I'm willing to estimate the γ-aminobutyric acid (GABA) content in a fermented cereal product, the spectrophotometer method I'm trying to follow is attached, the method requires for mixing the sample with three solutions (borate buffer, phenol reagent, and sodium hypochlorite NaClO), then boiling for 10 min, after that cooling for 20 min or until blue color generated, then reading the absorbance at 630-645 nm. However, I'm wondering if there is any alternative spectrophotometer method or if anyone had ever tried this method does it work? or are there any notes about it..