A survey of free glutamic acid in foods using a robust LC–MS/MS method

[Display omitted] •Addition of MSG to foods at high concentrations may cause health problems.•Demand exists for effective techniques for detection of MSG in foodstuffs.•A survey was performed for detection of free glutamic acid in foods by LC–MS/MS.•Findings were successfully confirmed with previous studies.•Applied method has a great potential for detection of added MSG in foodstuffs. An effective and simultaneous liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was used with the aim of quantifying monosodium glutamate (MSG) in foodstuffs, such as chips, taste cubes, sauces and soups. The results were linear (R2 = 1), with very low LOD and LOQ values, 1.0 µg/kg, 5.0 µg/kg, respectively. Excellent repeatability and reproducibility were also achieved. This highly sensitive and robust LC–MS/MS technique was applied successfully for the detection and quantification of MSG in a wide variety of foodstuffs. MSG contents ranged from 0.01 g/100 g to 15.39 g/100 g in food samples. Importantly, determination of free glutamic acid in the daily diet could also prevent various side effects associated with consumption of excess free glutamic acid.