Induced fluorescence derivatization (IFD) determination of monosodium glutamate (MSG) in broths

In this work, we conducted a study on the analysis of monosodium glutamate (MSG) in broths by the induced fluorescence derivatization (IFD) method. The method was based on the derivatization of naturally non-fluorescent MSG to form a fluorescent structure when reacting with orthophthalaldehyde (OPA). The chemical reaction parameters were optimized in an aqueous medium. The calibration curve was subsequently established under optimal conditions, and its linearity was assessed using variance analysis, which indicated a significant regression. The low LOD (0.006 ng mL^-1) and LOQ (0.018 ng mL^-1) values, compared with reference values, reveal the high sensitivity of the IFD method. The quantity of MSG contained in the kg of broth was determined, with values ranging from 2.5 to 20 g. The daily dose obtained ranged from 17 to 137 mg person^-1 day^-1. The mean recovery close to 100 % shows the accuracy of the method.