L-Tyrosine A Tip for Promoting Analyte Ionization with LC-MS – AppNote
May 14, 2012
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Date: 14-MAY-2012 Last Updated: 22-AUGUST-2026
Analyte Ionization using L-TyrosineFigures A and B show the Peak for L-Tyrosine obtained with two LCMS Methods. The analysis shown in Figure B was performed with a stronger HILIC Solvent (DI Water) as component A of the Mobile Phase. The obtained Retention time was lower than in Figure A, as was the compound ionization.
An eluent containing 2-Propanol is a better choice for the analysis of this compound, since the ionization of L-Tyrosine is greater. In addition, the Solvents used in Figure A are recommended when biological samples are analyzed. As such, the Method can be directly transferred to the analysis of L-Tyrosine in plasma samples for monitoring of patients with Phenyloketonuria.
Peak:
L-Tyrosine
182.0812 m/z
Column: Cogent Diamond Hydride™, 4 µm, 100 Å
Catalog No.: 70000-15P-2
Dimensions: 2.1 x 150 mm
Mobile Phase:
Figure A
- A: 50% DI Water / 50% 2-Propanol / 0.1% Formic Acid v/v
- B: Acetonitrile / 0.1% Formic Acid v/v
- A: DI Water / 0.1% Formic Acid v/v
- B: Acetonitrile / 0.1% Formic Acid v/v
Gradient:
| Time (minutes) | %B |
|---|---|
| 0 | 90 |
| 4 | 30 |
| 6 | 30 |
| 7 | 90 |
Post Time: 3 minutes
Injection vol.: 1 µL
Flow rate: 0.4 mL / minute
Detection: ESI – POS - Agilent 6210 MSD TOF Mass Spectrometer
Sample Preparation: 500 mg L-Tyrosine capsule contents were dissolved in 500 mL of 50:50 Water / Acetonitrile. The solution was shaken for 20 minutes and filtered through a disposable 0.45 µm Nylon Syringe Filter (MICROSOLV Tech Corp.). The sample for injection was diluted 1:100 with a 50:50 Solvent A / Solvent B mixture.
t 0 : 0.9 minutes
Note: HILIC Methods have an inherent advantage in LCMS over Reversed Phase Methods in terms of Sensitivity. This is because Acetonitrile is more volatile than Water and hence more readily removed in LCMS, and HILIC Methods typically use a higher percentage of Acetonitrile in the Mobile Phase compared to Reversed Phase Methods.
