18th International Symposium on Hyphenated Techniques in Chromatography and Separation technology - Abstract Book

Importance of the topic

The 18th International Symposium on Hyphenated Techniques in Chromatography and Separation Technology (Leuven, May 2024) consolidated advances that address three pressing challenges in modern analytical chemistry: (1) the need to characterize extremely complex matrices (environmental, biological, food, fuels) with greater depth and confidence; (2) the imperative to scale analytic throughput while improving sustainability; and (3) the demand for multidimensional, orthogonal hyphenations and computational tools (AI, chemometrics, Bayesian methods) to extract actionable information from very large, multi‑modal datasets. The contributions demonstrate how innovations in stationary phases, hyphenation hardware, ion mobility, ultra‑high resolution MS, and sample preparation combine with smarter data processing to push boundaries in sensitivity, selectivity, and real‑world applicability.

Goals and overview of the symposium content

• Survey state-of-the-art hyphenated separations (GC×GC, LC×LC, SFC, TRLC) and complementary detectors (HRMS, Orbitrap, FTICR, TIMS, IMS, ICP-MS, VUV, REIMS, MSI).
• Showcase applied workflows: environmental non‑target screening, wastewater epidemiology, clinical breathomics and MSI, lipidomics for colorectal cancer, biopharmaceutical (mAb, oligonucleotide, mRNA) characterization, fuel and pyrolysis‑oil speciation, and food volatilomics.
• Present practical improvements: green solvent strategies, multicolumn countercurrent purification (MCSGP), microfabricated columns (µPAC), needle‑trap/exhaustive microextraction, aptamer sorbents, and 3D‑printed sorbents for tailored extraction.
• Expose data analysis innovations: AI/computer vision for GC×GC, Bayesian frameworks for chromatographic big data, ANN and predictive equations for SFC‑MS optimization, and chemometric/ML tools for non‑target prioritization.

Instrumentation

• Chromatography: GC×GC, comprehensive LC×LC, SFC and UHPSFC, temperature‑responsive LC (TRLC), capillary electrophoresis (CE), hydrophilic interaction LC (HILIC), ion‑pair RPLC for oligonucleotides, micro‑pillar array columns (µPAC), microreactor‑MS interfaces.
• Mass spectrometry and orthogonal selectors: High‑resolution TOF, Orbitrap, FT‑ICR, trapped ion mobility spectrometry (TIMS), cyclic IMS (cIMS), traveling‑wave IMS (TWIMS), ion mobility‑HRMS hybrids, REIMS, MALDI‑ISD, ICP‑MS(/MS), GC‑APCI, ESI, APCI, Unispray.
• Detectors and sample interfaces: Refractive Index Detector (RID) combined with TRLC, VUV, flame ionization (FID) coupled to GC×GC, thermal desorption (TD) and SBSE for volatile capture, needle‑trap devices (NTD), automated IMERs and on‑line SPE, membrane microfluidic suppressors, pyrolysis GC‑HRMS.
• Auxiliary hardware and formats: immobilized enzyme reactors (IMERs), multicolumn countercurrent (MCSGP) preparative platforms, robotic liquid‑handling for CRM production, 3D‑printed sorbents and consumables, active solvent modulation (ASM) and valve architectures for LC×SFC coupling.

Methodological trends and study approaches

• Orthogonality-first separations: combining polar and nonpolar selectivities (e.g., LC×SFC, HILIC×RPLC) to resolve isomers and isobaric interferences.
• Multimodal detection: linking chromatographic retention, accurate mass, MS/MS fragmentation, CCS (from IMS), and spectral libraries or IR‑IS to strengthen identifications in target/suspect/non‑target workflows.
• Green and preparative chromatography: replace acetonitrile with greener modifiers (ethanol, isopropanol, DMC), adopt MCSGP to recycle overlapping fractions and cut solvent use dramatically in peptide purification.
• High‑throughput tradeoffs: sub‑5 min lipidomics with HT‑4D‑TIMS or short nanoLC gradients for intact glycoproteins and proteomics, balanced against needs for resolution and spectral clarity.
• Sample preparation innovations: exhaustive needle‑trap sampling, aptamer/oligosorbents for selective enrichment, 3D‑printed sorbents for bespoke extraction geometry and selectivity, combined SPE workflows for wide polarity capture in river water NTS.
• Advanced data science: AI/computer vision for GC×GC pattern realignment and aroma fingerprinting; Bayesian approaches to probabilistic peak detection, alignment and deconvolution; ANN models to predict SFC‑MS make‑up solvent effects from molecular descriptors.

Main results and discussion

• Temperature‑Responsive LC (TRLC) expands RID applicability by replacing solvent gradients with temperature profiles, enabling water‑only elution for non‑UV analytes and providing nearly universal, overlapping calibration behavior for chemically related species.
• Greening preparative LC: replacing ACN with greener solvents (ethanol, i‑propanol, DMC) and adopting MCSGP reduced solvent consumption for peptide purification (icabitant example) by >80% versus single‑column RPLC.
• AI accelerates interpretation of multidimensional GC×GC‑MS data: computer vision and augmented visualization compensate for retention shifts, aid deconvolution and aroma blueprinting, and support marker discovery in food volatilomics and sensomics.
• Hyphenated IMS‑HRMS (TIMS‑TOF, cIMS) markedly improves non‑target screening of halogenated and other environmental contaminants: drift/time filtering cleans spectra, CCS values add orthogonal confidence and enable isomer distinction in dust and urine studies.
• Advances in MS‑based structure ID: new fragmentation methods (EAD, UVPD), IR‑IS, H/D exchange, quantum chemical prediction and machine learning are progressively replacing or complementing NMR for metabolite/structural assignments at trace levels.
• Microfabricated columns (µPAC Gen2) and novel pillar geometries provide significant intrinsic improvements in efficiency and permeability; radial/rectangular pillar variants reduce side‑wall effects and enhance uniform flow fields for nano‑LC proteomics.
• Needle‑Trap Devices (NTDs) and filter‑incorporated NTDs enable exhaustive active sampling of vapors and particle‑bound organics, enabling robust onsite sampling and improved quantification vs non‑exhaustive SPME.
• Multidimensional LC×SFC and RPLC×SFC proved particularly powerful for neutral isomeric loads (lignin oligomers, phytosterols, polymers), with online coupling strategies overcoming aqueous/CO2 incompatibility via valve schemes and partial‑fill/ split injection approaches.
• Non‑target workflows applied at scale: wastewater‑based epidemiology using direct‑injection LC‑MS(/QTOF) screened >2000 samples and a suspect library of >1200 compounds, resulting in hundreds of unique detections; data handling and prioritization are critical bottlenecks.
• Clinical translation: mass spectrometry imaging (MSI) and REIMS show promise for peri‑operative diagnostics and single‑cell lipid/protein mapping; breathomics protocols standardized across centers produced a panel discriminating interstitial lung disease in systemic sclerosis (AUC ~0.82).

Practical benefits and applications

• Environmental monitoring: TIMS‑HRMS and advanced SPE protocols deliver higher confidence in non‑target discovery and retrospective event detection (industrial fires, novel POPs, plasticizer metabolites).
• Biopharma: integrated multi‑dimensional platforms (ProtA → IMER → SEC/IEX/RP + HRMS) permit comprehensive antibody CQAs from a single injection; optimized HILIC/IP‑RPLC strategies improve oligonucleotide and glycoprotein characterization while maintaining MS compatibility.
• Food and flavor: GC×GC‑TOF and AI‑supported visualization disentangle complex aroma signatures for ingredient selection, off‑flavor detection and product development of alternative proteins.
• Fuels and circularity: GC×GC‑FID/qMS and probabilistic property models enable compositional prescreening of sustainable aviation fuels and plastic pyrolysis oils, guiding upgrading strategies and predicting sooting/ignition behavior.
• Regulatory and routine analysis: robotic DEM‑IDMS workflows and automated QbD chromatographic method development speed up CRM certification and robust HPLC method optimization for QC labs.

Future trends and opportunities

• Deeper integration of AI with analytical pipelines: real‑time chromatogram alignment, automated annotation with multi‑parameter scoring (RT+m/z+MS/MS+CCS+IR), and predictive models for method transfer and hardware settings (e.g., SFC make‑up solvent).
• Higher dimensional separations mainstreamed: LC×SFC and GC×GC with programmable second‑dimension temperature promise increased 2D peak capacity and better handling of the general elution problem.
• Microfabrication and additive manufacturing: µPAC evolution toward sub‑micron features and tailored 3D‑printed sorbents will enable bespoke columns and sample‑preparation devices for niche workflows (nano‑LC proteomics, targeted extraction).
• Greener separations at scale: replacement of harmful solvents, solvent recycling (MCSGP), miniaturization and on‑line sample processing will be increasingly required for sustainable analytics and preparative campaigns.
• Quantitative non‑target screening standardization: harmonized QA/QC, robust signal processing, and probabilistic identification frameworks (Bayesian) will be essential to move NTS from research to regulatory and routine contexts.
• Convergence of in situ/clinical MS modalities: portable/ex vivo REIMS, rapid MSI and advanced sampling (NTD, direct thermal desorption) will accelerate point‑of‑care molecular classification and intraoperative decision support.

Conclusion

The Leuven symposium documented a field in active maturation: hyphenated separations are no longer incremental add-ons to detectors but form coherent, application‑driven toolboxes combining orthogonal separations, selective enrichment and multidimensional detection. The interplay between hardware (µPAC, TRLC, SFC×LC, IMS, high‑res MS) and software (AI, Bayesian methods, chemometrics) is the decisive factor to exploit complex matrices at scale. Practical implementations—greener solvents, automated workflows, on‑line digestion/enrichment, and validated NTS pipelines—show the community is moving toward higher throughput, sustainability and regulatory readiness while preserving or improving confidence in identifications and quantitation.

References

• Selected representative citations from symposium abstracts (formatted):
• Baert M. et al. Anal. Chem. 2020, 92, 9815–9822. (Temperature‑responsive LC polymer phases)
• Bandini E.; Lynen F. Anal. Chim. Acta 2022, 1231, 340441. (TRLC + RID)
• Caratti A. et al. J. Chromatogr. A 2023, 1699, 464010. (Augmented visualization & GC×GC)
• Müller B. H. et al. Anal. Chem. 2023, 95, 17586–17594. (SWIM in TIMS for resolving power)
• Sadighi R. et al. Anal. Chim. Acta 2024, 1287, 342074. (Online multimethod platform for mAbs)
• Pawliszyn J. Trends Anal. Chem. 2022, 153, 116643. (Needle‑trap technology review)
• Camperi J.; Pichon V.; Delaunay N. J. Pharm. Biomed. Anal. 2020, 178, 112921. (Intact protein glycoforms by LC‑MS)
• Leppert J. et al. J. Chromatogr. A 2023, 1699, 464008. (Retention parameter estimation for GC)