Internal standard signal suppression by co-eluting analyte in isotope dilution LC-ESI-MS

The Analyst ◽  
2002 ◽  
Vol 128 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Luis E. Sojo ◽  
Gina Lum ◽  
Priscilla Chee
Keyword(s):  
Isotope Dilution ◽  
Internal Standard ◽  
Esi Ms ◽  
Standard Signal ◽  
Signal Suppression

scholarly journals Ultrahigh-Throughput ESI-MS: Sampling Pushed to Six Samples per Second by Acoustic Ejection Mass Spectrometry

2020 ◽  
Author(s):  
Tim Häbe ◽  
Chang Liu ◽  
Tom Covey ◽  
Roman P. Simon ◽  
Wolfgang Reindl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Enzyme Assay ◽  
Sampling Rate ◽  
Internal Standard ◽  
Stress Tests ◽  
Esi Ms ◽  
Droplet Ejection ◽  
Signal Suppression ◽  
Dog Plasma ◽  
Open Port

<div> <p> We present an acoustic ejection mass spectrometry (AEMS) setup for ESI-MS based sample </p><p> injection at a sampling rate faster than current ESI and MALDI techniques. A modified acoustic </p><p> droplet ejection system was combined with an open port interface and a modified ESI source. To </p><p> simulate applications of drug metabolism and pharmacokinetics analysis and high-throughput </p><p> screening campaigns, two stress tests were performed regarding ion suppression and system </p><p> endurance in combination with minor sample preparation. Maximum sampling rate was 6 Hz for </p><p> dextromethorphan and d3-dextrorphan (each 100 nM) for 1152 injections in 63 s at FWHM of </p><p> 105 ms and %RSD of 7.7%/7.5% without internal standard correction. Enzyme assay buffer and </p><p> crude dog plasma caused signal suppression of 51%/73% at %RSD of 5.7%/6.7% (n = 120) and </p><p> stable OPI performance during 1100 injections. An endurance buffer revealed minor OPI pollution </p><p> and constant signals for >25.000 injections (%RSD = 8.5%, n = 10,557). </p></div>

scholarly journals Ultrahigh-Throughput ESI-MS: Sampling Pushed to Six Samples per Second by Acoustic Ejection Mass Spectrometry

2020 ◽  
Author(s):  
Tim Häbe ◽  
Chang Liu ◽  
Tom Covey ◽  
Roman P. Simon ◽  
Wolfgang Reindl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Enzyme Assay ◽  
Sampling Rate ◽  
Internal Standard ◽  
Stress Tests ◽  
Esi Ms ◽  
Droplet Ejection ◽  
Signal Suppression ◽  
Dog Plasma ◽  
Open Port

<div> <p> We present an acoustic ejection mass spectrometry (AEMS) setup for ESI-MS based sample </p><p> injection at a sampling rate faster than current ESI and MALDI techniques. A modified acoustic </p><p> droplet ejection system was combined with an open port interface and a modified ESI source. To </p><p> simulate applications of drug metabolism and pharmacokinetics analysis and high-throughput </p><p> screening campaigns, two stress tests were performed regarding ion suppression and system </p><p> endurance in combination with minor sample preparation. Maximum sampling rate was 6 Hz for </p><p> dextromethorphan and d3-dextrorphan (each 100 nM) for 1152 injections in 63 s at FWHM of </p><p> 105 ms and %RSD of 7.7%/7.5% without internal standard correction. Enzyme assay buffer and </p><p> crude dog plasma caused signal suppression of 51%/73% at %RSD of 5.7%/6.7% (n = 120) and </p><p> stable OPI performance during 1100 injections. An endurance buffer revealed minor OPI pollution </p><p> and constant signals for >25.000 injections (%RSD = 8.5%, n = 10,557). </p></div>

Revealing changes in curcumin bioavailability using vitamin C as an enhancer by HPLC-MS/MS

2019 ◽  
Vol 16 ◽  
Author(s):  
Xufen Dai ◽  
Jiaxue Hao ◽  
Ying Feng ◽  
Jing Wang ◽  
Qiannan Li ◽  
...  
Keyword(s):  
Vitamin C ◽  
High Performance ◽  
Internal Standard ◽  
Fold Increase ◽  
Rat Plasma ◽  
Pharmacokinetic Parameters ◽  
Solution Ph ◽  
Esi Ms ◽  
Simple Strategy ◽  
Isolated Compound

Background: Curcumin (CUR), a natural isolated compound from turmeric, has been the promising star in fighting many diseases but the broad application of curcumin has been limited ascribed to low bioavailability. Objective: The aim of this study is to pursue the enhancement of curcumin bioavailability through co-administration of vitamin C. Methods: Such purpose was achieved through the analysis of curcumin pharmacokinetics by high performance liquid chromatography coupled with electrospray ionization - tandem mass spectrometry (HPLC - ESI - MS/MS). The plasma was separated on a C18 reverse phase column using acetonitrile and ammonium formate solution (pH 6.5; 2.0 mM) at 0.8 mL/min. MS/MS detection was carried out in negative mode using mass patterns of m/z 367.0 > 216.7 for curcumin and m/z 265.2 > 223.9 for internal standard (honokiol). Results: Successful application of the proposed method in the pharmacokinetic study presented clear changes in key pharmacokinetic parameters including the growth of AUC (0-t) up to 2.4 times, 2.2-fold increase of Cmax, 2.2-fold loss of CL, and 1.5-fold diminishment of t1/2. Conclusion: We developed an HPLC-ESI-MS/MS method for determination of curcumin in rat plasma and validated the improvement of bioavailability of curcumin through co-administration of vitamin C. We reasoned these changes to the inhibition of lipid peroxidation induced by the use of vitamin C. Such a simple strategy is possible to become an alternative for enhancing curcumin efficiency in practice.

scholarly journals Pressurized Solvent Extraction with Ethyl Acetate and Liquid Chromatography—Tandem Mass Spectrometry for the Analysis of Selected Conazole Fungicides in Matcha

Toxics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 64 ◽  
Author(s):  
Renata Raina-Fulton ◽  
Aisha Mohamad
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Matrix Effects ◽  
Tandem Mass ◽  
Esi Ms ◽  
Signal Suppression ◽  
Target Analytes ◽  
Matrix Components ◽  
Pressurized Solvent Extraction

The extraction of powdered nutraceuticals is challenging due to the low water content and high concentration of matrix components that can lead to significant matrix effects in liquid chromatography-positive ion electrospray ionization-tandem mass spectrometry (LC-ESI+-MS/MS). In this study we assess the feasibility of using pressurized solvent extraction with ethyl acetate to reduce the co-extraction of polar matrix components. Pigment attributed to chlorophyll was removed with in-cell clean-up utilizing Anasorb 747, Florisil®, and C18. Visible inspection of the extracts showed that pigment was removed from matcha, a powdered green tea sample. Pressurized solvent extraction with in-cell clean-up can be utilized to remove pigments from powdered samples such as nutraceuticals. Average matrix effect of the 32 target analytes that observed mass spectrometric signal suppression or soft MS signal enhancement was −41 ± 19% with the majority of analytes having a protonated molecular ion with m/z of 250 to 412. As generally moderate signal suppression was observed for conazole fungicides and structurally related compounds analyzed by LC-ESI+-MS/MS, it is recommended that matrix matched or standard addition calibration is used for quantitation. Catachins, other polyphenols, and caffeine are expected to contribute to the matrix effects observed in LC-ESI+-MS/MS. Diniconazole, fenbuconazole, and tebufenozide were the only target analytes with severe MS signal enhancement. Low levels (0.002–0.004 mg/kg) of prothioconazole-desthio and flusilazole were detected, along with trace levels of tebuthiuron in matcha.

scholarly journals First Synthesis of (−)-Altenuene-D3 Suitable as Internal Standard for Isotope Dilution Mass Spectrometry

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4563
Author(s):  
Michael A. Sebald ◽  
Julian Gebauer ◽  
Thomas Sommerfeld ◽  
Matthias Koch
Keyword(s):  
Mass Spectrometry ◽  
Antimicrobial Activity ◽  
Stable Isotope ◽  
Total Synthesis ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Internal Standard ◽  
Biological Properties ◽  
Mycotoxin Analysis ◽  
Activity Optimization

Metabolites from Alternaria fungi exhibit a variety of biological properties such as phytotoxic, cytotoxic, or antimicrobial activity. Optimization of a literature procedure culminated in an efficient total synthesis of (−)-altenuene as well as a stable isotope-labeled derivative suitable for implementation in a LC-MS/MS method for mycotoxin analysis.

scholarly journals Quantitative Analysis of 2-Aminoacetophenone in Off-Flavored Wines by Stable Isotope Dilution Assay

1996 ◽  
Vol 79 (2) ◽  
pp. 583-586 ◽  
Author(s):  
Bettina Dollmann ◽  
Dominicus Wichmann ◽  
Alfred Schmitt ◽  
Hans Koehler ◽  
Peter Schreier
Keyword(s):  
Quantitative Analysis ◽  
Stable Isotope ◽  
Isotope Dilution ◽  
Internal Standard ◽  
Stable Isotope Dilution Assay ◽  
Isotope Dilution Analysis ◽  
Model Experiments ◽  
Stable Isotope Dilution ◽  
Isotope Dilution Assay ◽  
Dilution Assay

Abstract Isotope dilution analysis was used to quantitate 2- aminoacetophenone in wines exhibiting the so- called untypical aging off-flavor. d3-Aminoacetophe- none was synthesized and used as isotopomeric internal standard. The method of quantitation was verified by several model experiments. In the off-flavored wines studied, amounts of 2-aminoacetophe none ranging from 0.7 to 12.8 μg/L were determined.

Accurate LC-ESI-MS/MS quantification of 2′-deoxymugineic acid in soil and root related samples employing porous graphitic carbon as stationary phase and a13C4-labeled internal standard

2014 ◽  
Vol 35 (9) ◽  
pp. 1375-1385 ◽  
Author(s):  
Yvonne Schindlegger ◽  
Eva Oburger ◽  
Barbara Gruber ◽  
Walter D. C. Schenkeveld ◽  
Stephan M. Kraemer ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Internal Standard ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Esi Ms ◽  
Deoxymugineic Acid

Signal suppression/enhancement in HPLC-ESI-MS/MS from concomitant medications

2007 ◽  
Vol 21 (11) ◽  
pp. 1143-1150 ◽  
Author(s):  
Rachael Leverence ◽  
Michael J. Avery ◽  
Olga Kavetskaia ◽  
Honggang Bi ◽  
Cornelis E. C. A. Hop ◽  
...  
Keyword(s):  
Esi Ms ◽  
Signal Suppression ◽  
Concomitant Medications

scholarly journals Quantification of Serum and Urinary S-Adenosylmethionine and S-Adenosylhomocysteine by Stable-Isotope-Dilution Liquid Chromatography-Mass Spectrometry

2004 ◽  
Vol 50 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Sally P Stabler ◽  
Robert H Allen
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Stable Isotope ◽  
Isotope Dilution ◽  
Biological Fluids ◽  
Internal Standard ◽  
Fractional Excretion ◽  
Liquid Chromatography Mass Spectrometry ◽  
Stable Isotope Dilution ◽  
Chromatography Mass Spectrometry

Abstract Background: We have developed an assay that uses stable-isotope-dilution liquid chromatography–mass spectrometry to assess S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in body fluids to investigate the relationship of these metabolites to hyperhomocysteinemia. Methods: Commercially obtained SAM (D3 methyl) and 13C5-SAH uniformly labeled in the adenosyl moiety, which was synthesized using S-adenosylhomocysteine hydrolase, were added to samples followed by perchloric acid protein precipitation, C18 chromatography, and analysis by liquid chromatography–mass spectrometry with quantification by comparison of the areas of internal standard and endogenous peaks. Results: Estimates of intraassay imprecision (CV) were 5% and 17% for SAM and SAH, respectively (n = 10). SAM decreased and SAH increased in serum and plasma samples at both 4 °C and room temperature over 80 h. SAM and SAH were unstable in samples stored longer than 2 years at −20 °C. In 48 volunteers, the estimated reference intervals [from mean (2 SD) of log-transformed data] for serum SAM and SAH were 71–168 and 8–26 nmol/L, respectively. Fractional excretion of SAM was higher than that of SAH, and the urinary SAM:SAH ratio was much higher than the serum or erythrocyte SAM:SAH ratios. Conclusions: Stable-isotope-dilution liquid chromatography–mass spectrometry can be used to quantify SAM and SAH in biological fluids and tissues. Sample handling and storage must be stringently controlled for any epidemiologic or clinical use of such assays.

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