Abstrato

New FIA-spectrophotometric methods for determination of arginine in grape juice samples via sakaguchi reaction after separation with strong cation-exchange resin

BushraB.Qassim, Sarah F.Hameed

Simple and sensitive batch and FIA-spectrophotometric methods for determination of L- arginine in grape juice samples from different origins, these methods were based on oxidation – condensation of L – arginine with á – naphthol and urea in presence of sodium hydroxide as a medium for amino acid reaction.Ared color developed when adding sodium hypobromite as oxidizing agent for amino acid. The colored productwas soluble in water and stable for more than 1 hour and the absorbtion was measured at a maximum absorbance at 501 nm. A graphs of peak height versus concentration show that Beer, s law was obeyed over the concentration range of 1 – 45 and 3 – 1400 µg.ml-1 of arginine with detection limits of 0.468 and 0.12 µg. ml -1 of arginine for batch and FIAmethods respectively. The optimized FIA procedure sample with a throughput of 45 sample / hour. All different chemical and physical experimental conditions affecting on the development and stability of the colored product were studied and the proposed methods were applied successfully for the determination of arginine in grape juice samples.