Becauseof the interferences present ingrape juice, sample treatment was
necessary. Previous reports of solidphaseextraction (SPE) usedC18 cartridges
with15-20%acetonitrileas the final extraction solvent.
6,7
Tomatch themobilephase
in this analysis,methanol was usedat concentrations of 20%, 50%, and100%. Both
C18 tubes and carbonmolecular sieve (Carboprep™) tubeswere tested. Good
recoverieswereobtainedusingeither 20%or 50%methanol and theC18phase;
however, the lower concentrationofmethanol resulted ina cleaner final extract.
Good recoverieswere obtainedwith theCarboprep™ tubes aswell, with100%
methanol.
ExtractionProcedure
1. Conditioning
a. Apply 3mLmethanol
b. Apply 3mLdeionizedwater
2. SampleApplication
a. Apply 4mL sample tomoist SPE tube, gravity feed
3. Wash
a. Pull remaining sample through tube, using vacuum
b. Apply 3mLwater
c. Removeexcesswater from bedunder vacuum
4. Elution
a. Apply 2mLelution solvent, gravity feed, dilute to volume
SolidPhaseExtractionof HMF from JuiceSamples
