News from LabRulezGCMS Library - Week 28, 2026

The presentation describes the development of a chemometric workflow for advanced fuel sample analysis using GC×GC-TOFMS data. The work was carried out by the University of Washington in collaboration with Chevron Technical Center, with the goal of improving the characterization of complex petroleum-based samples. Moving from conventional GC to comprehensive two-dimensional GC increased peak capacity and chromatographic resolution, but also created the need for more advanced methods to generate reliable peak tables across many chemically diverse fuel samples.

The key method presented is a tile-based Fisher Ratio approach implemented through ChromaTOF Tile. This method identifies analytes that show statistically significant concentration differences between sample classes. Instead of relying only on peak detection or manual alignment, the workflow uses chromatographic “tiles” to reduce the impact of retention-time shifting and to capture both major and trace-level components. The study included multiple fuel classes, including hydrobate, reformate, naphtha, FCC gasoline, and blanks.

Because Fisher Ratio values alone do not directly indicate whether a compound is truly detectable, the authors added a blank-based p-testing strategy. Three blank chromatograms were used to estimate background signal distributions for each tile, and confidence intervals were then applied to determine whether each detected hit was present in individual sample classes. This produced a master peak table covering 719 hits across nine fuel sample classes. The results showed good reproducibility, with only 6.3% of classifications being heterogeneous across replicates.

Overall, the presentation concludes that the tile-based workflow can generate comprehensive and reproducible peak tables with reduced user intervention, while preserving the ability to recover trace analytes in complex petroleum samples. The approach should be broadly applicable to other complex sample types and could also be adapted using chemometric metrics other than Fisher Ratio, depending on the experimental design and analytical goals.

3. Shimadzu / ASMS: Is Your Next Sip Safe? A Simple, Rapid Method for Measuring volatile PFAS in Juices.

• Poster
• Full PDF for download

Per- and polyfluoroalkyl substances (PFAS) pollution is a growing global concern due to links with adverse health effects, many of which remain poorly understood. 1 Accurate detection and quantification are therefore essential. While PFAS analysis has traditionally focused on water, attention is rapidly expanding to food and beverages, where testing remains limited despite high stakes and increasing regulations. 2 A recent PFAS lawsuit against a juice manufacturer underscored the heightened public scrutiny of PFAS in juices, placing food safety and brand reputation at risk. 3 This study presents a Headspace Solid-Phase Microextraction– Triple Quadrupole Gas Chromatography/Mass Spectrometry (HS-SPME GC/MS/MS) method for PFAS quantitation in juices. GC/MS enables analysis of volatile PFAS unsuitable for LC/MS, while HS-SPME offers rapid analysis with minimal sample preparation in complex matrices.

Methods

A volatile PFAS analysis method was developed on a Shimadzu GCMS-TQ8040 NX with an AOC-6000 Plus multifunctional autosampler equipped with a solid phase microextraction (SPME) module (Figure 1).

Results 

The system was deemed free of contaminants and inferences. None of the target PFAS in the method blank were found in quantifiable concentration. In the study, the calibration curve for each target included at least seven calibrators. Calibration curve results showed a good linear fit for all compounds with coefficient of determination (R2 ) ≥ 0.993. The linear range and R2 of each PFAS target are shown in Table 3.

Conclusion

Overall, these results demonstrate the robustness and reliability of the method for PFAS analysis in two carton apple juices (Brands X and Y), one plastic bottled apple juice (Brand X), and a berry blend carton juice (Brand X). Given the diversity of matrices evaluated, the method may also be suitable for other beverages, including sports drinks and vitamin-enhanced waters

4. Thermo Fisher Scientific / ASMS: Enhanced sensitivity for the quantitative analysis of pesticides using a GC Orbitrap MS

• Poster
• Full PDF for download

Detection of pesticide residues in fruits and vegetables is essential for food safety, but it can be challenging in complex, highly pigmented matrices due to interferences. Orbitrap technology provides high resolution and mass accuracy, enabling confident identification of coeluting and isobaric compounds while reducing false results. Furthermore, the FS-HRAM acquisition enables simultaneous quantitation and screening within a single analysis with the capability of retrospective data analysis, allowing laboratories to reprocess datasets for additional or emerging compounds without re-injecting samples. The Orbitrap Exploris GC S mass spectrometer features the Thermo Scientific NeverVent Advanced Electron Ionization Source (NVAEI) which offers an improved design providing enhanced sensitivity and robustness, allowing for increased instrument uptime and maximized sample throughput for rapid return on investment (ROI).

Materials and methods

Data analysis 

Data was acquired, processed and reported using the Thermo Scientific Chromeleon Chromatography Data System (CDS) software, which provides integrated instrument control, automated workflows, and an intuitive interface for data analysis, customizable reporting, and compliant data management in accordance with FDA 21 CFR Part 11 and European Commission (EU) Annex 11. Its advanced reprocessing capability streamlines sequence setup, data review, and reporting offering the possibility to easily flag and check compliance with the current regulations.

Results Compliant analyte identification The use of HRAM-GCMS reduces the matrix interferences ensuring a confident and selective identification of analytes (Figure 1). All target compounds satisfied the SANTE criteria at the default MRL of 10 µg/kg and more than 90% were confirmed at concentrations of 1 µg/kg following the SANTE/11312/2021v2026 guidance criteria of: 

• two ions were detected for each pesticide with mass accuracy ≤ 5 ppm with precursor and product ions in the extracted ion chromatograms fully overlapped, 
• due to the added value of accurate mass measurement, matching ion ratios is not necessary, however, an ion ratio (IR) deviation within ± 30% (relative) of the average of calibration standards from the same sequence was considered to provide additional support for identification
• retention times (RT) within a tolerance of ± 0.1 minutes

Sensitivity performance (IDL) and analytical linearity Instrument sensitivity was evaluated using calculated IDLs derived from replicate injections of low-level, matrix-matched standards. The Orbitrap Exploris GC S demonstrated detection limits at levels at or below 0.5 µg/kg for most of the investigated pesticides (Figure 2). Linear dynamic range was evaluated using matrix-matched calibration curves ranging 0.5–200 µg/kg, with each calibration level injected in triplicate. All target analytes demonstrated excellent linearity, with coefficients of determination (R²) > 0.993, response factor (%RSD) values below 20% across the calibration range, and ion ratios (IRs) within ±30% of the average calibration standard values. System suitability for quantitative analysis was confirmed by calculated concentrations within ±20% of expected values and recoveries ranging from 96% to 104%. An example of calibration curve for Aldrin is shown in Figure 3.

Conclusions 

The results obtained in these experiments demonstrate that the Orbitrap Exploris GC S mass spectrometer equipped with NeverVent AEI ion source represents a reliable tool for analysis of pesticides in complex matrices. 

• The Orbitrap Exploris GC S offers a simple approach for the multiresidue analysis of pesticides allowing for full-scan acquisition combined with high mass resolving power 
• The NeverVent AEI ion source is designed for ultra-trace concentration detection, making it ideal for challenging applications ensuring detection limits at levels at or below 0.5 µg/kg for most of the investigated pesticides 
• Confident identification of compounds can be easily achieved through i). high spectral quality, ii). high spectral fidelity, ensuring consistent spectrum independently from concentration, and iii). consistent mass accuracy irrespectively of analyte concentration and time 
• System suitability for quantitative analysis was demonstrated with R2 >0.993, RF %RSD across the entire calibration curve < 20, and IRs within ± 30% of the average of calibration standards, calculated amounts within 20% the expected values, and percentage recovery (%) ranging from 96 to 104.