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Isobaric Compounds
Organic Acids Separated in ANP
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printable Application Sheet
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Notes: The method presented was found to be superior to other classical assays and HPLC methods, and to be an attractive
choice for the analysis of these compounds. Fumaric and maleic acids are impurities found in tartaric and malic acids and
their amounts are officially limited by the FDA.
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Two isobaric (same molecular mass) Organic Acids Retained and Separated
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% ammonium formate
B: 90% acetonitrile + 10% DI water + 0.1% ammonium formate |
| Mobile Phase |
Gradient:
| Time |
%B |
Time |
%B |
| 0.0 |
90 |
7.1 |
30 |
| 3.0 |
90 |
8.0 |
30 |
| 6.0 |
70 |
8.1 |
90 |
| 7.0 |
70 |
10.0 |
90 |
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| Flow Rate |
0.4 mL/min. |
| Peaks |
1. Maleic acid 115.0031 m/z (M-H)-
2. Fumaric acid 115.0031 m/z (M-H)-
Sample mixture was prepared in 50% DI water/50% acetonitrile. |
| Detection |
ESI – neg - Agilent 6210 MSD TOF mass spectrometer |
Discussion
Low molecular mass isobaric acids were retained and separated using a Cogent Diamond Hydride™ column in the Aqueous Normal Phase
(ANP) mode of LC-MS chromatography. The method described above was able to resolve two acids which have identical molecular mass.
The separation of the two compounds may be necessary in order to determine which of the acids is present in the sample matrix by the
Mass Spectrometer.
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