Supercritical fluid chromatography tandem mass spectrometry

Hoke, S.H., 2ndetal., Comparison of packed-column supercritical fluid chromatography -tandem mass spectrometry with liquid chromatography-tandem mass spectrometry for bioanalytical determination of (R)- and (S)-ketoprofen in human plasma following automated 96-well solid-phase extraction, Anal. Chem., 72(17), 4235, 2000. 

Chen, J. et al., Supercritical fluid chromatography-tandem mass spectrometry for the enantioselective determination of propranolol and pindolol in mouse blood by serial sampling, Anal. Chem., 78(4), 1212, 2006. 

Hsieh, Y. et al., Chiral supercritical fluid chromatography/tandem mass spectrometry for the simultaneous determination of pindolol and propranolol in metabolic stability samples, Rapid Commun. Mass Spectrom., 19(21), 3037, 2005. 

Coe, R.A., Rathe, J.O., and Lee, J.W., Supercritical fluid chromatography-tandem mass spectrometry for fast bioanalysis of R/S-warfarin in human plasma, J. Pharm. Biomed. Anal., 42(5), 573, 2006. 

Huang, E. Henion, J.D. Covey, T.R. Packed-column supercritical fluid chromatography-mass spectrometry and supercritical fluid chromatography-tandem mass spectrometry with ionization at atmospheric pressure. J. Chromatogr. 1990, 5II, 151-110. 

Spell JC, Srinivasan K, Stewart JT, Bartlett MG. 1998. Supercritical fluid extraction and negative ion electrospray liquid chromatography tandem mass spectrometry analysis of phenobarbital, butalbital, pentobarbatal and thiopentoal in human serum. Rapid Commun Mass Spectrom 12 890. 

Anacleto, J. E., Ramaley, L., Boyd, R. K., Ploeasance, S., QuiUiam, M. A., Sim, P. G., and Benoit, F. M., Analysis of polycychc aromatic compounds by supercritical fluid chromatography mass spectrometry using atmospheric-pressure chemical ionization. Rapid Commun. Mass Spectrom., 5, 149-155,1991. Mansoori, B. A., Isomeric identification and quantification of polycychc aromatic hydrocarbons in environmental samples by liquid chromatography tandem mass spectrometry using a high pressure quadrupole collision cell, Rapid Common. Mass Spectrom., 12, 712-728, 1998. 

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. 

Supercritical-fluid chromatography has been applied by Ramsey et al. (213) for the determination of trimethoprim, along with three steroid hormones, in swine kidney. Separation was performed on a Spherisorb 5 amino-bonded column, using carbon dioxide with methanol modifier as the mobile phase. Detection at levels greater than 10 ppm was accomplished by tandem mass spectrometry using thermospray interface. However, this method lacks the sensitivity required to detect the low ppb levels likely to occur in milk and tissues. 

Hsieh et al. (2006a) demonstrated the use of packed-column supercritical fluid chromatography (SFC) combined with atmospheric pressure chemical ionization (APCI)—tandem mass spectrometry (MS/MS) for the analysis of metabolic stability samples. For the SFC step, the mobile phase is liquid carbon dioxide with some organic modifiers added to adjust the retention time of the analytes. In this report, the primary organic modifier was methanol, and the authors described how the percentage of methanol in the mobile phase varied the retention of the analytes and affected the relative response of the test compounds in the APCI source. The authors also demonstrated that the results obtained by the SFC—APCI—MS/MS assay were equivalent to those obtained by a conventional HPLC—APCI—MS/MS assay, as shown in Figure 12.3. 

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