What absorbs at 3348 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3348 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 3348 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

• Amine primary confidence 1.0

  “The appearance of the peak cm-1 at 3348 was attributed to the presence of primary amine stretches [10].”

  Ishak 等 - 2020 - The Effect of Crosslinking Agent on Protein-Based DOI: 10.1063/5.0016189
• Silicon (Si) confidence 1.0

  “Peak Assignment of PAL and the Stretching According to the Spectrum of the PAL Casting Film in Figure 1 and the Spectrum of the Si Substrate in Figure 2 (cm-1) peak position assignment N-H 3348 asym stretching of NH2 ((cid:238)) N-H 3200 sy”

  Lu 和 Mi - 2005 - Characterization of the interfacial interaction be DOI: 10.1021/ma0486896
• Alkyl C-H confidence 1.0

  “vibration.27 cm-1 CH stretching are related to C=C bonds in the aromatic The absorptions at 3348, 2889, 1647, 1431, rings of lignin and C-O-C stretching of cm-1 hemicelluloses.33-35Generally, 1373, 1166, 1058, 1033 and 897 are related the b”

  Allouch 等 - 2019 - CHARACTERIZATION OF COMPONENTS ISOLATED FROM ALGER DOI: 10.1016/j.pecs.2012.02.002
• Hydroxyl (O-H) confidence 1.0

  “The BC film showed peaks centered at 3348 2S, Supplementary cm-1 cm-1 assigned to O-H and C-H stretching, respectively.”

  Modified bacterial cellulose scaffolds for localized doxorubicin release in human colorectal HT-29 cells DOI: 10.1016/j.colsurfb.2016.01.007
• Acetate confidence 1.0

  “[24] C-O-C bending OH stretching 3348 Polydopamine [86]”

  Kravanja 和 Finsgar - 2021 - Analytical Techniques for the Characterization of DOI: 10.3390/biomedicines9121936
• Hydroxyl (O-H) confidence 1.0

  “The vibration band at cm-1 3348.4 observes the OH stretching that overlap with amine and NH amide of Chitosan observes.”

  Nugraheni 等 - 2016 - Study of Thermal Degradation of PVAChitosanGelat DOI: 10.1063/1.4958590
• Amide confidence 1.0

  “Probably, the first band at 3348 bands belong to the C-N bond in aromatic secondary”

  Santiago-Medina 等 - 2017 - Polycondensation Resins by Lignin Reaction with (P DOI: 10.7569/JRM.2017.634142
• Hydroxyl (O-H) confidence 1.0

  “In the pure chitosan membranes (Figure 7B(a)), cm-1, the characteristic peaks were around 3348 and 3297 which were attributed to the stretching cm-1 vibration of the -OH groups and -NH groups, respectively [59].”

  Xing 等 - 2020 - Effects of Different TiO(2)Nanoparticles Concentra DOI: 10.3390/nano10071365