Esterases and lipases enzymes are widespread in all living cells, serving as important players in energy metabolism and in the recycling of cellular components. In microbiology C8-esterase activity can be used to detect Salmonella strains and more specifically, it also allows to distinguish them from other enteric bacteria. Likewise, Pseudomonas species can be detected as these organisms produce extracellular lipases. AquaSpark™ caprylate is a dioxetane-based chemiluminescent substrate forC8-esterase (C8E) and lipase activity. Upon hydrolytic cleavage byC8-esterase or lipase, AquaSpark™ caprylate spontaneously emits a strong green light. AquaSpark™ caprylate (A-8167_P00) is the firstsingle-compound chemiluminescent substrate commercially available for highly sensitive esterase and lipase assays in vitro and in vivo. The AquaSpark™ probes are superior probes for research and diagnostic applications. They offer unique advantages as they can work as single agents, they have a higher efficiency and sensitivity, and they do not need expensive additive when used in water.