Development of in situ microbial ATP analyzer and internal standard calibration method

Integrated and miniaturized in situ analyzers to estimate microbial biomass has been developed so far. The analyzer has the capability to perform the luciferin-luciferase bioluminescence reaction to determine the concentration of microbial adenosine-5'-triphosphate (ATP). The latest analyzer had been mounted on an ROV and evaluated at deep-sea environments. In this study, the method for in situ calibration that utilizes caged ATP as an internal standard is proposed to improve reliability of the in situ analyzer. Experiments confirmed that caged ATP was photolyzed with appropriate reproducibility by using a simple microfluidic device with the UV-LED light source.