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HPLC Application Sheet
Large Substituted Phenolic Compounds: Cogent Silica-C™ vs. Leading Brand by Normal Phase
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Substituted phenols are separated by the Normal Phase mode on two different types of columns
Note: With the Cogent Silica-C™ column, almost all of the silanols on the silica surface are substituted with Si-H and
water is not strongly associated by the stationary phase. Drying of the MP solvents is not essential and subsequent analyses
are very reproducible, day to day as well as run to run.
The identity of the peaks was confirmed using Atmospheric Pressure Chemical Ionization in the positive and negative mode:
APCI+, APCI-
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printable Application Sheet
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Method Conditions
| Column A |
Cogent Silica-C™, 4µm, |
| Dimensions |
4.6 x 75mm |
| Column B |
Leading brand, Silica column, 5µm, |
| Dimensions |
4.6 x 150mm |
| Mobile Phase |
95:5 Hexane/Ethyl Acetate
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| Flow rate |
1.0 mL/minute |
| Injection Volume |
1 µL |
| Samples |
1 mg/mL of proprietary compounds;
1- phenolic with aldehyde
2- parent phenolic compound
3- phenolic with a ketone
Dissolved in the mobile phase |
| Detection |
Diode Array |
Discussion
The Cogent Silica-C™ column was compared with a leading brand Silica HPLC column for separation of three proprietary
phenol compounds using normal phase conditions. The Cogent Silica-C™ column provided satisfactory selectivity under
isocratic elution conditions. The column displayed typical normal phase elution for the phenols, i.e. retention increased
as the amount of the least polar component in the mobile phase increased. In addition, the separation, when using the Cogent
Silica-C™ column is extremely reproducible (%RSD 0.2) even though the solvents were not dried in any special way. This
makes normal phase much easier to perform.
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