vitamin c determination in various fruit juices over time n.
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Vitamin C Determination in Various Fruit Juices Over Time - PowerPoint PPT Presentation


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Vitamin C Determination in Various Fruit Juices Over Time. Andrew Mullenax Sam Yatzkan. Instrumentation. UV-Vis LC/MS HPLC. Procedure. Samples diluted 1:10 (v/v) Room Temperature Half Opened, Half Closed Vacuum Filtered-Samples with visible solids. Samples. Simply Lemonade Brand.

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Presentation Transcript
instrumentation
Instrumentation
  • UV-Vis
  • LC/MS
  • HPLC
procedure
Procedure
  • Samples diluted
    • 1:10 (v/v)
  • Room Temperature
  • Half Opened, Half Closed
  • Vacuum Filtered-Samples with visible solids
samples
Samples

Simply Lemonade Brand

Dole Brand

ascorbic acid standards
Ascorbic Acid Standards
  • 5, 10, 20, 30ppm
  • Spiked Samples
  • Characterized Wavelength: 262nm
  • HPLC: Retention Time of ~1.6 minutes
    • Solvent Mixture of .50mL/min degassed H2O and Methanol
  • LC/MS: Retention Time of ~1.6 minutes
    • Solvent Mixture of .75mL/min degassed Methanol and .25mL/min degassed H2O
conclusion
Conclusion
  • Results not very reliable since we had varying retention times
  • Did not get very good separation in chromatographs of the samples
  • Too difficult to tell whether or not vitamin c concentration actually decreased over time
improvements to be made
Improvements To Be Made
  • Better solvent system
  • Better/Different Instrument Settings
  • Dilute more
  • Vacuum Filter All Samples Regardless
references
References
  • Lee, H. S. HPLC Method for Separation and Determination of Nonvolatile Organic Acids in Orange Juice. JAFC, 1993, 41(11), pp. 1991-1993.
  • Nisperos-Carriedo, M. O.; Buslig, B. S.; Shaw, P. E. Simultaneous Detection of Dehydroascorbic, Ascorbic, and Some Organic Acids in Fruits and Vegetables by HPLC. Chem. Anal. 1992, 40(7), pp 1127-1130.
  • Silva, F. O.; Total ascorbic acid determination in fresh squeezed orange juice by gas chromatography. Food Control, 2005, 16(1), pp 55-58.
  • V., K.; D., S.; E., M. Ascorbic acid content of commercial fruit juices and its rate of loss upon storage. Food Chemistry, 2000, 70(3), pp 325-328.