Principles and Practice of Chromatography - Thin Layer Chromatography Apparatus > Page 61

Data Acquisition and Processing System

A diagram of e chromatographic data acquisition and processing system is shown in figure 29.

Figure 28 The Data Acquisition and Processing System

The actual format of the data system can vary widely from manufacturer to manufacturer. Most systems have a means for real time monitoring the detector output either by using an ancillary recorder or by computer software, the chromatogram being drawn by the computer on the printer. The signal from the detector is first scaled, usually to a range from 0 to 5 volt by a suitable amplifier and the scaled signal is then digitized by means of an A/D converter. The data is then regularly read by the computer and stored on disk. The data may be partially processed 'on the fly' or processed at the completion of the analysis.

Thin Layer Chromatography Apparatus

Thin layer chromatography appears to have been first developed and utilized by Schraiber in 1939 (11). Schraiber working with Izmailov at the Khar'kov Chemistry and Pharmacy Research Institute employed the techniques for the analysis of pharmaceuticals. In her own words,

" It occurred to us that a thin layer of the sorbent could be used in lieu of a strip of paper; also we felt that the flat bed could be considered as a cut-out of the adsorbent column. We believed that in carrying out the separation process in such a layer, the process would be accelerated significantly. In our work, we deposited a drop of the solution being investigated on the flat adsorbent layer and observed the separation into concentric circular zones which could become visible because of their fluorescence in the light of a UV lamp."