What absorbs at 1548 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1548 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 1548 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

• Amide confidence 1.0

  “Explicit assignment in text: 'amide I and amide II regions (1695 and 1548 cm-1)'”

  Baldauf 等 - 2007 - Effect of selective growth media on the differenti DOI: 10.1016/j.mimet.2006.06.012
• confidence 1.0

  “The results showed major changes in lipids (vibration 1744 assigned to C=O stretching) cm-1 cm-1 and proteins (vibrations 1648 assigned to C=O stretching of amide I and 1548 assigned to N-H bending and C-N stretching in amid II).”

  Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan DOI: 10.1016/j.vibspec.2019.04.005
• Amide confidence 1.0

  “The characteristic absorption peaksarefoundtobeat2922cm-1isduetotheC Hstretching,1566cm-1iscorrespondsto cm-1 cm-1 C stretching vibration of quinoid ring, 1548 for C N bond stretching, 1494 C cm-1 is corresponds to stretching vibration of b”

  Patil 等 - 2011 - Electrical Conductivity of PolyanilineNiZnO3 Comp DOI: 10.1080/00150193.2011.620836
• Amide confidence 1.0

  “A low intensity of the is quite different from the spectrum of the reference amide II peak is indicative of a relatively small contricm-1, peaks at 1548 paper.”

  Povolotckaia 等 - 2019 - Biodamage to Paper by Micromycetes under Experimen DOI: 10.1134/S0030400X19040209
• Acetate confidence 1.0

  “c 0 obs IIbandat1548cm-1 α At the higher concentration of neem oil nanoemulsion (NE), can due to CNstretching C=O stretchingand amide be equated to (K [NE]/1 + K app[NE]).”

  Probing the interaction of neem oil based nanoemulsion with bovine and human serum albumins using multiple spectroscopic techniques DOI: 10.1016/j.molliq.2015.09.022
• Amide confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Interaction of NAEn-s-n gemini surfactants with bovine serum albumin A structure–activity probe DOI: 10.1016/j.jlumin.2012.08.058
• Amide confidence 1.0

  “The bands of the Amide II group at 1548 cm-1 and 1515 cm-1 1730-1760 has also been analyzed.”

  Andjelic 等 - 2023 - Characterization of Different Types of Epiretinal DOI: 10.3390/ijms24054834
• confidence 1.0

  “e r cm-1 band at 1548 corresponding to the N-H bending vibration of the amine group.”

  Coutinho 等 - 2012 - Microfabricated photocrosslinkable polyelectrolyte DOI: 10.1039/C2JM31374J.