资源描述：
《development of spme devices and coatings》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。
1、3DevelopmentofSPMEDevicesandCoatingsJanuszPawliszynDepartmentofChemistry,UniversityofWaterloo,Waterloo,Ontario,Canada3.1HistoricalPerspectiveTheearlyworkonlaserdesorption/fastgaschromatography(FastGC)conductedinourlaboratoryresultedinrapidseparationtimes,evenfo
2、rveryhighmolecular1massspecies.However,thepreparationofsamplestookhours,whichwasmorethananorderofmagnitudelongerthantheseparationtimes.Opticalfibreswereusedinthisexperimenttotransmitlaserlightenergytothegaschromatography(GC)instrument.Thesamplepreparationproces
3、susedwasanalogoustostandardsolventextractionprocedures.Thefibretipwascoatedwiththesamplebydippingoneendoftheopticalfibreinthesolventextract,coatingthefibreandthenremov-ingthevolatilesolventsthroughevaporation.Thefibretip,preparedinsuchaway,wasinsertedintotheinj
4、ectorofagaschromatograph,andanalyteswerevolatilisedontothefrontoftheGCcolumnbymeansofalaserpulse.Duringthiswork,aneedforrapidsamplepreparationtechniqueswasrecognisedinordertoretainthetimeefficiencyadvantagesmadepossiblebyusingthelaserpulseandahigh-speedseparati
5、oninstrument.Thechallengewasaddressedusingfibresbecauseopticalfibrescouldbecoatedwithseveraltypesofpolymericfilms.Theoriginalpurposeofthecoatingswassimplytoprotectthefibresfrombreakage.Becauseofthethinfilmsused(10100μm),theexpectedextractiontimesforthesesystem
6、swereveryshort.Inaddition,novelfilmscouldbepreparedbasedontheknowledgegainedfromfusedsilicacapillarycolumnmanufacturingexperience.IntheinitialworkonSPME,sectionsoffusedsilicaopticalfibres,bothuncoatedandcoatedwithliquidandsolidpolymericphases,weredippedintoan2a
7、queoussamplecontainingtestanalytesandthenplacedinaGCinjector.Thepro-cessofintroducingandremovingthefibresrequiredtheopeningoftheinjector,whichresultedinlossofheadpressureatthecolumn.Despitetheirbasicnature,theearlyexperimentsprovidedveryimportantpreliminarydata
8、thatconfirmedtheusefulnessofthissimpleapproachbecausebothpolarandnon-polarchemicalspecieswereextractedrapidlyandreproduciblyfromaqueoussamples.Thedevelopmentofthetechniqueac
