HPSECelutioninNaNO,0.05MpH7Dicarboxylic acids110A-HA(oxidized coal)pH7100HA2B=topH3.5withHCI90A80--BAMw=-14.4 %.C70..DC=withHOOC-COOH.....EsaAMw=-41.7 %60F50D=with HOOC-CH,-COOHAMw=-48.2 %40E=withHOOC-(CH,)2-COOH,3020AMw=-50.0%10F=withHOOC-(CH)3-COOH0AMW=-72.2%Piccolo,Conte,Spaccini,Chiarella(2003).Biology andFertility of Soils,37:255-259
Dicarboxylic acids A=HA (oxidized coal) pH 7 B= to pH 3.5 with HCl ΔMw=-14.4 % C=with HOOC-COOH , ΔMw=-41.7 % D=with HOOC-CH2 -COOH ΔMw=-48.2 % E=with HOOC-(CH2 )2 -COOH , ΔMw=-50.0 % F=with HOOC-(CH2 )3 -COOH ΔMw=-72.2 % HPSEC elution in NaNO3 0.05 M pH 7 Piccolo, Conte, Spaccini, Chiarella (2003). Biology and Fertility of Soils, 37:255-259 Intensity (mV)
EFFECTOFELUENTCOMPOSITIONONMOLECULARSIZEDISTRIBUTIONOFHAINSTEADOFLOWERINGTHEpHOFHUMICSOLUTIONSWERETHEMOBILEPHASESTOBEVARIEDINpHBUTNOTINIONICSTRENGTHSOLUTIONS OF HUMICSUBSTANCESDISSOLVEDWITHCONTROLELUENTATpH7WEREINJECTEDINTOHPSECANDELUTEDWITHMOBILEPHASEMODIFIEDBYADDITIONWITHMETHANOL(pH6.97),HCI(pH5.54)ANDACETICACID(pH5.7)
EFFECT OF ELUENT COMPOSITION ON MOLECULAR SIZE DISTRIBUTION OF HA INSTEAD OF LOWERING THE pH OF HUMIC SOLUTIONS, WERE THE MOBILE PHASES TO BE VARIED IN pH BUT NOT IN IONIC STRENGTH SOLUTIONS OF HUMIC SUBSTANCES DISSOLVED WITH CONTROL ELUENT AT pH 7 WERE INJECTED INTO HPSEC AND ELUTED WITH MOBILE PHASE MODIFIED BY ADDITION WITH METHANOL (pH 6.97), HCl (pH 5.54) AND ACETIC ACID (pH 5.7)
HA(Lignite)indifferentHPSECeluentsA=NaNO,pH7;B=+CH,OHpH6.9;C=+HCIpH5.54;D=+CHCOOHpH5.7RIUV280nm200-5.0-AB8CCDD4.0150TNSITOATW3.0-100-2.0-50-1.0-0.03642306182430121236182442ELUTION VOLUME(mL)ELUTIONVOLUME(mL)Conte,Piccolo.EnvironmentalScience&Technology(1999)33:1682-1690
HA (Lignite) in different HPSEC eluents A= NaNO3 pH 7; B= +CH3 OH pH 6.9; C=+HCl pH 5.54; D=+CH3 COOH pH 5.7 Conte, Piccolo. Environmental Science & Technology (1999) 33:1682-1690 UV 280 nm RI D D
HPSECBEHAVIOURHUMIICSUBSTANCESVERSUSUNDISPUTEDPOLYMERSPolymers such as polysaccharides andpolystyrenesulphonates are commonly used as proxystandards to evaluate nominal molecular sizes of humicsubstancesHowever,if humic substances are supramolecularassociations, they should have a differentHPSECbehaviour than real polymers such as polysaccharides andpolystyrenesulphonatesThe two classes of compounds were compared whenaqueous solutions were modified by addition of either HCloraceticacid
HPSEC BEHAVIOUR HUMIC SUBSTANCES VERSUS UNDISPUTED POLYMERS Polymers such as polysaccharides and polystyrenesulphonates are commonly used as proxy standards to evaluate nominal molecular sizes of humic substances However, if humic substances are supramolecular associations, they should have a different HPSEC behaviour than real polymers such as polysaccharides and polystyrenesulphonates The two classes of compounds were compared when aqueous solutions were modified by addition of either HCl or acetic acid
HPSEC response to pH changes in solutions of truepolymeric standards such as polystirenesulphonates (UV)andpolysaccharides (RefractiveIndex)UV detectionRefractiveindexdetection222020(no18(n1816161414容pH=7.0OpH=7.012pH=3.5byHCI12AApH=3.5byHCIpH=3.5byAcOH-pH=3.5byAcOH1010891011121398101112Ln (MW)Ln (MW)Piccoloetal(2000).Royal SocietyofChemistry,SpecialPublicationno.259,CambridgeUK,pp.111-124
HPSEC response to pH changes in solutions of true polymeric standards such as polystirenesulphonates (UV) and polysaccharides (Refractive Index ) UV detection Refractive index detection Piccolo et al. (2000). Royal Society of Chemistry, Special Publication no. 259, Cambridge, UK, pp.111-124