Designation:D7687−11StandardTestMethodforMeasurementofCellularAdenosineTriphosphateinFuel,Fuel/WaterMixtures,andFuel-AssociatedWaterwithSampleConcentrationbyFiltration1ThisstandardisissuedunderthefixeddesignationD7687;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversaprotocolforcapturing,ex-tractingandquantifyingthecellularadenosinetriphosphate(cellular-ATP)contentassociatedwithmicroorganismsfoundinfuels,fuel/watermixturesandfuel-associatedwater.1.2TheATPismeasuredusingabioluminescenceenzymeassay,wherebylightisgeneratedinamountsproportionaltotheconcentrationofcellular-ATPinthesamples.Thelightisproducedandmeasuredquantitativelyasrelativelightunits(RLU)whichareconvertedbycomparisonwithanATPstandard,computationtopgATP/mLandoptionalfurthertransformationtoLog10[pgATP/mL].1.3Thistestmethodisequallysuitableforuseasalaboratoryorportablemethod.1.4Thistestmethodislimitedtofuelswithanominalviscosity#75cStattesttemperature.1.5ThistestmethoddetectsATPconcentrationsintherangeof5.0pgATP/mL(0.699log10[pgATP/mL])to100000pgATP/mL(5.000log10[pgATP/mL])for20mLsamplesoffuelorfuel/watermixtures,and20pgATP/mL(1.301log10[pgATP/mL])to400000pgATP/mL(5.602log10[pgATP/mL])for5mLsamplesoffuel-associatedwater.NOTE1—TheserangeswerecalculatedwiththeformulaforcalculatingsampleATPinpg/mLprovidedin12.1basedontheminimumrecom-mendedRLUfora1ngATP/mLstandardwhenusingthereagentsspecifiedinSection7andtheluminometerspecifiedin6.4andcorrectedwithareagent-methodblankasdeterminedinAppendixX5.1.6Providinginterferencescanbeovercome,biolumines-cenceisareliableandprovenmethodforqualifyingandquantifyingATP.ThistestmethoddoesnotdifferentiatebetweenATPfromdifferentsources,forexample:fromdiffer-enttypesofmicroorganisms,suchasbacteriaandfungi.1.7ThevaluesstatedinSIunitsaretoberega...
