News from LabRulezGCMS Library - Week 42, 2026

Ultra Inert Focus inlet liners are designed to minimize this variability. Two internal focal points hold a bed of deactivated glass wool at a fixed position: the lower point sets wool placement, and the upper point maintains that position during use while moderating solvent-vapor expansion after injection. The result is more consistent sample introduction, reliable needle wiping, and improved injection-to-injection reproducibility, particularly for injection modes in which the sample is deposited directly onto the wool bed.^4,5 The large surface area of the glass wool also promotes more uniform heat transfer, improving the vaporization and column transfer of less volatile compounds.^1,4 

Efficient sample introduction alone does not guarantee chromatographic performance. Once vaporized, analytes can encounter exposed silanol groups and other active sites within the inlet that may contribute to adsorption, catalytic degradation, and analyte loss.^3,6 The effect is usually most apparent for acidic, basic, polar, and otherwise reactive compounds, where these interactions can produce peak tailing, reduced recovery, and poor quantitative reproducibility.^4,6 Previous studies have shown that liner surface activity can affect active compound response, calibration behavior, and sensitivity⁶ , and that improved deactivation of both the liner and the glass wool can reduce these effects.⁴ Agilent Ultra Inert technology deactivates and minimizes residual activity within the liner, reducing the analyte interactions that can compromise recovery, peak shape, and quantitative performance.^4,6 

Active compounds interact with surfaces throughout the GC/MS flow path, so overall system inertness is an important consideration when evaluating inlet liner performance.^7,8 Liner performance is therefore assessed here within the broader context of flow path inertness rather than as an isolated inlet component. Both analytical columns used in this work, Agilent J&W DB-5ms Ultra Inert and Agilent J&W DB-5Q, come from the same development path toward inert, low-bleed GC/MS columns. The J&W DB-5ms Ultra Inert is a premium phenyl arylene column, virtually equivalent to a (5%-phenyl)‑methylpolysiloxane phase, that pairs Ultra Inert surface deactivation with low-bleed chemistry.⁹ Every column is individually inertness tested with a demanding probe mixture before release^9,10, establishing a verified baseline of low surface activity that supports symmetric peak shapes, high signal-to-noise ratios, and reliable recovery for challenging semivolatile analytes such as acidic phenols, aromatic amines, and nitroaromatics.^10,11 

The J&W DB-5Q is the next generation of this premium column family, building on the DB-5ms UI design by combining Ultra Inert deactivation with ultralow‑bleed chemistry.¹² The DB-5Q phase retains DB-5ms-type selectivity, so existing 5ms-based methods and retention time libraries transfer directly¹², while the ultralow-bleed chemistry further reduces the column bleed contribution to baseline rise and mass spectral interference during high-temperature operation.^12,13 The result is high signal-to-noise performance, mass spectral integrity, fast conditioning, and durability across general-use and trace‑level applications.

Peak shape and reproducibility 

Two 4 mm open-bottom inlet liners, the Agilent Ultra Inert Focus Open (part number 5190-7107) and the Agilent Standard Deactivation Focus Open (part number 210-4004-5), were evaluated on two premium Agilent columns, DB-5ms UI (part number 122-5532UI) and DB-5Q (part number 122-5532Q), for a total of four liner and column configurations. Performance was benchmarked with 105 semivolatile target compounds representative of EPA method 8270 (Table 1), chosen for their breadth of chemical classes and analyte behaviors rather than to define an intended application. Each compound was analyzed as five replicate injections of a 50 part per billion (ppb) standard solution with helium carrier gas on an Agilent 8890 GC coupled to an Agilent 7000E triple quadrupole GC/MS fitted with a 6 mm source extractor lens.

Conclusion 

Neither the liner nor the column alone determined performance in this study; injection-to-injection precision and peak symmetry tracked the inertness of the flow path. 

• Flow path inertness drives performance. Pairing the Agilent Ultra Inert Focus Open inlet liner with the Agilent J&W DB-5Q column gave the best peak shape and precision in the study: 76.2% of peaks in the ideal symmetry window (0.9 to 1.2) and 94.3% of compounds below 5% RSD. 
• Controlled wool placement improves reproducibility. Controlled wool placement in the Ultra Inert Focus Open inlet liner, combined with deactivation via Agilent Ultra Inert technology, produced the most consistent injection-to-injection performance tested, with a mean of 2.38% RSD. 
• Active analytes benefit the most. Pairing the Ultra Inert deactivation of the Focus Open inlet liner with the next-generation inertness of the J&W DB-5Q column delivered the largest peak symmetry gains for the most surface-sensitive compounds: weak acids (70.7%), weak bases (77.5%), phenols and halogenated phenols (72%), and aromatic amines and azo compounds (92.7%). 
• Agilent J&W DB-5ms Ultra Inert remains an excellent column for EPA method 8270. Every J&W DB-5ms UI configuration delivered excellent precision across the full 105-compound list, consistent with its individually verified inertness testing, and it remains a best-in-class choice across many semivolatile and general-purpose application spaces. 
• The Agilent J&W DB-5Q column further improves performance for active compounds. As the next generation of Ultra Inert, ultralow‑bleed column chemistry, J&W DB-5Q extended the symmetry and precision gains to the analytes most likely to limit method robustness, while retaining DB‑5ms-type selectivity so existing methods and retention time libraries transfer directly. 

Together, the Ultra Inert Focus Open inlet liner and the J&W DB-5Q column give analysts a practical way to align inlet inertness with column inertness, improving reproducibility and active‑compound peak shape.

2. LECO: The Utility of Pyrolysis with Enhanced Chromatography– Time-of-Flight Mass Spectrometry for the Characterization of Nylon

• Application note
• Full PDF for download

Nylon is an engineered polymer that is synthesized through the reaction between dicarboxylic acid and diamine. It consists of a series of repeated amide groups that result in a polymer that has superior strength, durability, and abrasion resistance. Also featuring a low molecular weight and low cost of production, nylon is a popular choice within the world of polymers. Originally used as an alternative for silk, it quickly found many applications when WWII started in 1939, where it was used in textiles to create parachutes, ropes, and clothing for the war. Now, nylon can be found in anything from instruments like guitar strings to self-care products like toothbrushes. 

Modern-day consumers are given a variety of options for toothbrushes. They can pick a toothbrush with medium, soft, or even extra soft bristles. Having different options for bristle types allows consumers to make choices that are closely tailored to their oral health needs. Most consumer toothbrushes use nylon for their bristles, the exception being premium or biodegradable toothbrushes that use polybutylene terephthalate (PBT) or polyethylene terephthalate (PET). In this application note, we utilized TD/Py-GCxGC-TOFMS for the characterization of nylon in typical consumer toothbrush bristles (Figure 1).

Experimental 

Toothbrushes were purchased from local pharmacies. Sample preparation involved cutting the bristles near the base using wire cutters without removing material from the toothbrush handle. One or two bristles (approximately 5 mm in length) were placed into 60 µL quartz microtubes, which were then transferred to quartz inlet liners for analysis. 

Pyrolysis was carried out using a Pegasus BTX 4D instrument equipped with a GL Sciences Optic 4 inlet.¹ GC-TOFMS and ® GCxGC-TOFMS data were processed using ChromaTOF software with automated peak finding and spectral deconvolution for untargeted workflows, including spectral similarity searches against extensive reference libraries and mass delta (ΔM) calculations for molecular ion evaluation.

Conclusion 

The LECO Pegasus BTX 4D demonstrates exceptional capability for the characterization of polymeric materials, particularly when leveraging GCxGC-TOFMS. The enhanced chromatographic resolution and sensitivity provided by GCxGC generated rich, high quality pyrolysis spectral data, enabling robust and unambiguous characterization of key polymeric markers. In this study, characteristic markers associated with Nylon 6, Nylon 66, and polyethylene were confidently annotated from toothbrush bristles, underscoring the instrument’s suitability for real world industrial applications involving complex polymer matrices and consumer product analysis.

3. Shimadzu: Quantitative Analysis of Polycyclic Aromatic Hydrocarbons in Five Edible Oil Samples by GCMS-TQ8050NX

• Application note
• Full PDF for download

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of organic compounds containing two or more fused aromatic rings, formed primarily during the incomplete combustion of organic materials. PAHs are lipophilic organic contaminants that readily accumulate in lipid-rich foods such as edible oils and fats. Longterm exposure to PAHs increases the risk of cancer, harms the heart and lungs, and weakens the immune system. To protect consumer health, the European Commission (EU) 2023/915 has established maximum levels (MLs) for several PAHs[1] in edible oils and fats. Among all, benzo[a]pyrene (BaP) serves as the primary marker compound, while compliance is based on the sum of four priority PAHs (PAH4): BaP, benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), and chrysene (CHR) (Fig. 1). The maximum levels are 2 µg/kg for benzo[a]pyrene (BaP) and 10 µg/kg for the sum of the four marker PAHs (PAH4). For coconut oil and cocoa butter, the maximum level for PAH4 is 20 µg/kg. 

The analysis of PAHs in edible oils is challenging because the high triglyceride content and other matrix components can interfere with chromatographic analysis. Therefore, efficient sample extraction and cleanup procedures are recommended for trace-level determination. In the present study, Molecularly Imprinted Polymer Solid-Phase Extraction (MIP-SPE) was employed for extraction and cleanup. A highly sensitive GCMS/MS method was developed for 14 PAHs including regulated PAHs in five commonly used edible oils namely corn oil, olive oil, sesame oil, coconut oil and rice bran oil.

Materials and methods

The quantification of PAHs was carried out using a Shimadzu GCMS-TQ8050 NX, equipped with the HTA 2800T “all-in-one GC autosampler”. This autosampler can perform liquid injections, headspace analysis as well as Solid - Phase Microextraction (SPME).

Conclusion

A highly sensitive GC-MS/MS method was developed for the determination of 14 PAHs in five edible oils namely; olive oil, coconut oil, sesame oil, rice bran oil, and corn oil using the Shimadzu GCMS-TQ8050 NX. 

Sample preparation was performed using AFFINIMIP® SPE PAHs Molecularly Imprinted Polymer Solid-Phase Extraction (MIP-SPE) columns, which provided effective cleanup and selective extraction of PAHs from the complex oil matrix. 

The developed protocol is suitable for analyzing PAHs in complex, highly pigmented, and high-fat cooking oil matrices containing triglycerides, plant sterols, vitamins, and natural antioxidants. 

Better recoveries were obtained for the heavier PAHs across the tested oil matrices, demonstrating the reliable performance of the MIP-SPE method. The results also satisfied the criteria specified in Commission Regulation (EU) 2023/915 for PAHs in edible oils.