High-performance liquid chromatographic-electrospray mass spectrometric analysis of phenolic acids and aldehydes

The present work describes the development of an HPLC-electrospray mass spectrometric method for the analysis of phenolic acids and aldehydes. These compounds are important for the quality of foods and feeds, such as dietary fiber supplements, wine and lignicellulose by-products. Good separation was obtained with a phenyl column (3 μm particle size, 150 mm×3.9 mm I.D.), using McOH-H₂O (30:70, v/v) as the mobile phase with 0.01% CH,COOH and 0.2 mM tetraethyl ammonium iodide as the ion pairing agent, at a flow-rate of 0.3 ml/min. This system permits post column splitting of the eluate for analysis by electrospray mass spectrometry with a flow-rate of 11 μl/min. This new method is extremely sensitive and less than 6 pg/inj of the studied phenols can be identified and quantified. This method was applied to standard compounds as well as to components of high-fiber dietary supplements (primarily wheat bran), cornmeal, and oat bran.