A.GilsonPipetmenAutopipets(andsimilarmodels) WeprimarilyusetheGilsonautopipetsinthecorecourselabs.Wehavefoursizesidentifiedbythenumberontheroundbuttonontheplunger.Thevalueisthemaximumvolumeinmicrolitersthatcanbetransferredwiththatsizepipet. SizeindicatorbuttononaGilsonP1000.
Otherautopipetsizeswehaveonhand. P1000 P200 P100 P20
Whatsizeofautopipetisrightforthejob?
RULEOFTHUMB:AlwaysselecttheSMALLESTsizepipetthatwillhandlethevolumeyouwishtomovetoachievethegreatestaccuracy.Accuracydecreasesasyouuseunnecessarilylargepipetsforsmallvolumes.
Thefollowingtableshowstheusefulvolumerangesforeachpipettype.Makespecialnoteoftheminandmaxvalues.
SIZE UsefulRange MaxVolume MinVolume P1000 200-1000ul 1000ul 200ul P200 20-200ul 200ul 20ul P100 10-100ul 100ul 10ul P20 0.5-20ul 20ul 0.5ul B.HowtoReadtheVolumeontheAutopipet
Lookatthefrontfaceofthepipetandyouwillseeawindowwith3(three)digitsinside.ThediagrambelowshowstheMAXIMUMvaluethatcanorshouldbedialedinoneachsizepipet.Toexceedthesevalueswillputthepipetoutofcalibration.Besideeach"window"belowisthenumbersplaceitrepresents.Pleasetakethetimetolearnhowtoreadthemsoastoavoiddamagingthembydialingvaluesoutoftheirrange.
GilsonP1000scalewindow.
P1000 P200,P100 P20 1 1000"s
100"s
10"s
2,1 100"s
10"s
1"s
2 10"s
1"s
1decimal
0 0 0 0 0 0 C.Howtochangetheloadvolume:
Holdthepipetorhorizontallywiththeplungertoyourleft.Changeorsettheloadvolumebyturningtheknurledplasticknobatthetopofthehandgrip.Rollittowardsyoutodecreasethevaluesandawayfromyoutoincrease.WATCHCAREFULLYasyouchangethevaluestomakesureyoudon’ttakethenumbersoutofrange.Ifindoubt,reviewtheallowablevolumesforeachsizepipetor,andthenaskforhelp.
D.Technique
- GRIP:Holdthepipetorlikeaknifeinahorrorflickwithyourindexfingerontheplunger.Yourindexfingergivesyoumuchfinercontrolovertheplungeraction.
- LOADING:Loadasteriletip(blueforP1000;yellowforP200andallsmallersizesincludingVWRautopipets)andthenreclosethetipboxtomaintainsterilitiy.
- Pushtheplungerdownslowlytothepointoffirstresistance:thissetstheloadvolume.
- Whileholdingtheplungerattheloadvolumesetpoint,putthetipintothesolutionsothatitisimmersedjustenoughtocovertheend(3-4mm).
- Slowlyreleasetheplungertodrawuptheliquidmakingsuretokeepthetipimmersed.Visuallyinspecttheloadtomakesureitiscorrect.
DELIVERY:Todeliverthevolume,placethetipintothereceivingvesselandpresstheplungerallthewaytothebottom-thisexpellsalltheliquidandgivesalittleextravolumetogetthelastdropletout-ANDTHEN,WITHOUTRELEASINGTHEPLUNGER,withdrawthetip. CHANGETIP?RepeatasnecessaryusingthesametipifNOTchangingsolutions.Useafreshtipforeverychangeofsolution,orwheneveritisprudenttomaintainsterileconditionsandavoidcrosscontaminationofsolutionsorcultures. TIPDISCHARGE:Whileholdingthetipoveranappropriatewastereceptacle,pressthewhitetipdischargeslideronthebackofthegrip.
E.SmallVolumesTechnique:Withsmallvolumes,especiallythe1-10ulrangeusedinmolecularBIOLOGyprotocols,youmustkeeptrackofthedropletsyoupipet.Carefullyexpelltheliquiddropletonthesidewallofthetubesothatyoucanseeit. Ifaddingtoalargervolume,flushthetipwiththesolventliquidafterexpellingthedroplettomakesureyougetallthedeliveryliquid.Withsmallvolumesyou"llusuallyneedtocentrifugeandthenvortexthetubetogetagoodmixingofthereagents.
F.ASimpleCheckforProperCalibration
Checkthecalibrationofyourmicropipetbyusingthefactthat1ulofdeionized(ordistilled)waterhasamassof1ug.Pipetarangeofvolumesspanningthemicropipet"susuablerangeandmassthemonatoploadingbalancehavingatleast3decimalplaceaccuracy.Pipetshavinggreaterthan0.1%errorshouldberecalibrated.
G.InstructionsforUsingtheVWR5-50ulAutoPipets
TheVWR5-50ulautopipetsfunctionsimilarlytotheGilsonPipetmanautopipets.Themajordifferenceliesinhowtosettheloadvolume.Thisisfurthercomplicatedbythelossofthe1ulindexring(whichsurroundstheplunger)fromseveralofthepipets.
Theplungerhastwostops,thefirstbeingtheloadvolume,thesecondfordischargevolume.Thesepipetorsusethesamesmallyellowtips(yellowororangeboxes)asusedforP200andsmallerGilsonautopipets.Thetipejectorisadarkgraybuttonnearthetopofthehandgrip(seediagrambelow).
Howtosettheloadvolume:
Theplungerhasaverticallinedemarcatedbyhorizontalticksateach5ulincrementfrom0ulto50ul(toptobottom–seediagramatright).Whentheplungerisrotatedtoaligntheverticalmarkwiththe"zero"referencemarkontheindexring,theloadvolumeisthatofthehorizontallinejustshowingabovetheindexring.Inthediagramtotherightthatvolumeis10ul.
Incrementsof1ulareachievedbyturningtheplungerCWtowardthe"+"symboltoincreasevolumeorCCWtowardthe"-"symboltodecreasevolume.Eachclickalignstheverticallinewithanewreferencemarkontheindexring.Toset13ul,goto10ulandthen3clicksCW.
Above:SideviewofVWR5-50ulautopipetsetto10ul. Above:Pipetsetto20ul. Onsomeofthepipetorstheindexringismissing.Tomaintaintheirutility,wehavemarkedthe1ulincrementsandthezeroreferencepointwithafelttiponthetopofthehandgrip.Thediagrambelowshowsthepipetorproperlysetfor10ul.Theindexringisequivalentindepthtothe5ulintervalsontheplunger.Theabsenceoftheindexringthereforeletsthe15ulmarkshowjustatthetopofthehandgrip.Toreadtheactualvolumeyou’llhavetosubtract5ulfromtheapparentvolume(15ulintheexample)indicatedatthetopofthehandgrip(seediagram).Askforhelpifyou’rehavingdifficultyreadingorsettingthecorrectloadvolume.
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