ASTM International

Standard Test Method for Adenosine Triphosphate (ATP) Content of Microorganisms in Water
 N D4012

Annotation

This test method covers a protocol for capturing, extracting and quantifying the cellular adenosine triphosphate (cATP) content associated with microorganisms normally found in laboratory cultures, waters, wastewaters, and in plankton and periphyton samples from waters.

The ATP is measured using a bioluminescence enzyme assay, whereby light is generated in amounts proportional to the concentration of ATP in the samples. The light is produced and measured quantitatively as relative light units (RLU) which are converted by comparison with an ATP standard and computation to pg ATP/mL.

This method does not remove all known chemical interferences, known to either luminesce in the 530 + 20 nm range, or to quench light emitted in that range. It should not be used to determine ATP concentrations in samples with dissolved organic compounds, heavy metals or >10 000 ppm total dissolved solids. Alternative methods have been developed for determining ATP concentrations in fluids samples likely to contain such interferences (Test Methods D7687 and E2694).

Knowledge of the concentration ofATP can be related to viable biomass or metabolic activity of microorganisms (Appendix X1).

This test method offers a high degree of sensitivity, rapidity, accuracy, and reproducibility.

The analyst should be aware that the precision statement pertains only to determinations in reagent water and not necessarily in the matrix being tested.

This test method is equally suitable for use in the laboratory or field.

The method normally detects cATP concentrations in the range of 0.1 pg cATP/mL (–1.0Log10 [pg cATP/mL]) to 4 000 000 pg cATP/mL (6.6 Log10 [pg cATP/mL]) in 50 mL water samples.