scholarly journals Guide to Semi-Quantitative Non-Targeted Screening Using LC/ESI/HRMS

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3524
Author(s):  
Louise Malm ◽  
Emma Palm ◽  
Amina Souihi ◽  
Merle Plassmann ◽  
Jaanus Liigand ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Retrospective Analysis ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Final Decision ◽  
Less Is More ◽  
Targeted Analysis ◽  
Targeted Screening ◽  
Negative Ionization Mode ◽  
Negative Ionization

Non-targeted screening (NTS) with reversed phase liquid chromatography electrospray ionization high resolution mass spectrometry (LC/ESI/HRMS) is increasingly employed as an alternative to targeted analysis; however, it is not possible to quantify all compounds found in a sample with analytical standards. As an alternative, semi-quantification strategies are, or at least should be, used to estimate the concentrations of the unknown compounds before final decision making. All steps in the analytical chain, from sample preparation to ionization conditions and data processing can influence the signals obtained, and thus the estimated concentrations. Therefore, each step needs to be considered carefully. Generally, less is more when it comes to choosing sample preparation as well as chromatographic and ionization conditions in NTS. By combining the positive and negative ionization mode, the performance of NTS can be improved, since different compounds ionize better in one or the other mode. Furthermore, NTS gives opportunities for retrospective analysis. In this tutorial, strategies for semi-quantification are described, sources potentially decreasing the signals are identified and possibilities to improve NTS are discussed. Additionally, examples of retrospective analysis are presented. Finally, we present a checklist for carrying out semi-quantitative NTS.

scholarly journals Determination of Ten Corticosteroids in Illegal Cosmetic Products by a Simple, Rapid, and High-Performance LC-MS/MS Method

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Vita Giaccone ◽  
Giuseppe Polizzotto ◽  
Andrea Macaluso ◽  
Gaetano Cammilleri ◽  
Vincenzo Ferrantelli
Keyword(s):  
High Performance ◽  
Skin Diseases ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Cosmetic Products ◽  
Chromatography Method ◽  
Esi Ms ◽  
Negative Ionization Mode ◽  
Negative Ionization

The aim of our present work was the development of a rapid high-performance liquid chromatography method with electrospray ionization and tandem mass spectrometry detection (LC-ESI-MS/MS) for the determination of several corticosteroids in cosmetic products. Corticosteroids are suspected to be illegally added in cosmetic preparations in order to enhance the curative effect against some skin diseases. Sample preparation step consists in a single extraction with acetonitrile followed by centrifugation and filtration. The compounds were separated by reversed-phase chromatography with water and acetonitrile (both with 0.1% formic acid) gradient elution and detected by ESI-MS positive and negative ionization mode. The method was validated at the validation level of 0.1 mg kg−1. Linearity was studied in the 5–250 μg L−1 range and linear coefficients (r2) were all over 0.99. The accuracy and precision of the method were satisfactory. The LOD ranged from 0.085 to 0.109 mg kg−1 and the LOQ from 0.102 to 0.121 mg kg−1. Mean recoveries for all the analytes were within the range 91.9–99.2%. The developed method is sensitive and useful for detection, quantification, and confirmation of these corticosteroids in cosmetic preparations and can be applied in the analysis of the suspected samples under investigation.

scholarly journals An optimized LC-HRMS untargeted metabolomics workflow for multi-matrices investigations in the three-spined stickleback

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260354
Author(s):  
Emmanuelle Lebeau-Roche ◽  
Gaëlle Daniele ◽  
Aurélie Fildier ◽  
Cyril Turies ◽  
Odile Dedourge-Geffard ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Gasterosteus Aculeatus ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Research Field ◽  
Untargeted Metabolomics ◽  
Whole Body ◽  
Systematic Analysis ◽  
Fish Model ◽  
Ionization Mode

Environmental metabolomics has become a growing research field to understand biological and biochemical perturbations of organisms in response to various abiotic or biotic stresses. It focuses on the comprehensive and systematic analysis of a biologic system’s metabolome. This allows the recognition of biochemical pathways impacted by a stressor, and the identification of some metabolites as biomarkers of potential perturbations occurring in a body. In this work, we describe the development and optimization of a complete reliable methodology based on liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) for untargeted metabolomics studies within a fish model species, the three-spined stickleback (Gasterosteus aculeatus). We evaluated the differences and also the complementarities between four different matrices (brain, gills, liver and whole fish) to obtain metabolome information. To this end, we optimized and compared sample preparation and the analytical method, since the type and number of metabolites detected in any matrix are closely related to these latter. For the sample preparation, a solid-liquid extraction was performed on a low quantity of whole fish, liver, brain, or gills tissues using combinations of methanol/water/heptane. Based on the numbers of features observed in LC-HRMS and on the responses of analytical standards representative of different metabolites groups (amino acids, sugars…), we discuss the influence of the nature, volume, and ratio of extraction solvents, the sample weight, and the reconstitution solvent. Moreover, the analytical conditions (LC columns, pH and additive of mobile phases and ionization modes) were also optimized so as to ensure the maximum metabolome coverages. Thus, two complementary chromatographic procedures were combined in order to cover a broader range of metabolites: a reversed phase separation (RPLC) on a C18 column followed by detection with positive ionization mode (ESI+) and a hydrophilic interaction chromatography (HILIC) on a zwitterionic column followed by detection with negative ionization mode (ESI-). This work provides information on brain, gills, liver, vs the whole body contribution to the stickleback metabolome. These information would help to guide ecotoxicological and biomonitoring studies.

scholarly journals Untargeted Metabolomic Profiling of Early Diet Energy Intake in C57BL/6 N Mice Reveals Differences Associated with Diet and Aberrant Crypt Foci

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1249-1249
Author(s):  
Haley Chatelaine ◽  
Spencer Kyle ◽  
Cynthia Ramazani ◽  
Susan Olivo-Marston ◽  
Emmanuel Hatzakis ◽  
...  
Keyword(s):  
High Performance ◽  
Linear Models ◽  
High Resolution Mass Spectrometry ◽  
Control Diet ◽  
Aberrant Crypt Foci ◽  
Funding Sources ◽  
Negative Ionization Mode ◽  
Ionization Mode ◽  
Negative Ionization ◽  
Polar Extracts

Abstract Objectives A high-fat (H) diet leads to obesity, a known risk factor for colorectal cancer (CRC). In contrast, calorie restriction (E) is associated with reduced CRC risk. However, the metabolome associated with H vs. E-associated CRC risk has never been directly compared. The different influences of these diets on the proximal (PC), medial (MC), and distal (DC) colon metabolome has also not been studied. Thus, the objective is to elucidate metabolites associated with abberant crypt foci (ACF) number, a marker of CRC risk, in each colon region after consumption of H, E, or a normocaloric control diet (C). Methods 3-week-old C57BL/6 N mice were fed a C, E, or H initiation diet for 13 weeks. In weeks 16–21, animals were injected with azoxymethane to initiate ACF formation, and switched to a C, E, or H progression diet (for a total of 9 diet groups: CC, CH, CE, HH, HC, HE, EE, EC, EH). Polar extracts of the colon regions (i.e., PC, MC, and DC) were analyzed using ultra-high performance liquid chromatography-high resolution mass spectrometry method (HRMS) and 1H NMR metabolomics methods. Linear models assessed the main effects of ACF, initiation diet, progression diet, as well as the diet * ACF interaction, on relative metabolite concentration in each colon region. Results Following HILIC-HRMS analysis of extracts in positive and negative ionization mode, 492 and 415 metabolites were detected, respectively. Linear models revealed 21 metabolites were significantly associated with initiation E diet * ACF (8 unique to MC, 13 unique to PC), 14 with initiation H diet * ACF (only in DC), 27 with progression H diet * ACF (14 unique to DC, 2 to MC, 11 to PC) and 20 with progression E diet * ACF (17 unique to DC, 1 to PC, and 1 common to both). Pathway integration and authentication of tentative metabolite identities with chemical standards is underway. Conclusions Diet * ACF interaction significantly influences multiple metabolite concentrations. Little to no overlap is observed between metabolites associated with ACF in a given colon region and the other regions tested, revealing that the diet * ACF interaction is region-specific. Future studies in humans will determine if these metabolites may serve as early biomarkers for CRC diagnosis. Funding Sources Sample analyses were supported by NIH Award Number Grant P30 CA016058, OSU, and OSUCCC.

A Fast and Sensitive Method Combining Reversed-Phase Chromatography with High Resolution Mass Spectrometry to Quantify 2-Fluoro-2-Deoxyglucose and Its Phosphorylated Metabolite for Determining Glucose Uptake

2019 ◽  
Author(s):  
Ashley Williams ◽  
Deborah Muoio ◽  
Guofang Zhang
Keyword(s):  
Glucose Uptake ◽  
Biological Samples ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Sodium Adduct ◽  
Negative Mode ◽  
Glucose Analogues ◽  
Positive Mode ◽  
Q Exactive ◽  
Glucose Analogue

Quantative measurements of the glucose analogue, 2-deoxyglucose (2DG), and its phosphorylated metabolite (2-deoxyglucose-6-phosphate (2DG-6-P)) are critical for the measurement of glucose uptake. While the field has long identified the need for sensitive and reliable assays that deploy non-radiolabled glucose analogues to assess glucose uptake, no analytical MS-based methods exist to detect trace amounts in complex biological samples. In the present work, we show that 2DG is poorly suited for MS-based methods due to interfering metabolites. We therefore developed and validated an alternative C18-based LC-Q-Exactive-Orbitrap-MS method using 2-fluoro-2-deoxyglucose (2FDG) to quantify both 2FDG and 2FDG-6-P by measuring the sodium adduct of 2FDG in the positive mode and deprotonation of 2FDG-6-P in the negative mode. The low detection limit of this method can reach 81.4 and 48.8 fmol for both 2FDG and 2FDG-6-P, respectively. The newly developed method was fully validated via calibration curves in the presence and absence of biological matrix. The present work is the first successful LC-MS method that can quantify trace amounts of a nonradiolabeled glucose analogue and its phosphorylated metabolite and is a promising analytical method to determine glucose uptake in biological samples.

Investigation of Phenolic Content in Five Different Pine Barks Species Grown in Turkey by HPLC-UV and LC–MS

2021 ◽  
Author(s):  
Mehmet Emin Şeker ◽  
Ali Çelik ◽  
Kenan Dost ◽  
Ayşegül Erdoğan
Keyword(s):  
Sample Preparation ◽  
Orthophosphoric Acid ◽  
Phenolic Content ◽  
Reversed Phase ◽  
Uv Detector ◽  
Epicatechin Gallate ◽  
Rp Hplc ◽  
Phenolic Constituents ◽  
Preparation Step ◽  
Very High

Abstract Investigation of phenolic content from different pine bark species grown in Turkey was performed using a reversed-phase high pressure liquid chromatography with ultraviolet (RP-HPLC-UV) method. All phenolic constituents were separated in <26 min on reversed-phase C18 column with gradient mobile phase that consists of orthophosphoric acid, methanol and acetonitrile. Detections were made on an UV detector at 280 nm and at a flow rate of 1 mL/min. Samples were prepared according to Masqueller’s conventional sample preparation method with slight modifications. To avoid the reduction in extraction efficiency the sample preparation step was carried out under argon atmosphere. The linearity of the method was between 0.9994 and 0.9999. The detection limits for the five phenolic constituents ranged from 0122 to 0.324 mg/L. Catechin and taxifolin were found in all pine barks at a concentration of 0.065 ± 0.002–1.454 ± 0.004 and 0.015 ± 0.001–23.164 ± 0.322 mg/g, respectively. Epicatechin was determined in four pine barks between 0.027 ± 0.001 and 0.076 ± 0.002 mg/g, ferulic acid in two pine barks between 0.010 ± 0.001 and 0.022 ± 0.001 mg/g and epicatechin gallate in only one of the pine barks at 0.025 ± 0.001 mg/g. Finally, the total amount of phenolic compounds and antioxidant capacities of the pine barks were found to be very high.

scholarly journals A combined flow injection/reversed phase chromatography – high resolution mass spectrometry workflow for accurate absolute lipid quantification with 13C- internal standards

The Analyst ◽  
2021 ◽  
Author(s):  
Harald Schoeny ◽  
Evelyn Rampler ◽  
Yasin El Abiead ◽  
Felina Hildebrand ◽  
Olivia Zach ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Flow Injection ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Internal Standards ◽  
Lipid Quantification ◽  
High Resolution Mass ◽  
Resolution Mass

We propose a fully automated novel workflow for lipidomics based on flow injection- followed by liquid chromatography high resolution mass spectrometry (FI/LC-HRMS). The workflow combined in-depth characterization of the lipidome...

scholarly journals An RP-LC-UV-TWIMS-HRMS and Chemometric Approach to Differentiate between Momordicabalsamina Chemotypes from Three Different Geographical Locations in Limpopo Province of South Africa

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1896
Author(s):  
Pieter Venter ◽  
Kholofelo Malemela ◽  
Vusi Mbazima ◽  
Leseilane J. Mampuru ◽  
Christo J. F. Muller ◽  
...  
Keyword(s):  
Molecular Species ◽  
High Resolution Mass Spectrometry ◽  
Parent Compound ◽  
Travelling Wave ◽  
Reversed Phase ◽  
Limpopo Province ◽  
Leaf Extracts ◽  
Triterpenoid Glycosides ◽  
Ht 29 ◽  
Geographical Locations

Momordica balsamina leaf extracts originating from three different geographical locations were analyzed using reversed-phase liquid chromatography (RP-LC) coupled to travelling wave ion mobility (TWIMS) and high-resolution mass spectrometry (HRMS) in conjunction with chemometric analysis to differentiate between potential chemotypes. Furthermore, the cytotoxicity of the three individual chemotypes was evaluated using HT-29 colon cancer cells. A total of 11 molecular species including three flavonol glycosides, five cucurbitane-type triterpenoid aglycones and three glycosidic cucurbitane-type triterpenoids were identified. The cucurbitane-type triterpenoid aglycones were detected in the positive ionization mode following dehydration [M + H − H2O]+ of the parent compound, whereas the cucurbitane-type triterpenoid glycosides were primarily identified following adduct formation with ammonia [M + NH4]+. The principle component analysis (PCA) loadings plot and a variable influence on projection (VIP) analysis revealed that the isomeric pair balsaminol E and/or karavilagen E was the key molecular species contributing to the distinction between geographical samples. Ultimately, based on statistical analysis, it is hypothesized that balsaminol E and/or karavilagen E are likely responsible for the cytotoxic effects in HT-29 cells.

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