Hvad absorberer ved 1680 cm⁻¹ i et FTIR-spektrum?
Et bånd nær 1680 cm⁻¹ kan pege på flere funktionelle grupper. Nedenfor er de mest sandsynlige tildelinger, rangeret efter hvor meget publiceret bevis der understøtter hver — hver enkelt spores til litteratur (DOI) og krydsvalideres mod vores 130.000+ referencespektre og vidensgraf.
Backed by 8 cited sources
Hurtigt svar
Et bånd nær 1680 cm⁻¹ fortolkes normalt ved at kontrollere, hvilke funktionelle grupper der gentagne gange forekommer der i litteraturen, og derefter bekræfte mindst en eller to yderligere peaks i den samme prøve. Denne side rangerer disse tildelinger efter akkumuleret evidens snarere end efter en enkelt fast lærebogsregel.
Mulige funktionelle gruppetildelinger
| Funktionel gruppe | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| Carbonyl (C=O) | 30 | 22 | 1,0 |
| Amide | 29 | 25 | 1,0 |
| Carboxyl (COOH) | 15 | 12 | 1,0 |
| Methacrylate | 14 | 10 | 1,0 |
| Acetate | 14 | 10 | 1,0 |
| Ketone | 13 | 9 | 1,0 |
| Ester | 12 | 9 | 1,0 |
| Alkyl C-H | 7 | 7 | 1,0 |
| N h | 7 | 7 | 1,0 |
| Alkene (C=C) | 5 | 5 | 1,0 |
| Protein beta sheet | 5 | 5 | 1,0 |
| Secondary amine | 5 | 5 | 1,0 |
| Hydroxyl (O-H) | 4 | 2 | 1,0 |
| Protein beta turn | 3 | 3 | 1,0 |
| C n single bond | 3 | 3 | 1,0 |
| Aromatic ring | 3 | 2 | 1,0 |
| Methoxy (OCH3) | 3 | 2 | 1,0 |
| C-O single bond | 3 | 2 | 1,0 |
| Hydrogen bond | 3 | 2 | 1,0 |
| Ammonium | 2 | 2 | 1,0 |
| Carbohydrate | 2 | 2 | 1,0 |
| N-O bond | 2 | 2 | 1,0 |
| Protein | 2 | 1 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Bromine | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Protein alpha helix | 1 | 1 | 1,0 |
| Urethane | 1 | 1 | 1,0 |
| Sulfate (SO4) | 1 | 1 | 1,0 |
| Carbonate | 1 | 1 | 1,0 |
| Aldehyde (CHO) | 1 | 1 | 1,0 |
| Bronsted acid site | 1 | 1 | 1,0 |
| Methyl | 1 | 1 | 1,0 |
| C c single bond | 1 | 0 | 1,0 |
| Nitrate | 1 | 0 | 1,0 |
| Phosphate (PO4) | 1 | 0 | 1,0 |
Rangering afspejler akkumuleret litteraturevidence, ikke en enkelt fast regel. Bekræft altid mod din prøvekontekst.
Spektrumlogik
Dette bånd bliver meningsfuldt kun, når det læses sammen med sine nabotoppe. I praksis ser analytikere først på tildelingerne ovenfor, og kontrollerer derefter, om den samme prøve også viser andre toppe, der forventes for det samme strukturelle motiv. Et enkelt bånd nær 1680 cm⁻¹ er normalt ikke nok til materialeidentifikation alene.
Anvendelse i virkeligheden
Denne type forespørgsel er almindelig ved polymeridentifikation, screening af ukendt plast, fejlfinding i kvalitetskontrol, verifikation af genanvendt materiale og litteraturunderstøttet gennemgang af peak-tildeling.
Almindelige fejl
- Behandling af et isoleret bånd som bevis på et materiale uden at kontrollere mindst en eller to understøttende toppe.
- Ignorerer overlap: flere funktionelle grupper kan bidrage nær samme bølgetal.
- Spring validering over, når additiver, blandinger, oxidation eller forurening kan forvrænge spektret.
Verifikationsrådgivning
Når tvetydighed fortsat består, valider hypotesen med DSC, GC-MS eller TGA, især for blandinger, nedbrudte prøver og fyldte polymerer.
Litteratur bag disse tildelinger
-
Alkene (C=C) tillid 1,0
“(cm-1) Component Spectral band Associated vibration C-C/C-O COM 780 single bond stretching C-C/C-O 1318 single bond stretching C-O 1630 double bond stretching C-O COD 1680 double bond stretching”
High precision mapping of kidney stones using mu;IR spectroscopy to determine urinary lithogenesis DOI: 10.1002/jbio.201300201 -
Amide tillid 1,0
“Finally, two major bands, the amide I and II cm-1, 1680-1500 bands observed in are discussed.”
Hirashima 等 - 2005 - ATR-FTIR spectroscopic study on hydrogen bonding o DOI: 10.1021/ma051081s -
Amide tillid 1,0
“aromatic ring and foremost absorption bands at 1692, 1620 and 1600 Both spectrum cm-1 peaks at 1680 and 1550 NNMB and NMB FAXs are related to amide I and II, respectively.”
Biochemical and Structural Characterization of Ferulated Arabinoxylans Extracted from Nixtamalized and Non-Nixtamalized Maize Bran DOI: 10.3390/foods11213374 -
Hydrogen bond tillid 1,0
“amide I band is more sensitive than amide II band concernindicatingthatthecarbonylstretchingvibrationofaminoacid ing the hydrogen bonding-related secondary structure, thus side chains of PGAIPG was exposed markedly in the pH 2.5 1680cm-1 th”
Lin 等 - 2005 - PHand thermal-dependent conformational transitio DOI: 10.1016/j.peptides.2004.11.005 -
Alkyl C-H tillid 1,0
“Drying droplets of mM of intact ketone moieties and the reduced strength of methylglyoxalsolutionsontheATRdiamondcrystalsurface bands in the region we assign to dioxolane structures CdO produced strong absorbance bands in both the (1680 ind”
Loeffler 等 - 2006 - Oligomer formation in evaporating aqueous glyoxal DOI: 10.1021/es060810wCCC -
Amide tillid 1,0
“Note that the subbands of amide I shown as shoulders in the absorption spectrum are seen in the Stark (cid:24)1630 (cid:24)1680 cm-1.”
Park 等 - 2000 - Vibrational Stark spectroscopy of NO bound to heme DOI: 10.1021/ja0014741 -
Alkene (C=C) tillid 1,0
“In contrast cm-1, to the Raman signal, the FT-IR spectrum shows the most intense vibrational mode at 1680 bond.12,13 attributed to the vibrational motion of the alkene group (C=C) and the C=O Although cm-1.”
EXPRESS: Vibrational Spectroscopic Characterization and Coherent Anti-Stokes Raman Spectroscopy (CARS) Imaging of Artepillin C DOI: 10.1177/0003702820904456 -
Bronsted acid site tillid 1,0
“Meanwhile, the peaks at 1467 4+)),20 s(NH while the two peaks at 3161 Brønsted acid sites ((cid:238) cm-1 weaken and remain until 473 K before and 1680 cm-1 and 3246 are attributed to s(NH 3) coordinated to Lewis (cid:238) cm-1 is disappear”
Pena 等 - 2004 - Identification of surface species on titania-suppo DOI: 10.1021/jp0313122
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