The invention relates to a fluorescent
signal enhancement method for detecting
escherichia coli by an
enzyme substrate process, and belongs to the technical field of
escherichia coli detection. An
enzyme substrate targeted by the method provided by the invention is MUG, and the technical problems that a combination of 366 nm excitation and 450 nm emission is adopted in the prior art, after the MUGbackground is excited by 366 nm, the MUG background has certain
fluorescence intensity at 450 nm, when the concentration of
escherichia coli is very low, the yield of 4-MU is low, a product
signal isinseparable from a background
signal, so that water samples with an extremely low
escherichia coli concentration cannot be detected by current methods are solved. The method for detecting the
escherichia coli by the
enzyme substrate process provided by the invention adopts the manner of adding one-step operation after the end of incubation and before
fluorescence measurement; the operation is that the pH is adjusted to >=9 by using an alkaline
reagent, the absorption peak of the product 4-MU can be obviously enhanced, the absorption peak of the substrate MUG changes little, so that the product signal can be separated from the background signal; and through the operation provided by the invention, the difference in
fluorescence intensity between the product signal and the background signalis increased by five times, and the method is particularly suitable for detection of the
escherichia coli with a very low concentration.