Integration of Rapid Derivatization and Gradient Elution Techniques for Enhanced High‐Performance Liquid Chromatography Analysis of Key Amino Acids in Wheat Flour

A rapid pre‐column derivatization process before ultraviolet chromatographic analysis using a Pico‐Tag C18 column was developed in combination with modified gradient elution techniques for the analysis of key amino acids (proline and glutamine) in wheat flour. With use of a vacuum concentrator at 45°C, the pre‐column derivatization process was significantly accelerated before entering a reverse‐phase high‐performance liquid chro‐matography. When running at an optimized scheme—in which the gradient elution started at a flow rate of 1 mL/ min and then gradually increased to 1.3 mL/min in 22 min, followed by reset to 1 mL/min at 45 min—the profiled mobile phase mixture was able to yield chromatograms with desirable retention factor and resolution.