What absorbs at 1518 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1518 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.

가능한 작용기 할당

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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 1518 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.

이 할당의 배경이 되는 문헌

• Alkyl C-H 신뢰도 1.0

  “The band at 1518 is generally ascribed to cm-1 C-H bending vibration and the band at 1030 assigned to C-O stretching of acetyl groups present in PVA.”

  Devi 等 - 2019 - Structural and optical studies on PVA capped SnS f DOI: 10.1088/1674-4926/40/5/052101
• Protein 신뢰도 1.0

  “A which are characteristic of proteins were observed with a maximum at around 1634 and 1518 cm-1, cm-1) which are indicative of the amide I band (1750-1600 and amide II band (1550-1510 cm-1), respectively.”

  Rafe 和 Razavi - 2015 - Effect of Thermal Treatment on Chemical Structure DOI: 10.1080/10942912.2014.999864
• Aromatic ring 신뢰도 1.0

  “theae (PT) is phylogenetically related to 3deformations)andemercm(cid:1)1 (CAH Pestalotiopsis, which has been reported to decolourize raw textile gence of peaks at 1518.20 bending in aromatic ring)”

  Decolourization of malachite green dye by endolichenic fungi from the lichen Usnea sp.: A novel study on their dye removal potential DOI: 10.1016/j.jksus.2021.101579
• 신뢰도 1.0

  “Since the color of melanin is resulted 184 from the absorption of light by electrons of chromophores (dihydroxyindole units in the 185 cm-1 eumelanin), stronger peak at 1518 of the N-H and C-N bands of SI melanin explains the N”

  Isolation and characterization of melanin from black garlic and sepia ink DOI: 10.1016/j.lwt.2018.09.033
• C c single bond 신뢰도 1.0

  “and (iv) the appearance of two IR bands According to Figure 5, the IR spectrum of protein G is dominated by two IR bands with maxima at 1699 and 1780 cm-1, both assigned to the C=O vibrational mode whose cm-1, at 1518 and 1634 which were as”

  Optical Evidence for the Assembly of Sensors Based on Reduced Graphene Oxide and Polydiphenylamine for the Detection of Epidermal Growth Factor Receptor DOI: 10.3390/coatings11020258
• C c single bond 신뢰도 1.0

  “C = O stretch, O7-H22 bend, and ring A C-C stretch at 1518 cm-1 cm-1, and 1518 Table 1 presents the relative absorbances in the SC layers at 1652 which correspond to the amounts of GEN that penetrated into the SC after conventional and”

  Balazs 等 - 2016 - ATR-FTIR and Raman spectroscopic investigation of DOI: 10.1364/BOE.7.000067
• Alkene (C=C) 신뢰도 1.0

  “Weak band near 1518 our results of DPPH assay obtained for methanolic arose from C=C stretching vibrations of phenoextracts.”

  Morphology, physicochemical properties and antioxidant capacity of bee pollens DOI: 10.17221/139/2018-CJFS
• Hydroxyl (O-H) 신뢰도 1.0

  “The hydroxyl groups bending vibrations exist at 1518 cm-1 and 1750 [34].”

  Kinetics of Dehydroxylation and Decarburization of Coal Series Kaolinite during Calcination: A Novel Kinetic Method Based on Gaseous Products DOI: 10.3390/ma14061493