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Perica - 2005/11/28 18:55
Dears,
I am working on HPLC system with PDA detector. My field work is beverages (nonalcoholic drinks).
Question is:
Analysis of additives and vitamines in soft drinks were excellent on Column Varian C18 250mm x 4.6mm
Now I work on ChromSep HPLC column SS 250 x 4.6mm Incl. holder with ChromSep guard column ChromSpher 5 C18
Analysis (Na-benzoat, K-Sorbate, Citric acid, Absorbic acid) on this column are bad. Only coffeine analyse is OK.
Mobile phase: 80% KH2PO4 0.025M, pH4.5 + 20% ACN
Flow rate: 1.3ml/min
Wavelength: 235nm
Mode: Isocratic
Do you have any suggestions? Maybe different mobile phase or something else.
Do you have application notes for these kind of analysis on this type of column (without ion-par reagense)?
Thank you and best regards
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