What absorbs at 1627 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1627 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

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

Possible materials

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 1627 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

• Hydroxyl (O-H) confidence 1.0

  “Meanwhile, a moderately sharp peak emerged cm-1 at 1627 corresponds to the hydroxyl (O-H) bending vibrational mode [32].”

  Aziz 等 - 2023 - Water remediation capability of cubic-phase CdS na DOI: 10.15251/DJNB.2023.181.203
• Carbonyl (C=O) confidence 1.0

  “cm-1 and 2856 are characteristic stretch, two bands at 2933 viewed at wileyonlinelibrary.com] ─CH ─CH of aliphatic asymmetric and symmetric stretching of 2 cm-1 verified groups, and the amidic carbonyl stretch at 1627 the”

  Influence of amine‐terminated additives on thermal and mechanical properties of diglycidyl ether of bisphenol A (DGEBA) cured epoxy DOI: 10.1002/app.48404
• Acetate confidence 1.0

  “cm-1, the monomers of both gums, as well as the bands present at 1627 and 1409 which are related to The band on the scaffold spectrum at 1149 cm-1 is derived from the C-O type bonds present in the monomers of both gums, as well as the bands”

  Development of Composite Scaffolds Based on Cerium Doped-Hydroxyapatite and Natural Gums—Biological and Mechanical Properties DOI: 10.3390/ma12152389
• C=n confidence 1.0

  “cm-1, For quantification, absorbance of C=O stretch cantered at 1754 between wave number of 1750 - cm-1 cm-1, 1730 was selected for Aspirin and absorbance of C=N stretch cantered at 1627 between 1690 cm-1 - 1620 was used for Omeprazole.”

  Chandarana 和 Kapupara - 2020 - Fourier Transform Infrared Spectrophotometry An E DOI: 10.30744/brjac.2179-3425.AR-25-2020
• Amide confidence 1.0

  “The FTIR spectrum of extracellular mycosynthesis of ZnO NPs by Alternaria alternata cm-1 showed the absorption band at 1627 corresponding to the amide I of polypeptides [18].”

  An Investigation of the Cytotoxicity and Caspase-Mediated Apoptotic Effect of Green Synthesized Zinc Oxide Nanoparticles Using Eclipta prostrata on Human Liver Carcinoma Cells DOI: 10.3390/nano5031317
• Carbonyl (C=O) confidence 1.0

  “The band at 1627 was Lathyrus sativus peel extract could be conceptualized by the following (C-- ascribed due to the carbonyl group O) of carboxylic acid (capping reaction Scheme 1 proposed by (Awwad and Salem, 2012) and (Ramesh cm(cid:0) 1”

  Green synthesis of magnetite nanoparticles using Lathyrus sativus peel extract and evaluation of their catalytic activity DOI: 10.1016/j.clet.2021.100117
• Acetate confidence 1.0

  “Moreover, the peak at 1627 corresponds to -C=O cm-1 should be a sign of the excess of GA [18] and the disappearance of peak at 1400 for -CH and -CH”

  Hendrawanh 等 - 2019 - Poly (vinyl alcohol)glutaraldehydePremna oblongi DOI: 10.1088/1757-899X/509/1/012048
• Carboxyl (COOH) confidence 1.0

  “Stronger to carboxyl ion stretching band Cumolative intensity of ester carbonyl peak at 1746 compared to 40 free carboxyl band at 1627 indicated an increase in the”

  Nisinloaded alginatehigh methoxy pectin microparticles: preparation and physicochemical characterisation DOI: 10.1111/ijfs.12516