Fluorescence Analysis Of Phytic Acid

Phytate(IP6),a fully phosphorylated form of inositol,is a naturally occurring component and the principal storage source of phosphorus in many plants.Due to both potentially detrimental and beneficial effect of IP6,it is very necessary to develop a reliable method for the determination of IP6 in order to make a valuable evaluation on its metabolism in human body.The high-performance ion chromatography, spectrophotometry,NMR spectroscopy,atomic emission spectrometry and HPLC are the methods to analyse IP6.In this paper,two novel methods were developed for determination of phytic acid.They are fluorimetric method and synchronous fluorescence method.1)Fluorimetric methodThe method is based on a fluorimetric replacement reaction,in which the foreign phytic acid replace the Cu²⁺ion from Cu²⁺-gelatin complex, liberating the fluorescent gelatin molecule.The fluorescence of the solution would accordingly recover proportionally to the amount of the added phytic acid.The excitation wavelength is 273.5 nm and the characteristic emission wavelength is 305.0 nm,respectively.The calibration graph has been divided into two sections.One section was linear over the range of 0.4-2.4 mg L^-1with a linear regression equation of I_f=-0.895+15.146c(R²＞0.9993),and the other over the range of 2.4-9.2 mg L^-1with a linear regression equation of I_f=-29.526+ 26.113c(R²＞0.9996),respectively.The proposed method was applied to the determination of phytic acid in urine samples.Comparison of the obtained results with the reported HPLC was performed,indicating the proposed method was reliable.2)Synchronous FluorescenceThe method is based on a complex reaction,in which the foreign phytate with 1,10-Phenanthroline(phen)and Fe³⁺format a ternary complex.The synchronous fluorescence intensity of the solution was accordingly enhanced proportionally to the increase of the phytate concentration.The constant wavelength synchronous luminescence was adopted in the study,and theΔλwas set as 40.0 nm.The linear range is 0.33-32.34 mg L^-1with the linear equation of I_f=8.770+2.980c(R²＞0.9994).The proposed method was applied to the determination of phytate in foods samples,and it was compared with the UV-spectrophotometry method,the results show the proposed method was reliable.