Citric Aconitic and Maleic Acids Analyzed with LC-MS - AppNote
May 15, 2012
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Date: 15-MAY-2012 Last Updated: 24-AUGUST-2026
Low Molecular Weight Organic AcidsLow mass Acids were retained and Separated in this Method with the HILIC mode of HPLC. The Method was able to resolve the three compounds in 10 minutes. Limits of Detection (LOD) for them ranged from 0.05 to 24 micromolar.
Peaks:
1. Maleic Acid
115.0031 m/z (M-H)-
2. Trans-Aconitic Acid
173.0086 m/z (M-H)-
3. Citric Acid
191.0192 m/z (M-H)-
Column: Cogent Diamond Hydride™, 4 μm, 100Å
Catalog No.: 70000-15P-2
Dimensions: 2.1 x 150 mm
Mobile Phase:
— A: DI Water / 0.1% Ammonium Acetate
— B: Acetonitrile / 0.1% Ammonium Acetate
Gradient:
| Time (minutes) | %B |
|---|---|
| 0 | 90 |
| 2 | 90 |
| 5 | 70 |
| 6 | 70 |
| 6.1 | 30 |
| 7 | 30 |
| 7.1 | 30 |
| 10 | 90 |
Detection: ESI – neg - Agilent 6210 MSD TOF Mass Spectrometer
Sample Preparation: Sample mixture was prepared in 50:50 DI Water / Acetonitrile
Notes: HILIC Chromatography with MS Detection (HILIC - LC-MS) has become more and more popular for analysis of certain mixtures of organic acids because of the Simplicity, Rapidity and Stability of the Method. The statutory Methods for the determination of low molecular mass organic acids are Turbidimetric and Colorimetric Methods and Ion-Exchange Chromatography. “Turbidimetry by means of calcium oxalate precipitation and colorimetry by means of Zinc Ferricyanide color development are time-consuming and only achieve limited rather than exact results”.
