What absorbs at 1552 cm⁻¹ in an FTIR spectrum?
A band near 1552 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
Quick answer
A band near 1552 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.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Amide | 8 | 7 | 1.0 |
| N h | 6 | 6 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| chitosan | 1552, 1650, 1655 | Alkyl C-H, Amide, Methacrylate | 3 |
| sodium alginate | 1552, 1636, 1080 | Alkyl C-H, Methacrylate, Amide | 1 |
| carrageenan | 1552, 1156, 1100 | Methacrylate, Alkyl C-H, Amide | 1 |
| hydrogel | 1552, 1632, 1062 | Amide, Methacrylate, Alkyl C-H | 1 |
| chitin | 1552, 1650, 1655 | Amide, Alkyl C-H, Methacrylate | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 1552 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
confidence 1.0
“The amide II absorption bands of ASC and PSC were detected at wavenumbers of 1546.84 cm-1 and 1551.66 cm-1, respectively.”
Song 等 - 2019 - Physicochemical and Biocompatibility Properties of DOI: 10.3390/md17030137 -
confidence 1.0
“Published cm(cid:2)1 presents a strong band at 1040 form a covalently-bound monolayer on chemically grown silicon characteristic of the is oxide.19,20 cm(cid:2)1, Si-O linkage as well as a band at 1552 Thus, in this synthesis, SiBr immediat”
A one-pot synthesis of water soluble highly fluorescent silica nanoparticles DOI: 10.1039/c6tb02813f -
Alkyl C-H confidence 1.0
“For instance, a single 3300 band was observed As expected, when the amount of HNa increased in the uncrosslinked blend, peaks for NH and OH stretching absorptions but the bands at 2870 (CH stretching), 1552 (amide cm-1 from HNa tend to be m”
Gabriela Chuc-Gamboa 等 - 2021 - Antibacterial Behavior of Chitosan-Sodium Hyaluron DOI: 10.3390/app1103 -
confidence 1.0
“(2012) reported that the cm-1 II-band at 1552 was determined analogous to the method of Sannan, Kurita, Ogura, bridge oxygen stretching band at 1163 cm-1 in the infrared spectrum is the most suitable and Iwakura (1978) for transmission IR s”
Extraction Optimization and Structural Characteristics of Chitosan from Cuttlefish (S. pharaonis sp.) Bone DOI: 10.3390/ma15227969 -
Acetate confidence 1.0
“shifted by 8 units to higher wavenumbers and occurs at 1552 The band of stretching vibrations of C-O group from the ether's part of the naproxen structure was shifted by”
Semi-Crystalline Copolymer Hydrogels as Smart Drug Carriers: In Vitro Thermo-Responsive Naproxen Release Study DOI: 10.3390/pharmaceutics13020158 -
Amide confidence 1.0
“difference in the position of the amide II band (1552 cm-1) in the (a)/G spectrum with reference to the cm´1) The difference in the position of the amide II band (1552 in the (a)/G spectrum with reference control sample (1544 cm-1) is 8 cm-”
Physicochemical Properties of Biopolymer Hydrogels Treated by Direct Electric Current DOI: 10.3390/polym8070248 -
confidence 1.0
“Amide II at cm-1 1552 arose from the bending vibration of the N-H groups and the stretching vibrations of the C-N groups.”
Flavor, antimicrobial activity and physical properties of gelatin film incorporated with of ginger essential oil DOI: 10.1007/s13197-021-05080-x -
C c single bond confidence 1.0
“Furthermore, for the spectrum of cm-1 1545, and 1552 cm-1, respectively, can be attributed to the C-C stretching vibration of benzene ring HACSa, HACCa, HACPc, and HACGa, absorption peaks at 781, 767, 772, 735, 739 corresponded 1478cm-1 [3,”
Modification of Hydroxypropyltrimethyl Ammonium Chitosan with Organic Acid: Synthesis, Characterization, and Antioxidant Activity DOI: 10.3390/polym12112460
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