Determination of Folic Acid Content in Sports Nutrition Food by SPE-HPLC with Post-Column Oxidation Derivatization Fluorescence Spectrometry

A method for the determination of folic acid in sports nutrition food by solid phase extraction and HPLC post column oxidation derivative fluorescence was developed. The pretreatment methods of precipitated protein method,enzymolysis protein method and solid phase extraction columns were investigated respectively,and the optimized conditions of mobile phase were obtained. Weak reversed-phase anion-exchange Strata-X-AW solid-phase extraction columns were used for purification,and Venusil MP C₁₈ columns were used for separation. Post-column derivatization instrument for oxidative derivatization(5% potassium persulfate solution),and 50 mmol potassium dihydrogen phosphate(pH3.5):acetonitrile=90:10 (V/V)was the final choice of mobile phase,and then the content of folic acid was detected by fluorescence detector. The results showed that the linearity of the method was suitable in the range of 0.232~2.318 μg/mL,R²=0.9971,the injection volume was 10 μL,the limit of quantitative of the instrument was 0.0774 μg/mL. The sensitivity was enough to meet the needs of folic acid detection in sports nutrition food,the recovery of the method was between 96.98% and 100.50%,and the standard and sample solutions were stable in 8 h. This newly developed method could not only solve the problems of extraction,purification,but also have advantages of convenience,accuracy,wide linear range,high sensitivity. Never the less,it was reproducible,specific,and robust with high recovery rate,which could meet the needs of the quantification of folic acid in sports nutrition foods.