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简介：U-shapedmicro-nanochannelscangeneratesignificantflowdisturbanceaswellaslocallyamplifiedelectricfield,whichgivesitselfpotentialtobemicrofluidicmixers,electrokineticpumps,andevencelllysisprocess.NumericalsimulationisutilizedinthisworktostudythehiddencharacteristicsoftheU-shapedmicro-nanochannelsystem,andtheeffectsofkeycontrollingparameters(theexternalvoltageandpressure)onthedeviceoutputmetrics(current,maximumvaluesofelectricfield,shearstressandflowvelocity)wereevaluated.Alargeportionofcurrentflowingthroughthewholesystemgoesthroughthenanochannels,ratherthanthemiddlepartofthemicrochannel,withitsvalueincreasinglinearlywiththeincreaseofvoltage.Duetothelocaliondepletionnearmicro-nanofluidicjunction,significantlyenhancedelectricfield(asmuchas15foldatV=1VandP0=0)aswellasstrongshearstress(leadingtoelectrokineticflow)isgenerated.Withincreasingexternalpressure,bothelectricfieldandshearstresscanbeincreasedinitially(duetoshorteningofdepletionregionlength),butaresuppressedeventuallyathigherpressureduetothedestructionofiondepletionlayer.Insightsgainedfromthisstudycouldbeusefulfordesigningnonlinearelectrokineticpumpsandothersystems.

简介：OrganicmodifierswereeffectivebothtoextendthemigrationtimewindowandtoimprovetheseparationofveryhydrophobiccompoundsinMEKC.Aniterationmethodwasusedtodeterminethemigrationtimeofmicelles.Thequantitativerelationshipbetweenthecapacityfactork’andtheconcentrationoforganicmodifierswasderived,whichwasinvestigatedexperimentally.Thelinearsolvationenergyrelationships(LSER)methodologywasappliedtoMEKC,andgoodlinearrelationshipsbetweenInk’andsolvatochromicparametersof15soluteswereobtainedinthepresenceoforganicmodifierindifferentconcentrations,whichindicatedanewaccessinMEKCtopredictk’fromthestructuralparametersofsolutes.TheeffectofcolumntemperatureTonk’wasalsoinvestigated.

简介：Theoriginofpseudopeakwasstudiedbymeansofmicellarelectrokineticcapillarychromatographywithcetyltrimethylaminiumbromideasthepseudostationaryphase.Ithasbeenpointedthattwopeaksmayappearforonecomponentundercertainconditions.Experimentsshowedthattherelativeareasofthetwopeaksofanalytedependedonthetimeandthetemperatureofreactionbetweenanalyteandsurfactant,andtheconcentrationofsurfactantinthesamplesolution.Itmeansthattheinteractionbetweentheanalyteandthesurfactantisaslowprocess,andastablesubstancecanbeproducedfromtheinteraction.Itisthesubstanceandtheanalytethatmayleadtotheformationoftwopeaks.Thefastinteractionmechanismbetweenthesoluteandthemicellarshouldbequeriedfromtheexperimentresult.

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