ICPMS
More information
WebinarsAbout usContact usTerms of use
LabRulez s.r.o. All rights reserved. Content available under a CC BY-SA 4.0 Attribution-ShareAlike
Author
LabRulez
LabRulez
Everything from the world of analytical chemistry in one place. We connect people in solving their problems. At Labrulez you will find all the necessary information easily, quickly and clearly. Stop searching and start finding.
Tags
Scientific article
Various
Logo of LinkedIn

Can NMR-HetCA be a Reliable Prediction Tool for the Direct Identification of Bioactive Substances in Complex Mixtures?

Tu, 14.1.2025
| Original article from: Analytical Chemistry, Vol 96/Issue 50
The goal of this study is to develop and evaluate a rapid, cost-effective NMR-HetCA-based method for identifying bioactive natural products in plant extracts.
<p>Anal. Chem. 2024, 96, 50, 20090-20097: Can NMR-HetCA be a Reliable Prediction Tool for the Direct Identification of Bioactive Substances in Complex Mixtures?</p>

Anal. Chem. 2024, 96, 50, 20090-20097: Can NMR-HetCA be a Reliable Prediction Tool for the Direct Identification of Bioactive Substances in Complex Mixtures?

The goal of this study is to address the challenges of conventional natural product isolation methods, which are time-consuming, costly, and often yield moderately active or already known compounds. This is achieved by developing and evaluating a nuclear magnetic resonance-heterocovariance (NMR-HetCA) approach for rapid and cost-effective identification of bioactive metabolites in plant extracts prior to isolation.

Using artificial fractions (ArtFrcts) and an artificial extract (ArtExtr), the study combines fast centrifugal partition chromatography (FCPC) fractionation, NMR profiling, and DPPH inhibitory activity testing. Advanced chemometric tools, including HetCA and STOCSY, are applied to identify bioactive compounds with high accuracy. The method demonstrated the ability to directly identify 52.6% of active compounds, increasing to 63.2% with spectral alignment, showcasing its potential as an efficient tool for natural product discovery.

The original article

Can NMR-HetCA be a Reliable Prediction Tool for the Direct Identification of Bioactive Substances in Complex Mixtures?

Vaios Amountzias, Antigoni Cheilari, Argyro Vontzalidou, Dimitra Benaki, Evagelos Gikas, Nektarios Aligiannis

Analytical Chemistry, Vol 96/Issue 50

https://doi.org/10.1021/acs.analchem.4c05080

licensed under CC-BY 4.0

 

Selected sections from the article follow. Formats and hyperlinks were adapted from the original.

Abstract

Conventional isolation methods in natural products chemistry are time-consuming and costly and often result in the isolation of moderately active compounds or the detection of already known natural products (NPs). A fast and cost-effective way to identify bioactive metabolites in plant extracts prior to isolation has been developed based on the nuclear magnetic resonance (NMR)-heterocovariance approach (NMR-HetCA). In order to evaluate in depth the application of this chemometrics-based drug discovery methodology, simple mixtures of 10 standard NPs simulating a fast centrifugal partition chromatography (FCPC) fractionation (artificial fractions, ArtFrcts), as well as a more complex mixture of 59 natural standard substances simulating a crude plant extract (artificial extract, ArtExtr), were prepared. FCPC was employed for the fractionation of the ArtExtr, while the inhibitory activity of all fractions against DPPH was evaluated, and their chemical profile was recorded using NMR spectroscopy. Spectral information was processed in the MATLAB environment, and statistical approaches, including HetCA and statistical total correlation spectroscopy (STOCSY), were applied to identify bioactive compounds. Total heterocovariance plots (pseudospectra) facilitated the detection of highly correlated metabolites and led to the direct identification of 52.6% of the active compounds. The success in identifying the ArtExtr bioactive substances increased to 63.2% when spectral alignment was implemented. HetCA incorporates chromatographic (fractionation), spectroscopic (NMR profiling), and bioactivity results along with advanced chemometrics and could be established as a method of choice for the rapid and effective identification of bioactive NPs in plant extracts prior to isolation.

Introduction

Conventional methods used for the isolation and identification of bioactive constituents of crude extracts in NPs chemistry are time-consuming, costly, and often result in the reisolation and reidentification of known molecules or the detection of moderately and/or nonactive ones. (1,2)

The need for the fast identification of secondary metabolites in extracts prior to their isolation has led to the development of powerful analytical methods that facilitate high-throughput screening and dereplication strategies. (3−6) Two important tools are the STOCSY (7) and the statistical heterospectroscopy (SHY), (8) operating in the MATLAB environment. STOCSY benefits from the multicollinearity observed among the intensity variables within a collection of spectra, e.g., 1H NMR spectra. It creates a pseudo-two-dimensional NMR spectrum, illustrating the correlations among the intensity levels of different peaks throughout the entire sample based on the Pearson correlation coefficient. (7,9) SHY functions by examining the inherent covariance among signal intensities within the same or associated molecules, as determined by measurements using different techniques (e.g., NMR and MS) across sets of samples. (8) A similar approach to STOCSY, using semiselective or selective TOCSY, was proposed by Sandusky and Raftery (10,11) for the detection of minor compounds in honey and urine. STOCSY and/or SHY have been used for the identification of metabolites in biofluids and plant extracts, (12−15) while Borges et al. (16) created a free-to-use pipeline called Data Fusion-based Discovery (DAFdiscovery) using these algorithms in the Python environment. Similar approaches to SHY are the 3D cross-correlation (3DCC), used for the characterization of complex glycan mixtures by integration of 1H NMR and LC-MS, (17−19) as well as the calculation of Pearson's correlations using Excel (Microsoft, Redmond, WA, USA). (20) Other approaches for the dereplication of secondary metabolites in extracts include the combination of separate dereplication processes carried out by 1H NMR and LC-MS using databases and the comparison of the predicted 1H NMR spectra of the identified compounds with the experimental ones. (21−23) In addition to the dereplication of secondary metabolites with the help of MS, a few studies have utilized NMR databases (24−27) regarding 13C (28−31) or 2D (32−34) experiments.

The need to identify bioactive compounds in extracts necessitated the correlation of the spectral data with the bioactivity. In pursuit of this objective, several studies have employed chemometrics, notably utilizing orthogonal partial least squares to latent structures (OPLS) modeling. (35,36)

A more recent methodology toward detecting the bioactive components of a mixture prior to their isolation is HetCA that was developed in our lab. (37) HetCA implements a modified SHY algorithm and uses the crosscov and corr functions to calculate the covariance and Pearson's correlation coefficient between the 1H NMR spectra and corresponding biological activity. Among the different programming languages, the MATLAB environment is used. The result is a plot resembling a 1H NMR spectrum (pseudospectrum), where the covariance and correlation coefficient between NMR resonances and activity values are visualized. There have been a few publications using this approach to correlate bioactivity with the spectral data of secondary metabolites. (38−40)

In our group, chemometrics-based drug discovery methodologies have been successfully applied in the past for the detection of secondary metabolites in plant extracts that were active against tyrosinase, acetylcholinesterase, and hyaluronidase. (37,41−43) In these studies, biological activity results were statistically correlated with NMR and/or high-performance thin layer chromatography (HPTLC) profiles, while for the detection of bioactive substances, descriptive and/or multivariate statistics were implemented, respectively. In the case of NMR, HetCA was proved to be powerful in the detection of bioactive compounds, including minor ones, prior to isolation, such as 2,4,3′-trihydroxydihydrostilbene in Morus alba (37) and 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose (PPG) in Paeonia parnassica. (43) Nevertheless, a limited number of substances have been detected or identified relative to those present in an extract. The underlying cause of this observation can be due to three main reasons as follows: (a) issues of the chromatographic process, (b) choice of data processing methods, and (c) the difference in substance content (major and minor compounds) and their concentration variance within the extract and fractions. Moreover, the result of falsely positive detections arose questions about whether NMR-HetCA can detect all the bioactive compounds in the sample. In any case, the encouraging results of these works prompted us to conduct a thorough evaluation of this chemometrics-based methodology, both to determine its success rate and to engage in process optimization through the identification of factors that contribute to the inadequate identification of bioactive ingredients.

As a first step, the fractionation of a plant extract by FCPC was simulated, overcoming issues possibly caused by the chromatographic process by using 10 standard substances to prepare 12 ArtFrcts. DPPH assay was used to test the scavenging activity of the ArtFrcts due to its reproducibility, simplicity, and quantitative results, as well as the availability of literature data and the low cost of the assay. Furthermore, the additive activity of the compounds is mostly observed. NMR-HetCA analysis was applied to all of the spectral and bioactivity information (total HetCA) to evaluate the algorithm performance under controlled conditions. As a second step, a crude plant extract was approximated by preparing a complex mixture of 59 standard substances (ArtExtr) and the chromatographic fractionation step was involved in the evaluation of HetCA performance. One of the most important steps in the effective detection of bioactive secondary metabolites through HetCA is fractionation of the initial mixture. An efficient fractionation ensures sufficient variance of the concentration of the compounds in several fractions. This concentration variance, in correlation with the variation of the fractions’ activity through HetCA, can result in the detection of the bioactive compounds. Among the chromatographic techniques, FCPC was selected for the fractionation of the ArtExtr since it is advantageous due to its high loading capacity, the lack of solid stationary phase that could withhold basic compounds, the high sample recovery, the broad elution range, the easy change between normal (NP) and reverse (RP) phase, the wide range of solvents that can be used, and the high separation capability with the selection of a proper solvent system. (44,45) The fractions resulting from FCPC were profiled by HPTLC and 1H NMR, and their antiradical activity was evaluated (Figure S1). Applying total HetCA analysis in a complex artificial mixture of known compounds bearing various chemical properties, we aimed to explore possible challenges during plant extract analysis through a systematic and thorough investigation. Furthermore, this study significantly improves the understanding of the application of STOCSY, SHY, and HetCA methodologies in complex mixtures analysis, since they share the same principle of method, highlighting their pros and cons by utilizing mixtures of standard compounds.

Experimental Section

Solvents and Reagents

All solvents were of analytical grade and were purchased from Merck (Merck, Darmstadt, Germany), while 2,2-diphenyl-1-picrylhydrazyl (DPPH) was purchased from Sigma-Aldrich (Sigma-Aldrich, Steinheim, Germany). Water was produced by a LaboStar PRO TWF system (Evoqua Water Technologies, Pittsburgh, USA). For the standard compounds, see the Supporting Information.

Sample Preparation

ArtFrcts Preparation

Ten standard compounds listed in Table S1, in various concentrations, were used for the preparation of 12 ArtFrcts (Figure S2). The samples were assayed for in vitro antiradical assay evaluation and were analyzed by NMR-HetCA.

ArtExtr Preparation

A mixture (ArtExtr) composed of 59 standard compounds (Figure S2 and Table S2) was prepared with 50 mg of each compound diluted in 50 mL of MeOH. Mole fractions of all compounds were used in order to simplify the concentration and activity covariance study (Table S2).

Anal. Chem. 2024, 96, 50, 20090-20097: Figure 2. Total HetCA plots and zoomed areas (10.00−0.00 and 7.60–6.40 ppm, respectively) resulted from the covariance of the ArtExtr fractions’ NMR data with their corresponding DPPH scavenging activity (a) prior to spectral alignment and (b) after spectral alignment. The left Y axis of each HetCA plot denotes the covariance, the right Y axis represents the correlation coefficient, and the X axis indicates the 1H-chemical shift (ppm).

FCPC

The fractionation of the ArtExtr was performed by FCPC (FCPC KROMATON, France) with a 1000 mL column and adjustable rotation of 650–1700 rpm, equipped with a Gilson PLC 2250 pump and a fraction collector compact system (Gilson Incorporated, Middleton, USA). The ArtExtr was fractionated using a step-gradient elution–extrusion method consisting of n-Hept, EtOAc, n-BuOH, MeOH, and H2O in ascending mode (See Supporting Information, Table S3). The resulting 69 pooled fractions were filtered and forwarded for NMR-HetCA, HPTLC profiling, and in vitro antiradical assay evaluation.

Evaluation of Free Radical Scavenging Activity by DPPH Assay

The DPPH assay was used for the biological screening for the standard substances, ArtFrcts and ArtExtr fractions, as previously described by Lee et al. (46) with minor modifications (See Supporting Information). The absorbance was measured at 517 nm, using a Tecan Infinite M1000 PRO microplate reader (Tecan GmbH, Grödig/Salzburg, Austria), while the system was operated under Tecan i-control v.1.11. All evaluations were performed in triplicate, while gallic acid was used as the positive control (IC50 = 30.2 μM). The in vitro DPPH inhibition assay for the ArtFrcts, as well as for the pure substances, was performed at 50 and 25 μg/mL. In the case of standard substances comprising the ArtExtr, IC50 values were calculated for the most active ones. Regarding the ArtExtr FCPC fractions, the evaluation took place at a final concentration of 75 μg/mL in the well.

HPTLC

For the chemical profiling of the ArtExtr fractions, the filtered samples dissolved in MeOH were applied on HPTLC plates by using an automatic TLC Sampler 4 (ATS-4, CAMAG, Muttenz, Switzerland). The chromatographic separation was performed in an Automatic Developing Chamber 2 (ADC 2), while the documentation was carried out in CAMAG Visualizer 2. The system was operated under the VisionCats 3.0 software (CAMAG) (See Supporting Information).

NMR Spectroscopy and Data Pretreatment

For the 1H NMR experiment, the samples were dissolved in methanol-d4 containing tetramethylsilane (TMS) as a reference (Euriso-Top, Saint-Aubin, France) at a concentration level of 10 mg/mL for the unfiltered ArtFrct samples and 3 mg/mL for the filtered ArtExtr FCPC samples. After sonication (5 min) in an Ultra Sonic bath (Elma Schmidbauer GmbH, Singen, Germany), 650 μL was transferred to 5 mm NMR tubes (LabScape, Bruker, Germany). The 1H NMR spectra were acquired at 298 K ± 0.1, after a 5 min resting period for temperature stabilization, on a Bruker Avance III 600 MHz NMR spectrometer equipped with a 5 mm PABBI 1H/D-BB inverse detection probe. Experiments were performed in automation mode using a BACS-60 sample changer operated by IconNMR. Data acquisition and processing were done with Bruker TopSpin 3.6. Profiling 1H NMR spectra were acquired using the water suppression 1D NOESY pulse program with the following settings: relaxation delay (d1) = 6 s, acquisition time = 2.73 s, FID (free induction decay) data points = 64 k, spectral width = 20 ppm, and number of scans = 128. The transmitter offset was set manually in order to achieve the optimal suppression of the residual water signal. FIDs were multiplied by an exponential weighting function corresponding to a line broadening of 0.3 Hz prior to Fourier transformation. Automated processing was carried out for phase correction and baseline correction. Chemical shift values were referenced to the residual methanol signal (3.31 ppm). 1H NMR spectral alignment was based on a segment-wise peak alignment and was performed in pairs, with the last one set as the “active” spectrum for the alignment of the next spectrum using MestRe Nova 14.2.1 (Mestrelab Research, Santiago de Compostela, Spain) using the implemented cross-correlation algorithm. The first derivative was used, while the missing values filling method was linear.

NMR-HetCA Approach

Regions excluded from the integration of the 1H NMR spectra were the residual methanol-d4 signal (3.29–3.36 ppm) and the water peak (4.76–4.82 ppm). NMR spectra were processed in the MATLAB environment (bucketing of spectra and correlation with DPPH radical scavenging activity) through HetCA as previously described. (37) The covariance and correlation between NMR resonances and activity values were visualized through the generated NMR pseudospectra, i.e., the HetCA plots. Each point of the HetCA plots depicted the covariance, where positive or negative peaks indicated positive or negative covariance values, respectively. They were additionally color-coded according to the respective correlation coefficients, ranging from blue for those that show low correlation to deep red for those that show high correlation. Besides HetCA plots, structural identification of the compounds in the pseudospectra was further accomplished by applying STOCSY on selected peaks and by comparing with the 1H NMR spectra of the standard substances.

Conclusions

In this study, HetCA methodology’s possibilities and limitations were evaluated under controlled conditions using the ArtFrcts and the ArtExtr fractions. A certain variety of standard compounds was selected for the preparation of artificial mixtures aiming to cover several issues that occur during complex mixture analysis including sample preparation and use of various chromatographic, spectroscopic, and/or bioactivity techniques. This approach facilitated the detection and identification of the majority of bioactive compounds in these mixtures without the need for their isolation, offering solutions to the challenges discussed below.

Special care is required to include all of the components of the respective mixture in the study or to identify and record the components that have been removed during the chromatographic fractionation procedures and/or during the NMR process and biological assays. Due to the structural complexity and the wide polarity range of the components, precipitation is often observed during the preparation of the initial sample, resulting in the loss of a part of the extract from the chromatographic separation, and consequently from the study. Moreover, precipitation sometimes occurs during the preparation of the samples, both for NMR experiments and for in vitro biological assays, resulting to an underestimation of some compounds’ concentration and/or activity. Therefore, it is considered reasonable to study the physicochemical properties of the components of a mixture (e.g., plant extracts containing alkaloids) in order to optimally choose biphasic solvent systems for the fractionation by FCPC and to improve the processing protocols of the samples under study in order to avoid the aforementioned phenomena. All techniques should be carried out with the same set of prepared samples to avoid different concentration issues between them.

The components’ wide distribution in the fractions resulting from the chromatographic fractionation is crucial for the successful application of the HetCA, which can be achieved by FCPC. However, the choice of biphasic solvent systems, as well as the chromatographic method, is decisive for achieving a satisfactory distribution of the substances. The profiling of the chemical content of the produced fractions, both by chromatographic (HPTLC) and spectroscopic (NMR) techniques, is considered appropriate to evaluate the distribution of the substances before applying HetCA. The preparation of the samples, the acquisition of 1H NMR spectra, and the evaluation of the biological properties of the fractions need to be carried out by the same protocols, respectively, in order to minimize the influence of the aforementioned procedures on the results of the study.

The absence of buffering conditions when using organic solvents can result in minor chemical shift variations in the 1H NMR spectra due to the coexistence of acidic and basic compounds. Therefore, spectra alignment is crucial for more reliable results, since compounds with misalignment issues will be hindered from the generated HetCA plots. Moreover, the HetCA plots are more well-defined and easier to interpret, leading to more reliable results. In total HetCA, all fractions are considered, the whole range of biological activity values is included, and the results are more reliable, compared to pseudospectra generated from small groups of spectra.

As discussed, NMR-HetCA can give some misleading results (false-negative and false-positive identification of bioactives). The main cause for false negative results is the coelution of active compounds at low concentration with more active compounds at a higher concentration. On the other hand, false positive results can be produced by a comparable distribution of active and nonactive substances in the same fractions, phenomena of cumulative and/or synergistic activity of the coeluted substances, and a low variation in the bioactivity of the fractions. Nevertheless, the combination of selected procedures in HetCA methodology, such as FCPC fractionation and NMR spectral data correlation with bioactivity, facilitates the detection and identification of the majority of bioactive compounds and reduces the laboratory time needed to study a plant extract, since reisolation of known compounds is omitted. Besides time, the cost of a phytochemical study is decreased as well by reducing the volume of organic solvents needed. Furthermore, the detection of minor metabolites, which would otherwise be very difficult with conventional methods, can be achieved, making NMR-HetCA a competent tool in natural product research.

Overall, the HetCA approach can be used as a method of choice for the detection and identification of the majority of the active substances in a complex mixture prior to their isolation, provided that special care is taken in order to minimize the aforementioned reasons that cause incorrect predictions. Further investigation is needed for more complex bioactivity essays (e.g., enzymes), since the synergism and antagonism of the mixture ingredients are common.

LabRulez
Logo of LinkedIn
 

Related content

Simultaneous TG/DTA - DTG-60 Series

Others
| 2024 | Shimadzu
Instrumentation
Thermal Analysis
Manufacturer
Shimadzu
Industries
Materials Testing

Agilent 8800 ICP-QQQ Upgrades

Others
| 2024 | Agilent Technologies
Instrumentation
ICP/MS, ICP/MS/MS
Manufacturer
Agilent Technologies
Industries

Sensitivity Evaluation and Example Analysis of Microscopic Targets with Thermoelectrically Cooled MCT Detector

Applications
| 2025 | Shimadzu
Instrumentation
FTIR Spectroscopy, Microscopy
Manufacturer
Shimadzu
Industries

Precision and Detail Ensured by Scanning Electron Microscopy

Technical notes
| 2024 | ALS Europe (ALS Czech Republic)
Instrumentation
X-ray, Microscopy
Manufacturer
Industries
Materials Testing

ICP-OES Analysis of Electrolytes for All-Vanadium Redox Flow Batteries

Applications
| 2024 | Agilent Technologies
Instrumentation
ICP-OES
Manufacturer
Agilent Technologies
Industries
Energy & Chemicals
 

Related articles

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light
Article | Science and research

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light

The growing influence of AI brings with it huge energy demands, which in turn bring large-scale climate challenges. Ondřej Wojewoda from CEITEC BUT brings a revolutionary solution in his PhD thesis.
CEITEC
tag
share
more
Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone
Scientific article | Various

Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone

The goal of this study is to design, synthesize, and characterize novel cyclic α-tetralone-based synthetic cathinones and determine their absolute configurations.
LabRulez
tag
share
more
Webinars LabRulezICPMS Week 6/2025
Article | Webinars

Webinars LabRulezICPMS Week 6/2025

This week 7 webinars: pH measurment, AAS & MW & ICP, Scratch Measurement, Atomic Spectroscopy, Data Integrity, hallenging ICP-OES Applications.
LabRulez
tag
share
more
News from LabRulezICPMS Library - Week 6, 2025
Article | Application

News from LabRulezICPMS Library - Week 6, 2025

This week we bring you Technical notes by Shimadzu, Agilent Technologies and Thermo Fisher Scientific!
LabRulez
tag
share
more
 

Related content

Simultaneous TG/DTA - DTG-60 Series

Others
| 2024 | Shimadzu
Instrumentation
Thermal Analysis
Manufacturer
Shimadzu
Industries
Materials Testing

Agilent 8800 ICP-QQQ Upgrades

Others
| 2024 | Agilent Technologies
Instrumentation
ICP/MS, ICP/MS/MS
Manufacturer
Agilent Technologies
Industries

Sensitivity Evaluation and Example Analysis of Microscopic Targets with Thermoelectrically Cooled MCT Detector

Applications
| 2025 | Shimadzu
Instrumentation
FTIR Spectroscopy, Microscopy
Manufacturer
Shimadzu
Industries

Precision and Detail Ensured by Scanning Electron Microscopy

Technical notes
| 2024 | ALS Europe (ALS Czech Republic)
Instrumentation
X-ray, Microscopy
Manufacturer
Industries
Materials Testing

ICP-OES Analysis of Electrolytes for All-Vanadium Redox Flow Batteries

Applications
| 2024 | Agilent Technologies
Instrumentation
ICP-OES
Manufacturer
Agilent Technologies
Industries
Energy & Chemicals
 

Related articles

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light
Article | Science and research

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light

The growing influence of AI brings with it huge energy demands, which in turn bring large-scale climate challenges. Ondřej Wojewoda from CEITEC BUT brings a revolutionary solution in his PhD thesis.
CEITEC
tag
share
more
Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone
Scientific article | Various

Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone

The goal of this study is to design, synthesize, and characterize novel cyclic α-tetralone-based synthetic cathinones and determine their absolute configurations.
LabRulez
tag
share
more
Webinars LabRulezICPMS Week 6/2025
Article | Webinars

Webinars LabRulezICPMS Week 6/2025

This week 7 webinars: pH measurment, AAS & MW & ICP, Scratch Measurement, Atomic Spectroscopy, Data Integrity, hallenging ICP-OES Applications.
LabRulez
tag
share
more
News from LabRulezICPMS Library - Week 6, 2025
Article | Application

News from LabRulezICPMS Library - Week 6, 2025

This week we bring you Technical notes by Shimadzu, Agilent Technologies and Thermo Fisher Scientific!
LabRulez
tag
share
more
 

Related content

Simultaneous TG/DTA - DTG-60 Series

Others
| 2024 | Shimadzu
Instrumentation
Thermal Analysis
Manufacturer
Shimadzu
Industries
Materials Testing

Agilent 8800 ICP-QQQ Upgrades

Others
| 2024 | Agilent Technologies
Instrumentation
ICP/MS, ICP/MS/MS
Manufacturer
Agilent Technologies
Industries

Sensitivity Evaluation and Example Analysis of Microscopic Targets with Thermoelectrically Cooled MCT Detector

Applications
| 2025 | Shimadzu
Instrumentation
FTIR Spectroscopy, Microscopy
Manufacturer
Shimadzu
Industries

Precision and Detail Ensured by Scanning Electron Microscopy

Technical notes
| 2024 | ALS Europe (ALS Czech Republic)
Instrumentation
X-ray, Microscopy
Manufacturer
Industries
Materials Testing

ICP-OES Analysis of Electrolytes for All-Vanadium Redox Flow Batteries

Applications
| 2024 | Agilent Technologies
Instrumentation
ICP-OES
Manufacturer
Agilent Technologies
Industries
Energy & Chemicals
 

Related articles

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light
Article | Science and research

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light

The growing influence of AI brings with it huge energy demands, which in turn bring large-scale climate challenges. Ondřej Wojewoda from CEITEC BUT brings a revolutionary solution in his PhD thesis.
CEITEC
tag
share
more
Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone
Scientific article | Various

Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone

The goal of this study is to design, synthesize, and characterize novel cyclic α-tetralone-based synthetic cathinones and determine their absolute configurations.
LabRulez
tag
share
more
Webinars LabRulezICPMS Week 6/2025
Article | Webinars

Webinars LabRulezICPMS Week 6/2025

This week 7 webinars: pH measurment, AAS & MW & ICP, Scratch Measurement, Atomic Spectroscopy, Data Integrity, hallenging ICP-OES Applications.
LabRulez
tag
share
more
News from LabRulezICPMS Library - Week 6, 2025
Article | Application

News from LabRulezICPMS Library - Week 6, 2025

This week we bring you Technical notes by Shimadzu, Agilent Technologies and Thermo Fisher Scientific!
LabRulez
tag
share
more
 

Related content

Simultaneous TG/DTA - DTG-60 Series

Others
| 2024 | Shimadzu
Instrumentation
Thermal Analysis
Manufacturer
Shimadzu
Industries
Materials Testing

Agilent 8800 ICP-QQQ Upgrades

Others
| 2024 | Agilent Technologies
Instrumentation
ICP/MS, ICP/MS/MS
Manufacturer
Agilent Technologies
Industries

Sensitivity Evaluation and Example Analysis of Microscopic Targets with Thermoelectrically Cooled MCT Detector

Applications
| 2025 | Shimadzu
Instrumentation
FTIR Spectroscopy, Microscopy
Manufacturer
Shimadzu
Industries

Precision and Detail Ensured by Scanning Electron Microscopy

Technical notes
| 2024 | ALS Europe (ALS Czech Republic)
Instrumentation
X-ray, Microscopy
Manufacturer
Industries
Materials Testing

ICP-OES Analysis of Electrolytes for All-Vanadium Redox Flow Batteries

Applications
| 2024 | Agilent Technologies
Instrumentation
ICP-OES
Manufacturer
Agilent Technologies
Industries
Energy & Chemicals
 

Related articles

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light
Article | Science and research

Spin waves as the key to more sustainable AI: Ondřej Wojewoda makes a breakthrough in measurement using Brillouin spectroscopy of light

The growing influence of AI brings with it huge energy demands, which in turn bring large-scale climate challenges. Ondřej Wojewoda from CEITEC BUT brings a revolutionary solution in his PhD thesis.
CEITEC
tag
share
more
Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone
Scientific article | Various

Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone

The goal of this study is to design, synthesize, and characterize novel cyclic α-tetralone-based synthetic cathinones and determine their absolute configurations.
LabRulez
tag
share
more
Webinars LabRulezICPMS Week 6/2025
Article | Webinars

Webinars LabRulezICPMS Week 6/2025

This week 7 webinars: pH measurment, AAS & MW & ICP, Scratch Measurement, Atomic Spectroscopy, Data Integrity, hallenging ICP-OES Applications.
LabRulez
tag
share
more
News from LabRulezICPMS Library - Week 6, 2025
Article | Application

News from LabRulezICPMS Library - Week 6, 2025

This week we bring you Technical notes by Shimadzu, Agilent Technologies and Thermo Fisher Scientific!
LabRulez
tag
share
more
Other projects
GCMS
LCMS
Follow us
More information
WebinarsAbout usContact usTerms of use
LabRulez s.r.o. All rights reserved. Content available under a CC BY-SA 4.0 Attribution-ShareAlike