Quantitative assay of plasma homocysteine thiolactone by gas chromatography/mass spectrometry

2003 ◽  
Vol 17 (4) ◽  
pp. 358-362 ◽  
Author(s):  
Parham Daneshvar ◽  
Mehrdad Yazdanpanah ◽  
Carla Cuthbert ◽  
David E. C. Cole
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Plasma Homocysteine ◽  
Quantitative Assay ◽  
Gas Chromatography Mass Spectrometry ◽  
Homocysteine Thiolactone ◽  
Chromatography Mass Spectrometry

Quantification of homocysteine thiolactone in human saliva and urine by gas chromatography-mass spectrometry

2020 ◽  
Vol 1149 ◽  
pp. 122155 ◽  
Author(s):  
Justyna Piechocka ◽  
Monika Wrońska ◽  
Grażyna Chwatko ◽  
Hieronim Jakubowski ◽  
Rafał Głowacki
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Human Saliva ◽  
Gas Chromatography Mass Spectrometry ◽  
Homocysteine Thiolactone ◽  
Chromatography Mass Spectrometry

scholarly journals Gas Chromatography–Mass Spectrometry Based Approach for the Determination of Methionine-Related Sulfur-Containing Compounds in Human Saliva

2020 ◽  
Vol 21 (23) ◽  
pp. 9252
Author(s):  
Justyna Piechocka ◽  
Monika Wieczorek ◽  
Rafał Głowacki
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Human Saliva ◽  
Gas Chromatography Mass Spectrometry ◽  
Limit Of Quantification ◽  
Homocysteine Thiolactone ◽  
Chromatography Mass Spectrometry ◽  
First Choice ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

Gas chromatography–mass spectrometry technique (GC-MS) is mainly recognized as a tool of first choice when volatile compounds are determined. Here, we provide the credible evidence that its application in analysis can be extended to non-volatile sulfur-containing compounds, to which methionine (Met), homocysteine (Hcy), homocysteine thiolactone (HTL), and cysteine (Cys) belong. To prove this point, the first method, based on GC-MS, for the identification and quantification of Met-related compounds in human saliva, has been elaborated. The assay involves simultaneous disulfides reduction with tris(2-carboxyethyl)phosphine (TCEP) and acetonitrile (MeCN) deproteinization, followed by preconcentration by drying under vacuum and treatment of the residue with a derivatizing mixture containing anhydrous pyridine, N-trimethylsilyl-N-methyl trifluoroacetamide (MSTFA), and trimethylchlorosilane (TMCS). The validity of the method was demonstrated based upon US FDA recommendations. The assay linearity was observed over the range of 0.5–20 µmol L−1 for Met, Hcy, Cys, and 1–20 µmol L−1 for HTL in saliva. The limit of quantification (LOQ) equals 0.1 µmol L−1 for Met, Hcy, Cys, while its value for HTL was 0.05 µmol L−1. The method was successfully applied to saliva samples donated by apparently healthy volunteers (n = 10).

scholarly journals Comparison of Three Different Plasma Homocysteine Assays with Gas Chromatography–Mass Spectrometry

1999 ◽  
Vol 45 (5) ◽  
pp. 670-675 ◽  
Author(s):  
Johan B Ubbink ◽  
Rhena Delport ◽  
Reiner Riezler ◽  
WJ Hayward Vermaak
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Plasma Homocysteine ◽  
Gas Chromatography Mass Spectrometry ◽  
Negative Bias ◽  
Positive Bias ◽  
Fluorescence Polarization Immunoassay ◽  
Chromatography Mass Spectrometry ◽  
Methionine Load ◽  
Plasma Thcy

Abstract Background: Various methods are available to measure plasma total homocyst(e)ine (tHcy) concentrations, but whether plasma tHcy assays may be used interchangeably is not known. Methods: Results from three different methods [HPLC with fluorescence detection, enzyme immunoassay (EIA), and fluorescence polarization immunoassay (FPIA)] to determine fasting (n = 163) and post-methionine load (n = 80) plasma tHcy concentrations were compared with those obtained by gas chromatography–mass spectrometry (GC-MS). Difference plots on non-transformed and log-transformed data were used to assess the agreement between HPLC and GC-MS, EIA and GC-MS, and FPIA and GC-MS. Results: The closest agreement between methods was observed between GC-MS and FPIA for fasting tHcy concentrations, with 95% of the FPIA values between 19% above and 24% below the corresponding GC-MS results. Post-methionine load tHcy concentrations measured by EIA showed the least agreement with GC-MS, with 95% of values measured by EIA ranging between 52% above and 16% below the GC-MS values. With respect to GC-MS, the above-mentioned methods showed a negative bias for fasting tHcy concentrations, but a positive bias for both immunoassays for post-methionine load tHcy concentrations. Conclusions: The agreement among methods is insufficient to allow them to be used interchangeably. The intermethod differences emphasize the need for standardization of plasma tHcy assays.

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