HILIC Separation of Common Preservatives – Citric Acid, Ascorbic Acid and EDTA

Citric acid, ascorbic acid, and EDTA are commonly used in food and pharmaceutical industry as preservatives. These compounds are very polar in nature. They are weak organic acids with limited UV activity. Retention and separation is achieved on HILIC mixed-mode Obelisc N column. All three compounds are retained by combination of strong HILIC and strong anion-exchange mechanisms. Separation can be monitored by ELSD, LC/MS, UV or Corona CAD. In contrast to other HILIC column, Obelisc N has two ionizable groups basic and acidic which provide ion-exchange interaction in addition to hydrophilic interaction. This allows to use less acetonitrile for HILIC separation.


Column Obelisc N , 4.6x150 mm, 5 µm, 100A
Mobile Phase MeCN/H2O
Buffer AmAc pH 4.0
Flow Rate 1.0 ml/min
Detection ELSD


Class of Compounds Acid, Vitamin B₆, Hydrophobic, Ionizable
Analyzing Compounds Citric acid, ascorbic acid and EDTA

Application Analytes:
Ascorbic Acid
EDTA (Ethylenediaminetetraacetic Acid)
Vitamin C