Flow injection spectrophotometric assay of α-amylase activity Original Research Article

A spectrophotometric flow injection method for the determination of α-amylase activity is proposed. The method is based on the analysis of the maltose obtained during the hydrolysis of amylose in the presence of α-amylase and relies on the reaction of 3,5 dinitrosalicylic-acid and maltose at boiling temperatures to form a brick red coloured complex, monitored spectrophotometrically at 540 nm. The method has proved to be highly sensitive and rapid to allow analysis of 60 samples per hour. The % R.S.D. of this method was found to be <0.5% with the working activity range of 0.005–0.06 FAU. The detection limit was found to be 0.0048 FAU. (FAU: fungal amylase unit; 1 FAU is the amount of the enzyme that hydrolyses 5.26 g of starch per hour. 1 FAU=249.85 SIGMA).