Modern Techniques in TLC

Although high pressure liquid chromatography (HPLC) has come into the limelight, thin-layer techniques refuse to take a back seat. For one thing thin-layer work can be carried out with a minimum expenditure in equipment. Numerous samples may be carried out simultaneously. This means that when you are searching for a separation method numerous solvent systems, adsorbents, and techniques can be tried at the same time. Once the correct separation system has been established repetitive analyses may be turned over to high pressure column chromatography or one can again run multiple samples by the thin-layer technique. Quantitive techniques and instruments are continually improving so that both speed and accuracy are being enhanced. A recent article describes the use of a soft laser scanning densitometer that is reported to give better resolution and higher accuracy than densitometers using the normal light sources. Automation keeps creeping into thin-layer work and while the attempts do not always succeed, it is important that work of this nature be continued. The latest in automated TLC is “programmed TLC” wherein the advantages of multiple development are made use of automatically. Isoelectric focusing is again stressed as an important new technique in thin-layer work which is constantly expanding in new directions with new materials and knowledge. Wherever ampholytes appear in biological systems this sensitive technique will be of interest and value.