical applications

► Torasemide, a new generation of high pyridine sulfonylurea loop diuretic. ► Torasemide reacted with TP to form a 3:1 ion-association complexes. ► The method had good selectivity. ► A highly sensitive, simple and quick method has been developed for the determination of Torasemide. ► The method can be applied satisfactorily to the determination of Torasemide in tablets and urine samples.