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Standard Test Method for Measurement of Cellular Adenosine Triphosphate in Fuel and Fuel-associated Water With Sample Concentration by FiltrationTranslate name
STANDARD published on 1.4.2021
Designation standards: ASTM D7687-21
Publication date standards: 1.4.2021
The number of pages: 10
Approximate weight : 30 g (0.07 lbs)
Country: American technical standard
Category: Technical standards ASTM
adenosine triphosphate, ATP, bacteria, bioburden, biodeterioration, biodiesel, biofuels, biomass, cellular, cellular-ATP, diesel, fuel, fuel-oil, fungi, gasoline, microbial contamination, microbiology, microorganisms,, ICS Number Code 75.160.20 (Liquid fuels)
|Significance and Use|
5.1This test method measures the concentration of cellular-ATP present in the sample. ATP is a constituent of all living cells, including bacteria and fungi. Consequently, the presence of cellular-ATP is an indicator of total metabolically active microbial contamination in fuels. ATP is not associated with matter of non-biological origin.
5.2This test method is similar to Test Method except for the volumes sampled.
5.3This test method differs from Test Method in that it utilizes filtration and wash steps designed to eliminate interferences that have historically rendered ATP testing unusable with complex organic fluids such as fuel and fuel-associated water.
5.4This test method differs from Test Method in several regards:
5.4.1Test Method reports relative light units (RLU). Consistent with Test Methods and , this test method reports ATP concentration.
5.4.2This test method detects only cellular-ATP and it can be used to detect cellular-ATP in fuels and fuel stocks from which small quantities of water do not separate readily (for example, ethanol blended gasoline containing ?5%v/v ethanol). Test Method cannot be used to recover ATP from fuels from which small quantities of water do not separate readily (for example, ethanol blended gasoline containing ?5% v/v ethanol).
5.4.3This test method measures cellular-ATP in a single measurement (as pg ATP/mL). Test Method detects total ATP (as RLU) and extra-cellular ATP (as RLU) using two separate analyses and permits computation of cellular-ATP (as RLU) as the difference between total and extracellular ATP.
5.4.4Test Method suggests a nominal 500mL fuel sample volume. This test method suggests a nominal 20mL fuel sample.
5.5This test method can be used with all fuels specified in Specifications , , , , , , , and and other fuels with nominal viscosities ?75cSt at 20 2.
5.6The ATP test provides rapid test results that reflect the total bioburden in the sample. It thereby reduces the delay between test initiation and data capture, from the 36h to 48h (or longer) required for culturable colonies to become visible, to approximately 5min.
5.7Although ATP data generally covary with culture data in fuel and fuel-associated water, different factors affect ATP concentration than those that affect culturability.
5.7.1Culturability is affected primarily by the ability of captured microbes to proliferate on the growth medium provided, under specific growth conditions. Consequently, a proportion of the active or inactive microbial population present in a sample may be viable but not detected by any one culture test.5.7.2ATP concentration is affected by: the microbial species present, the physiological states of those species, and the total bioburden (see ).
220.127.116.11One example of the species effect is that the amount of ATP per cell is substantially greater for active fungal cells than bacteria.
18.104.22.168Within a species, cells that are more metabolically active will have more ATP per cell than dormant cells, such as fungal spores. Because fungal spores are more hydrophobic than active fungal material (mycelium), spores may be the only indicator of fungal proliferation when fuel samples are taken from some fuel systems, but they will not be detected by a test for ATP.
22.214.171.124The greater the total bioburden, the greater the ATP concentration in a sample.
5.7.3The possibility exists that the rinse step ( ) may not eliminate all chemical substances that can interfere with the bioluminescence reaction ( ).
126.96.36.199The presence of any such interferences can be evaluated by performing a standard addition test series or dilution series as described in . The precision statement in Section will not apply.
5.8As explained in Test Method , there are inherent difficulties in assessing precision of microbiological procedures for fuels on account of the inherent variability of the determinant and various determinable and indeterminable sources of inaccuracy (see Guide ).
5.8.1The precision of any microbiological analytical method will generally be considerably less than that of methods widely used in the petroleum industry for analysis of physical and chemical properties of fuels.
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 ?75cSt 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 100000 pg ATP/mL (?5.000 log10[pg ATP/mL]) for 20mL samples of fuel and 20pg ATP/mL (?1.301 logNote 1:These ranges were calculated with the formula for calculating sample ATP in pg/mL provided in based on the minimum recommended RLU for a 1ng/mL ATP standard when using the reagents specified in Section and the luminometer specified in and corrected with a reagent-method blank as determined in .
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.
|2. Referenced Documents|
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