Research On Optimization And Application Of Determination Method Of ?-aminobutyric Acid In Jujube

High-performance liquid chromatography(HPLC)is currently the most commonly used method for the determination of ?-aminobutyric acid(GABA)content.However,the existing HPLC method has the disadvantages of too complicated mobile phase ratio,high flow rate,high system pressure,and analysis requirements.Therefore,this study took jujube as the research object.First,the pre-column derivatization HPLC method of dansyl chloride(Dansyl-CI),2,4-dinitrochlorobenzene(FDCB)pre-column derivatization HPLC method,Four methods of 2,4-dinitrofluorobenzene(FDNB)pre-column derivatization HPLC method and phenyl isothiocyanate(PITC)pre-column derivatization HPLC method were optimized and established;The GABA content of jujube and four kinds of jujube products was determined;finally,the four optimized GABA content determination methods were compared and analyzed.The following conclusions are obtained:1.Optimization and establishment of the method for the determination of GABA in jujube by dansyl chloride methodThrough research,it is concluded that methanol(A)and 0.5% formic acid(B)are mobile phases,elution gradient: 0-15 min,60%-80%(A);15-16 min,80-100%(A);16-20 min,100%(A);20-21 min,100-60%(A);21-25 min,60%(A);flow rate 0.7m L/min.The optimized chromatographic conditions have the advantages of stable baseline,high resolution,low system pressure and short analysis period.Under this analytical condition,the method has the characteristics of good linearity,low detection limit and quantification limit,high precision and high recovery rate.2.Optimization and establishment of 2,4-dinitrochlorobenzene method for determination of GABA in jujubeThe derivatization conditions were optimized using the same HPLC conditions as the dansyl chloride pre-column derivatization method,and the results were as follows: derivatization temperature 90?;derivatization time 1h;sodium borate concentration 0.01mol/L;The method has the characteristics of good linearity,low detection limit and quantification limit,high precision and high recovery rate.3.Optimization and establishment of 2,4-dinitrofluorobenzene method for the determination of GABA in jujubeUsing the same HPLC conditions as the dansyl chloride pre-column derivatization method,the derivatization conditions were optimized,and the results were as follows: the derivatization temperature was 60?;the derivatization time was 45min;and the amount of derivatizing agent was 1m L.The method has the characteristics of good linearity,low detection limit and quantification limit,high reproducibility and recovery rate.Quantitative analysis of GABA in large batches of jujube samples.4.Method optimization and establishment of the phenyl isothiocyanate method for the determination of GABA in jujubeThrough research,it is concluded that the flow rate is 0.7m L/min;the column temperature is 30?;the injection volume is 10?L;methanol(A)and 0.1 mol/L sodium acetate aqueous solution(p H=6.5,containing 0.5% triethylamine)(B)are flow Phase;elution gradient: 0-15 min,40%-60%(A);15-16 min,60-100%(A);16-20 min,100%(A);20-21 min,100-40%(A);21-30 min,40%(A);detection wavelength252 nm.The method has the characteristics of good linearity,low detection limit and quantification limit,high reproducibility and recovery rate.5.Determination of GABA in jujube samplesThe GABA content of 10 fresh jujube samples and 4 jujube products was analyzed,and the GABA content of 10 fresh jujube samples was in the range of 127.44-327.37 ?g/g DW,among which the GABA content of fresh Jun jujube was the highest,and the GABA content of fresh sour jujube was the highest.lowest content.Through the determination of GABA in 4 jujube products,the GABA content of dried jujube is the highest,exceeding 500?g/g DW,but the GABA content of jujube juice,jujube paste and jujube puree is much lower than that of dried jujube.Through the comparison of Dansyl-Cl,FDCB,FDNB and PITC methods,it was found that there was no statistically significant difference between the results of the four methods(p>0.05),indicating that all of them can be used for the determination of GABA content in batch jujube samples.However,considering factors such as derivatization temperature,derivatization steps,and reagent price,Dansyl-Cl and FDNB methods are ideal methods for the determination of GABA in bulk jujube samples.