What absorbs at 1691 cm⁻¹ in an FTIR spectrum?
A band near 1691 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
Jawapan pantas
A band near 1691 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.
Penetapan kumpulan berfungsi yang mungkin
| Kumpulan berfungsi | Fakta sokongan | Sumber dipetik | Keyakinan tertinggi |
|---|---|---|---|
| Amide | 10 | 8 | 1.0 |
| Carbonyl (C=O) | 7 | 6 | 1.0 |
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Ketone | 5 | 5 | 1.0 |
| Ester | 5 | 5 | 1.0 |
| Carboxyl (COOH) | 5 | 5 | 1.0 |
| Protein beta sheet | 2 | 2 | 1.0 |
| Protein | 2 | 2 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
Pemeringkatan mencerminkan bukti literatur terkumpul, bukan satu peraturan berwibawa. Sentiasa sahkan terhadap konteks sampel anda.
Logik spektrum
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 1691 cm⁻¹ is usually not enough for material identification by itself.
Penggunaan dunia sebenar
Jenis pertanyaan ini biasa dalam pengenalpastian polimer, saringan plastik tidak diketahui, penyelesaian masalah QC, pengesahan bahan kitar semula, dan semakan tugasan puncak yang disokong oleh literatur.
Kesilapan biasa
- Menganggap satu jalur terpencil sebagai bukti bahan tanpa memeriksa sekurang-kurangnya satu atau dua puncak sokongan.
- Mengabaikan pertindihan: pelbagai kumpulan berfungsi boleh menyumbang berhampiran nombor gelombang yang sama.
- Melangkau pengesahan apabila bahan tambahan, campuran, pengoksidaan, atau pencemaran boleh memesongkan spektrum.
Nasihat pengesahan
Apabila kekaburan masih ada, sahkan hipotesis dengan DSC, GC-MS, atau TGA, terutamanya untuk campuran, sampel terdegradasi, dan polimer terisi.
Literatur di sebalik penetapan ini
-
Water (H2O) keyakinan 1.0
“This side chain is increased, allowing water molecules to fully solvate the D-ringcarbonylandshiftingthevibrationalfrequencyto1691cm-1.”
Chenchiliyan 等 - 2023 - Ground-state heterogeneity and vibrational energy DOI: 10.1063/5.0135268 -
Protein keyakinan 1.0
“(1656cm(cid:2)1), a-helix b-sheet and Krimm [20] observed that The thyroid spectra, in addition to evident strong protein peaks 1691cm(cid:2)1) (1647cm(cid:2)1) (1626, 1679, and unordered secondary cm(cid:2)1 1659cm(cid:2)1, at 1547 and als”
Das 等 - 2008 - FTIR of touch imprint cytology A novel tissue dia DOI: 10.1016/j.jphotobiol.2008.05.012 -
Protein keyakinan 1.0
“Another peak at 1691 was likely (cid:2)-sheet indicative of a structure formed by unfolding and aggreof the protein via lyophilization [44].”
Additives affecting thermal stability of salmon calcitonin in aqueous solution and structural similarity in lyophilized solid form DOI: 10.1016/j.procbio.2011.08.017 -
C=n keyakinan 1.0
“The C=N stretching frequency of free aminoguanidine cm-1, bicarbonate is known to occur at 1691 and a peak was observed in the complexes at cm-1, 1650 indicating that the imine nitrogen atom is involved in the complexation.”
Synthesis and Crystal Structure of [Ni(Amgu)2]X2 – Novel Solid-State Precursors for NiO Nanoparticles DOI: 10.1016/j.ica.2018.07.021 -
C c single bond keyakinan 1.0
“weak C-H stretching at 3.86.05 3810.57 3859.98 We further observed sharp asymmetric C = O cm-1, cm-1 carboxylate at 1691.28 C-C ring stretching at 1419.30 and C-N stretching of a tertiary amine at cm-1.”
Characterizing and demonstrating the role of Klebsiella SSN1 exopolysaccharide in osmotic stress tolerance using neutron radiography DOI: 10.1038/s41598-023-37133-w -
Acetate keyakinan 1.0
“cm-1 The narrow peak at 1691 fits chiefly to C=O stretching.”
Influence of gamma irradiation on rosin properties and its antimicrobial activity DOI: 10.1038/s41598-023-31372-7 -
Acetate keyakinan 1.0
“Based on the study of the FTIR spectrum of cm-1, the FTIR spectrum of DMPA, the C=O absorption peak of DMPA is located at 1691 which DMPA, the C=O absorption peak of DMPA is located at 1691 cm-1, which proves that the prepolymers”
Synthesis of Linseed Oil-Based Waterborne Urethane Oil Wood Coatings DOI: 10.3390/polym10111235 -
Amide keyakinan 1.0
“1940.31 - 1999.62,1951.55 1905.70 Allene Results concerning the banana peels derived activated carbon were stretching) similar to those reported by Zheng and Wang [34], whereas some peaks - 1690.75 - - Primary amide (C--O stretching) were i”
Preparation and characterization of activated carbon from agricultural wastes and their ability to remove chlorpyrifos from water DOI: 10.1016/j.toxrep.2023.01.011
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