Hvad absorberer ved 1620 cm⁻¹ i et FTIR-spektrum?
Et bånd nær 1620 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 1620 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 |
|---|---|---|---|
| Amide | 34 | 30 | 1,0 |
| Hydroxyl (O-H) | 29 | 24 | 1,0 |
| Carbonyl (C=O) | 26 | 24 | 1,0 |
| Carboxyl (COOH) | 24 | 24 | 1,0 |
| Water (H2O) | 23 | 20 | 1,0 |
| Aromatic ring | 22 | 15 | 1,0 |
| Alkyl C-H | 19 | 16 | 1,0 |
| Alkene (C=C) | 16 | 14 | 1,0 |
| N h | 16 | 13 | 1,0 |
| Methacrylate | 14 | 14 | 1,0 |
| Acetate | 14 | 14 | 1,0 |
| Ester | 13 | 12 | 1,0 |
| Ketone | 12 | 12 | 1,0 |
| Protein beta sheet | 9 | 8 | 1,0 |
| C c single bond | 9 | 7 | 1,0 |
| Secondary amine | 7 | 6 | 1,0 |
| C=n | 7 | 6 | 1,0 |
| Hydrogen bond | 4 | 3 | 1,0 |
| C-O single bond | 3 | 3 | 1,0 |
| Methoxy (OCH3) | 3 | 3 | 1,0 |
| N-O bond | 3 | 3 | 1,0 |
| C n single bond | 3 | 3 | 1,0 |
| Carbohydrate | 3 | 2 | 1,0 |
| Methyl | 2 | 2 | 1,0 |
| Amine primary | 2 | 2 | 1,0 |
| Oxalate | 2 | 1 | 1,0 |
| N n bond | 2 | 1 | 1,0 |
| Amino acid | 1 | 1 | 1,0 |
| Protein beta turn | 1 | 1 | 1,0 |
| Carbonate | 1 | 1 | 1,0 |
| Protein alpha helix | 1 | 1 | 1,0 |
| Nitrile | 1 | 1 | 1,0 |
| Lignin | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Fluorine (C-F) | 1 | 1 | 1,0 |
| Metal hydroxyl | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Phenolic | 1 | 1 | 0,9 |
| Phosphate (PO4) | 1 | 0 | 1,0 |
| Lewis acid site | 1 | 0 | 0,9 |
Rangering afspejler akkumuleret litteraturevidence, ikke en enkelt fast regel. Bekræft altid mod din prøvekontekst.
Mulige materialer
| Materiale | Understøttende toppe | Overlappende grupper | Citerede kilder |
|---|---|---|---|
| PMMA | 1620, 1722, 1383 | Carbonyl (C=O), Carboxyl (COOH) | 1 |
| Polyaniline | 1620, 1565, 1570 | Amide | 1 |
| nanocellulose | 1620, 1540, 1646 | Amide, Hydroxyl (O-H) | 1 |
| soil | 1620, 575, 1240 | Hydroxyl (O-H), Carboxyl (COOH) | 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 1620 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
-
C c single bond tillid 1,0
“LLM confirmed rule peak-group candidate”
Electrically conductive nanocomposites of PMMA and carbon nanotubes prepared by in situ polymerization under probe sonication DOI: 10.1007/s11696-018-0443-5 -
Carboxyl (COOH) tillid 1,0
“COO-/C=C C-H vibrations 3rd peak showing the three main vibrational modes of CO (in order 2 (1620cm-1), 1525cm-1 (C=C).”
Demyan 等 - 2013 - Combining a coupled FTIR-EGA system and in situ DR DOI: 10.5194/bg-10-2897-2013 -
Aromatic ring tillid 1,0
“5 show also an overlapC@C cm-1, feature is connected with the stretching of quinoid rings that are ping band at 1620 undetected in Fig.”
Revisiting the Redox Transitions of Polyaniline. Semiquantitative Interpretation of Electrochemically Induced IR Bands DOI: 10.1016/j.jelechem.2021.115593 -
N-O bond tillid 1,0
“No peak was seen at 1620 due to ular hydrogen bonds get disturbed by LiCl/DMAc solvent system and (C\\O amide I stretching vibrations), verifying the complete removal Clformed a hydrogen bond between the anions and the hydroxyl”
Kale 和 Gorade - 2019 - Potential application of medical cotton waste for DOI: 10.1016/j.ijbiomac.2018.11.196 -
Protein beta sheet tillid 1,0
“The the band at 1668 During the binding of Cu(II) ions, the intensity of the band at cm-1 cm-1, β-sheet R-helix, are assigned to the which is assigned to an decreased while the bands at 1620 and 1680 1650 conformation.Thevalueof1620cm-1fora”
Kim 等 - 2010 - Molecular Rearrangement of Metal-Chelating Lipid M DOI: 10.1021/la902052f -
Hydroxyl (O-H) tillid 1,0
“The fundamental absorption peaks at 1620 & 3400 are assigned to the bending and stretching vibrations of O-H group.”
Kundu 等 - 2018 - Synthesis and characterization of iron and copper DOI: 10.1063/1.5051300 -
Carbohydrate tillid 1,0
“LLM confirmed rule peak-group candidate”
Lapuz 等 - 2022 - Production of Nanocellulose Film from Abaca Fibers DOI: 10.3390/cryst12050601 -
Carbonyl (C=O) tillid 1,0
“N A The infrared spectra of COM and COD have strong absorption peaks at 1620 and 1640 M cm-1, respectively, which are due to antisymmetric carbonyl stretching motions [23].”
Quantitative analysis of calcium oxalate hydrate urinary stones using FTIR and 950/912 cm-1 peak ratio DOI: 10.1016/j.vibspec.2019.03.006
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