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Reproducibility, Run to Run
Reproducible retention of aromatic amino acids using a Cogent Silica-C™ column and a simple LC-MS compatible mobile phase.
This is six chromatograms
laid on top of each other.
Click here to view
printable Application Sheet
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Note: The mixture of amino acids was prepared and injected without any derivatization. The mobile phase used is LC-MS
compatible.
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Method Conditions
| Column |
Cogent Silica-C™, 4µm, 100A |
| Catalog No. |
40000-75P |
| Dimensions |
4.6 x 75 mm |
| Solvents |
A: DI water + 0.1 % formic acid
B: acetonitrile + 0.1% formic acid |
| Mobile Phase |
80%B/20%A |
| Flow rate |
1.0 mL/minute (t0 = 0.85 min) |
| Peaks |
1. L-(+)-alpha-phenylglycine
2. L-phenylalanine |
| Injection Volume |
2 µL |
| Sample Matrix |
0.3 mg/mL of each sample dissolved in 50% acetonitrile/50% DI water + 0.5% formic acid. |
| Detection |
254 nm UV |
Discussion
Two important aromatic amino acids: L-(+) – alpha - phenylglycine and L – phenylalanine were analyzed using a Cogent Silica-C™
column and an ANP (aqueous normal phase) mobile phase. The retention of the amino acids was remarkably reproducible for more than 20
injections. For clarity purposes on the chromatogram presented only 6 consecutive injections are overlaid. The calculated %RSD for 20
injections were around 0.3%. Conclusion: these columns are not only very reproducible but extremely stable.
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