Transfer to “near-UHPLC” 2.2um Column, for the API Atorvastatin

This Application Note demonstrates how data obtained on a 4μm Cogent Bidentate C18 Column (Figure B) can be adapted for a 2.2μm Column (Figure A). The retention times of both analytes are very comparable in each figure. This method produces excellent Separation of the API and its main acid degradant and is LCMS compatible which can be used in clinical applications involving plasma samples.

Atorvastatin ChromatogramAtorvastatin Chemical Structures
1. Atorvastatin
2. Atorvastatin Lactone

Method Conditions
Figure A: Cogent Bidentate C18 2.o™, 2.2μm, 120Å
Figure B: Cogent Bidentate C18™, 4μm, 100Å
Catalog Nos.:
Figure A: 40218-05P-2
Figure B: 40018-05P-2
Column Dimensions: 2.1 x 50 mm
Mobile Phases:
A: DI Water / 10 mM Ammonium Acetate
B: 90% Acetonitrile / 10% DI Water / 10 mM Ammonium Acetate

Time (minutes) %B
0 40
1 100
6 100
7 40

Flow rates: 0.3mL/minute
Detection: UV @ 248 nm
Sample Preparation: 40 mg strength Lipitor® tablet (Atorvastatin) was ground and added to a 50 mL volumetric flask with a portion of Solvent B diluent. The solution was sonicated 10 minutes and diluted to mark with Solvent B. It was then filtered through a 0.45μm Nylon Syringe Filter (MicroSolv Tech Corp.). The filtrate was diluted 4x in a diluent of 50/50 Solvent B/ 1N HCl. It was heated in a dry bath for 10 minutes at 85°C.


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