Changing retention times of amino acids in biological extracts using ammonium acetate in HPLC methods. - Troubleshooting.
June 25, 2013
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If you observe changing retention times of amino acids using a Cogent Diamond Hydride™ HPLC column, consider the following.
Suggestions, tips and tricks
1. Acid in the Mobile Phase; Formic or acidic acid is generally used when analyzing amino acids, so the use of ammonium acetate (or formate) might be a problem.
2. Contamination from the biological samples. Try our conditioning protocol for biological samples.
3. Suggested Mobile phase: 50% methanol or 50% isopropanol +0.1 % formic acid or 0.2% acetic acid would be suggested to use with biological samples and amino acid analysis when using the Cogent TYPE-C™ Silica columns.
4. How long is your gradient's re-equilibration time? Follow our protocol on choosing a proper post time.
5. Is the column thermostated? If not, the variation may be due to changes in lab temperature.
Cogent Diamond Hydride HPLC Column Product Page
Suggestions, tips and tricks
1. Acid in the Mobile Phase; Formic or acidic acid is generally used when analyzing amino acids, so the use of ammonium acetate (or formate) might be a problem.
2. Contamination from the biological samples. Try our conditioning protocol for biological samples.
3. Suggested Mobile phase: 50% methanol or 50% isopropanol +0.1 % formic acid or 0.2% acetic acid would be suggested to use with biological samples and amino acid analysis when using the Cogent TYPE-C™ Silica columns.
4. How long is your gradient's re-equilibration time? Follow our protocol on choosing a proper post time.
5. Is the column thermostated? If not, the variation may be due to changes in lab temperature.
Cogent Diamond Hydride HPLC Column Product Page