Injectors for capillary gas chromatography and their application to environmental analysis

The application of different injectors in capillary gas chromatography (GC) analysis of semi-volatile organic contaminants in environmental samples prepared in organic solvents is reviewed. The injectors examined include a split/splitless injector in splitless mode (SS), cold on-column (COC), and programmable temperature vaporizer (PTV) and adaptations of these injector designs. Key issues when selecting an injector include properties of the analyte, such as potential for thermal degradation or discrimination of high boiling point compounds within the injector, and the ability of the GC systems to handle large volume injections (LVI) primarily to lower detection limits and allow direct coupling with sample preparation techniques such as at-line or on-line solid phase extraction (SPE). LVI also require consideration of matrix interference issues. This review examines only injector chamber modifications that are feasible with a standard GC configuration, however some modi. cations to the chromatographic system to extend the range of applicability of gas chromatography analysis for environmental samples are also noted.