AN SPE COLUMN TEFLON SLEEVE ASSEMBLY FOR IN-LINE RETENTION DURING SUPERCRITICAL-FLUID EXTRACTION OF ANALYTES FROM BIOLOGICAL MATRICES

An in-line collector assembly designed for use in supercritical fluid extraction (SFE) vessels is described. This assembly enables solutes e xtracted by supercritical fluids (SF) to be retained in-line on standa rd solid phase extraction (SPE) columns. The assembly consists of a st andard 1 mL or 3 mL SPE column fitted into a specially fabricated Tefl on(R) sleeve. The SPE column-Teflon sleeve assembly is inserted into t he SFE vessel followed by the sample matrix. This unit forms a leak-ti ght seal with the vessel's end-cap up to pressures of 680 bar. The cho ice of sorbents used in the in-line SPE columns is dependent upon the properties of the solute in the supercritical state. After SFE is comp leted, the SPE column is removed and the solutes are recovered in 1-2 mL of the eluting solvent. No further clean-up is normally required pr ior to chromatographic analysis of the analyte. A comparison was made of recoveries by in-line and off-line (after SF decompression) techniq ues for the SPE of three anabolic steroids in fortified chicken liver. The HPLC chromatograms of the steroids from the off-line SPE columns were too complex for quantitation, because of coeluting artifacts, whe reas chromatograms obtained from in-line SPE columns were free from UV -absorbing interferences and were easily quantified.