Hvad absorberer ved 1800 cm⁻¹ i et FTIR-spektrum?
Et bånd nær 1800 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 1800 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) | 27 | 22 | 1,0 |
| Amide | 16 | 16 | 1,0 |
| Carboxyl (COOH) | 14 | 12 | 1,0 |
| Methacrylate | 13 | 13 | 1,0 |
| Acetate | 13 | 13 | 1,0 |
| Ketone | 11 | 11 | 1,0 |
| Ester | 11 | 11 | 1,0 |
| Alkyl C-H | 10 | 9 | 1,0 |
| Hydroxyl (O-H) | 6 | 6 | 1,0 |
| Alkene (C=C) | 5 | 5 | 1,0 |
| N-O bond | 3 | 3 | 1,0 |
| Protein | 2 | 2 | 1,0 |
| Methoxy (OCH3) | 2 | 2 | 1,0 |
| C-O single bond | 2 | 2 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| C n single bond | 2 | 2 | 1,0 |
| Water (H2O) | 2 | 2 | 1,0 |
| Carbonate | 2 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Adsorbed carbon monoxide | 1 | 1 | 1,0 |
| Nucleic acid | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| Fatty acid | 1 | 1 | 1,0 |
| Lipid | 1 | 1 | 1,0 |
| C=n | 1 | 1 | 1,0 |
Rangering afspejler akkumuleret litteraturevidence, ikke en enkelt fast regel. Bekræft altid mod din prøvekontekst.
Mulige materialer
| Materiale | Understøttende toppe | Overlappende grupper | Citerede kilder |
|---|---|---|---|
| cotton fabric | 1800, 900, 862 | Methacrylate, Amide | 1 |
| DNA | 1800, 1712, 1660 | Amide, Methacrylate, Carbonyl (C=O) | 1 |
Materialer vises kun, når den samme litteraturpulje understøtter dette bånd og mindst en yderligere karakteristisk top.
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 1800 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
-
Hydroxyl (O-H) tillid 1,0
“1422.2 1423.5 1425.8 1425.7 1428.6 1426.9 1423.5 1428.6 Due to carbonation intensity increases 1484.6 1484.6 as hydration progresses - 1600 1673 1657.7 1657.7 1657.2 1640.3 1657.7 Due to H-O-H bending vibration 1800.3 1800 1795.2 - -”
Theoretical and experimental study of structures and properties of cement paste The nanostructural aspects of C–S–H DOI: 10.1016/j.jpcs.2011.05.001 -
Alkyl C-H tillid 1,0
“(2006) used the ratio of 1600/1030 (carquartz overtone bands between 1800 and 2000 and the cm-1 boxylate/polysaccharide) as an index of decomposition in peat, CH deformation band between 1270 and 1460 (Fig.”
Calderon 等 - 2011 - Chemical Differences in Soil Organic Matter Fracti DOI: 10.2136/sssaj2009.0375 -
Carbonyl (C=O) tillid 1,0
“LLM confirmed rule peak-group candidate”
Characterization of cotton fabric scouring by Fourier transform-infrared attenuated total reflectance spectroscopy, gas chromatography-mass spectrometry and water absorption measurements DOI: 10.1177/0040517518790976 -
Alkene (C=C) tillid 1,0
“Absorption bands in the region between 1800 and 1500 were mainly derived from the vibration of double bonds, such as C=N, C=O and C=C [21,25].”
Han 等 - 2018 - Insight into Rapid DNA-Specific Identification of DOI: 10.3390/molecules23112842 -
Alkene (C=C) tillid 1,0
“cm-1 The IR absorption bands in the region between 1800 and 1500 were mainly assigned to the C=C, C=N, and C=O stretching vibrations (Banyay et al., 2003;”
A novel FTIR discrimination based on genomic DNA for species-specific analysis of meat and bone meal DOI: 10.1016/j.foodchem.2019.05.088 -
Alkyl C-H tillid 1,0
“The spectra of goat leathers in region from 1800 to the vibrations at and at were almost absent in 2919cm(cid:3)1, 3003cm(cid:3)1 -C-H, were merged with the band at in the vegetable tanned the spectra of the chrome tanned leather.”
Hassan - 2019 - Fourier transform infrared spectroscopy to detect DOI: 10.1080/00387010.2019.1623262 -
Alkyl C-H tillid 1,0
“2917 corre3 Transmission FTIR Microscopic mode.32-34 sponded to the asymmetric CH stretching 2 Measurements cm(cid:1)1 The spectral absorption between 1800 and 1000 cm(cid:1)1 is the fingerprint region.”
Pressure dependence of human fibrinogen correlated to the conformational [alpha]-helix to [beta]-sheet transition: An Fourier transform infrared study microspectroscopic study DOI: 10.1002/bip.20012 -
Water (H2O) tillid 1,0
“and water peaks below 1800 As shown 20 21”
Powell 等 - 2017 - CO Adsorption on AuTiO2 Catalysts Observations, DOI: 10.1021/acs.jpcc.7b07249
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