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Conventional alkyl (C18) columns are frequently used for initial
method development, but often are not the best choice. C18
columns have poor retention for polar compounds and do not
perform well with aqueous mobile phases. In contrast,
Aqueous C18 columns are a more versatile choice, due to
much higher polar retention and compatibility with 100%
aqueous mobile phases. In this article, we demonstrate the utility of Aqueous C18
columns across a range of analytes relevant to dietary supplement testing.
Ideal for Multi-Vitamin Analyses—Easily Retains Water-Soluble Vitamins
Many consumers are augmenting their diets with multi-vitamins. These supplements
usually contain multiple water-soluble vitamins in a variety of chemical forms and con-
centrations. While water-soluble vitamins can be analyzed by HPLC, obtaining ade-
quate retention of hydrophilic analytes is often problematic. As shown in Figure 1, the
Ultra II® Aqueous C18 column provides excellent retention and completely resolves a
test mix of B vitamins.
Figure 1 A selective separation of seven B vitamins using a simple buffer:acetonitrile
gradient on an Ultra II® Aqueous C18 column.
Inj.: 1µL; Conc.: 100µg/mL each component; Sample diluent: water:methanol (70:30); Column: Ultra II® Aqueous C18; Cat.#:
9608565; Dimensions: 150mm x 4.6mm; Particle size: 5µm; Mobile phase: A. 10mM potassium phosphate (pH 2.5), B. acetonitrile;
Gradient (%B): 0 min. (2%), 1.5 min. (2%), 5 min. (75%); Flow: 1.5mL/min.; Det.: UV @ 210nm
Complete analytical conditions for chromatogram LC_PH0503 available at
Peak List
1. vitamin B3
2. vitamin B6
3. vitamin B5
4. vitamin B9
5. vitamin B12
6. vitamin B2
7. vitamin B7
LC_PH0503
Aqueous C18 LC Columns—More Versatile than
a C18 for Vitamins and Organic Acids
in Dietary Supplements
Ty W. Kahler, Innovations Chemist and Rick Lake, Pharmaceutical Market Development Manager
• Simplify method development for polar compounds.
• Higher retention and selectivity compared to a C18.
• Compatible with 100% aqueous mobile phases.
dietary supplements
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Good retention simplifies
method development.
Need to test for
pesticides too?
See p.12 for an LC/MS/MS analysis
of 280 pesticides on an Ultra
Aqueous C18 column.
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