Designation:D6187−97(Reapproved2010)StandardPracticeforConePenetrometerTechnologyCharacterizationofPetroleumContaminatedSiteswithNitrogenLaser-InducedFluorescence1ThisstandardisissuedunderthefixeddesignationD6187;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversthemethodfordelineatingthesubsurfacepresenceofpetroleumhydrocarbonsandotherhydrocarbonsusingafiberopticbasednitrogenlaser-inducedfluorescencesensorsystem.1.2Thepetroleumhydrocarbonsensingschemeutilizesafluorescencetechniqueinwhichanitrogenlaseremitspulsedultravioletlight.Thelaser,mountedontheconepenetrometerplatform,islinkedviafiberopticcablestoawindowmountedonthesideofapenetrometerprobe.Laserenergyemittedthroughthewindowcausesfluorescenceinadjacentcontami-natedmedia.Thefluorescentradiationistransmittedtothesurfaceviaopticalcablesforreal-timespectraldataacquisitionandspectralanalysisontheplatform.1.3Thissensorrespondstoanymaterialthatfluoresceswhenexcitedwithultravioletwavelengthsoflight,largelythepolycyclicaromatic,aromatic,andsubstitutedhydrocarbons,alongwithafewheterocyclichydrocarbons.Theexcitationenergywillcauseallencounteredfluorophorestofluoresce,includingsomemineralsandsomenon-petroleumorganicmatter.However,becausethesensorcollectsfullspectralinformation,discriminationamongthefluorophoresmaybedistinguishedusingthespectralfeaturesassociatedwiththedata.Soilsamplesshouldbetakentoverifyrecurringspectralsignaturestodiscriminatebetweenfluorescingpetroleumhy-drocarbonsandnaturallyoccurringfluorophores.1.4Thispracticeisusedinconjunctionwithaconepen-etrometeroftheelectronictype,describedinTestMethodD5778.1.4.1ThedirectpushLIFdescribedinthispracticecanprovideaccurateinformationonthecharacteristicsofthesoilsandcontaminantsencounteredinthevadosezoneandthesaturatedzone,althoughi...
