Sample Transfer Technique for Thin-Layer Chromatography/Fourier Transform Infrared Spectrometry

Abstract

A simple and convenient procedure for the transfer of separated zones from a thin-layer chromatographic (TLC) sheet to a powder layer of potassium bromide is described. The pattern of the zones separated in two dimensions on a TLC sheet is preserved during transfer; therefore, an infrared (IR) chromatogram corresponding to the original TLC pattern and an IR spectrum for each separated zone are easily recorded by diffuse reflectance Fourier transform IR spectrometry. The transfer process requires only 2 min, and the TLC sheet can be placed directly into the diffuse reflectance accessory of the spectrometer, which prevents sample loss and shortens data collection time. The limit of detection for anhydrous caffeine was 2 μg.