DRAMATIC ADVANCES IN ONLINE FOURIER-TRANSFORM IR DETECTION FOR CAPILLARY SUPERCRITICAL FLUID CHROMATOGRAPHY

We have shown that a flow cell Fourier transform (FT) IR detector for capillary supercritical fluid chromatography (cSFC) can give minimum detection limits which are much lower than any previouSly reported for on-line cSFC FT-IR. The system was tested using a range of analytes. The following reproducible values were obtained, using supercritical CO2 as the mobile phase: 2 ng for a polycyclic aromatic hydrocarbon (pyrene)-a rather weak infrared absorber, 95 pg for caffeine-a strong infrared absorber, and ca. 20 pg for the organometallic complex (mesitylene)chromium tricarbonyl-which has some intense infrared absorptions. These figures represent an improvement by a factor of at least 25 on comparable data in the literature. For caffeine a linear dynamic range of more than three orders of magnitude was established for this system.