ABSTRACT
Fourier transform infrared spectrometry (FTIR) has been widely used as a detection method for gas chromatography or supercritical fluid chromatography (SFC). The on-line SFC/FTIR coupling may be achieved either with packed or capillary columns. The infrared spectrometry (IR) spectrum of supercritical carbon dioxide presents, without offering a complete IR transparency, wider transparent IR regions compared to those of generally used solvents in high performance liquid chromatography. The on-line SFC/FTIR flow-cell must have a careful design to achieve low detection limit without decreasing the chromatographic resolution. The power of FTIR detection results from the ability to reconstruct chromatograms from single-scan interferometric data by two main methods; the first is the GRAM-SCHMIDT orthogonalization procedure and the second one gives specific IR window chromatograms. The separation of four pesticides has been achieved by SFC/FTIR on a capillary column with some serial detection modes, Many differences exist between a solute's vapor phase, condensed-phase and supercritical phase CO2 spectra.
