LimsPulse
Chromatography

Thin-Layer Chromatography (TLC)

Separates compounds as a solvent climbs up a thin layer of adsorbent on a glass, aluminium or plastic plate. Simple and cheap; used in pharma QC mainly for identification and limit tests for related substances.

  • Pharmaceutical
  • Herbal & natural products
  • Chemicals
  • Forensic
  • Education
Photo of a Thin-Layer Chromatography (TLC)
Photo: Daniel Dróżdż, CC BY 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the plate type, size and batch match the method; record the batch number.
  2. 2Activate plates in an oven if the method requires (e.g. 100–105 °C for about 1 hour) and cool in a desiccator.
  3. 3Prepare fresh mobile phase by measuring each solvent accurately and mixing well.
  • Prepare and handle mobile phases and spray reagents in a fume hood.
STAGE 2

Saturation and application

  1. 1Pour mobile phase into the chamber to a depth of about 0.5–1 cm, line it with filter paper, close it and allow it to saturate.
  2. 2Draw a light pencil line at the application height; never use ink, which will run.
  3. 3Apply the prescribed volumes as small spots or narrow bands, at least 1 cm apart and away from the plate edges. Dry between applications.
  • The application line must be above the solvent level, or the sample will dissolve into the tank.
STAGE 3

Development and visualisation

  1. 1Place the plate vertically in the chamber without splashing and close the lid at once.
  2. 2Develop until the solvent front reaches the marked distance, then remove the plate and mark the front with pencil.
  3. 3Dry the plate completely, then examine under UV light and/or apply the visualisation reagent as specified.
  4. 4Photograph the plate promptly; some spot colours fade.
  • Never look directly at the UV lamp; use the cabinet window or UV-protective glasses.
STAGE 4

Evaluation

  1. 1Check the method's system suitability requirement (e.g. two spots clearly separated) before reading the test.
  2. 2Measure distances from the origin to the spot centre and to the solvent front; calculate Rf values.
  3. 3Compare test spots with reference spots for position, colour and size or intensity.
  4. 4Record the result with the plate image attached.
In LimsPulse · Calibration Management

Keep every TLC in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how