16th MDCW 2025 (Day 3)

Program WEDNESDAY February 5, 2025

• Final Guidebook (PDF)
• Abstract Book (PDF)

8:00 - 8:30 AM Registration

8:30 - 8:50 AM - Multidimensional gas chromatography-mass spectrometry for the elucidation of indoor air quality improvements arising from planned interventions

• Patricia Forbes (University of Pretoria, Pretoria, South Africa)

Indoor air quality has a direct impact on human health, and encompasses exposure from both domestic and occupational environments. Combustion is a known source of semi-volatile organic compounds, including polycyclic aromatic hydrocarbons (PAHs), many of which may negatively impact human health with particular reference to respiratory illness and disease. Governments and industries may therefore undertake interventions to reduce combustion emissions and their associated impacts. A robust analytical methodology is required to correctly assess any improvements in the resulting air quality. Multidimensional gas chromatography-mass spectrometry (GC×GC-MS) is an indispensable tool in this regard, as the enhanced separation which it provides enables correct peak identification and quantification.

The results of two studies are presented which aimed to improve air quality by the implementation of combustion-related interventions. The first involved an occupational setting, whereby biodiesel was tested as an alternative to diesel in fueling a heavy duty vehicle in a South African underground platinum mine. Sampling of gaseous emissions onto multichannel polydimethylsiloxane traps was conducted in this confined environment (akin to indoor air) followed by GC×GC-MS analysis, focusing on PAHs. In the second study, the impact on domestic air quality resulting from the replacement of coal/wood stoves with gas stoves was assessed in an informal settlement in South Africa, by similarly sampling and analyzing the gaseous combustion emissions pre- and post intervention in 25 households and at eight ambient locations. The importance of utilizing multidimensional chromatography for these applications will be discussed in the context of the assessment of air quality improvements.

MDCW: Patricia Forbes - Multidimensional gas chromatography-mass spectrometry for the elucidation of indoor air quality improvements arising from planned interventions

8:50 - 9:10 AM - What’s in the dust? GC×GC-MS based non-target screening of house dust

• Andriy Rebryk

9:10 - 9:20 AM - TD-GC-MS/O and TD-GC×GC-HRTOFMS for the characterization of odorous compounds in recycled materials

• Catherine Brasseur

9:30 - 9:50 AM - An aliquot push-pull interface for coupling the first and second dimension separations in two-dimensional liquid chromatography

• Dwight Stoll (Gustavus Adolphus College, Saint Peter, USA)

Two-dimensional liquid chromatography (2D-LC) separations are increasing in popularity, both for the analysis of relatively simple, but hard-to-separate mixtures, and the analysis of highly complex mixtures such as those encountered in the analysis of biological samples. Despite advances in many aspects of the instrument hardware and software needed for routine use of 2D-LC, there are some aspects of the technology that have hardly changed since the first online 2D separations were demonstrated several decades ago. In this presentation we will describe a novel approach to interfacing the first and second dimensions of separation that addresses some of the shortcomings of existing technology. The approach – which we descriptively refer to as a “push-pull” interface – lets go of the conventional fixed loop feature of existing interfaces, and uses a precisely controlled, high pressure syringe to first “pull” in an aliquot of first dimension effluent that we desire to transfer to a second dimension for further separation. Then, it is “pushed” into the mobile phase stream of the second dimension and carried to the second dimension column. There are several advantages of this approach over existing ones, including software control of both the aliquot volume, and the rate at which the aliquot is fed into the second dimension mobile phase stream. In addition to an explanation of the modulation cycle, we will share results of preliminary work to illustrate the basic features of the interface/approach and show application examples that highlight the advantages of the push-pull interface over existing interfaces for 2D-LC.

MDCW: Dwight Stoll - An aliquot push-pull interface for coupling the first and second dimension separations in two-dimensional liquid chromatography

9:50 - 10:10 AM - Development of a MULTI-2D LC×LC-ESI/TPI-DUAL SOURCE-QTOF-MS for the analysis of complex samples

• Oliver Schmitz 

10:10 - 10:40 AM Coffee Break

10:40 - 11:00 AM - Characterization of chemical exposures from cannabis and vape devices using GC×GC-MS

• James Harynuk 

11:00 - 11:20 AM - Quantification of heterocyclic aromatic compounds (nso-het) in unfractionated and fractionated fuel samples by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

• Pedro Victor Bomfim Bahia

11:20 - 11:40 AM - Polyaromatic hydrocarbon quantification in plastic pyrolysis oils

• Melissa Dunkle 

12:20 - 12:40 PM - Sample preparation approaches coupled with GC×GC-MS for the characterization of new energy materials wastes

• Giulia Giacoppo

12:40 - 1:30 PM Lunch

1:30 - 1:40 PM - Pyrolysis and GC×GC-MS. a hot topic!

• Robert Cody (JEOL USA INC, PEABODY, MA, USA)

Thermal desorption and pyrolysis (TD/PY) is a valuable sample introduction method for materials analysis with combined gas chromatography and mass spectrometry (GC-MS). Polymers can be identified by their characteristic pyrograms, and a database is available for the major pyrolysis products. However, pyrolysis produces much more complex mixtures than can be separated by one-dimensional gas chromatography alone!

Comprehensive two-dimensional gas chromatography combined with mass spectrometry (GC×GC-MS) is a useful approach to monitor pyrolysis reactions on a small scale and characterize the products of pilot-plant pyrolysis. High-resolution mass spectrometry and soft ionization methods (chemical ionization, photoionization, and field ionization) are essential tools for the identification of unknowns in these complex mixtures. To view things from a completely different perspective, soft ionization and pyrolysis with a deactivated fused silica column that provides _no_ GC separation shows high-molecular-weight pyrolysis products that are not detectable by GC-MS or GC×GC-MS.

MDCW: Robert Cody - Pyrolysis and GC×GC-MS. a hot topic!

1:40 - 1:50 PM - Speciation of chlorine-contaning molecules in plastic pyrolysis oils 

• Bruno da Costa Magalhaes

1:50 - 2:00 PM - Application of pearson correlation coefficient to two-dimensional gas chromatography high-resolution time-of-flight mass spectrometry as a comparison and discovery-based technique

• Michelle Corbally

2:00 - 2:10 PM - Ambient ultrafine particles: classification, chemical characterization, and quantification of ubiquitous pahs via DTD-GC×GC-TOFMS

• Nadine Gawlitta

2:10 - 2:30 PM SCSC Poster Awards

P-2: OVERCOMING THE MODULATION CHALLENGES IN TWO-DIMENSIONAL
LIQUID CHROMATOGRAPHY

• Rick van den Hurk^1,2 (¹Analytical Chemistry group, van ’t Hoff Institute for Molecular Science (HIMS), Universiteit van Amsterdam, Amsterdam, Netherlands. ²Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, Netherlands.)

To improve the applicability of two-dimensional liquid chromatography (2D-LC), much of the recent research aims to solve one of its biggest challenges: solvent incompatibility. Solvent incompatibility occurs when complementary separation modes are coupled whereby the solvent of the first dimension is a strong eluent in the second-dimension separation mode. Several modulation strategies have been developed to tackle this problem, including stationary-phase-assisted modulation (SPAM), active solvent modulation (ASM), and at-column dilution. These strategies aid in (partially) solving incompatibility for specific samples and selectivity combinations. However, they also further complicate the intricate method-development process for 2D-LC separations. During any 2D-LC method-development process, whether it be heart-cutting or comprehensive, the same question inevitably returns: Which modulation strategy should be used, if any?

Automated method-development workflows aim to answer such questions for the users. However, such automated workflows do not currently aid in selecting modulation strategies. To enable optimization algorithms to address this issue, we need to determine the exact nature of complications and the conditions under which they occur.

In this presentation, we present advancements in unifying existing theoretical and practical knowledge on modulation strategies with new findings to address challenges in the automated selection and design of modulation setups. We provide examples of common separation mechanism combinations for both small and large molecules, including reversed-phase liquid chromatography (RPLC), hydrophilic interaction chromatography, and organic size-exclusion chromatography paired with RPLC. Key parameters for consideration during the selection and design process are emphasized.

MDCW: SCSC Poster Awards 2025 (Rick van den Hurk)

P-25: BREATH SAMPLING AND PATIENT CONSIDERATIONS FOR CLINICAL IMPLEMENTATION: A COMPARATIVE STUDY

• Thibault Massenet (University of Liège, Liège, Belgium. 2PSL University, Paris, France. 3CHU, Liège, Belgium)

This study presents a comprehensive comparison of three exhaled breath sampling methods: ReCIVA, Tedlar bags, and BioVoc. To rigorously evaluate these methods, we employed the Peppermint Initiative, a standardized protocol designed to induce a temporary alteration in the exhaled breath profile. This approach allowed us to track the washout curves of volatile organic compounds (VOCs) following the ingestion of peppermint oil. The collected samples were analyzed using two-dimensional gas chromatography (GC×GC) coupled with high- and medium-resolution mass spectrometry, ensuring detailed and robust analysis.

In addition to determining the most effective and reliable sampling technique for clinical use, this study also provides an overview of the commonly used methods, highlighting their strengths and weaknesses in a clinical context as the breathomics community moves towards standardizing collection procedures. This study is currently ongoing. 5 voluntary participants for each sampling method participated to the study. Samples were injected following strict QC protocols to ensure that variability was not instrument-related. Preliminary statistical analysis suggests that variability is induced by the sampling method, potentially linked to adsorption processes, although similar washout curves across all participants support the Peppermint Initiative as a reference for breath sampling assessments.

We also considered patient comfort and gathered feedback from hospital staff involved in sampling processes to ensure that the selected method is both analytically sound and clinically practical. The primary goal of this study is to deliver a detailed evaluation of these methods concerning their potential clinical application.

MDCW: SCSC Poster Awards 2025 (Thibault Massenet)

2:30 - 2:50 PM Closing Remarks

MDCW: Closing Remarks (Katelynn Perrault Uptmor)

MDCW: 16th MDCW 2025 (Day 3) - Pierre-Hugues Stefanuto, Dwight Stoll, Petr Vozka, Katelynn Perrault Uptmor