Analytical Applications Of Resonance Rayleigh Scattering Spectra In Alkaloids And Sulfonamides

Alkaloids and sulfonamides, whether in quantity or in the medicinal properties, have unique position. New RRS, SOS and FDS methods for the determination of matrine, oxymatrine, atropine sulphate, hyoscine butylbromide and sulfadimidine have been established and developed. It can be used in the determination of trace drugs in the natural medicine and the pharmaceutical preparation. Main investigated systems are listed as follow:1. Determination of Matrine and Oxymatrine in Radix Sophorae Flavescentis by Resonance Rayleigh Scattering and Resonance Nonlinear Scattering SpectraIn 0.1 mol/L (pH 1.0) HCl medium,12-tungstophosphoric acid (TP) reacted with matrine (Mat) and oxymatrine (Oxy) to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second-order scattering (SOS), and frequency doubling scattering (FDS) appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, SOS and FDS were located at 370 nm,670 nm and 393 nm, and the scattering intensities were proportional to the concentration of Mat and Oxy in certain ranges. Based on this, new methods for the determination of Mat and Oxy have been established. The detection limits (3σ) of these methods were in the range of 3.6～28.2 ng/mL. The RRS, SOS, and FDS characteristics, absorption spectrum characteristics and optimum reaction conditions of these systems were discussed. Effects of coexistent substances were tested, and the results demonstrated that the methods had good selectivity. It has been applied to the determination of Mat and Oxy in samples of radix sophorae flavescentis with satisfactory result. The reaction mechanism and reasons of RRS enhancement were discussed.2. Determination of Atropine Sulphate in Atropine Sulphate Eye Ointment by Resonance Rayleigh Scattering TechniqueIn pH 3.0-4.5 HAc-NaAc buffer medium, a resonance Rayleigh scattering method was developed for the determination of atropine sulphate (AS). I₃^- reacted with AS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS) appeared and the intensities were enhanced greatly. The maximum wavelength of RRS was located at 634 nm. The scattering intensities were proportional to the concentration of AS. The detection limit (3a) was 6.5 ng/mL. The spectra characteristics, the optimum reaction conditions and influencing factors have been discussed. The method was selective. It has been applied to the determination of AS in atropine sulphate eye ointment with satisfying results.3. Determination of Hyoscine Butylbromide in Hyoscine Butylbromide Capsules by Resonance Rayleigh Scattering TechniqueIn pH 5.0 medium, a resonance Rayleigh scattering method was developed for the determination of hyoscine butylbromide (HBB). I₃^- reacted with HBB to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS) appeared and the intensities were enhanced greatly. The maximum wavelength of RRS was located at 623 nm. The scattering intensities were proportional to the concentration of HBB. The detection limit (3a) was 5.7 ng/mL. The spectra characteristics, the optimum reaction conditions and influencing factors had been discussed. The method is selective. It has been applied to the determination of HBB in capsules with satisfying results.4. Determination of Hyoscine Butylbromide with Ag⁺and Dihalogenated Fluorescein Dyes in Capsules by Resonance Rayleigh Scattering TechniqueIn pH 4.2～5.6 HAc-NaA buffer solution, hyoscine butylbromide (HBB) reacts with Ag⁺ and dihalogenated fluorescein dyes such as dichlorofluorescein (DCF), dibromofluorescein (DBF) and diiodofluorescein (DIF) to form a ion-association complex. This resulted in the significant enhancement of RRS intensity. The maximum wavelengths of RRS were located at 322 nm (DCF),320 nm (DBF) and 335 nm (DIF), respectively. The scattering intensities were proportional to the concentration of HBB. Based on these, new methods for the determination of HBB have been established. The spectra characteristics, the optimum reaction conditions and influencing factors have been discussed. It has been applied to the determination of HBB in capsules and the results were in good agreement with those obtained by the literature methods.5. Determination of Sulfadimidine with Potassium Permanganate by Resonance Rayleigh Scattering TechniqueIn 0.20 mol/L H2SO4 medium, a redox reaction took place between sulfadimidine (SM2) and potassium permanganate to form MnO₂ particles by heating. As a result, the new spectra of resonance Rayleigh scattering appeared and their intensities were enhanced greatly. The maximum peak of RRS was located at 595 nm, and the scattering intensities were proportional to the concentration of SM2. Based on it, a new method for the determination of SM2 has been established. The detection limit (3σ) was 8.6 ng/mL. Effects of coexistent substances were tested, and the results demonstrated that this method had good selectivity. It has been applied to the determination of SM2 in tablet with satisfactory results.