News from LabRulezGCMS Library - Week 35, 2024

Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 26th August 2024? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!

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This week we bring to you a posters from ASMS 2024 by LECO, Agilent Technologies, Shimadzu, and Thermo Fisher Scientific!

1. LECO: A Novel Long-Lifetime Ion Detector for GC-TOFMS and GCxGC-TOFMS with Sub-Femtogram Detection Limits

• poster / ASMS 2024

Introduction: Ion detection efficiency and fast response times are critical aspects of the ion detectors used in time-of-flight mass spectrometry (TOFMS). With modern advancements in ionization, ion optics, and ion transfer efficiency, TOFMS systems are capable of generating high ion flux onto the ion detectors. Having an ion detector that is capable of maintaining optimal performance over a long period of time while accepting high amounts of ion flux is a significant challenge in development of TOFMS instrumentation. Improvements in detector life will minimize maintenance costs and improve TOFMS user experience. A novel long-lifetime ion detector was developed in partnership with El Mul Technologies for use in LECO’s Pegasus® BTX GC and GCxGCTOFMS. The system was thoroughly evaluated for sensitivity and robustness, including longevity of the detector.

Conclusions: The Pegasus BTX GC(GCxGC)-TOFMS with a novel Long-Lifetime Ion Detector has demonstrated the following performance characteristics:

• Sub-2 fg IDL for GC-TOFMS and Sub-fg IDL for GCxGC-TOFMS
• Linear dynamic range of 5 orders of magnitude in GC-TOFMS and 4 orders of magnitude in GCxGC-TOFMS
• Robust operation: the detector bias remains consistent and BTX peak intensity remains consistent over long periods of time, even with large numbers of samples acquired and significant amounts of charge accumulation on the detector.

2. Thermo Fisher Scientific: Meeting the challenges of Dioxin analysis and more with GC-Orbitrap high mass resolution capabilities

• poster / ASMS 2024

Abstract

Purpose: Evaluate the performance of gas chromatography (GC) Orbitrap high mass resolution spectrometry for trace analysis of polychlorinated dibenzo-p-dioxins/furans (PCDD/PCDF) at current maximum allowable limits in soil according to EPA 1613 method criteria.¹

Method summary: Sample analysis was carried out on the Thermo ScientificOrbitrap Explorisᵀᴹ GC 240 mass spectrometer. A sample volume of 1.5 μL was injected for chromatographic separation using a TG-Dioxin (60 m × 0.25 mm, 0.25 μm) capillary GC column with a Thermo Scientific TRACE 1610 GC. Ion source conditions were optimized to fulfill sensitivity criteria of EPA 1613. Performance was evaluated through analysis of a raw soil extract previously analyzed using a regulatory compliant method². Quantification was performed using isotopic dilution in Thermo Scientific Chromeleon Chromatography Data System (CDS) software using the Dioxin Analyzer workflow .

Results: The Orbitrap GC mass spectrometer fulfilled the high sensitivity, mass accuracy and resolution criteria of EPA 1613 at femtogram (fg) levels within a raw soil extract. Combined with a large dynamic range (0.05 – 100 pg•μL⁻¹), the OE GC provides users with an alternative analytical approach to deliver sensitive and accurate analysis of PCDD/F while enabling laboratories to meet future analytical challenges with high resolution accurate mass data.

3. Shimadzu: Ensuring food safety through the study of potential extractables and leachables in roasted coffee packaging by ultra-sensitive Headspace GC/MS

• poster / ASMS 2024

Introduction

• The main function of food product packaging is to protect food against any contaminant. However, in some circumstances, this packaging can release possible substances that pose a risk to human health. These are extractables and leachables (E&L) compounds that migrate from materials into the product, especially under factors such as temperature, time, and solvents.
• Notably, Brazilian legislation lacks a consolidated assessment to monitor these compounds in the food industry.
• The Headspace Shimadzu HS-20 NX trap model allows the concentration of compounds, up to 10 times, in a trap material. This means that even very small traces of these contaminants can be detected and quantified accurately.
• When coupled with GCMS-QP2020 NX (Fig.1), the HS-20 NX becomes a powerful tool for identifying and analyzing potential toxic contaminants, significantly contributing to food safety and compliance with quality regulations.

Conclusion

• The use of HS-20 NX in Trap mode with GC/MS enabled the identification of over 100 compounds, comparing the spectra with the National Institute of Standard and Technology (NIST) library. Among these compounds are potential E&L substances, as well as coffee aroma components.
• This technique demonstrates high versatility and efficiency by providing high analytical sensitivity capable of identifying compounds even at low concentrations, something unachievable by conventional methods. This evolution represents a notable advancement in coffee and food quality control, enabling precise detection of essential characteristics and components to ensure the excellence of the final product and consumer health.

4. Agilent Technologies: Faster Qualitative Analysis of Essential Oils Using GC/MS with Hydrogen Carrier Gas and a Hydrogen Optimized EI Source

• poster / ASMS 2024

Introduction: Due to the price of helium (He), many laboratories are looking for alternative carrier gases for their gas chromatography/mass spectrometry (GC/MS) methods. This work describes the conversion of a GC/MS method for the identification of flavor and fragrance compounds in essential oils from helium to hydrogen (H₂). A single quadrupole GC/MS system was used with hydrogen carrier gas and an EI source optimized to provide spectral fidelity with hydrogen. To increase confidence in compound identifications, deconvoluted mass spectra and linear retention indices (RI) were searched against the NIST23 mass spectral library. A column and chromatographic conditions for hydrogen were chosen that reduce the analysis time by 2.5 times compared to the helium method and generates results comparable to helium.

Conclusions: The data presented here shows that H₂ can successfully be used as a carrier gas for flavor and fragrance analyses with the proper conversion steps.

• The choice of the 20 m x 0.18 mm id x 0.18 µm film HP-5MSUI column allowed a 2.5 times faster analysis with equivalent chromatographic resolution.
• The Method Translation calculator provided chromatographic conditions that maintained the same elution order as with the He method, resulting in excellent agreement of the RI values measured with both methods.
• The use of MassHunter Unknowns Analysis software to deconvolute spectra and search them with RI filtering against the NIST23 library significantly simplified identification of the flavor components.
• The HydroInert EI source minimized in-source reactions with H₂, resulting in higher LMS values.

For further details on this work, please see reference 3. Reference 4 provides more information on flavor components that can react with H₂ in the source, and which benefit from the use of HydroInert. Note that if He is available at an acceptable price, it is the preferred carrier for GC/MS and should be used. However, as shown in this work, H2 can be used if appropriate method adjustments are made to accommodate its use.