Optical Properties of Humic Substances and CDOM—Re

Optical Properties of Humic Substances and CDOM—Relation to StructureOpticalPropertiesofHumicSubstancesandCDOM:RelationtoStructureERINS.BOYLE,†NICOLASGUERRIERO,†ANTHONYTHIALLET,†ROSSANADELVECCHIO,*,‡ANDNEILV.BLOUGH*,†DepartmentofChemistryandBiochemistry,UniversityofMaryland,CollegePark,Maryland20742,andEarthSystemScienceInterdisciplinaryCenter,UniversityofMaryland,CollegePark,Maryland20742ReceivedNovember20,2008.RevisedmanuscriptreceivedJanuary30,2009.AcceptedFebruary3,2009.Thespectraldependenciesofabsorptionandfluorescenceemission(emissionmaxima(λmax),quantumyields(φ),andmeanlifetimes(τm))wereacquiredforacommerciallignin,SuwanneeRiverhumic(SRHA)andfulvic(SRFA)acids,andaseriessolidphaseextracts(C18)fromtheMiddleAtlanticBight(MABextracts).Theseparameterswerecomparedwiththerelativeaveragesizeandtotalligninphenolcontent(TLP).TLPwasstronglycorrelatedwithabsorptionat280and355nmfortheMABextracts,SRHA,andSRFA.Thespectraldependenceofλmax,φ,andτmwasverysimilarforallsamples,suggestingacommonphot