scholarly journals Dimethylcysteine (DiCys)/o-Phthalaldehyde Derivatization for Chiral Metabolite Analyses: Cross-Comparison of Six Chiral Thiols

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7416
Author(s):  
Ankhbayar Lkhagva ◽  
Hwan-Ching Tai
Keyword(s):  
Amino Acids ◽  
Chiral Separation ◽  
Reversed Phase ◽  
Liquid Chromatography Mass Spectrometry ◽  
Complex Samples ◽  
Significant Challenge ◽  
Metabolomics Study ◽  
Overall Performance ◽  
Metabolite Detection ◽  
Reversed Phase Lc

Metabolomics profiling using liquid chromatography-mass spectrometry (LC-MS) has become an important tool in biomedical research. However, resolving enantiomers still represents a significant challenge in the metabolomics study of complex samples. Here, we introduced N,N-dimethyl-l-cysteine (dimethylcysteine, DiCys), a chiral thiol, for the o-phthalaldehyde (OPA) derivatization of enantiomeric amine metabolites. We took interest in DiCys because of its potential for multiplex isotope-tagged quantification. Here, we characterized the usefulness of DiCys in reversed-phase LC-MS analyses of chiral metabolites, compared against five commonly used chiral thiols: N-acetyl-l-cysteine (NAC); N-acetyl-d-penicillamine (NAP); isobutyryl-l-cysteine (IBLC); N-(tert-butoxycarbonyl)-l-cysteine methyl ester (NBC); and N-(tert-butylthiocarbamoyl)-l-cysteine ethyl ester (BTCC). DiCys and IBLC showed the best overall performance in terms of chiral separation, fluorescence intensity, and ionization efficiency. For chiral separation of amino acids, DiCys/OPA also outperformed Marfey’s reagents: 1-fluoro-2-4-dinitrophenyl-5-l-valine amide (FDVA) and 1-fluoro-2-4-dinitrophenyl-5-l-alanine amide (FDAA). As proof of principle, we compared DiCys and IBLC for detecting chiral metabolites in aqueous extracts of rice. By LC–MS analyses, both methods detected twenty proteinogenic l-amino acids and seven d-amino acids (Ala, Arg, Lys, Phe, Ser, Tyr, and Val), but DiCys showed better analyte separation. We conclude that DiCys/OPA is an excellent amine-derivatization method for enantiomeric metabolite detection in LC-MS analyses.

scholarly journals Simultaneous Determination of Residues of Chloramphenicol, Thiamphenicol, Florfenicol, and Florfenicol Amine in Farmed Aquatic Species by Liquid Chromatography/Mass Spectrometry

2003 ◽  
Vol 86 (3) ◽  
pp. 510-514 ◽  
Author(s):  
Jeffery M van de Riet ◽  
Ross A Potter ◽  
Melissa Christie-Fougere ◽  
B Garth Burns
Keyword(s):  
Reversed Phase ◽  
Organic Layer ◽  
Aquatic Species ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Aqueous Layer ◽  
Operational Errors ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A liquid chromatographic (LC)/mass spectrometric (MS) method was developed for determining the residues of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in a number of aquatic species. The phenicols are extracted with acetone, the extracts are partitioned with dichloromethane, the aqueous layer is removed, and the organic layer is evaporated to dryness. The residue is dissolved in dilute acid and defatted with hexane, and the aqueous layer is prepared for analysis by LC. The phenicols are determined by reversed-phase LC by using a Hypersil C18-BD column with a water–acetonitrile gradient and MS detection using selectedion recording. Calibration curves were linear for all analytes between 0.015 and 0.425 ng injected. The relative standard deviations for measurements by the proposed method were <10% for all of the analytes studied, with re-coveries ranging from 71% for florfenicol amine to 107% for florfenicol in salmon tissue spiked at the 2 ng/g level. Detection limits of 0.1 ng/g for florfenicol and chloramphenicol, 0.3 ng/g for thiamphenicol, and 1.0 ng/g for florfenicol amine are easily obtainable. The operational errors, interferences, and recoveries for spiked samples compare favorably with those obtained by established LC methodology. The proposed method is simple, rapid, and specific for monitoring residues of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in a number of aquatic species.

scholarly journals DynaStI: A Dynamic Retention Time Database for Steroidomics

Metabolites ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 85 ◽  
Author(s):  
Santiago Codesido ◽  
Giuseppe Marco Randazzo ◽  
Fabio Lehmann ◽  
Víctor González-Ruiz ◽  
Arnaud García ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Metabolic Pathways ◽  
Structural Information ◽  
Chemical Properties ◽  
Reversed Phase ◽  
Liquid Chromatography Mass Spectrometry ◽  
Phase Gradient ◽  
Physico Chemical ◽  
Solvent Strength ◽  
Reversed Phase Lc

Steroidomics studies face the challenge of separating analytical compounds with very similar structures (i.e., isomers). Liquid chromatography (LC) is commonly used to this end, but the shared core structure of this family of compounds compromises effective separations among the numerous chemical analytes with comparable physico-chemical properties. Careful tuning of the mobile phase gradient and an appropriate choice of the stationary phase can be used to overcome this problem, in turn modifying the retention times in different ways for each compound. In the usual workflow, this approach is suboptimal for the annotation of features based on retention times since it requires characterizing a library of known compounds for every fine-tuned configuration. We introduce a software solution, DynaStI, that is capable of annotating liquid chromatography-mass spectrometry (LC–MS) features by dynamically generating the retention times from a database containing intrinsic properties of a library of metabolites. DynaStI uses the well-established linear solvent strength (LSS) model for reversed-phase LC. Given a list of LC–MS features and some characteristics of the LC setup, this software computes the corresponding retention times for the internal database and then annotates the features using the exact masses with predicted retention times at the working conditions. DynaStI (https://dynasti.vital-it.ch) is able to automatically calibrate its predictions to compensate for deviations in the input parameters. The database also includes identification and structural information for each annotation, such as IUPAC name, CAS number, SMILES string, metabolic pathways, and links to external metabolomic or lipidomic databases.

scholarly journals Towards Extending the Detection Window of Gamma-Hydroxybutyric Acid—An Untargeted Metabolomics Study in Serum and Urine Following Controlled Administration in Healthy Men

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 166
Author(s):  
Andrea E. Steuer ◽  
Justine Raeber ◽  
Fabio Simbuerger ◽  
Dario A. Dornbierer ◽  
Oliver G. Bosch ◽  
...  
Keyword(s):  
Drugs Of Abuse ◽  
Forensic Toxicology ◽  
Reversed Phase ◽  
Mixed Effect ◽  
Healthy Men ◽  
Metabolic Substrates ◽  
Gamma Hydroxybutyrate ◽  
Metabolomics Study ◽  
Detection Window ◽  
Negative Electrospray Ionization

In forensic toxicology, gamma-hydroxybutyrate (GHB) still represents one of the most challenging drugs of abuse in terms of analytical detection and interpretation. Given its rapid elimination, the detection window of GHB in common matrices is short (maximum 12 h in urine). Additionally, the differentiation from naturally occurring endogenous GHB, is challenging. Thus, novel biomarkers to extend the detection window of GHB are urgently needed. The present study aimed at searching new potential biomarkers of GHB use by means of mass spectrometry (MS) metabolomic profiling in serum (up to 16.5 h) and urine samples (up to 8 h after intake) collected during a placebo-controlled crossover study in healthy men. MS data acquired by different analytical methods (reversed phase and hydrophilic interaction liquid chromatography; positive and negative electrospray ionization each) were filtered for significantly changed features applying univariate and mixed-effect model statistics. Complementary to a former study, conjugates of GHB with glycine, glutamate, taurine, carnitine and pentose (ribose) were identified in urine, with particularly GHB-pentose being promising for longer detection. None of the conjugates were detectable in serum. Therein, mainly energy metabolic substrates were identified, which may be useful for more detailed interpretation of underlying pathways but are too unspecific as biomarkers.

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