TLC (Thin-Layer Chromatography)

Related terms

ASTM E2285 / E2286

The two ASTM International standards governing forensic ink examination: E2285 covers TLC-based ink alteration examination; E2286 covers HPLC-based ink comparison. Both are...

Ballpoint Ink

An oil-based, high-viscosity ink using a resin binder (alkyd or polyamide) in a high-boiling solvent (phenoxyethanol or benzyl alcohol), with triphenylmethane dyes...

HPLC-DAD

High-performance liquid chromatography with diode-array detection. Separates ink dyes on a C18 column and records UV-visible spectra at each elution point, providing...

Iron-Gall Ink

A historical ink formulation of ferrous sulphate, tannic acid (from oak galls), and gum arabic. The ferrous-tannate complex oxidises to brown ferric-tannate...

Phenoxyethanol

The primary high-boiling solvent in most modern ballpoint ink formulations. Its progressive evaporation from the dried ink film after writing is the...

Raman Microspectroscopy

A vibrational spectroscopy technique using a focused laser beam to excite molecular vibrations in an ink sample. Non-destructive. Primary method for toner...

Toner

A dry-powder printing material consisting of fine styrene-acrylate polymer particles carrying carbon black and organic pigment, electrostatically applied and thermally fused at...

USSS International Ink Library

A collection of ~10,000 dated writing ink formulations maintained by the United States Secret Service since 1968, providing a terminus post quem...

VSC (Video Spectral Comparator)

A multispectral imaging instrument used in document examination; illuminates the document at multiple wavelengths (UV, visible, near-IR, IR) and captures fluorescence and...

Explained in

• Ink Chemistry: TLC, HPLC, Raman and the Video Spectral Comparator WorkflowA planar chromatography technique on silica gel plates that separates ink dye mixtures by polarity. ASTM E2285 governs its forensic application. The Rf values...