Microplastics, per- and polyfluoroalkyl substances (PFAS), and other emerging pollutants persist in the environment, accumulate in food chains, and can harm ecosystems and human health at very low concentrations. For example, microplastics can transport other pollutants, and PFAS are linked to endocrine disruption, immune suppression, and increased cancer risk. These hazards make it essential for laboratories to detect these substances at ultra-trace levels, differentiate structurally similar compounds, and process samples quickly to meet regulatory demands.
To address these needs, this article draws on insights from the High Performance Liquid Chromatography (HPLC) 2025 conference that took place in Bruges in June 2025. Advances in PFAS detection, microplastics characterization, non-targeted screening, and sustainable chromatography were presented at the conference, with a focus on improving limits of detection (LOD), handling complex matrices, and integrating automation without sacrificing reproducibility.
Microplastics Testing Methods and Analytical Challenges
Microplastics vary in size, morphology, and chemical composition, complicating their separation and quantification.
Recent approaches to microplastics analysis combine:
- Size fractionation via asymmetric flow field-flow fractionation (AF4) or other field-flow separation prior to detection
- Liquid chromatography coupled with high-resolution mass spectrometry (LC–HRMS) to identify polymer additives, degradation products, and adsorbed contaminants
- Pyrolysis with gas chromatography and mass spectrometry (Py-GC/MS) for polymer backbone identification
Effective sample preparation strategies may involve multi-step filtration, enzymatic digestion to remove organic material, and density separation using saturated salt solutions, ensuring cleaner extracts for more accurate downstream analysis.
Regulatory context: The European Union (EU) Drinking Water Directive Annex I and proposed Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) amendments will require validated methods with defined recovery criteria (>70%) and reproducibility (relative standard deviation <15%).
PFAS Detection Techniques for Environmental and Food Safety Analysis
PFAS analysis demands ultra-trace quantification, including LODs in the low nanogram per liter or sub-nanogram per liter range, and isomer separation.
Common method elements include:
- Weak anion-exchange solid-phase extraction (SPE) for pre-concentration from water or food extracts
- Liquid chromatography with tandem mass spectrometry (LC–MS/MS) in negative electrospray ionization (ESI) mode, using multiple reaction monitoring (MRM) for quantitation
- High-resolution mass spectrometry (HRMS) for non-target PFAS screening and isomer profiling
- Matrix-matched calibration to minimize suppression from co-extracted organics
These capabilities demonstrate continued progress in refining PFAS detection workflows to improve precision, recovery, and overall reliability in complex environmental and food safety analyses.
Regulatory context: Compliance with United States Environmental Protection Agency (EPA) Methods 533 and 1633 or International Organization for Standardization (ISO) 21675 requires method detection limits <5 ng/L for priority PFAS.
Non-Targeted Screening of Emerging Contaminants
Emerging contaminants are chemicals or materials that are not yet widely regulated or routinely monitored but are increasingly recognized for their potential environmental and health risks. These may include pharmaceuticals, personal care products, plasticizers, flame retardants, and endocrine disruptors.
Non-targeted screening is particularly valuable for emerging contaminants because it allows laboratories to detect unexpected or previously unmonitored compounds without pre-defining target analytes. By capturing a broad range of chemical signals, it supports comprehensive risk assessment and discovery of new threats.
Such workflows often employ:
- LC–HRMS with full-scan acquisition
- Data-independent acquisition (DIA) for comprehensive fragmentation coverage
- Retention time prediction models and isotopic pattern matching for candidate filtering
- Suspect lists curated from regulatory databases such as the United States Environmental Protection Agency CompTox Chemistry Dashboard and the EU Watch List
Advances in data processing and machine learning are increasingly being applied to non-targeted workflows, helping to improve confidence in identifications and reduce the likelihood of false positives in suspect screening.
Regulatory context: The European Food Safety Authority (EFSA) and the United States Food and Drug Administration (FDA) guidance increasingly require inclusion of transformation products in residue monitoring programs.
Automated and Miniaturized Sample Preparation in Environmental Analysis
In many cases, the effectiveness of pollutant detection methods depends heavily on the quality of sample preparation. At HPLC 2025, notable innovations in this area included:
- Fully automated SPE platforms with online column switching to LC–MS
- Miniaturized extraction formats
- Electromembrane extraction (EME) for polar analytes
- Microfluidic sample preparation for high-throughput screening of food and environmental matrices
These innovations illustrate a broader shift toward more efficient and reliable sample preparation practices, aimed at supporting high-quality analytical results and greater operational efficiency in the laboratory.
Regulatory context: ISO/IEC 17025 accreditation requires documented validation of recovery, repeatability, and matrix effects for each target analyte.
Green Chromatography and Sustainable Laboratory Practices
The next step in strengthening environmental and food safety workflows is ensuring they are sustainable and resource‑efficient. Sustainability-focused method development at HPLC 2025 emphasized:
- Microbore and capillary liquid chromatography formats, reducing mobile phase usage
- Alternative aqueous-rich mobile phases to replace high-organic content separations
- Life-cycle assessments for consumables and columns to quantify environmental impact
Adoption of these methods can cut annual solvent costs while supporting corporate sustainability targets.
Regulatory context: While not mandated, adherence to green chemistry principles is promoted under the Organisation for Economic Co-operation and Development (OECD) and EU Green Deal frameworks and is increasingly favored in public tenders.
Advancing Environmental and Food Safety Testing Through Innovation
HPLC 2025 confirmed that advances in LC–MS, automated preparation, and data analytics are equipping labs to meet rising demands in environmental and food safety testing. By combining robust sample preparation, sensitive and selective analysis, and compliance with evolving regulatory requirements, laboratories can achieve both technical excellence and operational efficiency.