Direct fluid injection mass spectrometry

Supercritical Fluid Extraction (SCFE)—Direct Fluid Injection Mass Spectrometry (DFI-MS)... 

Smith and Udseth [154] first described SFE-MS in 1983. Direct fluid injection (DFT) mass spectrometry (DFT-MS, DFI-MS/MS) utilises supercritical fluids for solvation and transfer of materials to a mass-spectrometer chemical ionisation (Cl) source. Extraction with scC02 is compatible with a variety of Cl reagents, which allow a sensitive and selective means for ionising the solute classes of interest. If the interfering effects of the sample matrix cannot be overcome by selective ionisation, techniques based on tandem mass spectrometry can be used [7]. In these cases, a cheaper and more attractive alternative is often to perform some form of chromatography between extraction and detection. In SFE-MS, on-line fractionation using pressure can be used to control SCF solubility to a limited extent. The main features of on-line SFE-MS are summarised in Table 7.20. It appears that the direct introduction into a mass spectrometer of analytes dissolved in supercritical fluids without on-line chromatography has not actively been pursued. 

Smith R D, Fjeldsted J C, Lee M L 1982 Direct fluid injection interface for capillary supercritical fluid chromatography/mass spectrometry. J Chromatogr 247 231-243... 

R.D. Smith and H.R. Udseth, Mass spectrometry with direct supercritical fluid injection, Anal. Chem., 55 (1983) 2266-2272. 

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