• Top library match: 2-Hydroxyhexanedial #584

• A related‑literature correlation table strongly attributes the pair of bands at 1517 and 1337 cm⁻¹ to asymmetric and symmetric stretching modes of aromatic nitro groups [S2]. This assignment is chemically distinct from methoxy/methacrylate and raises the possibility of a contaminant or an alternative interpretation.
• Several candidates attribute peaks to inorganic species (sulfate at 671 cm⁻¹ [8], carbonate at 1434 cm⁻¹ [2]), which are incompatible with a purely organic methacrylate material and suggest either sample impurity or over‑interpretation.
• The library match is of extremely low confidence (15%), S-O the methoxy/methacrylate direction should be regarded as a weak inference rather than a definitive identification.
• The simultaneous presence of bands that can be read as aromatic nitro groups creates an unresolved contradiction; the current data cannot exclude the possibility that the sample contains an aromatic nitro compound instead of, or in addition to, the suggested methoxy/methacrylate chemistry.
• Many peak assignments rely on analogical or broad sources; the absence of a definitive standard spectrum prevents a firm structural conclusion.

Recommended next steps: Perform GC‑MS or NMR analysis to verify the presence of methacrylate or nitroaromatic moieties. Obtain a higher‑quality FTIR spectrum with improved signal‑to‑noise and, if possible, run a solvent extraction to isolate organic components for separate analysis. Compare with reference spectra of common methacrylate polymers (e.g., poly(methyl methacrylate), poly(ethylene glycol) dimethacrylate) and of simple aromatic nitro compounds to narrow the chemical class. Investigate the sample’s thermal behavior (TGA) and elemental analysis to complement the structural hypothesis.