What absorbs at 3331 cm⁻¹ in an FTIR spectrum?
A band near 3331 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Resposta rápida
A band near 3331 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possíveis atribuições de grupos funcionais
| Grupo funcional | Fatos de suporte | Fontes citadas | Maior confiança |
|---|---|---|---|
| Hydroxyl (O-H) | 8 | 8 | 1,0 |
| Hydrogen bond | 3 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Materiais possíveis
| Material | Picos de suporte | Grupos sobrepostos | Fontes citadas |
|---|---|---|---|
| TiO2 | 3331, 1700, 1093 | Metal oxygen, Hydroxyl (O-H) | 1 |
| polyurethanes | 3331, 1740, 1728 | N h | 1 |
| TiO | 3331, 1730, 1699 | Hydroxyl (O-H), Metal oxygen | 1 |
| polysaccharide | 3331, 1637, 1320 | Hydroxyl (O-H), N h | 1 |
| polyurethane | 3331, 2270, 1700 | N h | 1 |
| TiO2 nanoparticles | 3331, 1700, 455 | Hydroxyl (O-H), Metal oxygen, N h | 1 |
Os materiais são mostrados apenas quando o mesmo conjunto de literatura suporta esta banda e pelo menos um pico característico adicional.
Lógica do espectro
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 3331 cm⁻¹ is usually not enough for material identification by itself.
Uso no mundo real
Este tipo de consulta é comum em identificação de polímeros, triagem de plásticos desconhecidos, solução de problemas de CQ, verificação de materiais reciclados e revisão de atribuição de picos apoiada pela literatura.
Erros comuns
- Tratar uma banda isolada como prova de um material sem verificar pelo menos um ou dois picos de suporte.
- Ignorando sobreposição: vários grupos funcionais podem contribuir próximo ao mesmo número de onda.
- Ignorar a validação quando aditivos, misturas, oxidação ou contaminação podem distorcer o espectro.
Conselho de verificação
Quando a ambiguidade persistir, valide a hipótese com DSC, GC-MS ou TGA, especialmente para misturas, amostras degradadas e polímeros carregados.
Literatura por trás destas atribuições
-
Carbohydrate confiança 1,0
“Strong absorption was observed at 3279.62, 3272.35 glucose and galactose and xylose with different concentracm-1 corresponding to the hydroxyl vibration and 3331.21 tion which is dependent on many factors.”
Evaluation of the effect of soluble polysaccharides of palm kernel cake as a potential prebiotic on the growth of probiotics DOI: 10.1007/s13205-018-1362-4 -
Hydroxyl (O-H) confiança 1,0
“Interestengly, there was a strong absorption with a wide and strong band centred cm-1 at 3331 (O-H stretch) only observed in the untreated sample.”
Firsoni 等 - 2019 - Fiber Content and Relative Feed Value Estimation o DOI: 10.1088/1757-899X/546/4/042008 -
Hydroxyl (O-H) confiança 1,0
“cm-1 showed a decrease in the initial compounds and endings, especially at the 3331 peaks of the Delfín-Narciso,D.;Díaz,F.Impactof Geotrichum candidum O-H bonds.”
Impact of Dragon Fruit Waste in Microbial Fuel Cells to Generate Friendly Electric Energy DOI: 10.3390/su15097316 -
Acetate confiança 1,0
“assigned to the asymmetrical stretching of C-O-C groups and cm-1 The PU spectrum shows a strong absorption at 3331 cm-1 the C-O stretching vibrations at 1109 of the urethane arising from H-bonded N-H.”
Gabriela Echeverria 等 - 2015 - PolyurethanePoly(2-(Diethyl Amino)Ethyl Methacryl DOI: 10.1590/0104-1428.1716 -
N h confiança 1,0
“Explicit assignment in text: '3449 and 3331 (N-H stretch)'”
Supramolecular Interactions Induce Unexpectedly Strong Emissions from Triphenylamine-Functionalized Polytyrosine Blended with Poly(4-vinylpyridine) DOI: 10.3390/polym9100503 -
Metal oxygen confiança 1,0
“In TiO 2-DHBAOA, the bands at the FTIR spectrum of TiO cm-1, assigned to the stretching vibra3331 and 3233 tions of aldehyde phenolic -OH groups, and bands cm-1, corresponding to the bending at 1389 and 1192”
Radoman 等 - 2015 - Effect of surface modified TiO2 nanoparticles on t DOI: 10.3144/expresspolymlett.2015.83 -
Hydroxyl (O-H) confiança 1,0
“making it possible to observe the most intense peak at 3331 belonging to cm-1 substances such as carvings or leaves of any kind of fruit or vegetable are used as fuel, the the O-H bonds, while the peak at 2969 and 2805 belongs to the alkane”
Potential Use of Coriander Waste as Fuel for the Generation of Electric Power DOI: 10.3390/su15020896 -
Hydroxyl (O-H) confiança 1,0
“LLM confirmed rule peak-group candidate”
Salman 等 - 2020 - In Vitro Antimicrobial and Antioxidant Activities DOI: 10.3390/molecules25204685
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