What absorbs at 2877 cm⁻¹ in an FTIR spectrum?
A band near 2877 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 2877 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 |
|---|---|---|---|
| Alkyl C-H | 11 | 11 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 0.8 |
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 | 2877, 1650, 1655 | Alkyl C-H, Hydroxyl (O-H), N h | 2 |
| Cellulose | 2877, 1735, 1650 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| Epoxy | 2877, 1660, 1735 | Alkyl C-H | 1 |
| polydopamine | 2877, 1543, 1707 | Alkyl C-H, N h, Hydroxyl (O-H) | 1 |
| PEG | 2877, 1650, 1342 | Alkyl C-H, Hydroxyl (O-H) | 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 2877 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
-
Alkyl C-H confidence 1.0
“The C-H bond peak is observed at about 2877”
Removal of Hexavalent Chromium by Cross-Linking Chitosan and N,N’-Methylene Bis-Acrylamide DOI: 10.1007/s40710-020-00447-2 -
Alkyl C-H confidence 1.0
“For its part, cm-1 the FTIR spectrum of PEG exhibits bands at 2877 cm-1 C-H O-H of stretching vibration;”
Effect of PEG grafting density on surface properties of polyurethane substrata and the viability of osteoblast and fibroblast cells DOI: 10.1007/s10856-022-06668-1 -
Hydroxyl (O-H) confidence 1.0
“The pristine cellulose paper spectrum shown in Figure 4b shows a strong, broad band from 3600-3000 cm-1 resulting from the stretching vibrations cm-1 shows a strong, broad band from 3600-3000 resulting from the stretching vibrations of of t”
Well-Dispersed Silver Nanoparticles on Cellulose Filter Paper for Bacterial Removal DOI: 10.3390/nano11030595 -
Alkyl C-H confidence 1.0
“The FTIR peaks for were HCl cm-1 cm-1 cm-1 observed at 3357 (N-H and O-H stretching vibrations), 2920 and 2877 cm-1 (axial stretching of C-H in the polymer chain), 1656 (amide I vibration modes), 1568”
Physicochemical Properties and Functional Characteristics of Ecologically Extracted Shrimp Chitosans with Different Organic Acids during Demineralization Step DOI: 10.3390/molecules27238285 -
Alkyl C-H confidence 1.0
“However, peaks of 2877 and 3965 are for lipid, cholescm-1 terol, and proteins methyl (C-H bond) stretching, while the 3290 band is exhibiting -OH and -NH stretching”
A cutback in Imiquimod cutaneous toxicity; comparative cutaneous toxicity analysis of Imiquimod nanotransethosomal gel with 5% marketed cream on the BALB/c mice DOI: 10.1038/s41598-022-18671-1 -
Alkyl C-H confidence 1.0
“The bands at 2877 and 2921 cm-1 were attributed to C-H asymmetric and symmetric, respectively, whereas 3291-3610 corresponded to N-H and O-H stretching [42].”
Modified Poly(Lactic Acid) Epoxy Resin Using Chitosan for Reactive Blending with Epoxidized Natural Rubber: Analysis of Annealing Time DOI: 10.3390/polym14061085 -
confidence 1.0
“N-H stretching 3295 N-H stretching 1631 cm-1 3401 cm-1 1453 cm-1 2877 cm-1”
Effects of Cyclodextrins ( and ) and l-Arginine on Stability and Functional Properties of Mucoadhesive Buccal Films Loaded with Omeprazole for Pediatric Patients DOI: 10.3390/polym10020157 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
The Effect of Pollutant Gases on Surfactant Migration in Acrylic Emulsion Films: A Comparative Study and Preliminary Evaluation of Surface Cleaning DOI: 10.3390/polym13121941
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.