On-line Fourier transform infrared spectrometric detection in gradient capillary liquid chromatography using nanoliter-flow cells.
A capillary liquid chromatographic system has been successfully interfaced with a mid-IR Fourier transform infrared (FT-IR) spectrometer. Spectra were recorded on-line using a micromachined transmission CaF(2) cell (internal volume of 7.5 nL) that was placed on a dedicated beam condenser attached to the spectrometer. Linear gradients were run from (50:50) to (35:65) water (0.05% TFA)/acetonitrile in 15 min for the separation of standard solutions of four nitrophenols (4-nitrophenol, 3-methyl-4-nitrophenol, 2,4-dinitrophenol, and 2-nitrophenol) in a reversed phase system, providing limits of detection between 35 and 94 ng on-column. The changing background absorption due to gradient elution was successfully corrected by using a dedicated algorithm implemented in Matlab. When this chemometric data treatment was used, highly characteristic analyte spectra could be recorded as indicated by correlation coefficients between 89 and 95.8%, obtained when comparing mid-IR spectra of standard solutions and the spectra extracted from the chromatogram.
Quintás
Guillermo
G
Department of Analytical Chemistry, University of Valencia, 50th Dr. Moliner, 46100 Burjassot, Spain.
Kuligowski
Julia
J
Lendl
Bernhard
B
D000465:Algorithms; D002853:Chromatography, Liquid / Q000295:instrumentation* / Q000379:methods; D009596:Nitrophenols / Q000032:analysis*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D009596:Nitrophenols