SIMPLE AND VERSATILE INJECTION SYSTEM FOR CAPILLARY GAS-CHROMATOGRAPHIC COLUMNS PERFORMANCE EVALUATION OF A SYSTEM INCLUDING MASS-SPECTROMETRIC AND LIGHT-PIPE FOURIER-TRANSFORM INFRARED DETECTION

A cryogenic concentrator, a pre-trap, and ancillary systems were devel oped to facilitate the introduction of large volumes of either gaseous or liquid samples to a capillary GC column. This large-volume injecti on system, referred to as LVIS, is used in conjunction with the conven tional split/splitless injector of a gas chromatograph. The performanc e of the split/splitless injector is essentially unchanged by the inst allation of the cryogenic concentrator; thus, the gas chromatograph ca n be operated as usual. Reproducibility, accuracy, and inertness were demonstrated while performing injections of a hydrocarbon mixture (n-C -7-C-22) and the Grob-programmed test mixture. Liquid samples, up to 1 00 mu l, were conveniently handled by the system. Applicability to gas -phase analyses was demonstrated by sampling perfume components in the headspace of a granular detergent and by sampling pyrolysis products of Kraton 1107. When the LVIS was used with a gas chromatograph equipp ed with mass-selective (MSD) and light-pipe Fourier-transform infrared (FT-IR) [IRD] spectrometers, it was possible to achieve identificatio n limits by IRD approaching 1 ppb v/v when analyzing one liter of head space, and ca. 100 ppb when analyzing 100 mu l of a liquid sample. Ide ntification limits with the MSD were lower.