Novel reagents for quantitative analysis of valiolamine in biological samples by high-performance liquid chromatography with pre-column UV derivatization

A rapid, low-cost, high sensitive and quantitative method to detect valiolamine in a medium for microbial culture, involving derivatization with a new labeling reagent, 4-methoxybenzenesulfonyl fluoride (MOBS-F), followed by reverse-phase high-performance liquid chromatography with ultraviolet (UV) detection with simple operation procedure. 4-Methoxybenzenesulfonyl chloride (MOBS-Cl) and 2-nitrobenzenesulfonyl chloride (NBS-Cl) were compared with MOBS-F as novel reagents in this paper, and the MOBS-F was chosen as the most suitable derivatization reagent. The column was thermostatic at 35 °C, the mobile phase flow-rate was 1.0 mL/min and the detection wavelength was 240 nm. For a biological sample, the separation of the derivatives was achieved using a gradient mobile system. The elution program is 88% phosphate buffer (50 mM; pH = 3.0) and 12% methanol for 23 min, then 70% of phosphate buffer and 30% methanol for another 15 min and finally 88% of phosphate buffer and 12% of methanol for 5 min to re-equilibrate the column. The optimized conditions of the derivatization were as follows: derivatization reaction temperature 30 °C; derivatization reaction pH value 11.0, reaction time 10 min and MOBS-F concentration higher than 1.5 mg/mL for standard solutions and higher than 5.0 mg/mL for the biological sample. Calibration curves were linear in the range of 0.050–25 μg/mL for the standard solutions and 1.0–75 μg/mL for the biological sample. The sensitive analytical method is helpful to control the biotechnological process of voglibose production and product quality control.