Stir bar sorptive extraction‐liquid desorption applied to the analysis of hop‐derived bitter acids in beer by micellar electrokinetic chromatography

Stir bar sorptive extraction‐liquid desorption (SBSE‐LD) has been applied as an efficient sample preparation method for the analysis of beer bitter acids. Extracts free of almost all interfering compounds were obtained, allowing simultaneous analysis of iso‐α‐acids and reduced iso‐α‐acids. A robust micellar electrokinetic chromatography (MEKC) method was developed that enables fast separation of iso‐α‐acids and reduced iso‐α‐acids. Quantitative data are in good agreement with results obtained by high‐performance liquid chromatography (HPLC) using direct beer injection.