QUANTITATIVE-ANALYSIS USING DIRECTLY COUPLED SUPERCRITICAL FLUID EXTRACTION CAPILLARY GAS-CHROMATOGRAPHY (SFE-GC) WITH A CONVENTIONAL SPLIT SPLITLESS INJECTION PORT

Supercritical fluid extraction is directly coupled with capillary gas chromatography by a commercially available septumless injector. No heated transfer lines are required and, since the SFE effluent is depressurized inside the heated injection port, restrictor plugging is eliminated, thus allowing samples containing high concentrations of matrix components (e.g., water and elemental sulfur) to be analyzed. Good chromatographic peak shapes result even with the relatively high extraction flow rates (1 mL/min of supercritical fluid), which allows samples as large as 15 g to be analyzed in 1 h, including extraction, analyte concentration, and GC separation. Peak area reproducibilities compare favorably to those from conventional split injections. Good quantitative agreement with certified values for polycyclic aromatic hydrocarbons (PAHs) in a new standard reference material, marine sediment, is obtained. Increases in the rate of extraction of PAHs from the marine sediment when using N2O rather than CO2 are also discussed.; Supercritical fluid extraction is directly coupled with capillary gas chromatography by a commercially available septumless injector. No heated transfer lines are required and, since the SFE effluent is depressurized inside the heated injection port, restrictor plugging is eliminated, thus allowing samples containing high concentrations of matrix components (e.g., water and elemental sulfur) to be analyzed. Good chromatographic peak shapes result even with relatively high extraction flow rates (1 mL/min of supercritical fluid), which allows samples as large as 15 g to be analyzed in 1 h, including extraction, analyte concentration, and GC separation. Peak area reproducibilities compare favorably to those from conventional split injections. Good quantitative agreement with certified values for polycyclic aromatic hydrocarbons (PAHs) in a new standard reference material, marine sediment, is obtained.