<p><strong>Join us for a fascinating conversation with Dr. Subhoja Chakraborty from the University of Central Florida, whose cutting-edge research targets the global challenge of malaria drug resistance. Dr. Chakraborty shares her journey from structure-based drug design during her PhD to her recent collaborative work repurposing human kinase inhibitors as rapid, selective antimalarials against drug-resistant Plasmodium falciparum strains.</strong></p><h4><strong>In this episode, you'll learn:</strong></h4><ul><li>How structure-guided approaches reveal potential drug targets, including cysteine proteases like falcipain-2, and kinases implicated in malaria's complex life cycle.</li><li>The power of repurposing kinase inhibitors originally developed for cancer and other diseases, focusing on compound 12, which blocks hemozoin formation and protein kinase 6—key steps in parasite survival.</li><li>Lab techniques such as affinity, gel filtration, and size exclusion chromatography for recombinant protein purification—and how troubleshooting is crucial for high-yield, stable complexes.</li><li>Advances in mass spectrometry for characterizing protein interactions, validating drug targets, and mapping molecular pathways pivotal to malaria therapeutics.</li><li>Tips and lessons for new researchers facing the challenges of sample preparation, complex protocols, and working as part of a collaborative team.</li></ul><p>Dr. Chakraborty’s insights bridge the gap between basic science and translational drug discovery, offering hope for more effective, targeted malaria treatments in a world where resistance to frontline therapies threatens millions.</p><h4><strong>Referenced Papers:</strong></h4><ul><li>"Plasmodium falciparum protein kinase 6 and hemozoin formation are inhibited by a type II human kinase inhibitor exhibiting antimalarial activity" (Cell Chemical Biology, 2025)</li><li>"New insights of falcipain 2 structure from Plasmodium falciparum 3D7 strain" (BBRC, 2022)</li><li>"Structure-Based Optimization of Protease−Inhibitor Interactions to Enhance Specificity of Human Stefin‑A against Falcipain‑2 from the Plasmodium falciparum 3D7 Strain" (Biochemistry, 2023)</li></ul><p>If you’re a student, scientist, or simply passionate about advances in infectious disease research, this episode offers actionable insights, inspiring advice, and a front-row seat to innovation in combating malaria.</p><h3><strong>Video Transcription</strong></h3><h4><strong>From Structural Biology to Drug Discovery: Chromatography and Mass Spectrometry in Malaria Research</strong></h4><h5><strong>Introduction</strong></h5><p>In this discussion, Subhoja shares insights into her research journey, focusing on malaria drug discovery and the role of modern analytical techniques in biological and biomedical research. The conversation is aimed primarily at undergraduate students and early-career researchers interested in chemistry, biotechnology, and life sciences.</p><h5><strong>Research Focus: Malaria Drug Discovery and Kinase Targets</strong></h5><p>Subhoja is currently involved in malaria drug discovery research at the University of Central Florida, where she has been working since beginning her postdoctoral position two years ago. Her earlier PhD research focused on structure-based drug design in malaria, using a combination of in silico approaches, recombinant protein expression, and X-ray crystallography to determine precise three-dimensional structures of target proteins and their inhibitors.</p><p>This structural perspective provided a foundation for her current work, which centers on drug discovery through compound screening and repurposing. A recent publication from her laboratory explores the use of repurposed mammalian CDK-like kinase inhibitors as potential antimalarial agents. While such kinase inhibitors are well known in cancer and cardiovascular research, their application to malaria targets represents a novel and promising approach.</p><p>Kinases are attractive drug targets because of their central role in cell signaling and growth pathways. By targeting specific kinases involved in different stages of the malaria parasite life cycle—whether asexual growth, gametocytogenesis, or differentiation—it may be possible to significantly inhibit parasite growth and progression.</p><h5><strong>Chromatography in Protein Expression and Purification Workflows</strong></h5><p>Chromatography plays a critical role throughout Subhoja’s research. Her experience spans from basic chromatography techniques during her early training to advanced protein purification workflows using affinity chromatography, gel filtration (size exclusion chromatography), and ion exchange chromatography.</p><p>Recombinant proteins are routinely purified using affinity resins such as nickel or cobalt, followed by further purification to remove contaminants. Fast Protein Liquid Chromatography (FPLC) enables compact, stepwise purification workflows suitable for producing proteins for in vitro assays.</p><p>A recurring challenge in this process is the expression of high-molecular-weight proteins, which often accumulate in insoluble fractions or inclusion bodies. Careful selection of expression vectors, host systems, and induction conditions is therefore essential to maximize yield and solubility.</p><h5><strong>Integrating Size Exclusion Chromatography into the Workflow</strong></h5><p>Size exclusion chromatography (SEC) is typically used after affinity purification to further improve protein purity. Following elution with imidazole or glutathione, desalting is required to prevent buffer components from interfering with downstream assays. This is often achieved using desalting columns such as G-25 or PD-10.</p><p>To remove lower-molecular-weight contaminants, finer SEC media—such as Superdex or Sephacryl columns—are employed. Concentration steps using molecular-weight cut-off filters are then applied to obtain the desired protein concentration for functional studies.</p><p>These iterative purification and troubleshooting steps are a routine part of protein biochemistry and reflect the importance of methodical optimization and careful validation.</p><h5><strong>The Role of Mass Spectrometry in Biomolecular Characterization</strong></h5><p>Mass spectrometry is a key analytical tool in Subhoja’s research pipeline, particularly for target identification and validation. In both malaria and cancer research, MS is used alongside chromatography, immunoprecipitation, and pull-down assays to study protein interactions and molecular recognition events.</p><p>Affinity-based mass spectrometry enables the identification of binding partners and interactors, whether studying proteins, long non-coding RNAs, or protein complexes. Techniques such as native MS, tandem affinity purification, and proximity labeling (e.g., TurboID-based workflows) provide deeper insights into molecular networks and signaling pathways.</p><p>These approaches are essential for understanding how candidate drug targets function within complex biological systems.</p><h5><strong>Sample Preparation Challenges in Biological Research</strong></h5><p>Sample preparation remains one of the most challenging aspects of biological experimentation. Whole-cell lysates contain proteases, nucleases, and other components that can rapidly degrade target molecules. Preventing degradation requires minimizing preparation time, maintaining low temperatures, and using appropriate inhibitor cocktails.</p><p>Reproducibility is also critical: biological experiments require multiple replicates, and variability is often unavoidable. Careful handling, protocol optimization, and continuous troubleshooting are essential to ensure reliable results, whether preparing samples for chromatography, mass spectrometry, sequencing, or immunoprecipitation.</p><h5><strong>Advances in Chromatography and MS for Malaria Research</strong></h5><p>Modern advances in chromatography and mass spectrometry significantly enhance malaria research by enabling precise target identification, quantification, and functional characterization. Drug discovery workflows begin with construct design and recombinant expression, followed by purification and interaction studies.</p><p>In malaria research, stage-specific parasite biology requires careful extraction and analysis of proteins from different life cycle stages. Tandem affinity MS, immunoprecipitation, and in vivo validation studies help confirm target relevance and therapeutic potential.</p><p>Recent work on repurposed kinase inhibitors has shown promising results, including inhibition of hemozoin formation—a key detoxification pathway for the malaria parasite—highlighting the potential of such compounds for further development.</p><h5><strong>Malaria, Drug Resistance, and Global Impact</strong></h5><p>Malaria remains a major global health burden, with over 600,000 deaths annually and widespread drug resistance complicating treatment. Artemisinin resistance, particularly associated with mutations in the K13 propeller domain, has driven the search for new targets and therapies.</p><p>During her PhD, Subhoja focused on falcipain-2, a cysteine protease involved in hemoglobin degradation within the parasite. This pathway is critical for parasite survival and has emerged as a promising drug target. Her work revealed that falcipain-2 operates within a larger protein complex responsible for hemoglobin processing and amino acid release.</p><p>Understanding these molecular mechanisms is essential for developing robust, stage-specific antimalarial strategies.</p><h5><strong>Advice for Early-Career Researchers</strong></h5><p>For researchers just starting out, Subhoja emphasizes the importance of hands-on experience. Working directly with cells, lysates, and analytical tools is essential for truly understanding experimental systems. Failure is an inherent part of research, and perseverance is key.</p><p>Motivation, teamwork, careful sample handling, and thorough preparation all contribute to long-term success. Reading extensively, critically evaluating one’s own work, and appreciating incremental progress are vital aspects of a sustainable research career.</p><p>Every successful experiment—no matter how small—represents meaningful progress and contributes to the broader goals of science and medicine.</p><h5><strong>Closing Remarks</strong></h5><p>The discussion highlights how interdisciplinary approaches combining chromatography, mass spectrometry, structural biology, and biochemistry are driving advances in malaria drug discovery. Through careful experimental design, analytical rigor, and collaborative teamwork, researchers can address complex biological challenges and contribute to global health solutions.</p><blockquote><p><strong>This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.</strong></p></blockquote><blockquote><h4><strong>Concentrating on Chromatography Podcast</strong></h4><p>Dive into the frontiers of chromatography, mass spectrometry, and sample preparation with host David Oliva. Each episode features candid conversations with leading researchers, industry innovators, and passionate scientists who are shaping the future of analytical chemistry. From decoding PFAS detection challenges to exploring the latest in AI-assisted liquid chromatography, this show uncovers practical workflows, sustainability breakthroughs, and the real-world impact of separation science. Whether you’re a chromatographer, lab professional, or researcher you'll discover inspiring content!</p><p>You can find <strong>Concentrating on Chromatography Podcast </strong>in podcast apps:</p><ul><li><a target="_blank" rel="noopener noreferrer" href="https://open.spotify.com/show/1wZg67rCjoGju4yhqxI3tL"><strong>Spotify</strong></a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podcasts.apple.com/tz/podcast/concentrating-on-chromatography/id1788429185"><strong>Apple podcast</strong></a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podscan.fm/podcasts/concentrating-on-chromatography"><strong>podscan</strong></a></li></ul><p>and on <a target="_blank" rel="noopener noreferrer" href="https://www.youtube.com/@ChromatographyTalk/videos"><strong>YouTube channel</strong></a></p></blockquote>

Affinity, Gel Filtration, Size Exclusion Chromatography: Repurposing Kinase Inhibitors for Malaria

<p><strong>In the week of February 9, the following webinars await you in the field of liquid phase and especially HPLC and LC/MS.</strong></p><blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinars"><strong>👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</strong></a></h4><p><strong>👉 Search and filter in the largest global database</strong> with over <strong>5 000 GC, LC, MS and spectroscopy webinars</strong>.</p></blockquote><h5><strong>1. SelectScience: High-Throughput Stability Screening Strategies for Antibody Formulation</strong></h5><ul><li>Tu, 10.2.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5807">Registration</a></li></ul><p>Learn how high-throughput DLS/SLS and rapid-screening DSC accelerate stability assessment of high-concentration antibody formulations, enabling faster, data-driven biologics development.</p><h5><strong>2. Phenomenex: Big Scale, Big Wins – Prep Chromatography Explained</strong></h5><ul><li>We, 11.2.2026 10:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5793">Registration</a></li></ul><p>Learn how to scale analytical methods to preparative HPLC, optimize loading capacity, and understand the limits of preparative columns for pharmaceutical applications.</p><h5><strong>3. ALS Czech Republic: PFAS in Food &amp; Food Contact Material</strong></h5><ul><li>We, 11.2.2026 15:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5816">Registration</a></li></ul><p>Get a practical overview of PFAS in food and food contact materials, including EU and US regulations, key analytical challenges, and reliable PFAS testing strategies.</p><h5><strong>4. New Food Magazine: The Science of Next-Gen Ingredients – Fermentation, Formulation and Function</strong></h5><ul><li>We, 11.2.2026 16:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5720">Registration</a></li></ul><p>Explore how fermentation-driven innovation is transforming functional food ingredients and how advanced analytics optimize flavour, functionality, and stability.</p><h5><strong>5. SCIEX: Accurate Mass Fundamentals – Interpreting and Applying Your Data</strong></h5><ul><li>We, 11.2.2026 19:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5772">Registration</a></li></ul><p>Session 3 focuses on interpreting and applying accurate mass data to confirm compound identity, move beyond basic quantitation, and troubleshoot results for confident reporting.</p><h5><strong>6. Agilent Technologies: Process Analytical Techniques – Online HPLC for Real-Time Monitoring and Control of Bioprocesses</strong></h5><ul><li>Th, 12.2.2026 06:30 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5834">Registration</a></li></ul><p>Discover how PAT HPLC enables near-real-time monitoring of critical quality attributes in bioprocessing, with a case study on charge-variant control by cation-exchange chromatography.</p><h5><strong>7. Thermo Fisher Scientific: Introducing the Orbitrap Excedion Pro Hybrid MS</strong></h5><ul><li>Th, 12.2.2026 11:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5889">Registration</a></li></ul><p>Discover the new Orbitrap Exploris Pro with expanded ETD/EThcD capabilities for confident biopharmaceutical characterization, including intact proteins, PTMs, ADCs, and large biomolecules.</p><h5><strong>8. Waters Corporation: Planning Your NuGenesis Upgrade – Insights and Best Practices for a Smooth Transition</strong></h5><ul><li>Th, 12.2.2026 19:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5833">Registration</a></li></ul><p>Learn how to plan a successful NuGenesis upgrade, transition to Windows 11, and unlock new capabilities such as dashboards for real-time operational insights.</p><h5><strong>9. Thermo Fisher Scientific: Comprehensive Analytical Strategies for Peptide Therapeutics and GLP-1 Agonists with Agilent</strong></h5><ul><li>Th, 12.2.2026 19:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5814">Registration</a></li></ul><p>Explore analytical workflows for peptide therapeutics, including method development, peptide mapping, GLP-1 QC, and LC-MS strategies across Agilent platforms.</p><h5><strong>10. Agilent Technologies: Moving from R&amp;D and Limited QC on a UV-Vis-NIR Instrument to Large-Scale QC Using an Autosampler</strong></h5><ul><li>Th, 12.2.2026 20:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/2104">Registration</a></li></ul><p>This webinar covers practical aspects of adding and using an autosampler to maximize UV-Vis-NIR QC workflows at scale.</p><h5><strong>11. Agilent Technologies: LC Method Transfer – Hidden Challenges &amp; Absolute Solution</strong></h5><ul><li>Fr, 13.2.2026 06:30 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5787">Registration</a></li></ul><p>Discover why LC method transfer between legacy and modern systems is challenging, which hidden parameters affect retention and peak shape, and how to achieve robust, reliable results.</p>

Webinars LabRulezLCMS Week 07/2026

<p><strong>Charge detection mass spectrometry (CDMS) allows direct mass determination of individual ions and is increasingly used to study heterogeneous biological samples. This work demonstrates the use of Orbitrap-based CDMS/Direct Mass Technology (DMT) for quantitative analysis of transthyretin (TTR) tetramer samples below 100 kDa, extending CDMS beyond its traditional qualitative role.</strong></p><p>DMT resolved wild-type and C-terminally modified TTR homotetramers, as well as hybrid tetramers, enabling kinetic analysis of subunit exchange and stability. The approach also quantified thyroxine binding to TTR variants, revealing differences in binding affinity linked to C-terminal modification. By separating overlapping m/z signals through charge measurement, CDMS enables accurate mass and abundance determination, highlighting its potential for quantitative analysis of complex protein systems.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771"><strong>Dissecting Heterogeneous Populations of Protein-Complex Samples Using Direct Mass Technology</strong></a></h4><p>Robert L. Rider, Jared Hampton, Zhenyu Xi, Carter Lantz, Sangho D. Yun, Weijing Liu, Rosa Viner, Arthur Laganowsky, and David H. Russell*</p><p>Anal. Chem. 2025, 97, 49, 27057–27063</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acs.analchem.5c05771">https://doi.org/10.1021/acs.analchem.5c05771</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><p>Transthyretin (TTR) is a homotetrameric transport protein that circulates in plasma and cerebrospinal fluid, delivering thyroxine (T<sub>4</sub>) and retinol-binding protein–vitamin A complexes. <a href="javascript:void(0);">(1)</a> The stability of the TTR tetramer is central to its physiological role because dissociation into monomers can initiate misfolding and amyloid formation, leading to systemic or hereditary transthyretin amyloidosis. <a href="javascript:void(0);">(2)</a> Subunit exchange between wild-type (WT) and variant TTR proteoforms, including disease-associated mutations such as V30M and V122I, have been implicated in amyloid progression by generating hybrid tetramers (tetramers containing WT and mutant subunits) with altered stabilities. <a href="javascript:void(0);">(3,4)</a> Ligand binding, particularly at the two thyroxine-binding sites located at the dimer–dimer interface, can kinetically stabilize the tetramer and modulate amyloidogenicity. <a href="javascript:void(0);">(5,6)</a> Accurate measurement of both subunit exchange kinetics and ligand binding stoichiometry is therefore critical for elucidating the TTR dynamics and stability.</p><p>Affinity or sequence tags are widely employed in protein expression, purification, or detection. <a href="javascript:void(0);">(7,8)</a> While these tags are often assumed to be inert, their influence on protein structure and dynamics are rarely examined in detail. <a href="javascript:void(0);">(9,10)</a> Protein tags at the N- and C-terminus of TTR have been shown to have differing gas phase stabilities from those of WT-TTR. <a href="javascript:void(0);">(11)</a> The C-terminus is of particular interest because this region participates in the dimer–dimer interface that governs tetramer stability. <a href="javascript:void(0);">(11,12)</a> Characterizing how the C-terminal tag (CT) (-ASGENLFYQ) affects TTR’s solution stability and ligand binding is not only relevant for understanding TTR dynamics but also provides an example of how expression tags can alter protein dynamics. <a href="javascript:void(0);">(13)</a></p><p>Native mass spectrometry (nMS) has been invaluable for characterizing protein complexes, <a href="javascript:void(0);">(14)</a> yet conventional nMS often struggles with heterogeneous samples where overlapping charge state distributions and adduct heterogeneity limit resolution and quantitation. <a href="javascript:void(0);">(15)</a> Charge detection mass spectrometry (CDMS) addresses these limitations by independently measuring the charge and <i>m</i>/<i>z</i> of individual ions, enabling the direct determination of molecular mass and abundance. Development of CDMS has largely focused on achieving higher mass resolution <a href="javascript:void(0);">(16)</a> and extending measurements toward assemblies into the GDa range. <a href="javascript:void(0);">(17,18)</a> However, there is untapped utility for CDMS experiments other than mass and proteoform determination. Jordan et al. showed the capability to assess conformational heterogeneity of mAb aggregates using the added charge dimension that CDMS provides. <a href="javascript:void(0);">(19)</a> The current work demonstrates that CDMS can separate proteoforms with overlapping <i>m</i>/<i>z</i> values based on charge and quantify their relative abundances in complex mixtures. While nMS is already a highly quantitative technique, our results establish CDMS as an equally powerful tool for quantitative analysis in heterogeneous systems. <a href="javascript:void(0);">(20,21)</a></p><p>Here, we apply Orbitrap-based CDMS/Direct Mass Technology (DMT) using the selective temporal overview of resonant ions (STORI) approach <a href="javascript:void(0);">(22,23)</a> to quantitatively compare WT-TTR and CT-TTR, focusing on two biologically relevant properties: tetramer stability assessed via subunit exchange kinetics and ligand-binding affinity. Conventional nMS cannot fully resolve the overlapping charge states of WT- and CT-TTR or their ligand-bound states. However, DMT can resolve these species by directly measuring the mass (<i>m</i>/<i>z</i> × charge), enabling quantitation of all proteoforms. The data reveal that the CT tag alters tetramer stability and thyroxine-binding affinity, demonstrating the structural sensitivity of TTR to modifications at its C-terminus. More broadly, this work demonstrates the impact that protein tags can have on native protein interactions and highlights the broader utility of quantitative CDMS for probing heterogeneous biological samples.</p><h4><strong>Experimental Section</strong></h4><h5><strong>Data Collection</strong></h5><p>All experiments were conducted on a <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/560"><strong>Thermo Scientific Q-Exactive UHMR</strong></a> with added DMT capabilities (Bremen, Germany). Before DMT, mass spectra were collected at various resolving powers (6–200k) for each sample, with the instrument parameters reported in the Supporting Information (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c05771/suppl_file/ac5c05771_si_001.pdf">Table S1</a>). For DMT experiments, the trapping gas pressure in the HCD cell was reduced to 0.3–0.8 to attenuate the signal intensity to a single ion level, as well as decreasing the UHV pressure to assist ion retention through the entire transient of Orbitrap analysis. We observed no significant difference between mass spectra collected at various HCD cell pressures (Supporting Information, <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c05771/suppl_file/ac5c05771_si_001.pdf">Figure S1</a>). For DMT collection, automated ion control (AIC) and 100% target density were used with 200k resolving power.</p><h4><strong>Results and Discussion</strong></h4><p>CDMS has emerged as a powerful tool for analyzing heterogeneous biomolecular samples, enabling accurate, direct mass determination by simultaneously measuring the charge and <i>m</i>/<i>z</i> for individual ions. While CDMS has been widely applied for qualitative analyses, its potential for quantitative and less than MDa applications remains underexplored. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig1">Figure 1</a>A shows the theoretical mass spectrum of WT-TTR (14+ to 16+) and CT-TTR (15+ to 17+) homotetramers, where the two proteoforms become increasingly resolved as the charge states increase (&lt;3900 <i>m</i>/<i>z</i>). <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig1">Figure 1</a>B zooms in on the 14+ (WT) and 15+ (CT) charge states, highlighting their strong overlap, which prevents accurate deconvolution of the proteoforms by conventional methods. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig1">Figure 1</a>C displays theoretical distributions for 0, 1, and 2 T<sub>4</sub> bound states of both WT- and CT-TTR tetramers, where &lt;3900 <i>m</i>/<i>z</i> has observable separation between all proteoforms. However, for the 14+ and 15+ charge states of WT- and CT-TTR, respectively, the 0 T<sub>4</sub>- and 1 T<sub>4</sub>-bound populations overlap (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig1">Figure 1</a>D). Furthermore, commonly adducted species (Na<sup>+</sup>, K<sup>+</sup>, and Zn<sup>2+</sup>) observed in experimental spectra broaden these distributions, making it increasingly difficult to distinguish and deconvolute the proteoforms (see <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c05771/suppl_file/ac5c05771_si_001.pdf">Figure S2</a>). Here, we employ Orbitrap-based CDMS/DMT to overcome this <i>m</i>/<i>z</i> overlap to resolve and quantify hybrid tetramer formation and T<sub>4</sub> binding.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2025_97_49_27057_27063_Figure_1_A_Theoretical_mass_spectra_of_WT_TTR_and_CT_TTR_homotetramers_47232849d9.jpg" alt="Anal. Chem. 2025, 97, 49, 27057–27063: Figure 1. (A) Theoretical mass spectra of WT-TTR and CT-TTR homotetramers. (B) Zoomed-in view of the 14+ WT-TTR and 15+ CT-TTR distributions to show the large overlap of the proteoforms. (C) Theoretical mass spectra of WT-TTR and CT-TTR homotetramers with thyroxine (T4) binding. (D) Zoomed-in view of the 14+ WT-TTR and 15+ CT-TTR distributions where the 0 and 1 T4 have overlapping distributions. These theoretical distributions do not contain any commonly adducted species (Na+, K+, Zn2+), which broaden the distributions and create more overlap even for the proteoforms in the range 3300–3900 m/z (see Figure S2)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2025_97_49_27057_27063_Figure_1_A_Theoretical_mass_spectra_of_WT_TTR_and_CT_TTR_homotetramers_47232849d9.jpg 187w," sizes="100vw" width="1417" height="1182"></p><h5><strong>Thyroxine Binding to TTR Homotetramers</strong></h5><p>Thyroxine is the less active form of a thyroid hormone important for metabolism that binds to TTR for transport throughout plasma and cerebral spinal fluid. <a href="javascript:void(0);">(31)</a> Turnover of T<sub>4</sub> into T<sub>3</sub> (active) occurs after dissociation, where it can then modulate gene expression via binding to nuclear receptors. <a href="javascript:void(0);">(32)</a> The TTR tetramer gains substantial stability as it binds up to 2 T<sub>4</sub> at the tetramer interface, decreasing tetramer dissociation and SUE. <a href="javascript:void(0);">(33)</a> This has been shown previously to decrease the amyloidogenic rate of TTR, which led to tafamidis (similar in structure to T<sub>4</sub>) to be designed and is currently the only drug that is approved for clinical treatment of TTR amyloidosis. <a href="javascript:void(0);">(34)</a> Measuring the difference in binding affinity between TTR proteoforms may provide insight into regions of TTR or TTR intermolecular/intramolecular interactions that are important for binding of small molecules such as tafamidis and T<sub>4</sub>.</p><p>DMT was further applied to quantify T<sub>4</sub> binding to WT- and CT-TTR homotetramers, highlighting the technique’s utility in probing protein–ligand interactions. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig3">Figure 3</a>A shows a representative mass spectrum of TTR homotetramers in the presence of T<sub>4</sub>. While ligand-bound species can be observed, homotetramers cannot be confidently resolved across the entire 3000–5000 <i>m</i>/<i>z</i> range. By leveraging the charge-resolving capabilities of DMT, we achieve separation of the homotetramers (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c05771#fig3">Figure 3</a>B,C) and the 0, 1, and 2 ligand-bound states. The 2D plot clearly shows the gain in resolution achieved when charge is simultaneously measured with <i>m</i>/<i>z</i> by separating the 14+ and 15+ charge states for WT and CT, respectively, in the range 3900–4200 <i>m</i>/<i>z</i>. Additionally, using ion mobility does not provide the same kind of 2D resolution due to the similarity in arrival times for the homotetramer proteoforms, as evidenced by <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c05771/suppl_file/ac5c05771_si_001.pdf">Figures S4 and S5</a> (see the Supporting Information). These data provide evidence that when ion mobility is able to separate out species that overlap in <i>m</i>/<i>z</i> yet differ in mobility, CDMS could be an alternative or used complementarily since the species likely also differ in charge.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2025_97_49_27057_27063_Figure_3_A_Mass_spectra_of_WT_TTR_and_CT_TTR_homotetramers_with_thyroxine_binding_61b1e98a94.jpg" alt="Anal. Chem. 2025, 97, 49, 27057–27063: Figure 3. (A) Mass spectra of WT-TTR and CT-TTR homotetramers with thyroxine binding. Ligand binding can be resolved, but homotetramers cannot be confidently identified. Charge states labeled are for WT; CT is always one charge state higher at the same m/z range. (B) DMT heatmap resolving WT-TTR and CT-TTR homotetramers with the additional measurement of charge. (C) Deconvoluted mass spectrum from DMT analysis. Both homotetramers and their ligand binding are resolved, and fit for analysis is shown in red. (D) Mole fraction of each homotetramer and their thyroxine binding species. Error bars represent the standard deviation of replicates (n = 3). The significance for each ligand state is in respect to the left adjacent state. *p &lt; 0.05." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2025_97_49_27057_27063_Figure_3_A_Mass_spectra_of_WT_TTR_and_CT_TTR_homotetramers_with_thyroxine_binding_61b1e98a94.jpg 181w," sizes="100vw" width="1266" height="1094"></p><h4><strong>Conclusion</strong></h4><p>This work demonstrates that quantitatively, Orbitrap-based CDMS/DMT can determine differences in protein-complex stability and ligand binding. By directly comparing WT- with CT-TTR, we show that the CT tag accelerates tetramer dissociation while enhancing T<sub>4</sub> binding affinity. These results indicate that the C-terminus, located at the dimer–dimer interface, plays a more significant role in TTR stability and ligand recognition than previously appreciated. <a href="javascript:void(0);">(12)</a> Even the addition of a short peptide sequence perturbs noncovalent interactions at the interface, likely altering solvent accessibility, and the dynamics of the thyroxine binding channel. <a href="javascript:void(0);">(37,54)</a> Such findings underscore the importance of evaluating how seemingly minor sequence modifications, such as affinity tags, can influence fundamental biophysical properties.</p><p>Beyond TTR, this work positions quantitative CDMS as a broadly applicable strategy for analyzing heterogeneous protein systems, where charge domain separation overcomes the resolution limits of <i>m</i>/<i>z</i> domain measurements in traditional nMS experiments. While much of the field has emphasized extending CDMS to ultrahigh masses and maximal resolution, <a href="javascript:void(0);">(16,18)</a> our results highlight the underexplored potential of applying the method in the 1000–10,000 <i>m</i>/<i>z</i> range common to nMS experiments. This capability is directly relevant to heterogeneous membrane protein complexes, which often display broad distributions of oligomeric states, PTMs, lipid, and ligand adducts that complicate spectra. <a href="javascript:void(0);">(48,55)</a> Similarly, mAbs can oligomerize and exhibit mass heterogeneity from variable glycosylation, affecting pharmacokinetics, effector function, and stability. <a href="javascript:void(0);">(19)</a> CDMS may resolve and quantify such proteoforms in a single experiment without the need for charge reduction or chemical derivatization. <a href="javascript:void(0);">(48,56,57)</a></p>

Dissecting Heterogeneous Populations of Protein-Complex Samples Using Direct Mass Technology

Article

Webinars

Video

Scientists

Scientific article

Interview

Science and research

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.

LabRulez

Organomation, founded in 1959, designs and manufactures high-quality nitrogen evaporators and extraction systems. Known for innovation and durability, their lab instruments are used globally for efficient sample preparation with strong customer support.

Organomation

Thermo Scientific Dionex IonPac AS18 IC Columns

Use these longer 250mm Thermo Scientific™ Dionex™ IonPac™ AS18 columns higher resolution separations of more complex sample matrices.

<p><strong>Use these longer 250mm Thermo Scientific™ Dionex™ IonPac™ AS18 columns higher resolution separations of more complex sample matrices. Dionex IonPac AS18 columns are high capacity hydroxide-selective anion-exchange columns. They are the column of choice for monitoring inorganic anions in drinking water and wastewater samples for compliance with U.S. EPA Methods 300.0 (A) and 300.1. This column is also recommended when separating the common inorganic anions and low-molecular weight organic acids in diverse sample matrices including drinking water, wastewater, leachates, foods, beverages, pharmaceutical preparations, and scrubber solutions.</strong></p><h5><strong>High Resolution of Complex Sample Matrices</strong></h5><ul><li>Longer 250mm Dionex IonPac AS18 hydroxide-selective columns provide higher resolution separations of more complex sample matrices</li><li>Available in standard bore, microbore, and capillary formatsAnalysis of Common Inorganic Anions and Low Molecular Weight Organic</li></ul><h5><strong>Acids in Diverse Matrices</strong></h5><ul><li>Compliance monitoring of common anions in drinking water as specified in U.S. EPA Method 300.0 (A)</li><li>Determination of low levels of inorganic anions in complex matrices using large-loop injections</li><li>Superior retention and quantification of fluoride, acetate, and formate</li><li>Isocratic separation of common inorganic anions in 9 min in diverse matrices using a 250mm column</li><li>Higher-capacity applications use 250mm columns allowing injection of more concentrated samples without overloading or peak broadening</li><li>Compatible with organic solvents to enhance analyte solubility, modify column selectivity, or allow effective column cleanup</li></ul><h5><strong>Recommended for Inorganic Anions in Diverse Sample Matrices</strong></h5><ul><li>Source water and drinking water, municipal and industrial wastewater</li><li>Industrial cooling water, hazardous waste extracts and dump site leachates, acid rain</li><li>Foods and beverages, anionic counterions in pharmaceutical preparations and synthetic peptides</li><li>Polymers such as polyols and polysulfonates, scrubber solutions</li></ul><h5><strong>Multiple 250mm Formats for Application Flexibility</strong></h5><p>Get higher resolution separations of more complex sample matrices using these longer 250mm analytical columns. Choose from standard bore, microbore, and capillary formats and use the corresponding guard column to protect and increase the life of your analytical column. Use the:</p><ul><li>4x250mm standard bore column with the 4x50mm guard column</li><li>2x250mm microbore columns with the 2x50mm guard column</li><li>0.4x250mm capillary columns with the 0.4x50mm guard column</li></ul><h5><strong>Capillary Columns Reduce Operating Costs from Lower Eluent Requirements</strong></h5><p>Capillary columns provide significantly reduced operating and waste disposal costs through eluent conservation. Packed with the same material, the Dionex IonPac AS18 capillary columns provide the same performance as the standard bore and microbore counterparts. Operating costs are reduced because the capillary system operates at only 1% of the eluent flow rate of the standard bore system. Capillary columns are used with the Thermo Scientific™ Dionex™ ICS-4000 and ICS-5000+ Capillary systems.</p><h5><strong>Get Faster, High-Resolution separations from Dionex IonPac AS18-Fast and Dionex IonPac AS18-4µm Columns</strong></h5><p>For faster runs on relatively clean matrices, refer to the shorter 150mm Dionex™ IonPac™ AS18-Fast Hydroxide-Selective Anion-Exchange Columns<br>For fastest, highest resolution separations, refer to the small particle Dionex™ IonPac™ AS18-4µm Hydroxide-Selective Anion-Exchange Columns. Use of 4µm columns requires a high-pressure IC system.</p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 285 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity: </strong>285 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 5000 psi (345 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> IonPac AS18</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Ethylvinylbenzene/Divinylbenzene</li></ul>

Thermo Scientific Dionex IonPac AS19 IC Columns

Measure trace bromate and other oxyhalides in drinking water, ground water, wastewater, and other diverse sample matrices with Thermo Scientific Dionex IonPac AS19 Columns.

<p><strong>Measure trace bromate and other oxyhalides in drinking water, ground water, wastewater, and other diverse sample matrices with Thermo Scientific™ Dionex™ IonPac™ AS19 Capillary, Analytical &amp; Guard Columns. The column is specifically designed and recommended for determination of trace bromate, a toxic byproduct of ozone disinfection. The column's high capacity and selectivity facilitate the determination of bromate in drinking water at the low-μg/L level. The Dionex IonPac AS19 columns meet the performance requirements of U.S. EPA Methods 300.0 and 300.1.</strong></p><h5><strong>Reduce Operating Costs With our New Capillary Column</strong></h5><p>The Dionex IonPac AS19 Capillary column is packed with the same material as the equivalent standard bore version (providing the same performance as a 4 mm column), but requires only 1/100th the eluent flow rate. The capillary format provides the advantage of significantly reduced eluent consumption, which helps reduce operating costs.</p><h5><strong>Superior Chromatographic Performance</strong></h5><ul><li>High capacity: 240μeq per column (4x250mm)</li><li>Operates at ambient or elevated temperatures with column selectivity optimized for 30°C</li><li>Compatible with organic solvents</li><li>Low background signal and enhanced analyte sensitivity when using the Thermo Scientific™</li><li>Dionex™ Anion Self-Regenerating Suppressor (ASRS™ 300) and a Reagent-Free™ (RFIC™) system</li><li>Analyze a Wide Range of Oxyhalides and Inorganic Anions</li><li>Oxyhalides and common inorganic anions including fluoride, chlorite, bromate, chloride, nitrite, bromide, chlorate, nitrate, phosphate, and sulfate in drinking water, groundwater, wastewater, and other diverse sample matrices.</li><li>Analyzes most drinking water without the use of sample pretreatment or preconcentration.</li><li>Ideal when used with a Reagent-Free™ Ion Chromatography (RFIC)™ system for automatic eluent generation</li></ul><h5><strong>Designed for Detection of Trace Bromate</strong></h5><p>The key application for this column is the determination of trace bromate in drinking water matrices using a potassium hydroxide gradient with suppressed conductivity detection. The column's selectivity ensures that bromate can be quantified at low μg/L concentrations using suppressed conductivity detection even in the presence of very high concentrations of chloride, sulfate, and carbonate.</p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 240 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity: </strong>240 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Analysis of Trace Bromate in Drinking Water</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 3000 psi (207 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> IonPac AS19</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Polymeric</li></ul>

Thermo Scientific Dionex IonPac AS20 IC Columns

Simplify trace analysis of perchlorate in drinking water, surface water, and groundwater matrices using the Thermo Scientific Dionex IonPac AS20 Columns.

<p><strong>Simplify trace analysis of perchlorate in drinking water, surface water, and groundwater matrices using the Thermo Scientific™ Dionex™ IonPac™ AS20 Capillary, Analytical &amp; Guard Columns. The capacity and selectivity of this column ensures that perchlorate can be quantified at low μg/L concentrations using suppressed conductivity detection, even in the presence of very high concentrations of chloride, carbonate, and sulfate. This column is specified in U.S. EPA Method 314.1 for the determination of trace perchlorate in drinking water (Confirmatory Method) after sample preconcentration.</strong></p><h5><strong>Reduce Operating Costs With our New Capillary Column</strong></h5><p>The Dionex IonPac AS20 Capillary column is packed with the same material as the equivalent standard bore version (providing the same performance as a 4mm column) but requires only 1% of the eluent flow rate. The capillary format provides the advantage of significantly reduced eluent consumption, which helps reduce operating costs.</p><h5><strong>Superior Chromatographic Performance</strong></h5><ul><li>Recommended hydroxide-selective, anion-exchange column for trace perchlorate in environmental water samples</li><li>High Capacity: 310μeq per column. (4 x 250mm)</li><li>Increased mass sensitivity, reduced eluent consumption, and reduced operating costs</li><li>Operates at ambient or elevated temperature; column selectivity is optimized for 35°C operating temperature</li><li>Compatible with organic solvents</li></ul><h5><strong>For Best Results</strong></h5><ul><li>Use this column with a Reagent-Free™ IC (RFIC™) system and an eluent generator for optimum detection limits.</li><li>Use the Thermo Scientific™ Dionex™ Anion Electrolytically Regenerated Suppressor (AERS™ 500) or the Thermo Scientific™ Dionex™ Anion Capillary Electrolytic Suppressor (ACES™ 300) with the Dionex IonPac AS20 column for eluent suppression and enhanced analyte sensitivity.</li><li>Use the Thermo Scientific™ Cryptand C1 Concentrator column for sample preconcentration for analysis of trace perchlorate with the analytical column.</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 310 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity: </strong>310 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 4000 psi (275 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> IonPac AS20</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Polymeric</li></ul>

Thermo Scientific Dionex IonPac AS22 IC Columns

Thermo Scientific Dionex IonPac AS22 IC Columns provide fast analysis of drinking water, ground water and wastewater.

<p><strong>Designed specifically for compliance monitoring of inorganic anions in accordance with U.S. EPA Methods 300.0 (A), the Thermo Scientific™ Dionex™ IonPac™ AS22 IC Columns provide fast analysis of drinking water, ground water and wastewater. With the Dionex IonPac AS22 column, using a simple isocratic carbonate/bicarbonate eluent, common inorganic anions can be quickly separated in a variety of sample matrices including drinking water, wastewater, process streams, and scrubber solutions.</strong></p><h5><strong>Analysis of Common Inorganic Anions and Low Molecular Weight Organic Acids in Diverse Matrices</strong></h5><ul><li>Compliance monitoring of common anions in drinking water as specified in U.S. EPA Method 300.0 (A)</li><li>Fast isocratic separation of common inorganic anions in simple matrices in 8 min.</li><li>Isocratic separation of common inorganic anions in complex matrices in 12 min.</li><li>Excellent retention of fluoride from the water dip and resolution of fluoride, acetate, and formate</li><li>Excellent resolution of the carbonate peak away from peaks for common inorganic anions</li><li>Ideal alternative, using carbonate/bicarbonate eluents, for IonPac AS4A-SC, AS12A, AS14 and AS14A inorganic anion applications.</li><li>Solvent compatibility permits easy column cleanup after the analysis of samples with hydrophobic components.</li></ul><h5><strong>Multiple Formats Available for Application Flexibility</strong></h5><ul><li>4x250mm, 2x250mm analytical columns</li><li>4x50mm, 2x50mm guard columns</li><li>Longer 250mm columns facilitate higher resolution separations of more complex sample matrices</li><li>Smaller i.d. columns provide higher mass sensitivity, eluent and reagent conservation and lower operating costs</li></ul><p><strong>Note:</strong><i> For simple, accurate eluent preparation, use the IonPac AS22 Eluent Concentrate.</i></p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 210 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity: </strong>210 μeq</li><li><strong>Column Chemistry:</strong> Carbonate/Bicarbonate</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 3000 psi (207 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> IonPac AS22</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Polymeric</li></ul>

Thermo Scientific Dionex IonPac AS23 IC Columns

Measure trace bromate and other oxyhalides in drinking water, ground water with Thermo Scientific Dionex IonPac AS23 carbonate eluent anion-exchange column. 

<p><strong>Measure trace bromate and other oxyhalides in drinking water, ground water, wastewater, and other diverse sample matrices with the Thermo Scientific™ Dionex™ IonPac™ AS23 carbonate eluent anion-exchange column. The column is specifically designed and recommended for the determination of trace bromate, a toxic byproduct of ozone disinfection, in drinking water matrices. The column's high capacity and selectivity facilitate the determination of bromate in drinking water at the low-μg/L level in the presence of high concentration of chloride, sulfate and carbonate. The Dionex IonPac AS23 columns meet the performance requirements of U.S. EPA Methods 300.0 and 300.1.</strong></p><h5><strong>Analysis of Trace Level Bromate in Drinking Water</strong></h5><ul><li>Compliance monitoring of common anions and oxyhalides in drinking water as specified in U.S. EPA Method 300.0 and 300.1</li><li>Simple analysis of trace bromate in drinking water matrices using an isocratic carbonate/bicarbonate eluent with suppressed conductivity detection</li><li>Optimized selectivity to ensure low ppb determination of bromate in the presence of very high concentrations of chloride, sulfate, and carbonate</li><li>Separates oxyhalides and common inorganic anions in drinking water, groundwater, wastewater and other diverse sample matrices</li><li>High capacity for the analysis of most drinking water without the use of sample pretreatment or preconcentration</li><li>Solvent compatibility for easy column cleanup after the analysis of samples with hydrophobic components</li></ul><h5><strong>Multiple Formats Available for Application Flexibility</strong></h5><ul><li>4x250mm, 2x250mm analytical columns</li><li>4x50mm, 2x50mm guard columns</li><li>Longer 250mm columns facilitate higher resolution separations of more complex sample matrices</li><li>Smaller i.d. columns provide higher mass sensitivity, eluent and reagent conservation and lower operating costs</li></ul><p><strong>Note:</strong><i> For simple, accurate eluent preparation, use the Dionex IonPac AS23 Eluent Concentrate.</i></p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 320 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity: </strong>320 μeq</li><li><strong>Column Chemistry:</strong> Carbonate/Bicarbonate</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 3000 psi (207 bar)</li><li><strong>Solvent Compatibility:</strong> 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> IonPac AS23</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Polymeric</li></ul>

Thermo Scientific Dionex IonPac AS27 IC Columns

Achieve high resolution separations of trace oxyhalides and inorganic anions in drinking water using Thermo Scientific Dionex IonPac AS27 Analytical and Guard columns.

<p><strong>Achieve high resolution separations of trace oxyhalides and inorganic anions in drinking water using Thermo Scientific™ Dionex™ IonPac™ AS27 Analytical and Guard columns. These hydroxide-selective anion-exchange columns allows analysis of most drinking water preserved with ethylenediamine (EDA) without sample pretreatment or preconcentration. The Dionex IonPac AS27 columns meets the performance requirements of US EPA Methods 300.0 and 300.1.</strong></p><h5><strong>Analyzes Oxyhalides and Inorganic Anions in Drinking Water</strong></h5><ul><li>Optimized for analysis of trace bromate in drinking water preserved with EDA</li><li>High capcity: 220μeq per column (4x250mm)</li><li>Meets or exceeds performance requirements of US EPA Methods 300.0 and 300.1</li><li>Column selectivity is optimized for 30°C operating temperature</li><li>Compatible with organic solvents</li></ul><h5><strong>Choose from Multiple Formats for Application Flexibility</strong></h5><ul><li>4x250mm, 2x250mm, 0.4x250mm analytical columns</li><li>4x50mm, 2x50mm, 0.4x50mm guard columns</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 220 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity:</strong> 220 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 3000 psi (207 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> Super Macroporous Resin</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Polymeric</li></ul>

Thermo Scientific Dionex IonPac AS28-Fast-4μm IC Columns

Analyze trace inorganic anions and low molecular weight organic acids using the Thermo Scientific Dionex IonPac AS28-Fast-4μm ion chromatography (IC) columns. 

<p><strong>Analyze trace inorganic anions and low molecular weight organic acids using the Thermo Scientific™ Dionex™ IonPac™ AS28-Fast-4μm ion chromatography (IC) columns. Designed specifically for trace level analysis of high purity water from semiconductor and power industries, this column combines the selectivity of the Thermo Scientific™ Dionex™ IonPac™ AS15 column, with fast, high efficiency, and high resolution separations. The Dionex IonPac AS28-Fast-4μm columns uses smaller 4μm resin particles for more efficient separations resulting in more accurate peak integration and more reliable results.</strong></p><h5><strong>Applications for Dionex IonPac AS28-Fast-4μm IC Columns</strong></h5><ul><li>Separation of common anions and low molecular weight organic acids</li><li>For both high purity water matrices and complex matrices including chemical and petrochemical samples</li><li>Compatible with organic solvents to enhance analyte solubility, modify column selectivity, and facilitate effective column clean-up</li></ul><h5><strong>Superior Performance</strong></h5><ul><li>Improved efficiencies and resolution compared to the Dionex IonPac AS15 column</li><li>Easily transfer applications from the Dionex IonPac AS15 column to the AS28-Fast-4μm column due to the similar selectivity</li></ul><h5><strong>For Use With a High-Pressure IC System</strong></h5><p>Higher resolution is achieved through the use of smaller resin particles, which produce a column backpressure over 3000 psi at the standard flow rates. A high-pressure IC system, such as the Thermo Scientific™ Dionex™ ICS-5000+ HPIC™ or the Thermo Scientific Dionex ICS-4000 Capillary HPIC system is required to operate this column under standard conditions and take advantage of elevated flow rates and faster run times.</p><h5><strong>Reduce Operating Costs With Lower Eluent Requirements</strong></h5><p>The Dionex IonPac AS28-Fast-4μm capillary columns provide the same performance as the standard bore and microbore Dionex IonPac AS28-Fast-4μm columns because they are packed with the same material. Operating costs are reduced because the capillary system operates at only 1% of the eluent flow rate of the standard bore system, requiring less eluent and producing less waste.</p><h5><strong>Multiple Formats Available</strong></h5><ul><li>4 x 150mm and 2 x 150mm analytical columns</li><li>4 x 30mm and 2 x 30mm analytical guard columns</li><li>0.4 x 150mm capillary columns</li><li>0.4 x 35mm capillary guard columns</li><li>Smaller i.d. columns provide higher mass sensitivity, eluent and reagent conservation, and lower operating costs</li></ul><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 230 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity:</strong> 230 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 5000 psi (345 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% Acetonitrile, Methanol, and Isopropanol</li><li><strong>Stationary phase:</strong> Super Macroporous Ethylvinylbenzene Polymer Cross-Linked with Divinylbenzene</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Ethylvinylbenzene/Divinylbenzene</li></ul>

Thermo Scientific Dionex IonPac AS29-Fast-4μm IC Columns

Analyze inorganic anions in high ionic strength matrices using Thermo Scientific™ Dionex™ AS29-Fast-4μm ion chromatography (IC) columns.

<p><strong>Analyze inorganic anions in high ionic strength matrices using Thermo Scientific™ Dionex™ AS29-Fast-4μm ion chromatography (IC) columns. Specifically designed to handle high ionic strength samples, Dionex IonPac AS29-Fast-4μm columns can easily separate the common inorganic anions in less than 10 minutes and can tolerate samples with high or low pH without requiring any pretreatment. They are ideal for analzying drinking water, wastewater, process streams, and scrubber solutions. Use with the Dionex AS29 Eluent Concentrate for fast, convenient, and reliable eluent preparation.</strong></p><h5><strong>Fast separation of common inorganic anions with excellent resolution</strong></h5><ul><li>Achieve fast, isocratic separation of common inorganic anions in less than 10 minutes.</li><li>Analyze high ionic strength samples without compromising the separation of other analytes.</li><li>Excellent resolution of carbonate away from the common inorganic anions.</li><li>Robust stationary phase can tolerate acidic or basic samples without the need for pretreatment.</li><li>Similar peak efficiency to Dionex IonPac AS22-Fast-4μm column with the same elution order.</li><li>Solvent compatibility permits easy column cleanup after the analysis of samples with hydrophobic components.</li><li>Use with Dionex AS29 Eluent Concentrate for simple and accurate eluent preparation.</li></ul><h5><strong>Use with a High Pressure IC system</strong></h5><p>Higher resolution is achieved through the use of smaller resin particles, which produce a column backpressure over 3000 psi at the standard flow rates. A high-pressure IC system, such as the Thermo Scientific™ Dionex™ ICS-5000+ HPIC™ system or Thermo Scientific™ Dionex™ Integrion™ HPIC system is required to operate this column under standard conditions.</p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 126 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity:</strong> 126 μeq</li><li><strong>Column Chemistry:</strong> Carbonate/Bicarbonate</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 5000 psi (345 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% Organic HPLC Solvents</li><li><strong>Stationary phase:</strong> Super Macroporous Resin</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Ethylvinylbenzene/Divinylbenzene</li></ul>

Thermo Scientific Dionex IonPac AS30 IC Columns

Achieve high resolution separations of trace oxyhalides and inorganic anions in drinking water with Thermo Scientific Dionex IonPac AS30 columns.

<p><strong>Achieve high resolution separations of trace oxyhalides and inorganic anions in drinking water with Thermo Scientific™ Dionex™ IonPac™ AS30 columns. The column selectivity has been optimized for trace level analysis of bromate in drinking water preserved with ethylenediamine (EDA). EDA is used as a preservative in some drinking water samples and can cause interference with early eluting peaks. The high capacity of this hydroxide-selective anion-exchange column allows large loop injections for trace analysis (μg/L) without sample pre-treatment or preconcentration.</strong></p><h5><strong>Superior Chromatographic Performance</strong></h5><ul><li>Optimized for analysis of trace bromate in drinking water preserved with EDA</li><li>High capacity: 477 μeq/column (4 x 250 mm) allows large loop injections for trace analysis</li><li>Column selectivity has been optimized at an operating temperature of 30°C</li><li>Compatible with organic solvents</li></ul><h5><strong>Unique Selectivity for Samples Preserved with Ethylenediamine</strong></h5><p>The selectivity of the Dionex IonPac AS30 column has been optimized to facilitate quantitation of trace levels of bromate in drinking water containing up to 50 ppm ethylenediamine (EDA). Ethylenediamine is sometimes added to drinking water samples as a preservative and can react with carbonate to produce artifacts that interfere with early eluting analytes such as fluoride. The Dionex IonPac AS30 column minimizes this interference by increasing the separation between fluoride and the EDA carbamate artifact, allowing better integration of the fluoride peak. In comparison to the Dionex IonPac AS19 and IonPac AS27 columns, the Dionex IonPac AS30 column features unique selectivity and much higher column capacity to enable separation of fluoride from the EDA carbamate artifact as well as separation of carbonate and sulfate for better quantification of sulfate.</p><p>The Dionex IonPac AS30 column is suitable for determining bromate at 5 ppb in a matrix containing up to 50 ppm each of chloride, carbonate, and sulfate. For trace bromate analysis below 5 ppb in higher ionic strength matrices (where chloride levels exceed 50 ppm), the Dionex IonPac AS19 column is recommended. Alternatively, the Dionex IonPac AS27 column is recommended for higher ionic strength matrices preserved with EDA.</p><h5><strong>Use with a High-Pressure IC system</strong></h5><p>A high-pressure IC system such as the Thermo Scientific™ Dionex™ ICS-5000+, Dionex ICS-6000, or Dionex Integrion HPIC™ system is required to use this column under standard operating conditions.</p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 6 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity:</strong> 477 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 5000 psi (345 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> Super Macroporous Resin</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Ethylvinylbenzene/Divinylbenzene</li></ul>

Thermo Scientific Dionex IonPac AS32-Fast-4μm IC Columns

Resolve polythionates, persulfate, polysulfonated aromatics, and aromatic dyes and pigments with the Thermo Scientific Dionex IonPac AS32-Fast-4μm column.

<p><strong>Resolve polythionates, persulfate, polysulfonated aromatics, and aromatic dyes and pigments with the Thermo Scientific™ Dionex™ IonPac™ AS32-Fast-4μm column. The unique selectivity of the Dionex IonPac AS32-Fast-4μm column allows it to resolve trace amounts of perchlorate in matrices containing high levels of chloride and sulfate within ten minutes using simple, isocratic conditions. Compared to similar anion-exchange columns packed with 7-9μm resin particles, Dionex IonPac AS32-Fast-4μm columns produce more efficient peaks, resulting in more accurate integration and more reliable results.</strong></p><h5><strong>Superior Chromatographic Performance</strong></h5><ul><li>High capacity allows injection of complex matrices without overloading the column while maintaining excellent peak shapes for lower concentration analytes.</li><li>Ultralow hydrophobicity and reduced 150mm column length allow for fast analysis of highly polarizable anions such as perchlorate and iodide with a simple, isocratic eluent.</li><li>Quickly separate disparate concentration ratios (1:1000) of perchlorate in high sulfate matrices using simple, isocratic conditions.</li><li>Separate polythionates such as dithionate, trithionate, and tetrathionate.</li><li>Separate color additives including FD&amp;C Yellow #5, FD&amp;C Yellow #6, FD&amp;C Blue #1, and FD&amp;C Red #40 using a hydroxide gradient.</li></ul><h5><strong>Use with a High-Pressure IC system</strong></h5><p>A high-pressure IC system, such as the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/410"><strong>Thermo Scientific™ Dionex™ ICS-6000 HPIC system</strong></a> or <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/408"><strong>Thermo Scientific™ Dionex™ Integrion™ HPIC system</strong></a> is required to operate this column under standard conditions.</p><h4><strong>Specifications</strong></h4><ul><li><strong>Anion Exchange Capacity:</strong> 126 μeq</li><li><strong>Crosslinking: </strong>55% DVB</li><li><strong>Column Capacity:</strong> 126 μeq</li><li><strong>Column Chemistry:</strong> Hydroxide</li><li><strong>For Use With (Application):</strong> Anion Exchange</li><li><strong>Ion Exchange Group: </strong>Alkanol Quaternary Ammonium Ion</li><li><strong>Max. Pressure:</strong> 5000 psi (345 bar)</li><li><strong>Solvent Compatibility:</strong> pH 0 to 14, 0 to 100% HPLC Solvents</li><li><strong>Stationary phase:</strong> Super Macroporous Resin</li><li><strong>Format:</strong> Standard Bore</li><li><strong>Packing Material: </strong>Ethylvinylbenzene/Divinylbenzene</li></ul>

Products from category HPLC columns - page 7

Related content

Dissecting Heterogeneous Populations of Protein-Complex Samples Using Direct Mass Technology

Webinars LabRulezLCMS Week 07/2026

Affinity, Gel Filtration, Size Exclusion Chromatography: Repurposing Kinase Inhibitors for Malaria