Read the attached file.

Esam H. Mansour

In 2006, Basu et al have found way using biosensor made by co-immobilized L-GLOD and L-GLDH as the bio-component based on substrate recycling for highly sensitive MSG or L-glutamate determination. Another method is HPTLC. Or you can try to use Colorimetric Method.

Article A bionsesor on co-immobilized l-Glutmate oxidase and L-gluta...

HPLC would be my choice. The other method in the previous answers would also work, but I am not aware of a commercially available glutamate sensor based on immobilized enzymes. However, none are specific for monosodium glutamate. They detect total free glutamate, regardless of the source in the product. L-Glutamate is naturally present in meat and fish and cannot be distinguished from added MSG.

Perhaps the most used method is HPLC, with previous derivatazition (the most popular being PITC). We have also use GC for the analysis, and it works fine. There are several derivatizing options, but silylation using N-Methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and chloroformate derivatives are the most succesful ways, I would say. The EX:faast kit from Phenomenex works quite good and it is quite easy.

I found the biosensor method here. I am also in need a method now and will try to use my mix-mode column to determine MSG by LC/MS without derivatization.

I also find a test strip method below.

https://www.bioassaysys.com/L-Glutamate-Quick-Test-Strips.html?gclid=Cj0KCQiAkNfSBRCSARIsAL-u3X8EP8WN5DVq9eZifIA4gZBbdwFQfiFSd_GDxg2EV4a9rE1QoGV00lMaAo_GEALw_wcB

I am developing an LC/MS method to determine MSG without derivatization. MSG has MW of 187 but when I tune the solution, I found glutamic acid (MW 147) and see m/z of 148 in positive mode. So, the sodium may dissociate and give me glutamate anion the same way you put glutamic acid in water. I got good peak shape and retention on a mixed-phase mode column, no need for derivatization.