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Isobaric Acids Maleic & Fumaric
Retention, Separation & Detection
Method Conditions
| Column |
Cogent Diamond Hydride™, 4µm, 100A |
| Catalog No. |
70000-15P-2 |
| Dimensions |
2.1 x 150 mm |
| Solvents |
A: 50% Methanol / 50% Water / 0.05% Formic Acid
(strong solvent)
B: 90% Acetonitrile / 10% Water w/10mM Amm Acetate
(weak solvent) |
| Gradient |
Linear gradient over 10 minutes.
Adjustable per instrument. |
| Post time |
5 min. |
| Flow rate |
0.4 mL/min. |
| Injection |
1 microL |
| Samples |
1. Maleic Acid, 115 m/z (M - H)-
2. Fumaric Acid, 115 m/z (M - H)-
Sample stock solutions were made in acidified DI water at a
concentration of 0.2 mg/mL Samples for analysis were made by
diluting the stock 1:100 in 50:50 solution A and B. |
| Detection |
ESI – neg - Agilent 6210 MSD TOF mass spectrometer |
Discussion
Two isobaric acids, maleic and fumaric (115 m/z) are separated very well when using the solvents
above and a gradient method. Solvent A used in this application note contains 50% methanol which
is recommended when biological samples are used. This method is very reproducible and is very fast
to equilibrate between gradient runs with 0.08%RSD.
Maleic and fumaric are simple acids and the peak shape of these acids is not affected by the
presence of sodium in the system as with more complex acids. When analyzing complex compounds, it
is recommended that as much sodium be removed from the system as possible (i.e. replacing glass bottles
with Teflon bottles) or the mobile phase should be prepared fresh daily.
Notes: The gradient used for this application note was a simple linear gradient over 10 minutes. The
exact conditions are not provided since they will have to be adjusted depending on individual instrument
configuration.
It is important to remember not to overload the column or saturate the detector (it is recommended to
adjust the sample concentration so that injection is between 1 & 5 microL).
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