News from LabRulezLCMS Library - Week 40, 2025

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This week we bring you application note by Agilent Technologies and posters by Shimadzu / AOAC, Thermo Fisher Scientific and Waters Corporation / AOAC!

1. Agilent Technologies: Comparison of Dual Sorbent Solid Phase Extraction for PFAS Applications

Using dual-phase Agilent Bond Elut PFAS WAX/ Carbon S SPE cartridges for US EPA Method 1633

• Application note
• Full PDF for download

Many laboratories have opted to combine polymeric weak anion exchange (WAX) and graphitized carbon black (GCB) into single solid phase extraction (SPE) cartridges to streamline sample preparation and facilitate automation for the determination of Per- and Polyfluoroalkyl Substances (PFAS) in environmental samples. This modification is acceptable under Section 1.5 of US EPA Method 1633, if the method's quality control metrics are met.1 The Agilent PFAS WAX and Carbon S sorbents are specifically manufactured for PFAS applications and are lot-tested to ensure low PFAS residue and maximum recovery.2,3 Packing these sorbents into standard 6 mL SPE cartridges with low PFAS residue frits makes them ideally suited for automated methods requiring both WAX extraction and carbon matrix reduction. The extraction performance of the dual-phase Agilent Bond Elut PFAS WAX/Carbon S SPE cartridges are comparable to other commercial cartridges. This ensures seamless integration into existing workflows while assuring optimal performance for PFAS applications.

Experimental 

Extraction recoveries using the Bond Elut layered 200 mg PFAS WAX (top)/50 mg Carbon S (bottom) SPE cartridges (part number 5610-2237) were compared to two other commercial 200 mg WAX/50 mg GCB dual-phase cartridges (Table 1). Four replicate extractions were performed with each sorbent, except for benchmark B, where only two replicates were extracted. The target compounds included the 40 listed in Method 1633, spiked at a low-level concentration of 4 ng/L in 250 mL of reagent water. Target recoveries were quantified using 24 isotope-labeled extracted internal standards (EIS). Extractions were carried out using automated SPE. Method details were described in a previous application note.4

Conclusion 

Dual-phase Agilent Bond Elut PFAS WAX/Carbon S SPE cartridges are specifically manufactured for PFAS applications, with rigorous lot testing to ensure PFAS cleanliness and recovery. They enable efficient streamlined sample preparation and automation for EPA Method 1633. PFAS target and extracted internal standards recoveries are comparable to other dual-phase SPE cartridges, facilitating easy integration into existing EPA Method 1633 workflows.

2. Shimadzu / AOAC: Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Drinking Water and Milk using LC-MS/MS coupled with Online-SPE Interface

• Poster
• Full PDF for download

Per- and Polyfluoroalkyl Substances (PFAS) are a chemical group of organic fluorinated compounds, and perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are representative compounds. They have been used in applications such as water repellents, surface treatment agents, fire extinguishers, and coatings. PFAS are known to be widely present in the environment and wildlife due to their stable structure. Concerns about human exposure through diet have led various countries to conduct investigations into food contamination by PFAS.

We have examined a quantitative analysis method for 43 PFAS in tap water, drinking water, and milk, and developed a pretreatment and analysis method that realized labor and time savings using LC-MS/MS and automatic pretreatment equipment (Fig.1). For extraction from milk, the QuEChERS method was used with reference to the FDA method.

Experimental

• Automatic pretreatment equipment: SPL-W100 (AiSTI SCIENCE)
• LC-MS/MS: LCMS-8060RX (Shimadzu)

Conclusion

• LC-MS/MS methods were developed to analyze 43 PFAS in 11 minutes using automatic pretreatment, saving time and labor.
• We conducted recovery tests by adding samples to tap water, drinking water, and milk, and achieved the LOQ set by EPA regulations and AOAC criteria for all compounds.
• The quantitative values of the four main components in tap water were PFOA 0.00109 μg/kg, PFNA 0.00044 μg/kg, PFHxS 0.0004 μg/kg and PFOS 0.00063 μg/kg. PFAS was not detected above the detection limit in drinking water and milk.

3. Thermo Fisher Scientific: High-Throughput and Highly Selective Quantitative Lipidomics with the Stellar Mass Spectrometer – A Novel Hybrid Nominal Mass Instrument

• Poster
• Full PDF for download

The increasing prevalence of metabolic disorders underscores the need for robust, high-throughput clinical lipid panels and lipidomics methods to quantify lipid species comprehensively, with high precision and selectivity . Structurally related lipids, with varying fatty acid composition, were associated with distinct metabolic consequences and proven to have different biological roles. Thereby, measuring individual lipid species with highest selectivity possible is crucial for corroboration of clinical utility including the improved risk prediction and diagnostics. We present an advanced methodology leveraging the unique capabilities of the new Stellar mass spectrometer. This nominal mass instrument addresses current limitations in specificity and throughput by enabling fast acquisition parallel reaction monitoring, and revolutionizing lipidomics workflows by delivering unprecedented specificity and quantitation. This system combines a quadrupole and a dual cell linear ion trap that significantly improves the ion accumulation efficiency and scan speed. This allows for the acquisition of full MS2 spectra including multiple transitions, thus improving the annotation specificity by resolving isomeric lipids and structurally similar species. This unique capacity of Stellar MS positions it as a practical solution for translational research, biomarker discovery and clinical lipidomics where rapid, sensitive and selective lipid quantitation is essential.

Materials and Methods 

Sample Preparation 

Dried UltimateSPLASH ONE internal standard mixture (100 µL) was reconstituted in 25 µL of NIST human plasma SRM 1950 followed by the addition of 125 µL of isopropanol for lipid extraction. The supernatant was then transferred to LC vials for LC-MS analysis. Linearity assessment: different volumes of Avanti Research UltimateSPLASH ONE internal standard mixture (0.5, 1, 5, 10, 50, 100, and 500 µL) were evaporated to dryness, followed by the reconstitution with 25 µL NIST Plasma and 125 µL of isopropanol for lipid extraction. 

Data Acquisition 

Plasma lipid extracts were separated on a ACQUITY Premier BEH Amide column (1.7um, 100 mm x 2.1 mm I.D., Waters) and analyzed using a targeted LCMS lipidomics approach on Thermo Scientific Vanquish Duo UHPLC system coupled to a Stellar mass spectrometer (Figure 1) 1 . This method was built from a well-established selected reaction monitoring (SRM) method that we Converted to a parallel reaction monitoring (PRM) method by using only the unique precursors. As there are many isomeric lipids sharing the same mass, converting the method for the Stellar reduced 1,019 (579 positive mode; 440 negative mode) SRM precursors to 524 (233 positive mode; 291 negative mode) PRM precursors.

Conclusions 

• By integrating LipidCreator with Stellar MS, we expanded on an already thorough lipid workflow by increasing the number of targeted lipids (>50%) and transitions (>3/molecule) enabling higher confidence in lipid identification 
• Multiple transitions per precursor, combined with fast scan speeds, enhanced both the specificity and accuracy of lipid quantification, particularly for isomeric species. 
• Employing both HCD and CID simultaneously allowed for more robust characterization of sphingomyelins seen in the 2-3 transitions per species. 
• This high throughput, targeted approach addresses key limitations and provides a efficient platform for biomarker discovery 
• Also, look for our other poster showing a high-throughput targeted MS3 approach has been optimized on the Stellar MS, for the semi-quantification of TG species in human plasma.

4. Waters Corporation / AOAC: From Coop to Carton: A Study of PFAS in Backyard & Store-Bought Eggs Using Automation and LC-MS/MS

• Poster
• Full PDF for download

Consumers often view backyard chicken eggs as a healthier alternative to store-bought eggs. However, environmental factors such as contaminated soil, water, feed, and bedding may expose backyard chickens to per- and polyfluoroalkyl substances (PFAS). This study set out to compare PFAS levels in eggs from backyard flocks with those in cage-free eggs purchased from grocery stores. The challenge was to analyze whole egg—a dense protein- and fat-rich matrix—efficiently and reproducibly. To address this, an automated sample preparation workflow was developed, reducing analyst involvement, minimizing variability, and ensuring robust results.

Methods

The workflow combined automated extraction (CEM EDGE) with automated solid-phase extraction (PromoChrom SPE-03) using dual-phase Oasis GCB/WAX cartridges designed for PFAS. Key steps included:

• Homogenizing whole eggs and spiking with internal standards.
• Automated alkaline extraction cycles followed by nitrogen-assisted concentration.
• SPE cleanup with GCB/WAX cartridges to remove matrix interferences.
• Analysis by LC-MS/MS using a Waters ACQUITY Premier system coupled to a Xevo TQ Absolute mass spectrometer.

This approach enabled preparation in less than 15 minutes per sample, while the SPE system processed up to eight samples simultaneously in under 70 minutes. Altogether, the workflow provided consistent recoveries across a broad range of PFAS, including EU-regulated compounds such as PFOA, PFOS, PFNA, and PFHxS.

Conclusions

Automated sample preparation and SPE enabled reproducible, high-throughput analysis of PFAS in whole eggs—a challenging matrix. Results showed that backyard eggs generally contained higher PFAS concentrations and a wider variety of compounds than store-bought eggs, reflecting greater environmental exposure. In contrast, grocery store eggs contained certain PFAS precursors, suggesting possible legacy contamination. The method proved robust for both regulated and emerging PFAS, with recoveries in the acceptable 70–130% range. This workflow offers laboratories a reliable, future-proof solution for PFAS monitoring in foods, helping to ensure consumer safety and regulatory compliance.