A novel method for the measurement of dissolved adenosine and guanosine triphosphate in aquatic habitats: applications to marine microbial ecology

A novel method for the measurement of dissolved adenosine-5′-triphosphate and guanosine-5′-triphosphate (D-ATP and D-GTP, respectively) in marine and freshwater habitats was developed and applied to samples collected from the oligotrophic North Pacific Ocean. Both D-ATP and D-GTP are co-precipitated by authigenically formed Mg(OH)2 and can be concentrated by factors greater than 200-fold, for subsequent measurement by the firefly luciferin–luciferase bioluminescence reaction. The detection limit for this method was 2–3 pmol ml−1 of concentrated sample (equivalent to an in situ concentration of 10 pM) with a 5% precision at concentrations of 10 pmol ml−1 or above.