Determination of β-Carotene in Corn by In-Tube SPME Coupled to Micro-LC

An in-tube solid-phase microextraction-micro-liquid chromatography method was developed for the determination of carotenoids, in which a monolithic silica-ODS column (100 × 0.2 mm I.D.) was used as the extraction medium. The extraction column was pre-conditioned using 90% acetonitrile at a flow rate of 5 μL min−1 for 20 min and the extracted analytes were desorbed by the mobile phase (acetonitrile) and entered into the separation column (monolithic silica-ODS column, 350 × 0.2 mm I.D.). The detection limits for the carotenoids were from 7 to 20 ng mL−1. The relative standard deviations of retention time and peak area for each analyte were less than 4.6%. The method was used to determine trace amounts of β-carotene in corns.