Electrospray Ionization Tandem Mass Spectrometry in High-Throughput Screening of Homogeneous Catalysts.

ChemInform ◽  
2003 ◽  
Vol 34 (39) ◽  
Author(s):  
Peter Chen
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
High Throughput ◽  
High Throughput Screening ◽  
Tandem Mass ◽  
Homogeneous Catalysts ◽  
Ionization Tandem Mass Spectrometry

scholarly journals Evaluation of a Deuterium-Labeled Internal Standard for the Measurement of Sirolimus by High-Throughput HPLC Electrospray Ionization Tandem Mass Spectrometry

2008 ◽  
Vol 54 (8) ◽  
pp. 1386-1389 ◽  
Author(s):  
Sean O'Halloran ◽  
Kenneth F Ilett
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
High Throughput ◽  
Matrix Effects ◽  
Internal Standard ◽  
Tandem Mass ◽  
Esi Ms ◽  
Interpatient Variation ◽  
Ionization Tandem Mass Spectrometry

Abstract Background: Matrix effects in HPLC–electrospray ionization–tandem mass spectrometry (HPLC-ESI-MS/MS)1 can cause differences in the ionization of an internal standard (IS) compared with the analyte of interest. Unless sample cleanup or chromatographic conditions eliminate or minimize ion suppression or enhancement, variability in interpatient matrices may cause erroneous results. A stable isotope-labeled IS can be used to minimize analytical interpatient variation. Methods: We used protein precipitation and HPLC-ESI-MS/MS to quantify sirolimus (SIR) with both desmethoxyrapamycin (DMR) and deuterium-labeled sirolimus (SIR-d3) as the IS to analyze a range of whole-blood and extraction-matrix samples, and to estimate recovery, matrix effects, process efficiency, and interpatient variation. We also analyzed a series of blood samples from 72 patients taking SIR, including external proficiency-testing samples, with these ISs. Results: The range of interpatient assay imprecision (CV) values for the SIR assay was consistently lower with SIR-d3 (2.7%–5.7%) than with DMR (7.6%–9.7%). The results obtained with the 2 different ISs for the patient samples showed a linear relationship, but the results were higher with DMR as the IS than with SIR-d3. Conclusions: The use of SIR-d3 as the IS in the high-throughput HPLC-ESI-MS/MS assay of SIR yielded improved results compared with the use of DMR. SIR-d3 appears to be less affected by differences in the ionization of SIR and its IS caused by the variability of interpatient matrices. The IS-related difference in SIR estimation needs further investigation.

scholarly journals High-Throughput Quantification of Lysophosphatidylcholine by Electrospray Ionization Tandem Mass Spectrometry

2002 ◽  
Vol 48 (12) ◽  
pp. 2217-2224 ◽  
Author(s):  
Gerhard Liebisch ◽  
Wolfgang Drobnik ◽  
Bernd Lieser ◽  
Gerd Schmitz
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
High Throughput ◽  
Cholesterol Concentration ◽  
Tandem Mass ◽  
Plasma Samples ◽  
Internal Standards ◽  
Esi Ms ◽  
Ionization Tandem Mass Spectrometry

Abstract Background: Lysophosphatidylcholine (LPC) has been suggested to play a functional role in various diseases, including atherosclerosis, diabetes, and cancer mediated by LPC-specific G-protein-coupled receptors. Initial studies provided evidence for a potential use of LPC as diagnostic maker. However, existing methodologies are of limited value for a systematic evaluation of LPC species concentrations because of complicated, time-consuming procedures. We describe a methodology based on electrospray ionization tandem mass spectrometry (ESI-MS/MS) applicable for high-throughput LPC quantification. Methods: Crude lipid extracts of EDTA-plasma samples were used for direct flow injection analysis. LPC 13:0 and LPC 19:0 were added as internal standards, and the ESI-MS/MS was operated in the parent-scan mode for m/z 184. Quantification was achieved by standard addition. Data processing was highly automated by use of the mass spectrometer software and self-programmed Excel macros. Results: The calibrators LPC 16:0, LPC 18:0, and LPC 22:0 showed a linear response independent of sample dilution and plasma cholesterol concentration for both internal standards. The within-run imprecision (CV) was 3% for the major and 12% for the minor species, whereas the total imprecision was ∼12% for the major and 25% for the minor species. The detection limit was <1 μmol/L. Conclusion: The developed ESI-MS/MS methodology with an analysis time of 2 min/sample, simple sample preparation, and automated data analysis allows high-throughput quantification of distinct LPC species from plasma samples, which could be a valuable tool for the evaluation of LPC as diagnostic marker.

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