LUMINESCENT DETERMINATION OF FERULIC ACID IN GRAPES WINE

Abstract

The luminescent properties of important phenolic compounds – ferulic acid (FA), which is a quality marker of grape wines, were studied. It has been established that in thin layer of sorbent, FA has an intense intrinsic luminescence enhanced in the presence of yttrium (III) ions and a non-ionic surfactant Neonol 9-12. Optimal conditions for the sorbate complexation were found. The influence of yttrium (III) chloride ions concentration in solution, the acidity of the medium, surface-active and donor-active substances on the luminescence intensity of the sorbates complexes were studied. The maximum increase of I lum complex (2.5 times) in phase of sorbent is achieved in the micellar medium surfactant Neonol 9-12. The optimal conditions for chromatographic isolation of ferulic acid were found. The maximum increase of luminescence intensity was obtained on chromatographic plate Merck TLC Aluminum Plates. The n-butanol-acetic acid-water system (4: 1: 2) was chosen as the mobile phase. The yttrium (III) chloride in presence surfactant Neonol 9-12 was proposed as an enhanced solution. A 4% aqueous hexamine solution was used to achieve the optimal pH value (6,5-6,9) . The response factor of FA in this conditions was Rf = 0.52. The method of solid-phase luminescent determination of ferulic acid in wines of different manufacturers has been developed on the base of conducted research. FA content in wines were determined as per calibration curve, while registering I lum. of sorbates complexes yttrium (III) chloride with FA at λ=485 nm (λ exit = 365 nm). Correctness of results obtained was checked by the “entered-found” method. The determination accuracy and reliability was verified by statistical processing of the findings obtained. The relative standard deviation is (S r ) 4,5 – 7,8%. The FA detection limit was 0.03 µg/ml.