Retention for Highly Polar API

This API has very little Hydrophobic character and is not readily retained by Reversed Phase. The Peak that was obtained had excellent efficiency and symmetry. Three runs are shown in the figure in order to illustrate the repeatability of the data.

Peak:
Metronidazole

Method Conditions
Column: Cogent Diamond Hydride™, 4µm, 100Å
Catalog No.: 70200-05P-2
Dimensions: 2.1 x 50mm
Mobile Phase:
A: DI Water / 0.1% Formic Acid (v/v)
B: Acetonitrile / 0.1% Formic Acid (v/v)
Gradient:

Time (minutes) %B
0 95
1.5 95
6 50
7 95

Post Time: 5 minutes
Injection vol.: 0.2µL
Flow rate: 0.3mL / minute
Detection: UV @ 254nm
Sample Preparation: 250.0mg of 0.75% Metronidazole topical cream was added to a 25mL volumetric flask containing a portion of 50/50 Solvent A / Solvent B diluent. After sonicating 30 minutes, it was diluted to mark. Then a portion was filtered using a 0.45µm Nylon Syringe Filter (MicroSolv Tech Corp.).
t0: 0.6 minutes

Note: Metronidazole is a Nitroimidazole antibiotic agent. It is marketed under the trade names Flagyl®, Filmet®, and others.

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