Organic acid analysis using LC/MS is generally carried out with reversed phase separation mode. However, it’s difficult to retain from a complex matrix, because of its hydrophilicity.
In this study, an ion-exclusion chromatography single quadrupole LC/MS detection method for 13 organic acids was developed. Ion exclusion column (Agilent Hi-Plex H) was used at 45 degree C. The mobile phase were 0.01 % formic acid and acetonitrile (70:30) at a flow rate of 0.4 mL/min. Agilent 6120 single quadrupole with ESI ion source was used for detection.
The detection Limit are 2.5 ng/mL for pyruvic acid (PA), 100 ng/mL for acetic acid (AA). And the liner range are found to be 10 – 1000 ng/mL for PA, 100 – 1000 ng/mL for AA.
13 organic acids were separated and determined in approximate 20 min. The method can be used for complex matrix samples. And compared with UV detection, lower detection limit and higher selectivity are the advantage of this study.