IMPROVEMENTS IN ENVIRONMENTAL TRACE ANALYSIS BY GC-IR AND LC-IR

Research has been carried out to enlarge the potential of infrared (IR ) spectrometry as a detector in gas and liquid chromatography (GC and LC). The study has been directed to applications in environmental anal ysis. Examples of recently obtained results are presented. The analyte detectability of GC-IR has been improved by incorporation of an on-co lumn interface for the introduction of large sample volumes. The feasi bility of the technique is demonstrated by the identification of pesti cides in water at a level of 0.5 mu g l(-1) using on-line desorption o f pre-sampled solid-phase extracted cartridges. The detectability of L C-IR, based on solvent elimination interfacing, has been enhanced by o n-line trace enrichment. The applicability has been extended to buffer ed aqueous mobile phases by on-line post-column liquid-liquid extracti on into a volatile solvent, and to gradient separations by reduction o f the analytical flow using capillary LC combined with post-column add ition of a make-up liquid. With both techniques, herbicides have been identified in water samples in the low mu g l(-1) range. (C) 1997 Else vier Science B.V.