Quantitative ultraviolet measurements on wetted thin-layer chromatography plates using a charge-coupled device camera

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Thin-layer chromatography (TLC) is a widely used separation technique.
• UV imaging is a common detection method for TLC.
• Monitoring TLC during development is challenging.

Purpose of the Study:

• To investigate the feasibility of UV imaging for wet TLC plates.
• To compare the sensitivity of wet versus dry TLC plates for UV detection.
• To evaluate the impact of plate backing material on UV detection sensitivity.

Main Methods:

• UV imaging of benzophenone spots on TLC plates using a charge-coupled device camera.
• Comparison of imaging on wet and dry plates.
• Assessment of glass-backed versus aluminium-backed plates.

Main Results:

• Limits of detection were 5ng for wet plates and 3ng for dry plates.
• Linear relationship (r(2)>0.99) between peak area and sample loading in the nanogram range for both modes.
• Aluminium-backed plates showed increased sensitivity compared to glass-backed plates for wet UV measurements.

Conclusions:

• UV imaging of wet TLC plates is feasible and allows for monitoring during development.
• Aluminium-backed plates enhance UV detection sensitivity, potentially enabling real-time monitoring of separations.
• This technique offers a promising advancement for in-situ analysis in TLC.