1.1 This test method covers the measurement of adenosine triphosphate (ATP) in microorganisms in concentrations normally found in laboratory cultures, water, wastewaters, and in plankton and periphyton samples from waters.

1.2 Knowledge of the concentration of ATP can be related to viable biomass or metabolic activity, or by utilizing an average concentration (or amount) of ATP per cell, an estimated count of microorganisms can be obtained in the case of unispecies cultures.

1.3 This test method offers a high degree of sensitivity, rapidity, accuracy, and reproducibility. However, extreme care must be taken at each step in the analysis to ensure meaningful and reliable results.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.