Analysis by thermospray

Kim, H.-Y. and Salem, N. Jr (1986) Phospholipid molecular species analysis by thermospray liquid chromatography/mass spectrometry. Anal. Chem., 58, 9-14. 

Figure 9.4 High-pressure liquid chromatography separation of 50 pg of a natural phosphatidylcholine mixture from egg yolk. The reconstructed ion chromatograms of diglyceride ions were selected from data acquired by full mass scanning from 120 amu to 820 amu. The relative intensity is shown based on the peak height. Column 3 pm Ultrasphere-ODS (4.6 mm x 7.5 cm). Mobile phase MeOH/hexane/0.1 m NH4OAC (71 5 7), 1 mlmin . Reprinted with permission from Kim, H. Y. and Salem, N. Jr, Phospholipid molecular species analysis by thermospray liquid chromatography/mass spectrometry. Anal. Chem., 58 (1), 9-14, 1986.

Electrospray has been successful for numerous azo dyes that are not ionic salts. Several anthraquinone dyes have been analysed by LC-ESI-MS [552]. Electrospray achieves the best sensitivity for compounds that are precharged in solution (e.g. ionic species or compounds that can be (de)protonated by pH adjustment). Consequently, LC-ESI-MS has focused on ionic dyes such as sulfonated azo dyes which have eluded analysis by particle-beam or thermospray LC-MS [594,617,618]. Techniques like LC-PB-MS and GC-MS, based on gas-phase ionisation, are not suitable for nonvolatile components such as sulfonated azo dyes. LC-TSP-MS on... 

Frolich and colleagues (1998) analyzed ACh in human CSF by different methods, which included thermospray/mass spectroscopy, HPLC/mass spectroscopy, HPLC-EC Pt electrode and gas chromatogra-phy/mass spectroscopy (GC/MS). An SPE extraction was used for cleanup and concentration. Samples were run with and without the IMER to rule out any interference by physostigmine, a cholinesterase inhibitor, in the HPLC-EC assay. HPLC-EC and GC-MS gave data correlations with similar sensitivities, but the HPLC-EC values were 39% lower. Analysis using thermospray/mass spectroscopy and HPLC/ mass spectroscopy did not provide adequate sensitivity and the data obtained were inconsistent. 

Confirmation by LC-MS This method is not used much, since it involves expensive apparatus, and rather good experience in the technique is needed. Abramson (66) illustrated the advantages resulting from the combination of liquid chromatography and mass spectrometry for ochratoxin A in barley. Among the types of interfaces most used for ochratoxin A analysis were thermospray, direct liquid induction (DLI), and... 

GC Galletti, J Eagles, FA Mellon. Analysis of low molecular weight plant phenolics by thermospray liquid chromatography/mass spectrometry. J Sci Food Agric 59 401-404, 1992. 

Voyksner, R. D. Bursey, J. T. Hines, J. W. 1985. Analysis of candidate anticancer drugs by thermospray high-performance liquid chromatography-mass spectrometry. J. Chromatogr., 323,383-394. 

In the second approach, the P-CD CSP was connected directly to the mass spectrometer using a thermospray interface. A mobile phase of 0,1 M ammonium acetate (pH 5) and flow rate of 1.2 mL/mtn were employed during the analysis. By using deuterium-labeled racemic terbutaline as the internal standard, linear calibration curves were obtained down to 4 pmol. 

Figure 2. A) Trypsin hydrolysis/HPLC/thermospray MS analysis of Y-endorphin. The two tryptic fragments (T1 and T ) were separated by HPLC (10% isopropanol in aqueous ammonium acetate (0.1 M) pH 7.1, 1 mL/min) and detected by thermospray MS. B,B ) Thermospray mass spectra of tryptic fragments and Tg separated by HPLC after hydrolysis. C,Cj) Thermospray spectra from trypsin hydrolysis followed by HPLC then carboxypeptidase A, B, and Y hydrolysis for the partial amino acid sequencing of Y-endorphin.

Analysis of Xenobiotic Conjugates by Thermospray liquid Chromatography/Mass... 

Metabolite M4 was analyzed by thermospray LC/MS (Fig. 5a) and produced a protonated molecular ion at m/z 497, 499 (confirmed by fast atom bombardment mass spectral analysis). This mass spectrum, as well as proton NMR analysis (not shown) was consistent with the acyl carnitine conjugate of the parent. Fragmentation occurred via loss of the carnitine moiety to give m/z 371, 373 the fragment ion at m/z 455, 457 could correspond to an... 

Despite outstanding FD measurements in laboratories at Mainz and a few other places, analysis of glucuronic acid conjugates by FAB is generally more reliable than FD analyses. However, FAB is also not completely reliable. We have worked with some glucuronic acid conjugates which provided neither an anion or cation spectrum from a variety of FAB matrices. In one of these cases the analysis has been obtained successfully by thermospray. 

Kwakman and co-workers (1992) used disk extraction to isolate organophosphorus pesticides on-line with gas chromatography for rapid analysis. The method is on-line for sorption and elution using ethyl acetate as a desorbing solvent and a retention time gap approach for the GC analysis. The detection limit was 10 to 30 ng/L in tapwater and 50 to 100 ng/L in river water. Barcelo and co-workers (1993) and Molina and co-workers (1994) also found that organophosphorus pesticides and triazines could be effectively isolated on disks for further analysis by HPLC/MS using thermospray and electrospray. 

Thernospray HPLC/MS. Urine extracts were analyzed by thermospray/HPLC/MS to Identify the metabolites present. A Finnigan 4500 series mass spectrometer Interfaced with a Vestec Thermospray unit was used to perform the analysis. The aerosol thermocouple of the Interface was replaced with a repeller which was connected to an external power supply. The samples were analyzed under thermospray/fllament chemical Ionization with pulsed +/- Ion detection. A mobile phase consisting of acetonitrlle/0.1 M ammonium acetate with a linear gradient of 9X to 65% over 30 minutes was used In the anlaysls. 

The following reversed-phase system has been used for the analysis of Catharanthus alkaloids including vinblastine by thermospray liquid chromatography-mass spectrometry (120). u Bondapak Ci8 (30cm x 3.9mm), reversed-phase column. 

Kim, H.-Y. and Sawazaki, S. (1993) Structural analysis of hydroxy fatty acids by thermospray liquid chromatography/tandem mass spectrometry. Biol. Mass Spectrom., 22, 302-10. 

Kim, H.-J. Ball, D. Giles, J. White, F. Analysis of thermally produced compounds in foods by thermospray liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. J. Agric. Food Chem. 1994, 42, 2812-2816. 

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