1.1This test method covers a protocol for capturing, extracting and quantifying the cellular adenosine triphosphate (cellular-ATP) content associated with microorganisms found in fuels and fuel-associated water.
1.2The ATP is measured using a bioluminescence enzyme assay, whereby light is generated in amounts proportional to the concentration of cellular-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, computation to pg ATP/mL and optional further transformation to Log10[pg ATP/mL].
1.3This test method is equally suitable for use as a laboratory or portable method.
1.4This test method is limited to fuels with a nominal viscosity ≤75 cSt at test temperature.
1.5This test method detects ATP concentrations in the range of 5.0 pg ATP/mL (≈0.699 log10[pg ATP/mL]) to 100 000 pg ATP/mL (≈5.000 log10[pg ATP/mL]) for 20 mL samples of fuel and 20 pg ATP/mL (≈1.301 log10[pg ATP/mL]) to 400 000 pg ATP/mL (≈5.602 log10[pg ATP/mL]) for 5 mL samples of fuel-associated water.
Note 1:These ranges were calculated with the formula for calculating sample ATP in pg/mL provided in 12.1 based on the minimum recommended RLU for a 1 ng/mL ATP standard when using the reagents specified in Section 7 and the luminometer specified in 6.4 and corrected with a reagent-method blank as determined in Appendix X5.
1.6Providing interferences can be overcome, bioluminescence is a reliable and proven method for qualifying and quantifying ATP. This test method does not differentiate between ATP from different sources, for example: from different types of microorganisms, such as bacteria and fungi.
1.7The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8This 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.