FTIR (Fourier Transform Infrared Spectroscopy)
Definition
A vibrational spectroscopy technique used in toner analysis to identify the polymer backbone and functional group composition of toner binder material; ATR sampling mode allows surface analysis without sample preparation.
- What it identifies
- Functional groups (sulphates, carbonates, silicates) and polymer composition
- Key advantage
- Works on both crystalline and amorphous phases; ATR mode additionally allows surface analysis without sample preparation
- Forensic use cases
- Building materials (cement, plaster), printer toner analysis, photocopier examination
Common questions
What is FTIR used for in forensic material analysis?+
FTIR identifies functional groups like sulphates, carbonates, and silicates in samples regardless of whether they're crystalline or amorphous. It pairs well with X-ray diffraction (XRD) because while XRD works best on ordered crystal structures, FTIR picks up the amorphous phases that XRD misses, giving you a more complete picture of a material's composition.
How does FTIR help in toner and printer examination?+
In toner analysis, FTIR identifies the polymer backbone and functional groups in the toner binder material. The ATR (attenuated total reflectance) mode lets analysts examine the surface of a sample without complex prep work, making it quick to compare toner from different printers or cartridges.
Why is FTIR complementary to XRD rather than a replacement?+
XRD excels at analyzing crystalline materials with ordered atomic structures, but struggles with amorphous (non-crystalline) phases. FTIR looks at molecular vibrations and functional groups, so it catches the formless components that XRD cannot. Using both gives you a fuller chemical profile.
Related terms
- ASTM C150
- US standard specifying Portland-cement composition limits and performance requirements by type (I through V); referenced in forensic mineral-phase characterisation.
- Calcium Sulphate Hemihydrate
- CaSO4 . 1/2 H2O; produced by heating gypsum, rehydrates to gypsum on setting; the basis of plaster of Paris and most interior...
- Clinker
- The nodular intermediate product of Portland-cement manufacture, consisting of C3S, C2S, C3A and C4AF mineral phases before grinding.
- Copy Generation
- The number of copying steps between the original document and the copy under examination; each generation introduces resolution loss, noise amplification, and...
- CSID (Called Subscriber Identification)
- The configurable name string transmitted by a fax machine during session setup and printed in the fax header bar on the received...
- ENFSI ENG-FG1
- The European Network of Forensic Science Institutes' guidelines for forensic geological evidence, published in 2018 by the Expert Working Group on Forensic...
- Ettringite
- A calcium sulfoaluminate hydrate that forms early in cement hydration and can re-form later from delayed sulfate attack; its presence or alteration...
- Fax Header Bar
- The line of text printed at the top of each received fax page under regulatory requirements (US FCC 47 CFR 68.318, UK...
- Ghost Image
- A faint background impression of a previously copied document visible in a later photocopy, arising from incomplete cleaning of residual toner from...
- MMR Compression (Modified Modified READ)
- An ITU-T fax compression standard (T.6) used in high-quality fax transmission modes; produces characteristic compression artefacts visible in fine character strokes of...
- Platen Glass
- The flat transparent surface on which original documents are placed for scanning in a photocopier or flatbed scanner; contamination or scratches on...
- Polyester Toner
- A toner binder formulation based on polyester resin, dominant in office photocopiers and laser printers from the 2000s onward; characterised by FTIR...
Explained in these topics
- Cement, Plaster and Building-Material EvidenceIdentifies functional groups (sulphates, carbonates, silicates) in a sample regardless of crystallinity; complementary to XRD for amorphous phases.
- Photocopier and Fax Examination, and Toner AnalysisA vibrational spectroscopy technique used in toner analysis to identify the polymer backbone and functional group composition of toner binder material; ATR sam...