FDA hydrolysis effectively reflects soil microbial activity, changes in soil quality, and the transformation of organic matter in ecosystems, making it one of the important biological indicators in soil quality research.
Determination Principle: FDA is a colorless compound that can be hydrolyzed by various soil enzymes in the medium. Through a dehydration reaction, the final enzymatic product, fluorescein, is produced, which is stable and not easily decomposed. Fluorescein exhibits a strong absorption peak at 490 nm. FDA hydrolase activity can be calculated by measuring the change in absorbance at 490 nm.