COUPLING OF REVERSED-PHASE LIQUID COLUMN CHROMATOGRAPHY AND FOURIER-TRANSFORM INFRARED SPECTROMETRY USING POSTCOLUMN ONLINE EXTRACTION AND SOLVENT ELIMINATION

An on-line postcolumn extraction module was used in conjunction with a solvent elimination interface for the semi-on-line coupling of revers ed-phase liquid chromatography (RP-LC) and Fourier transform infrared spectrometry (FT-IR). The extraction module consisted of a phase segme ntor, an extraction coil, and a phase separator, Dichloromethane was u sed as extraction solvent. The organic phase delivered by the separato r was evaporated by a spray-jet assembly that simultaneously deposited the extracted analytes onto a zinc selenide window, which was subsequ ently analyzed by FT-IR microscopy, The method is evaluated by studyin g parameters such as postcolumn band broadening, phase separation effi ciency, evaporation efficiency, extraction yield, eluent composition, and use of nonvolatile buffer salts, Good-quality spectra were obtaine d for test compounds (phenylureas and quinones), which were separated by RP-LC using a buffered eluent with high water content, Large-volume injections allowed FT-IR detection at the submicrogram per milliliter level.