What absorbs at 3349 cm⁻¹ in an FTIR spectrum?
A band near 3349 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 3349 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) | 6 | 6 | 1,0 |
| N h | 3 | 3 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Protein | 1 | 1 | 1,0 |
| Hydrogen bond | 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 | 3349, 1700, 1093 | Hydroxyl (O-H), Methoxy (OCH3) | 1 |
| GO | 3349, 1720, 1182 | Hydroxyl (O-H), Methoxy (OCH3) | 1 |
| chitosan | 3349, 1650, 1655 | Hydroxyl (O-H), N h, Methoxy (OCH3) | 1 |
| TiO2 nanoparticles | 3349, 1700, 455 | Hydroxyl (O-H), Methoxy (OCH3), 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 3349 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
-
Hydrogen bond confiança 1,0
“The strong peak at 3349 attributed to the intra-molecular hydrogen bonds for (3)O-H-O(5), as shown in Fig.”
Manuscript Preparation Instruction for Publishing in Computer Modeling in Engineering and Science (CMES) DOI: 10.3970/cmc.2018.03608 -
Hydroxyl (O-H) confiança 1,0
“After modification, a strong and wide band of O-H that overlapped with N-H band (3349 cm-1) cm-1.”
Synthesis and characterizations of o-nitrochitosan based biopolymer electrolyte for electrochemical devices DOI: 10.1371/journal.pone.0212066 -
Secondary amine confiança 1,0
“In peak at 1746 cm-1 cm-1 M4T2,the broad PVP peak FTIR spectrum at 3349 represents the stretching vibration M4T2,the broad PVP peak FTIR spectrum at 3349 cm-1 represents the stretching vibracm-1 of the secondary amine N-H group present in P”
TiO2 Nanoparticle Filler-Based Mixed-Matrix PES/CA Nanofiltration Membranes for Enhanced Desalination DOI: 10.3390/membranes11060433 -
N h confiança 1,0
“cm-1 vibration of the sulphonamide (3395 in pure furosemide, 3397 in physical mixtures), NH stretchingvibrationofthesecondaryaminegroup(3348cm-1 3349cm-1 inpurefurosemide, inphysical”
Kovacs 等 - 2020 - Influence of Aqueous Solubility-Enhancing Excipien DOI: 10.3390/pharmaceutics12040385 -
confiança 1,0
“3357 and Cd (3353 A decrease in the peak wavenumbers occurred in the spectra for Cu for Cu assigned at a band of 3349 cm-1, Pb (3330 cm-1) and Zn (3341 cm-1).”
Sensitivity and Calibration of the FT-IR Spectroscopy on Concentration of Heavy Metal Ions in River and Borehole Water Sources DOI: 10.3390/app10217785 -
Protein confiança 1,0
“The bands between 3349 and 3374 represents the secondary structure of the protein skeleton, which is often used for the quan-”
Tomczynska-Mleko 等 - 2023 - Co-Gelation of Pumpkin-Seed Protein with Egg-White DOI: 10.3390/foods12102030 -
Hydroxyl (O-H) confiança 1,0
“LLM confirmed rule peak-group candidate”
Reduced graphene Oxide/NiO based nano-composites for the efficient removal of alizarin dye, indigo dye and reduction of nitro aromatic compounds DOI: 10.1016/j.heliyon.2023.e17162 -
Hydroxyl (O-H) confiança 0,9
“Broadest absorption peak around 3349 mainly assigned to O-H stretching.”
Geng 等 - 2020 - Quality Attributes and Microstructure of Cell Wall DOI: 10.3136/fstr.26.281
Tem um espectro com esta banda?
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