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Easy Amino Acid Method
Reduced Sample Prep and Handling
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printable Application Sheet
Notes: L-Arginine is classified as a semi essential or conditionally essential amino acid, that plays an important function in
the metabolism of organisms. It is used to remove waste products (for example ammonia) and to make other compounds (L–proline,
creatine, cell signaling molecule: nitric oxide (NO) and L-glutamate). The nitric compound made from L-arginine relaxes blood
vessels.
The Aspartic acid and glutamic acid levels increase in the midbrain with Parkinon’s disease (PD) indicating participation of
these amino acids in PD pathogenesis. The levels of these two amino acids are also relevant to other neurological diseases as
Alzheimer disease (AD) and schizophrenia. Therefore the determination of the changes of the two amino acids levels in
biological samples is essential to research the pathogenesis of the above mentioned diseases as well as establishment of the
treatment scheme.
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L – aspartic acid (Asp) and L - arginine (Arg) in synthetic urine
Method Conditions
| Column |
Cogent Diamond Hydride™, 4µm, 100A |
| Catalog No. |
70000-15P-2 |
| Dimensions |
2.1 x 150 mm |
| Solvents |
A: DI water + 0.1% formic acid
B: acetonitrile + 0.1% formic acid + 0.005% TFA |
| Mobile Phase |
Isocratic: 90% B / 10% A |
| Flow Rate |
400 µL/min. |
| Sample |
1mg/mL of each:
1. L – aspartic acid and
2. L - arginine dissolved in 50% acetonitrile/ DI water/0.1 % TFA.
Sample for injection: Stock solution diluted 1:100 with the mobile phase. |
Peaks
(Compounds) |
1. L–aspartic acid, 134 m/z, RT = 2.45 min
2. L–arginine, 175 m/z, RT = 9.05 min |
| Detection |
ESI – pos - Agilent 6210 MSD TOF mass spectrometer |
Discussion
Two amino acids are adequately retained and can be easily quantified in this method with very little sample prep. There is no need for
any derivatizing with this method because of the combination of the mass spectrometric detection and the Aqueous Normal Phase (ANP)
method. Also, this method produces reliable and reproducible results. The column lifetime with this method is exceptionally good.
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