ADMA and SDMA Separation analyzed with ELSD- AppNote
March 28, 2025
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Separation of Structural Isomers
ADMA (Asymmetric Dimethylarginine) and SDMA (Symmetric Dimethylarginine) are structural isomers and isobaric compounds, sharing the same m/z value. Separating these compounds is crucial, even when using LC-MS detection. While MS-MS detection can differentiate these compounds based on their distinct fragmentation patterns, the availability of such detection is not always guaranteed.
This method utilizes ELSD and demonstrates the separation of both compounds using the Diamond Hydride.
Column: Cogent Diamond Hydride™, 4µm, 100Å
Catalog No.: 70000-10P
Dimensions: 4.6 mm x 100mm
Mobile Phase:
A: 50%DI water/10 mM ammonium formate, pH 4.9
B: Acetonitrile 90%/10% DI water+10 mM ammonium formate pH: 5.12
Injection vol.: 3µL
Flow rate: 0.5 mL / minute
Detection: ELSD, temp: 500C, Gain
Sample Preparation: 0.1 mg/mL ADMA + SDMA in 50:50 ACN:DI Water
Note: The method employed utilized a Reverse Phase chromatography gradient with a Cogent DH™.
It is important to note that this method requires longer equilibration times—approximately 10 to 15 minutes—between runs to ensure reproducible results.
ADMA (Asymmetric Dimethylarginine) and SDMA (Symmetric Dimethylarginine) are structural isomers and isobaric compounds, sharing the same m/z value. Separating these compounds is crucial, even when using LC-MS detection. While MS-MS detection can differentiate these compounds based on their distinct fragmentation patterns, the availability of such detection is not always guaranteed.
This method utilizes ELSD and demonstrates the separation of both compounds using the Diamond Hydride.
Peaks:
1. Unknown 2. SDMA 3. ADMA
Column: Cogent Diamond Hydride™, 4µm, 100Å
Catalog No.: 70000-10P
Dimensions: 4.6 mm x 100mm
Mobile Phase:
A: 50%DI water/10 mM ammonium formate, pH 4.9
B: Acetonitrile 90%/10% DI water+10 mM ammonium formate pH: 5.12
Injection vol.: 3µL
Flow rate: 0.5 mL / minute
Detection: ELSD, temp: 500C, Gain
Sample Preparation: 0.1 mg/mL ADMA + SDMA in 50:50 ACN:DI Water
| Time (minutes) | %B |
| 0 | 20 |
| 1 | 30 |
| 5 | 30 |
| 6 | 50 |
| 7 | 50 |
| 8 | 90 |
| 9 | 90 |
| 11 | 20 |
| 15 | 20 |
It is important to note that this method requires longer equilibration times—approximately 10 to 15 minutes—between runs to ensure reproducible results.