FLOW-INJECTION BIOLUMINESCENT DETERMINATION OF ATP BASED ON THE USE OF THE LUCIFERIN-LUCIFERASE SYSTEM

A flow-injection system is described for assay of low levels of ATP as based on reaction with luciferase-luciferin with ensuing detection of the bioluminescence generated. The system employs a dual-injection valve which permits simultaneous injection of individually metered zones of the ATP-containing sample and enzyme solutions. By appropriate configuration of the injection valve, any unused enzyme solution is recycled thereby saving this costly reagent. At a consumption of 30-50 mu l of enzyme and sample solutions, respectively, a detection limit of ca. 10(-10) M ATP was achieved. Aqueous ATP standard solutions in the nM and pM range proved very unstable, and had to be stabilised with addition of EDTA in order to yield reproducible readouts. The performance of the system is discussed and compared with previously published systems for this kind of assay, and it is concluded that the limit of detection primarily is dictated by the ambient contaminatory level of ATP.