Abstract: A supercritical fluid extraction (SFE) system. The SFE system includes a mechanism for providing supercritical fluid for extracting analyte from a sample. The SFE system also includes an extraction vessel and a mechanism for moving the extraction vessel into fluidic communication with the SFE system so that supercritical fluid can flow through the extraction vessel and extract analyte from the sample. Preferably, the SFE system is additionally comprised of a mechanism for holding a plurality of extraction vessels and an extraction chamber assembly. In this design, the moving mechanism selectively moves an extraction vessel from the holding mechanism into the extraction chamber in fluidic communication with the SFE system. Preferably, the SFE system further includes a computer for controlling the functions of the SFE system. The computer, for instance, could automatically and sequentially control the supercritical fluid extractions of the samples within the holding mechanism.

Abstract: An assembly is shown over the top portion of the outer body 14 of a reference electrode or combination pH/reference electrode. An element 50 such as a turning ring covers the fill hole 16 through the outer body 14. In one position of the element 50, a sealing element 24 such as an O-ring forms a passage between fill hole 16 and a through hole 52 through element 50. In other positions of element 50, the sealing element 24 seals the fill hole 16. In embodiments shown, a housing 30 is integral with the cap assembly (60, 70) and aligns the sealing element 24 over the fill hole 16.

Abstract: A combination pH/reference electrode is provided with the two electrochemical references being symetrically thermally insulated from the sensing membrane and being thermally adjacent each other. The portion of the pH fill buffer in contact with the inner surface of the sensing membrane is thermally insulated, as by KCl crystals, to rapidly equilibrate in temperatures with the sample solution.

Abstract: A double junction reference electrode which includes an inner body enclosing an inner chamber, a reference element disposed within and extending through the inner body, an outer body disposed around the inner body and enclosing an outer chamber between the inner body and the outer body, an inner ion path through the inner body and providing for the flow of ions between the inner and outer chambers, an outer ion path through the outer body and providing for the flow of ions between the outer chamber and the area exterior of the outer body, a means for introducing an electrolyte into the inner and outer chambers, and a means for releasably joining the inner and outer bodies together to form a unitary electrode structure.