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

Dole Brand

Simply Lemonade Brand

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

Data – UV-VisSamples Day 1 Characterized

WavelengthDay 2 Characterized

Wavelength (nm)Day 3 Characterized

Wavelength (nm)Day 4 Characterized

Wavelength (nm)

Cran-Apple Juice Closed 255 257 251

Pineapple Juice Closed 276 278 274

White Grapefruit Closed 301 316 298

Lemonade Closed 227 228 226

Cran-Apple Juice Opened 252 253 250

Pineapple Juice Opened 280 284 307

White Grapefruit Opened 200 331

Lemonade Opened 232 281

HPLC Calibration Curve

0 5 10 15 20 25 30 350

200000

400000

600000

800000

1000000

1200000

1400000

1600000

f(x) = 40878.8813559322 x + 78171.6779661018R² = 0.986656891788446

Concentration v. Area

Concentration (ppm)

Area

Data - HPLCSamples Day 1 Concentration (ppm) Day 2 Concentration (ppm) Day 3 Concentration (ppm) Day 4 Concentration (ppm)

Cran-Apple Juice Closed 423.0 1094.0 1117.0 1249.0

Pineapple Juice Closed 1101.0 940.0 1171.0 1073.0

White Grapefruit Closed 353.0 354.0 67.0 99.0

Lemonade Closed 69.0 183.0 163.0 262.0

Cran-Apple Juice Opened 1160.0 873.0 781.0 1231.0

Pineapple Juice Opened 1296.0 922.0 563.0 460.0

White Grapefruit Opened 534.0 178.4 64.0

Lemonade Opened 35.0 230.0 36.0

LC/MS Calibration Curve

0 5 10 15 20 25 30 350

5

10

15

20

25

f(x) = 0.713694915254237 x − 0.872542372881354R² = 0.958536471126957

Concentration v. % Area

Concentration (ppm)

Area

(%)

Data – LC/MSSamples Day 1 Concentration

(ppm)Day 2 Concentration

(ppm)Day 3 Concentration

(ppm)Day 4 Concentration

(ppm)

Pineapple Juice Closed 264.0 220.2 30.7

Lemonade Closed 266.5 291.1 1080.2

Cran-Apple Closed 733.3 126.3 291.9

White Grapefruit Closed 699.5 640.3 246.0

Pineapple Juice Opened 542.2 30.7 299.5

Lemonade Opened 300.9 161.1 535.2

Cran-Apple Juice Opened 348.7 203.8 73.5 446.4

White Grapefruit Opened 924.4 1268.3 307.2

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

• Better solvent system

• Better/Different Instrument Settings

• Dilute more

• Vacuum Filter All Samples Regardless

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.