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Thermal Analysis of Ammonium Acetate and Ammonium TFA
(2023-07-17 20:05:21)

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Heterocyclic Amines
(2023-07-15 19:46:35)

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Skellysolve
(2023-07-13 19:42:30)
SkellysolveAisessentiallyn-pentane,b28-30°/atm,SkellysolveBisessentiallyn-hexane,b60-68°/atm,阅读全文]
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Mukaiyama aldol addition
(2023-07-11 18:53:00)

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Pivalic Acid
(2023-07-09 20:43:22)

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Packing a Column and Performing a Separation with Sephadex? LH-2
(2023-07-07 21:36:43)

PACKINGACOLUMNSimplestepstoclarifyasamplebeforeapplyingittoacolumnwillavoidtheriskofblockage,reducetheneedforstringentwashingproceduresandextendthelifeofthechromatographymedium.Filterorcentrifugeallsolventsandsamplesbeforeuse. RefertoTable6.4tocalculatetheamountofdrymediumrequiredastheextentofswellingdependsuponthesolventsystem.SwellSephadex®LH-20foratleast3hatroomtemperatureinthesolventtobeus...[阅读全文]
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Ammonium acetate
(2023-07-07 20:09:07)

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Diaion HP 20 and Sephadex LH-20
(2023-07-05 19:10:18)

HP-20isapolymericreversephase,soitwillbehaveprettymuchlikeC18intermsofaseparationmechanism.Startwithwater,andrunagradientwithmethanolorethanolasdescribedabove.Onecanuseacids(trifluoro,formic,oraceticacid)ifneededtosharpenpeaks.Forloadingthesample,soundslikeyoursampleissolubleinwatersoaliquidloadisappropriate. [阅读全文]
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Mass spectrometry separates isotopes
(2023-07-02 15:18:02)

Youwillknowintheorythatmostelementsnaturallyexistasmixturesofisotopes.Ifyoudidn’tbelieveit,nowyouwill.Chlorineisnormallya3:1mixtureof35Cland37Cl(hencetheobviouslyfalserelativeatomicmassof‘35.5’forchlorine)whilebromineisanalmost1:1mixtureof79Brand81Br(hencethe‘average’massof80forbromine!).Massspectrometryseparatestheseisotopessothatyougettruenotaveragemolecularweights....[阅读全文]
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Carboxylic acids (R–CO2H) contain the carboxyl group CO2H
(2023-07-02 13:17:37)

Astheirnameimplies,compoundscontainingthecarboxylicacid(CO2H)groupcanreactwithbases,
losingaprotontoformcarboxylatesalts.Ediblecarboxylicacidshavesharpflavoursandseveralare
foundinfruits—citric,malic,andtartaricacidsarefoundinlemons,apples,andgrapes,respectively.[阅读全文]
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