Hvad absorberer ved 1720 cm⁻¹ i et FTIR-spektrum?
Et bånd nær 1720 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 1720 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) | 129 | 113 | 1,0 |
| Carboxyl (COOH) | 83 | 76 | 1,0 |
| Ester | 75 | 70 | 1,0 |
| Amide | 73 | 68 | 1,0 |
| Acetate | 73 | 68 | 1,0 |
| Methacrylate | 72 | 67 | 1,0 |
| Ketone | 65 | 61 | 1,0 |
| Methoxy (OCH3) | 16 | 15 | 1,0 |
| C-O single bond | 16 | 15 | 1,0 |
| Alkyl C-H | 12 | 11 | 1,0 |
| Hydroxyl (O-H) | 8 | 7 | 1,0 |
| Alkene (C=C) | 6 | 6 | 1,0 |
| Aromatic ring | 5 | 4 | 1,0 |
| Secondary amine | 4 | 4 | 1,0 |
| N h | 4 | 4 | 1,0 |
| Urethane | 4 | 4 | 1,0 |
| C n single bond | 3 | 3 | 1,0 |
| Acetyl | 3 | 3 | 1,0 |
| Water (H2O) | 3 | 3 | 1,0 |
| Methyl | 3 | 3 | 1,0 |
| Carbohydrate | 3 | 3 | 1,0 |
| Ring structure | 3 | 2 | 1,0 |
| Protein | 2 | 2 | 1,0 |
| Aldehyde (CHO) | 2 | 2 | 1,0 |
| N-O bond | 2 | 2 | 1,0 |
| Hydrogen bond | 2 | 2 | 1,0 |
| Lignin | 2 | 2 | 1,0 |
| Imide | 2 | 2 | 0,9 |
| Oxygen heterocycle | 1 | 1 | 1,0 |
| Amino acid | 1 | 1 | 1,0 |
| Oxalate | 1 | 1 | 0,9 |
| C=n | 1 | 1 | 0,6 |
Rangering afspejler akkumuleret litteraturevidence, ikke en enkelt fast regel. Bekræft altid mod din prøvekontekst.
Mulige materialer
| Materiale | Understøttende toppe | Overlappende grupper | Citerede kilder |
|---|---|---|---|
| starch | 1720, 1650, 1540 | Amide | 1 |
| polystyrene | 1720, 1020, 1600 | Carbonyl (C=O), Amide | 1 |
| LDPE | 1720, 1737, 747 | Carbonyl (C=O) | 1 |
| polysaccharides | 1720, 1053, 1143 | Carbonyl (C=O), Amide, 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 1720 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
-
Carboxyl (COOH) tillid 1,0
“LLM confirmed rule peak-group candidate”
Structural modification and functional improvement of starch nanoparticles using vacuum cold plasma DOI: 10.1016/j.ijbiomac.2019.12.167 -
Carboxyl (COOH) tillid 1,0
“cm(cid:1)1 in The appearance of an absorption peak at 1720 purified milled HEC/AA samples was attributed to C¼¼O stretching vibrations of the carboxyl group in AA, which demonstrated the success of grafting.”
Solid state mechano-chemical grafting copolymerization of hydroxyethyl cellulose with acrylic acid DOI: 10.1002/app.30098 -
Carbonyl (C=O) tillid 1,0
“[32] built a regression model to determine FFA content by identifying the ν(C=O) ester vibration and the ν(C=O) of the carboxylic acid, which corresponded to 1747 and the 1720 cm-1, respectively.”
Monitoring Enzymatic Hydroesterification of Low-Cost Feedstocks by Fourier Transform InfraRed Spectroscopy DOI: 10.3390/catal9060535 -
Acetate tillid 1,0
“The to 1600 acyl groups, C-O (peak at 1220 and cm-1) = bacteria used LDPE as their source of carbon and made the carbonyl groups, C O (peak near 1720 was mainly necessary changes incorporating the functional groups to modify found.”
Biodegradation of Unpretreated Low-Density Polyethylene (LDPE) by Stenotrophomonas sp. and Achromobacter sp., Isolated From Waste Dumpsite and Drilling Fluid DOI: 10.3389/fmicb.2020.603210 -
Acetate tillid 1,0
“cm-1, For E1 (Fig.3a), the intensities of the absorptions at 1514 assigned to the aromatic C=C cm-1, deformation, and near 1720 assigned to the C=O stretching band in the lignin, increase from the surface to the depth.”
FTIR spectroscopy of woods: a new approach to study the weathering of the carving face of a sculpture DOI: 10.1016/j.saa.2014.10.011 -
Acetate tillid 1,0
“(2002) studied the heat degradation of lignin in hardwood and softwood cm-1 and obtained an increase in the peak at 1720 with increasing temperature, which they concluded to be due to the production of C=O bonds in lignin.”
Esteves 等 - 2013 - CHEMICAL CHANGES OF HEAT TREATED PINE AND EUCALYPT DOI: 10.4067/S0718-221X2013005000020 -
Carboxyl (COOH) tillid 1,0
“This D3 band, which is mainly responsible for symmetric stretching bands occur at 1651 and 1405 in the the severe band overlap in the Raman spectra of both diesel polyitaconic carboxylate and are typical of polycarboxylates acids.12 soot an”
Gaffney 等 - 2015 - Characterization of Fine Mode Atmospheric Aerosols DOI: 10.1021/jp510361s -
Ester tillid 1,0
“The spectrum shows reduction in the and appearance of a new cm(cid:3)1 cm(cid:3)1 intensity of the anhydride band at 1780 and 1857 peak at 1720 due to the ester and the carboxylic acid”
Galgali 等 - 2007 - Sugar-linked biodegradable polymers Regio-specifi DOI: 10.1016/j.carbpol.2006.06.035
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