How can you identify humic acid from FTIR?
This page summarizes the recurring FTIR evidence reported for humic acid, including the most frequent peaks, supporting functional groups, and literature-backed interpretation patterns. It is a structured evidence page, not a claim of automatic single-spectrum certainty.
Backed by 11 cited sources
Quick answer
humic acid is usually reported with a recurring pattern of peaks and functional-group evidence. The most useful approach is to cross-check at least two characteristic peaks before treating it as a match, then verify whether the full spectrum still fits the same material family.
Peak interpretation
Possible materials / groups
| Functional group | Evidence |
|---|---|
| Methacrylate | 13 |
| Acetate | 13 |
| Alkyl C-H | 12 |
| Carboxyl (COOH) | 12 |
| Methoxy (OCH3) | 12 |
| C-O single bond | 12 |
| Hydroxyl (O-H) | 9 |
| Aromatic ring | 4 |
Spectrum logic
The logic here is evidence aggregation: repeated literature mentions of humic acid, repeated peak positions, and repeated functional-group associations. A strong material hypothesis should still be supported by multiple peaks that agree with each other, not by one headline band alone.
Real-world usage
This page is designed for polymer identification, incoming-material QC, unknown plastic analysis, recycled-content review, and literature-backed interpretation of reference spectra.
Common mistakes
- Calling a material match too early because one famous peak is present.
- Ignoring sample prep, fillers, oxidation, water, or additives that can change the apparent pattern.
- Using literature evidence without checking whether your own sampling mode and spectrum quality are comparable.
Verification advice
Use DSC, GC-MS, or TGA to validate the material hypothesis when the peak pattern is ambiguous or mixed.
Literature behind this page
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confidence 4.0
humic acid
Properties of humus-like substances isolated from organic wastes and their effects on structures of soil humus by Fourier transform infrared spectroscopy DOI: 10.1080/03650340.2020.1818072 -
confidence 4.0
humic acid
Properties of Humic Substances in Composts Comprised of Different Organic Source Material DOI: 10.3390/agriculture12111797 -
confidence 4.0
humic acid
Terrestrial humic-like fluorescence peak of chromophoric dissolved organic matter as a new potential indicator tracing the antibiotics in typical polluted watershed DOI: 10.1016/j.jenvman.2018.09.013 -
confidence 4.0
humic acid
Co-Thermal Oxidation of Lignite and Rice Straw for Synthetization of Composite Humic Substances: Parametric Optimization via Response Surface Methodology DOI: 10.3390/ijerph192416875 -
confidence 4.0
humic acid
Polarity-Based Sequential Extraction as a Simple Tool to Reveal the Structural Complexity of Humic Acids DOI: 10.3390/agronomy11030587 -
confidence 4.0
humic acid
Kinetics and Thermodynamics of Uranium (VI) Adsorption onto Humic Acid Derived from Leonardite DOI: 10.3390/ijerph16091552 -
confidence 4.0
humic acid
Instrumental and Experimental Conditions for the Application of Fourier Transform Infrared Analysis on Soil and Humic Acid Samples, Combined with Chemometrics Tools and Scanning Electron Microscopy DOI: 10.5935/0103-5053.20150170 -
confidence 4.0
humic acid
Multi-spectroscopic Investigation on Mechanism of Binding Interaction between Humic Acid and Ciprofloxacin DOI: 10.6023/A21080408 -
confidence 4.0
humic acid
A novel method of three-dimensional hetero-spectral correlation analysis for the fingerprint identification of humic acid functional groups for hexavalent chromium retention DOI: 10.1039/c7ra12146f -
confidence 2.5
humic acid
Optimized coagulation of humic acid and mineral turbidity at alkaline pH using high basicity PACl DOI: 10.2166/ws.2020.141
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