Application description
Amino acids are very polar compounds which are used as a building blocks in pharmaceutical industry. They are widely used as supplements and food additives. Depending on the pH of the mobile phase they can exist in acidic, basic or zwitter-ionic form. At pH below 3, amino acids are basic in nature and have the highest hydrophobicity. Within pH of 3 to 7 amino acids are in zwitter-ionic form where they are the most hydrophilic. There is no mechanism of retention on reversed-phase column and amino acids are not retained. Bufferless ion-separation (BLIS) was introduced by SIELC as a way to retain and analyze amino acids in reversed-phase cation-exchange mode. This mode allows to analyze amino acids as zwitter-ions without any ions/buffers in the mobile phase. The method was adopted for analysis of amino acids on core-shell mixed-mode columns. A similar approach on a reversed-phase core-shell column results in distorted peaks and no separation or significant retention to achieve baseline separation.
Conditions of Experiment
| Column: |
Coresep 100 |
| Separation Modes: |
reversed-phase and cation-exchange |
| Column Dimenstions: |
3.2 x 50 mm, 2.7 um, 90A |
| Mobile Phase: |
20% ACN with no additives |
| Detection: |
UV 205 nm, ELSD |
| Sample: |
0.3 mg/ml |
| Injection: |
1 uL |
| Flow rate: |
1 ml/min |
Analytes
| Class of compounds: |
Amino acid, Supplement |
| Nature of compounds: |
Hydrophilic, Polar, Zwitterionic |
| Compounds: |
Methionine, Tyrosine, Phenylalanine |
