producemediawiki

mediawiki  时间:2021-04-13  阅读:()
LEAPTechnologiesMinimizingandEliminatingCarryoverinPALSystemsAPrimerforReducingCarryoverinPALAutosamplerSystemsAPrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies2005TableofContentsWhatisCarryover3WhatCausesCarryover3WheretheResidualLingers.
3WhatcanbeDonetoMinimizeCarryover4TheBasics4Syringes.
4ValvesandTubing.
5Component&MaterialChoices6StepstoMinimizeorEliminateCarryoverinPALSystems7Hardware7WashProcedures&Solvents.
8Techniques.
9SpecialMacros/Cycles9TroubleshootingSummary.
11ListofReferences11Appendix.
12APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20053Twoofthebiggestproblemsinchromatographyarereproducibilityandcarryover.
Thisdocumentisintendedasabriefoverviewoftheissueofcarryover,andtoprovidesomesuggestionsastohowtominimizeoreliminateitasitrelatestoLEAPPALsystems.
WhatisCarryover"Carryover"isadetectorresponsefromapreviouslyinjectedsample,detectablewhenasubsequentinjectionismade.
Theresponseisbestseenwhenthatsubsequentinjectionisa"blank",i.
e.
aninjectionofmobilephasewithnoneofthecompoundintentionallyincluded.
Wheneveraninjectionsystemthatcomesintodirectcontactwithsamplesolutionsgets"re-used"forsubsequentinjections,carryoverwilloccurtoacertainextent.
Itnowbecomesaquestionofdetectorsensitivity.
Theimproveddetectorsensitivitymightbeattheheartofthe"rash"ofcarryoveroccurrencesinrecentyears.
Thefirstquestionauserneedstoansweris:DoestheamountofcarryovermatterHowdoesitcomparetothecompound-specificdetectionlimitsandtoerrorlimitsofthesamplepreparationandLCmethodsExample:Eventhoughvisible,apeakbelowthedetectionlimitforaspecificcompoundis,bydefinition,notdetected.
Intheliterature,carryoverisusuallyquantifiedasapercentagevalueofeitherthe"UpperLevelofQuantitation"(ULOQ)orthe"LowerLevelofQuantitation"(LLOQ).
Thisvalueisalwayscompoundspecificand,therefore,meaninglesseitherbyitselforreferringtoadifferentcompoundthantheoneyouarehavingproblemswith.
Example:UsingaLEAPCTCautosampler,thecarryoverforAcetaminophene(Tylenol)wasdeterminedtobe0.
0004%ULOQ.
Thisisafantasticnumberbutsaysnothingabouttheautosamplerperformanceusingyoursamples.
Duetothesereasonsnogeneralvalueforcarryovercanbegivennorguaranteedforaspecificanalyticalproblem/task.
WhatCausesCarryoverCarryoveriscausedbyafailuretocompletelyeliminateresidualcompoundsfromaprevioussampleinjectionintotheHPLCsystem.
Thelingeringresidualbecomesmixedwithasubsequentinjection.
Thiscanresultfrominadequateorineffectiveflushingafterthepreviousinjection,orbysomeorallofthesamplecomponentsbecomingtemporarilytrappedorboundtothesurfacematerialsomewhereintheHPLCpathway.
WheretheResidualLingersPossiblesitesforresidualaccumulationincludeanywhereandeverythingfromthesyringetothedetector,buttheinjectionvalveandthesyringearethemostlikelyplacesforcompoundstobeunintentionallyretained.
Anysurfacethatisnotcompletelyinerthasthepotentialtobeanadsorptionsite.
Forexample,certaincompoundstendtoadsorbontoactivesitesinStainlessSteel,evenintheflowpath,andrequireenoughoftherightwashsolventintherightconcentrationtobereleased.
ThiscanalsobetrueforPEEKtubing,dependingonthenatureoftheanalytesandthematrix.
Moreinsidiousare"deadvolume"spaces,wheresamplecanremaintrappedafteraninjection,sometimesevenafterroutinerinsing.
TwocommonexamplesofdeadvolumespacesaretheAPrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20054insideofthesamplesyringeneedleandthevalveinjectionportinletincludingthevalverotorgroove.
Seefigure1.
However,anyspacewheresampleisnotcompletelydisplacedorpurgedbymobilephaseorwashsolventsisapotentialproblem.
Thebiggestsourceofthistypeofcarryoverisfromthefittingsandhowtheyaremade.
Forexample,PEEKfittingswithPEEKferrulescanslipunderhighpressurecreatingadeadvolumeandthusallowingsampletobetrapped.
WhatcanbeDonetoMinimizeCarryoverTheBasicsObviously,flushingthesyringeandvalveisessential.
TheLEAPCTCPALhastwowashstationsincludedasastandardaccessory.
Theselectionofsolventsandflushvolumesareofparamountimportanceandcontrolledbytheuser.
Althoughitmayseemobvious,itisworthstatingthatflushingwithineffectivesolvent(s)isuseless.
Youneedtoconsiderthebasicruleofsolubility:"LikeDissolvesLike".
Therearemanyfactorsthatwillinfluencetheeffectivenessoftherinse,solventstrengthandpolarityamongthem,buttherearenohardandfastrulesthatapplytoeverycase.
Consequently,theend-userchemistmustbesuretochoosesolventsthatwillgetthejobdone.
Often,aone-twopunchofsolvents,e.
g.
anaqueousfollowedbyanorganicwash,canbemoreeffectivethanjustone.
"Cocktails"ofwashsolventmodifierslike0.
1%to1.
0%ofvolatileacid,baseorsaltsmayproducethedesiredresult.
Itisimportanttomakesurethatthechoicesofsolventsarenotimmisciblewitheachother.
SyringesThechoiceofsyringecansignificantlyaffectcarryover.
Needle,plungerandbarrelcharacteristicscanallcontributetoorreduceproblems.
ForLC,theneedleshouldalwaysbea22gauge,pointstyle3,i.
e.
withablunttip,toensureagoodsealatthebottomofthevalveinlet(assumingproperpenetration).
Useofanyothertipwillresultinanunswept"deadvolume"areaaroundthetip,aprimarycauseofcarryover.
Theinnerdiameter(i.
d.
)oftheneedledeterminestheinnersurfaceareaexposedtosampleandtheresidualleftinthedeadvolumeoftheneedleaftertheplungerhasfullyexpelledthecontentsofthebarrel.
Obviously,asmalleri.
d.
reducesboth.
A"gauge22s"needlehasasmalleri.
d.
thana"gauge22"byafactorofapproximately10.
Seefigure2.
Itcanpotentiallyreducecarryoverbyreducingthesurfaceareaandneedlevolume,albeitwithsomesacrificeofinjectionspeedduetothegreaterrestrictionandahigheroccurrenceofneedlecloggingduetothesmallerinnerdiameter.
Figure1:Cutoutofaninjectionvalve;Aninjectionleavestheinjectionportinletfilledwithsample.
Additionallyincaseofaloopoverfillinjection,arotorgroovewillalsocontainsample.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20055However,additionalrinsescansomewhatreducethepracticaldifferencebetweenthetwo.
Aswiththerestofthesystem,inreducingcarryoverfromthesyringe,theimportanceofdeterminingthemosteffectivesolventsandperformingadequatewashescannotbeoverstated.
Also,thoughmoreexpensive,itispossibletofindneedleswithTeflon(PTFE)orglasscoatingstoreduceadhesion.
Buildupofcompoundsontheinnersurfaceoftheglassbarrelhasbeenclearlyestablishedasaproblem,bothinpotentialleechingintosubsequentsamplesandevenmorenotablyincausingprematurewearofplungertips.
Wornplungertipshavechannelsandpocketswhichareabletoretainsamplesolution.
Bettersyringeshavepolishedand/ortreatedsurfacestoreducethisphenomenon,andtheproperselectionofwashsolventsandtheirapplicationcansubstantiallyreducethisbuildupanditseffects.
Variouscompoundsareusedasplungertipmaterial,thoughmostareeitherPTFEorPolyethylene(PE).
Thereislittleevidencethattheplungertipcontributessignificantlytocarryoverandthedifferenceinthematerialsprimarilyinfluencesdurability.
However,thereisonewayinwhichtheplungercancontributetothecarryoverproblem:iftheplungerfailstoreachthebottomofthebarrel,especiallyduringrinsing,adeadvolumeareawillexistbetweenthetipandthebarrelbottom.
Itisrecommendedthatplungerswithavariableplungerstopareverycarefullyadjusted,oravoidedaltogether.
ValvesandTubingRegularlycheckthatthevalveinletsleevefitssnuglyaroundthesyringeneedlewheninserted.
Otherwise,replacetheinletsleeve.
Thiscaneasilybedeterminedbyinsertingtheneedleintothevalveinletbyhand.
Typicallytheneedlesleeveshouldbechangedevery15to60daysdependingonthenumberofinjectionsmadeandifsaltsarepresentinsampleand/orwashsolutions.
Besurethattheinletsleeveiscorrectlydimensioned.
Thereshouldbeapproximately2.
5mmoftubingbelowtheferrule.
Ifthetubingbelowiseitherlongerorshorter,adeadvolumewillresultinthevalveinjectionport.
Seefigure3.
UseonlyLEAP-approvedinletsleevestoensureconformitytospecifications.
Whenconnectingtubingorloopstothevalve,besurethattheendsarecleanlycutandperpendicular,andtakecaretofullyinsertthetubingendsintoeachportandpushthetubingasyoutightenthefittings(toeliminateanygapbetweentheendofthetubingandthebottomoftheport).
Avoid"Fingertight"fittingsanduserealcrimp-styleferrulefittings.
Fingertightfittingscanloosenenoughunderhighpressuretocauseadeadvolumewithoutleaking.
Figure2:DimensionalcomparisonofcommonlyusedsyringeneedlesizesforLCinjections.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20056TypicallyPEEKtubingproduceslesscarryoverthanStainlessSteel(SS)tubing,butStainlessSteelferrulesseemtooutperformPEEKferrules.
CaremustbeusedwhenusingaSSferruleonPEEKtubingtopreventclosingoffthei.
d.
byexcesscrimpingand,thus,causingablockageintheflowpath.
InrecentyearsathirdalternativetubingmaterialbecamepracticalforuseinLCapplications.
FusedsilicainformofPEEKsiltubingoffersuniqueanddifferentmaterialpropertiescomparedtoPEEKandSS.
PEEKsilcomesinpre-cuttubinglengthswithpolishedandperpendicularcuttubingendsandshouldbeusedwithoutfurthercuttingorshortening.
CuttingPEEKsilwithoutpropertoolswillresultinajaggededgeofthefusedsilicainnertubingendswhichthenresultsincarryoverandblockagesdownstream.
Seefigure4.
Considerusingavalvethatwillbeinertwithyoursamples.
Valcovalvescomeinseveralmaterialchoices,Nitronic60StainlessSteel,HastelloyC,PAEKpolymeric,andeitherthestandard"rotor"designortheCheminertdesign.
TheValcon"H"rotor,whichisaproprietarypolymerofcarbonfiberreinforcedPTFEisthestandardrotormaterial.
TheValcon"E"materialisamixtureofPAEKandPTFEandismoreinertthanValconH,however,itdoesnotwithstandhigherpressuresverywellandwearsoutmorequicklyasaresult.
The"H"versionisgoodupto10,000PSIandtheEmaterialisgoodupto3,500PSI.
Therotorneedstobecheckedforscratchesorwear.
Replaceascratchedorwornvalverotor.
CheminertvalveswithPAEKstatorandValcon"E"rotoraremoreinertthanstainlesssteelvalves.
(Note:youcanconsulttheVICI(Valco)catalogforadditionalspecificmaterialdescriptionsandcompatibilityissues.
)Component&MaterialChoicesChoosethepropervalvedesignandmaterialbasedonthepotentialforcarryover.
Figure3:Theimportanceofacorrecttubinglengthbelowtheferrule.
Tubingbeingtooshortorlongcanbothproducedeadvolumewhichinturncancausecarryover.
Figure4:CrosssectionofPEEKsiltubing.
Pre-cuttubinglengthscomewithpolishedperpendiculartubingendsandshouldnotbecutorshortenedbytheenduser.
DrawingcourtesyofSGE,Inc.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20057Choosethepropersyringedesignandsizeforyourapplicationandwashingneeds.
Choosetheproperneedleformat,e.
g.
,"gauge22"vs.
"gauge22s".
Choosethepropertubingmaterialforthesampleloopandothertubingconnections.
Choosetheappropriatesolventsforwashing/rinsingpurposes.
Determineifancillarywashingdeviceswillberequiredi.
e.
LEAPValveSelfWashSystem,ortheDilutormodule.
Orderadditionalcontrolsoftwaretoruncustommacrosorcycleswithspecialwashprocedures.
StepstoMinimizeorEliminateCarryoverinPALSystemsHardware1.
AdjustNeedlepenetrationinthevalveinletto0.
2mmfromthebottomoftheinletport.
Usingthehandheldcontroller,movetheneedleslowlydownuntilaclearaudiblenoise("clunk")occurs.
Movetheneedle0.
2mmupwardsandchecktheposition,again.
2.
Replaceinjectionvalveinletsleevesevery15to60daysorsoonerdependingonthenumberofinjections.
3.
Checktherotorandstatorofthevalveforscratches-theseareconvenientplacesforcompoundstoberetained.
Thestatorcanbecleanedultrasonicallyandtherotorshouldbereplacedasneeded.
4.
Checkthesyringefordiscolorationontheplunger,plungertipwearandtightnessoftheplungerinthesyringebarrel.
5.
Avoidwettingofthelowerneedleguideontheinjectionhead.
Ifthelowerneedleguideisgettingwet,trytofindthesourceoftheliquidandcorrecttheproblem.
ItmaybecomingfromasplashingeffectintheWashStation,fromablockedWashStationdrainlineorfromsamplingoutofopenvials/wells.
6.
RuntheWashStationutilityusingthehandheldcontrollerandverifyactuationoftheWashStationsolenoidvalvesandthegravity-fedflowofwashsolvent.
7.
VerifythatthedrainlineoftheWashStationisnotblockedwhichcanpreventfreshsolventfromgettingintotheWashStation.
8.
BesurethatthecapsonthewashsolventsupplybottlesoftheWashStationareloosetoprovideventilation.
Ifthecapsaretight,arelativevacuummaydevelopinthebottlesasthesolventsareconsumed.
Thisdiminishedpressurewillresultindiminishedsolventflowand,inturn,reducestheefficacyofsyringeneedlewashingFigure5:Positioningoftheinjectionheadneedleguiderelativetotheinjectionvalveinlet.
A2mmgappreventsliquidpossiblypresentontheneedleguideundersidefromcontaminatingtheinjectionvalveinletport.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20058attheWashStation.
(Note:NormallythereisasmallholeinthecapsprovidedfromCTCespeciallyforthisreason.
However,theholeissmallandonthesideofthecapandinsomecasesmaynotprovideadequateventilation.
Thus,aloosenedcapwillhelptoensurethataircanenterthebottle.
)WashProcedures&Solvents9.
Usetwodifferentwashsolvents,e.
g.
,polarvs.
non-polar.
Makesurethatwashsolventsarecompatible/misciblewitheachotherandwiththesamplesolution.
Asolventmiscibilitytableisprovidedintheappendixtoofferhelpinthewashsolventselectionprocess.
10.
Addavolatilesolventmodifiertothewashsolutions,e.
g.
,acids,bases,salts,etc.
Inadditiontowashsolventmiscibility,thewashsolventmodifiersthemselvesneedtobemiscible/solubleinallwashsolventsandsamplesolution.
11.
Usethemostappropriatewashsolvents.
Example:Whenthesamplecontainsproteins,firstrinsewithanacidifiedaqueoussolvent(e.
g.
,90:10water/Acetonitrilewith0.
5%Formicacid),followedbyamoreaggressiveorganicsolvent(e.
g.
,30:70water/Acetonitrilewith0.
5%Formicacid).
Theacidifiedaqueoussolventwillkeeptheproteinssolubleandminimizetheprobabilityofdenaturing,inturnreducingthechancesoftheproteinsstickingtotheinnersurfacesofthevalveorsyringe.
Theorganicwashsolventwillwashawaythesmallmoleculeanalytes.
Thisexampleillustratesthattheorderofwashsolventsisimportant.
Performasyringewashwiththeaqueoussolventpriortothenextinjectiontoremoveanyhighorganicconcentrations.
12.
Increasethenumberofsyringerinsesandthenumberofvalverinses.
Usea2-to-1ratioofvalvewashestosyringewashes.
13.
Lengthenrinses,possiblyincludinga"dwell"timetopromotea"leeching"effect.
14.
UseaValveSelfWashingSystemorthePALDilutormoduletoincreasethevolumeofvalvewashes.
DilutorasWashStation:-AddingaCTCdilutorcanprovidegreatlyenhancedflushingofthesyringeandvalve.
Alargevolumeofsolventispasseddirectlyintoandthroughthesyringeandhasbeenshowntosignificantlyimproverinsingresults.
(Note:Thisislimitedtoeithera20uLor80uLsamplesyringesize.
)Thisaccessorypermitstheflushingofthevalvewhiletheneedleremainsinthevalveimmediatelyafterinjection.
Youwillhavetodoatleastonesyringeneedlewashinwashsolvent1and/or2priortothenextinjectiontoremoveanyanalytesfromtheneedle'sexternalsurface.
ValveSelf-WashingSystem:-MacroshavebeendevelopedtocontroltheLEAPValveSelfWashingSystemtoprovidespecificwashtimesforthevalve.
Highervolumesofsolventcanbeusedforcleaningthevalvewhilethesyringeisbeingwashedseparately.
Syringelifeisgreatlyenhancedwiththistechnique.
Thesyringeneedleshouldbewashedatleastonceinwashsolvent1and/or2priortothenextinjection.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies20059Techniques15.
Partialloopfillinjectionsisolatethesamplesolutionwithavolumeofsolventthatwasleftintheloop.
Thisprocedurecanminimizeconcentratedsamplecomingintocontactwithvalverotorgrooves,thewasteportoutletandfittings.
Makesurethatthevalveisplumbedinsuchawaythatthesampleleavestheloopthesamewayitcamein,e.
g.
,"lastinfirstout".
Seefigure6.
Theuppersamplevolumelimitforpartialloopfillinjectionsis1/3ofthesampleloopvolume.
(Note:Incaseofloopoverfillinjections,theinjectionvolumeneedstobeatleast3timestheloopvolume.
)SpecialMacros/CyclesCreatemacros/cyclesforthefollowingspecialmethodstohelpminimize/eliminatecarryover.
ThiswillrequiretheuseofCycleComposersoftwaremacrosorCycleEditorsoftwarecycles.
Macro/cycleoperationrequireseitherthenativesoftwarerunningconcurrentlyorLCdatasystemsoftwarecontrollingthePALbasedonmacros/cycles.
Examplesinclude:NeedleDip:-Dipthesyringetipintowashsolvent(s),aftersamplehasbeenaspiratedintothesyringe,justbeforetheinjectiontocleantheoutsideoftheneedlebeforeitisinsertedintotheinjectionport.
Thisprecludesmatrixand/oranalytesfromcontaminatingtheneedleinletsleeveandinjectionport.
ValveToggleandLoopRinse:-Whenoverfillingtheloop,boththeinletandoutletoftheloopmaycontaminatetherespectivecrossoverports.
Togglingthevalveaftertheinjectionsubjectsbothcrossoverportstocleanmobilephase,whichcanreducetheconcentrationofanalytesinthevalve.
Asyringewashoftheinjectionloopcanbeaccomplishedaswell.
Thetogglingofthevalveshouldbedonewhenthegradientstrengthisatitshighestpointtodissolveanyremaininganalytesinthecrossoverport.
Caremustbetakennottoleaveastrongsolventintheloopsothatthenextinjectionisnotsubjectedtothehighersolventstrength.
Theloopmaybewashedwithlowerstrengthsolventsothatthechromatographyisnotcompromised.
DispenseWashSolutionstoWaste:-WashsolventcanbedrawnfromthecapillarytubeoftheFastWashStationandejectedintothewasteposition,Figure6:Loopoverfillvs.
partialloopfillinjections;Duringpartialloopfillinjections,thenumberofrotorandvalvesurfacesincludingfittingsthatcomeincontactwithconcentratedsampleisreduced.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies200510insteadofejectingthecontaminatedsolutionbackintothecapillarytube.
Notethatthisprocedureshouldbefollowedbyatleastonemoreregularwashstepincludingwashsolventejectionintothecapillarytubetorinsetheoutsideoftheneedle.
Undernormaloperation,thesolenoidvalvesclosebeforeawashsolventejection,thus,forcingtheexpelledsolventaroundtheoutsideoftheneedle.
)SandwichInjection:-Asolventplugmaybepickedupbeforethesampleisaspiratedinorderto"isolate"thesyringeplungertipfromcontactwithanalytes.
Thesamesolventplugwillalsocometorestintheinjectionportinletandadjacentrotorgrooveafterthesampleinjectionismade.
Notethatthisprocedureissuccessfulonlyifmixingstrokesarenotrequiredandduringpartialloopfillinjections.
Itcanbedonewithorwithoutanairgapbetweenthesolventandsample.
Thetechniqueminimizesthecontactmadebetweentheconcentratedanalytesandthecrossoverportonthevalve.
Figure7:Sandwichedsamplepickupandinjection;Thesamplesolutionis"embedded"inasandwichofsolventandseparatedbysmallairgaps.
Afterinjection,thesamplewillendupinthemiddleoftheinjectionloop.
Onlysolventswithalowerelutionstrengththanthestartinggradientmobilephasecompositionshouldbeusedtobracketthesample.
APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies200511TroubleshootingSummaryChecktheeasiestthingsfirst.
WashthesyringeandvalvewiththeproperchoiceofsolventsCheckneedlepenetrationintheinjectionvalveCheckNeedleinletsleeveforwearCheckRotorforscratchesandreplaceasneededChecksyringetobesuretheplungerisgoingallthewaytothebottomofthebarrelChangeyourinjectionproceduregoingfromlowconcentrationstohigherconcentrationsifpossibleUseapartialLoopfillingtechniqueUseValconEinsteadofValconHrotormaterialCheckfittingsbetweenthesampleloopandvalveforproperinstallationUsecustomMacrosorcyclestoenhancerinsingListofReferencesDolan,J.
W.
"AutosamplerCarryover"LCGC19(2)February2001,164-168Dolan,J.
W.
"AttackingCarryoverProblems"LCGC19(10)October2001,1050-1054APrimerforReducingCarryoverinPALAutosamplerSystemsRev.
1.
1LEAPTechnologies200512AppendixWashSolventMiscibilityTable

台湾云服务器整理推荐UCloud/易探云!

台湾云服务器去哪里买?国内有没有哪里的台湾云服务器这块做的比较好的?有很多用户想用台湾云服务器,那么判断哪家台湾云服务器好,不是按照最便宜或最贵的选择,而是根据您的实际使用目的选择服务器,只有最适合您的才是最好的。总体而言,台湾云服务器的稳定性确实要好于大陆。今天,云服务器网(yuntue.com)小编来介绍一下台湾云服务器哪里买和一年需要多少钱!一、UCloud台湾云服务器UCloud上市云商,...

hostyun评测香港原生IPVPS

hostyun新上了香港cloudie机房的香港原生IP的VPS,写的是默认接入200Mbps带宽(共享),基于KVM虚拟,纯SSD RAID10,三网直连,混合超售的CN2网络,商家对VPS的I/O有大致100MB/S的限制。由于是原生香港IP,所以这个VPS还是有一定的看头的,这里给大家弄个测评,数据仅供参考!9折优惠码:hostyun,循环优惠内存CPUSSD流量带宽价格购买1G1核10G3...

IMIDC(rainbow cloud):香港/台湾/日本/莫斯科独立服务器特价,闪购大促销,最低30usd/月起

imidc怎么样?imidc彩虹网路,rainbow cloud知名服务器提供商。自营多地区数据中心,是 Apnic RIPE Afrinic Arin 认证服务商。拥有丰富的网路资源。 在2021年 6.18 开启了输血大促销,促销区域包括 香港 台湾 日本 莫斯科 等地促销机型为 E3係,参与促销地区有 香港 日本 台湾 莫斯科 等地, 限量50台,售罄为止,先到先得。所有服务器配置 CPU ...

mediawiki为你推荐
副刊2016年8月30日支付宝调整还款日支付宝调整花呗还款日,这个调整有没有对你造成什么影响?波音737起飞爆胎客机起飞的时候时速是多少?支付宝是什么什么是支付宝? 请详细介绍.宜人贷官网宜信信用贷款上征信吗购物车通过自己的体会总结购物车的作用佛山海虹海虹好吃吗,我从来没吃过网站制作套餐制作一个公司网站究竟需要多少费用呢??powerbydedecms织梦dedecms怎么去掉power by dedecms方法zencart模板zen cart模板怎么进行二次开发修改
手机域名注册 泛域名解析 海外服务器 ubuntu更新源 湖南服务器托管 秒杀预告 ntfs格式分区 七夕快乐英语 空间购买 阿里云官方网站 德隆中文网 1美元 攻击服务器 nnt fatcow 建站论坛 发证机构 hosting 美国服务器 hosts文件 更多