Liquid chromatography/mass spectrometry compatible approaches for the quantitation of folic acid in fortified juices and cereals using aqueous normal phase conditions

Abstract

Folic acid was separated under aqueous normal phase (ANP) conditions with Diamond Hydride™ columns and quantitated in fortified cereal and juice matrices using high performance liquid chromatography/ultraviolet absorption (HPLC-UV) and liquid chromatography/mass spectrometry (LC–MS) based methodologies. The folic acid was well-resolved from matrix components under the ANP conditions studied and allowed for the direct analyses of the fortified juices and cereals without the sample cleanup that is often required for other reported LC-based approaches. The calibration curve obtained from the LC–MS analyses demonstrated good linearity ( R 2 = 0.9997) in the studied concentration range of 0.05–0.5 mg/L. The spiked flour percent recovery was 90% with HPLC-UV and 91% with LC–MS. Spiked juice percent recovery was 102% with LC–MS. However, analyses of juices were unsatisfactory either in terms of recovery or sensitivity. Therefore, analyses of juices will either need to be performed by LC–MS or, if by HPLC-UV, will require sample cleanup. Three cereals and one juice were analyzed with the methods.