scholarly journals Determination of S-Adenosylmethionine and S-Adenosylhomocysteine in Plasma and Cerebrospinal Fluid by Stable-Isotope Dilution Tandem Mass Spectrometry

2000 ◽  
Vol 46 (10) ◽  
pp. 1650-1656 ◽  
Author(s):  
Eduard A Struys ◽  
Erwin E W Jansen ◽  
Kees de Meer ◽  
Cornelis Jakobs
Keyword(s):  
Mass Spectrometry ◽  
Cerebrospinal Fluid ◽  
Stable Isotope ◽  
Tandem Mass Spectrometry ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Internal Standard ◽  
Tandem Mass ◽  
Analytical Technique

Abstract Background: Available methods for the determination of nanomolar concentrations of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in plasma and cerebrospinal fluid (CSF) are time-consuming. We wished to develop a method for their rapid and simultaneous measurement. Methods: We used tandem mass spectrometry (MS/MS) for the simultaneous determination of SAM and SAH, with stable-isotope-labeled internal standards. The 13C5-SAH internal standard was enzymatically prepared using SAH-hydrolase and [13C5]adenosine. The method comprises a weak anion-exchange solid-phase extraction procedure serving as clean-up step for the deproteinized plasma and CSF samples. After clean-up, samples were injected on a C18 HPLC column, which was connected directly to the tandem mass spectrometer, operating in MS/MS mode. Results: In plasma samples, the intraassay CVs for SAM and SAH were 4.2% and 4.0%, respectively, and the interassay CVs were 7.6% and 5.9%, respectively. In CSF, the intraassay CVs for SAM and SAH were 6.8% and 6.9%, respectively, and the interassay CVs were 4.2% and 5.5%, respectively. Mean recovery of SAM and SAH for both matrices at two concentrations was 93%. Detection limits for SAM and SAH in samples were 7.5 and 2.5 nmol/L, respectively. Concentrations of SAM and SAH in plasma from healthy subjects were within the previously reported ranges. In 10 CSF samples, the mean concentrations (range) were 248 (137–385) nmol/L for SAM and 11.3 (8.9–14.1) nmol/L for SAH. Conclusions: SAM and SAH can be analyzed by MS/MS, taking optimal advantage of the speed and high sensitivity and specificity of this relatively new analytical technique.

scholarly journals Determination of Coumarin-type Anticoagulants in Human Plasma by HPLC-Electrospray Ionization Tandem Mass Spectrometry with an Ion Trap Detector

2002 ◽  
Vol 48 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Manfred Kollroser ◽  
Caroline Schober
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Solid Phase Extraction ◽  
Electrospray Ionization ◽  
Solid Phase ◽  
Internal Standard ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Ionization Tandem Mass Spectrometry

Abstract Background: Coumarin-type anticoagulants are used for the long-term treatment and prevention of thromboembolic disorders. The identification of these drugs is crucial in patients with an increased prothrombin time of unknown origin. The aim of this study was to develop a sensitive and specific method for the simultaneous determination of phenprocoumon, acenocoumarol, and warfarin in human plasma by HPLC-electrospray ionization tandem mass spectrometry. Methods: After addition of the internal standard, p-chlorowarfarin, plasma samples were extracted using Oasis® MCX solid-phase extraction cartridges. The compounds were separated on a Symmetry C18 column (Waters) with a mobile phase of acetonitrile–1 g/L formic acid (75:25 by volume) at a flow rate of 0.5 mL/min. Results: Extraction and separation of the three drugs and the internal standard were accomplished in 9 min. The overall extraction efficiency was >89% for all three compounds. The limits of detection were 1 μg/L for phenprocoumon and warfarin and 10 μg/L for acenocoumarol. Regression analysis of the calibration data revealed good correlation (r2 ≥0.995) for all compounds. Within-run accuracies for quality-control samples were ± 1% to 7% of the target concentration, with CVs <9%. Conclusions: The proposed method enables the unambiguous identification and quantification of phenprocoumon, warfarin, and acenocoumarol in both clinical and forensic specimens. This method combines a new, rapid solid-phase extraction procedure with an extremely fast chromatographic analysis, which is especially advantageous for clinical laboratories.

scholarly journals Determination of Free Levels of Cinitipride in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry

2008 ◽  
Vol 5 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Shikha M. N. Roy ◽  
Santos H. M. Yetal ◽  
Sangita V. Chavan ◽  
Vara D. R. Pradhan ◽  
Santosh S. Joshi
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Human Plasma ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Extraction Procedure ◽  
Internal Standard ◽  
Specific Method ◽  
Tandem Mass

A rapid, sensitive and specific method to quantify cinitapride in human plasma using risperidone as the internal standard is described. Sample preparation involved simple solid phase extraction procedure. The extract was analyzed by high performance liquid chromatography coupled to electrospray tandem mass spectrometry API-4000 (LC-MS/MS). Chromatography was performed isocratically on Thermo Hypurity C18analytical column, (50 mm x 4.6 mm, 5µm i.d.). The assay of cinitapride was linear calibration curve over the range 20.118 pg mL−1to 2011.797 pg mL−1. Plasma concentrations of cinitapride were determined by LC-MS/MS with a limit of quantification of 20.118 pg mL−1that allowed an appropriate characterization of the pharmacokinetic profile of cinitapride at the therapeutic dose. The method was successfully applied to the bioequivalence study of cinitapride tablet (1.0 mg) administered as a single oral dose.

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