Advion LC Resource GuideForever Chemicals: Liquid Chromatography for PFAS DetectionMethods and workflows for overcoming the challenges of PFAS analysisNEW REGULATIONSfor PFAS analysisBEST PRACTICESfor workflows and automationPURCHASINGquestions for LC instrumentsTable of Contents
3 PFAS Testing with Liquid Chromatography4 Questions to Ask When Buying a Liquid Chromatograph for PFAS Analysis6 LC-MS: A Powerful Tool in Unraveling the Mysteries of PFAS8 Labs Gear Up: Advanced PFAS Detection in Water Meets New Regulations2 Lab Manager
12 Exploring Options for PFAS Analysis in the LabIntroduction
PFAS Testing with Liquid ChromatographyA guide to standardized methods, workflows, and instrumentation considerations for reliable PFAS identification and quantification in different sample typesLiquid chromatography coupled to mass spectrometry (LC-MS) is the most widely used method to detect per- and polyfluoroalkyl substances (PFAS) in drinking water. As the need for PFAS analysis expands beyond water samples to include soil, tissues, and more, robust methods and workflows are needed to ensure accurate and reliable data.PFAS pose unique challenges for analysis. Often present in trace amounts, they require the high degree of sensitivity and low detection limits offered by LC/MS analysis for accurate detection. Contamination is a pervasive concern, as they can persist in LC instruments, consumables, and other laboratory items. Complex matrices, especially those contained in environmental samples like soil and wastewater, can also interfere with analysis.In 2019 the Environmental Protection Agency (EPA) released a solid-phase extraction (SPE) LC-MS/MS method for testing PFAS in drinking water. Since then, new methods have been released for analyzing PFAS in a wide range of sample matrices, including soil, groundwater, and biological tissue, among others. These standardized approaches address many challenges associated with PFAS testing.This resource guide takes an in-depth look at the role of LC in PFAS analysis, designed to help labs newly developing or expanding their PFAS testing processes enhance accuracy, efficiency, and reliability. It provides detailed insights onPFAS testing regulations, guidance on optimizing LC workflows, and important purchasing considerations for LC instruments intended for PFAS detection, with practical tips throughout and a reference chart of relevant EPA standard methods.
Questions to Ask When Buying a Liquid Chromatograph for PFAS Analysisby Lab ManagerA liquid chromatograph can be a large investment with a high total cost of ownership. Thhen selecting an instrument for PFAS analysis, there are some additional questionsto consider:1Does the instrument comply with regulatory requirements?EPA Methods are often used to test for PFAS compounds in drinking water and other environmental samples. It isimportant to ensure the LC instrument meets the regulatory requirements the EPA establishes.2What are the detection limits and sensitivity?PFAS are often present in water samples (as well as other sample types) in trace concentrations. The final National Primary Drinking Thater Regulation (NPDThR) announced in April 2024 specifies the Maximum Contaminant Levels for six PFAS in drinking water, ranging from 4.0 parts per trillion (ppt) to 10 ppt.1 The instrument must offer sufficient sensitivity to detect these compounds.3What sample types are compatible with the instrument?The first EPA Method was developed for drinking water samples. As the list of sample types grows to include soil, wastewater, biological tissues, and more, it is important to ensure they will be compatible with the instrument.4What is the throughput?Laboratories with a higher volume of samples may need to consider instruments that offer faster runtimes and higher throughput to meet demand.5What software is available?Does the software comply with regulatory requirements? Can it be integrated into data management systems and lab- oratory information management systems (LIMS)? Are there any automation features that can increase productivity?Are specialized columns available for PFAS analysis?6Reverse phase columns, Hydrophilic Interaction Liquid Chromatography (HILIC) columns, ion-exchange columns, and even specialized columns can be used for PFAS analysis. It is important to consider selectivity, sensitivity, resolution, and compatibility with detection methods when selectinga column.References:
1. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substanc-
es-pfasSustainability tipReducing injection volumes where possible can reduce the amount of solvent required for analysis.
LC-MS: A Powerful Tool in Unraveling the Mysteries of PFASPrecise analytical techniques offer a solution to this persistent problemby Magaret Sivapragasam, PhDPer- and polyfluoroalkyl substances (PFAS) are posing a "forever problem" due to their persistence in the environ- ment. Despite the known risks associated with these chemi- cals, they are still widely used in many consumer products.The most common method for testing PFAS is liquid chromatography-mass spectrometry (LC-MS). Samples containing PFAS, obtained from environmental matrices (water, soil, sediments) or biological tissues, undergo sample preparation, often through solid-phase extraction (SPE), andthen are injected into the LC system to separate individual PFAS compounds based on their chemical properties. This separation is achieved via a chromatographic column with a specific stationary phase, chosen based on the targeted PFAS compounds and the intended separation. Thithin the LC, PFAS compounds interact with the stationary phase(column) and the mobile phase (solvent). The preference of a compound for the stationary or mobile phase determines its retention time, with longer-chain PFAS compounds exhibit- ing different retention times than shorter-chain ones.Tips for choosing calibration standardsTypically, the longer a compound is retained in the col- umn, the less polar it is, facilitating the separation of PFAS compounds. The LC system then generates a chromatogram, where each PFAS compound appears as a distinct peak with an individual retention time. Specialized software is usedto analyze the data and quantify PFAS compounds. This analysis requires calibration standards with known concen- trations to ensure accurate quantification. Quality control measures such as method blanks and internal standardsare used to monitor and correct possible interferences and variability. These measures help ensure that accurate results are obtained.
Labs Gear Up: Advanced PFAS Detection in Water Meets New RegulationsHow laboratories are upgrading their PFAS detection capabilities in water to align with the latest regulatory standards for environmental safety and healthby Adam Dickie, PhDThe reach of per- and polyfluoroalkyl substances (PFAS) into water sources is emerging into stark visibility. For instance, the EPA's 2023 UCMR5 (Unregulated Contaminant Monitoring Rule) findings1 revealed PFAS in a third of major urban water systems, impacting an estimated 70 million residents2. These studies, testing just 29 out of an estimated 15,000 PFAS com- pounds, likely only hint at the full magnitude of contamination.The carbon-fluorine (C-F) bond, among the strongest in organic chemistry, endows PFAS with the ability to repel oil and water and resist degradation. Exposure to PFAS is linked to serious health outcomes, ranging from reproduc- tive issues5, immunotoxicity6, endocrine disruption7, and an elevated risk of cancer8.As the health impacts of PFAS came to light, the necessity for water testing swiftly escalated. Environmental laborato- ries, spanning both governmental entities and private sec- tors, stepped up to meet this demand. However, initial efforts to manage PFAS faced challenges due to the lack of enforce- able federal guidelines on the handling, manufacturing, disposal, and removal of these chemicals. The EPA provided only guidance, not mandatory directives. Consequently, regulatory responsibilities and certifications largely devolved to individual states, leading to a patchwork of regulations.By 2019, the EPA released Method 5339 to accompany Meth- od 537.110, providing laboratories with validated tests for 29 PFAS compounds in drinking water. Method 533 targets25 short-chain PFAS (4 to 12 carbons) using polystyrene divinylbenzene with a positively charged diamino ligand for extraction, differing from 537.1's styrene-divinylbenzenemedia. It leverages a weak anion exchange SPE cartridge and isotopic dilution for enhanced accuracy.Method 533 offers logistical benefits by reducing sample volume requirements and minimizing measurement inter- ference, streamlining the detection process. Meanwhile, Method 537.1 identifies four unique PFAS compounds beyond those covered by 533. The overlapping analytical frameworks offered to labs underscore a fundamental chal- lenge: the diverse properties of PFAS compounds necessitate specialized methods for accurate detection, especially at low concentrations. The EPA's proposed drinking water limits of four parts per trillion for perfluorooctanoic acid (PFOA) andperfluorooctanesulfonic acid (PFOS) require high-resolution techniques such as liquid chromatography/tandem mass spectrometry (LC-MS-MS).The limitations of testing methods designed solely for drink- ing water left environmental labs in a quandary for analyzing PFAS in soil, wastewater, and other samples. Enter lab-mod- ified methods, often bearing the "537M" designation, which adapted Method 537 for broader use. Though offering some consistency, these non-standardized approaches left data vulnerable to challenges.In January 2024, the EPA released Method 163311, a standard- ized approach for analyzing 40 PFAS compounds in diverse samples, including wastewater, groundwater, and fish tissue. This method, developed with extensive stakeholder feed- back, resolves the challenges of non-standardized testing and empowers labs to expand this list further.To handle PFAS in multiple matrices, Method 1633 describes a comprehensive process involving sample preparation,solid-phase extraction cleanup, and LC-MS-MS analysis. It outlines tailored procedures for aqueous, solid, and tissue samples, emphasizing homogenization, dilution, and specific reagent use for accurate PFAS extraction. Instrumental anal- ysis leverages ultrahigh-performance liquid chromatography and mass spectrometry, detailed with quality control steps for reliable PFAS quantification and identification.Thhile Method 1633 significantly improves PFAS detection accuracy and extends testing capabilities across various sam- ple types, challenges persist, particularly with complex sam- ples containing high solids. This complexity can strain labs striving to meet the method's rigorous acceptance criteria and necessitate additional resources for quality control and broader analyte characterization. Consequently, these factors might escalate both the duration and expense of analysis.Future advancements are being developed to mitigate these challenges, focusing on refining sample preparation techniques and enhancing analytical instruments for more efficient handling of complex samples. Innovations such as automated sample processing and improved SPE methods are poised to streamline the workflow, reduce potential errors, and lower analysis costs.Method Description537Determination of selected PFAS in drinking water by SPE and LC-MS/MS *(2009, since updated to 537.1)537.1 Determination of selected PFAS in drinking water by SPE and LC-MS/MS (2018/2020)8327PFAS using external calibration and MRM LC-MS/MS (2019): method for measuring 24 PFAS in non-drinking water533 Determination of PFAS in drinking water by isotope dilution anion exchange SPE and LC- MS/MS (2019)1633 Method for measuring 40 PFAS in wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and fish tissue.Other Test Method Measurement of selected PFAS from stationary sources: method for measuring 50 PFAS in (OTM)-45 air emissions from stationary sourcesOTM-50 Sampling and analysis of volatile fluorinated compounds from stationary sources using passivated stainless-steel canisters: method for measuring 30 PFAS in air emissions from stationary sources.
https://www.epa.gov/water-research/pfas-analytical-methods-development-and-sampling-researchRegarding procedural rigor, including a field reagent blank in each sample set is essential for validating the absence of con- tamination. Different methods, such as 537.1 and 533, slightly vary in handling field reagent blanks and preservatives. All bottles, whether for samples or blanks, undergo testing at the lab before distribution to confirm they are PFAS-free. Proper handling, such as not touching the inside of the bottle or lid, helps maintain sample integrity. Finally, transporting samples back to the lab in coolers with actual ice (to avoid PFAS con- tamination from substitutes) and ensuring they arrive at or below 10°C within 48 hours are critical steps.Automation and cheminformatics are revolutionizing PFAS testing, from sample preparation to data analysis. SPE robots automate extraction processes in water samples, efficient-ly handling tasks like sample loading and analyte elution. Concurrently, the analysis of PFAS, with its vast structural diversity, benefits from advanced computational tools. The re- cent development of 129 PFAS-specific fingerprints12 facilitates streamlined profiling and categorization, bypassing the need for expert input and enhancing computational models. Fur- thermore, an approach termed FluoroMatch Flow 2.013 opti- mizes the discovery process in LC-HRMS by automating data processing, employing a comprehensive confidence criterion to accurately identify PFAS compounds and reduce inaccuracies.As analytical methodologies for testing PFAS in water become more advanced and widespread, the focus will likely shift towards developing worldwide standards, ensuring con- sistency and comparability of data across borders. Collabo- rations between regulatory bodies, research institutions, and industry will be crucial in pooling resources and knowledge. The future promises innovations beyond enhanced detec- tion to solutions for its mitigation and removal, safeguarding water quality and public health.Sample collection for PFAS analysis requires meticulous attention to avoid contamination, as numerous items can introduce unwanted PFAS into samples.The following tips can help to ensure reliable sample collection.DO NOT…wear new, unwashed clothing, clothes treated for water resistance, or garments washed with fabric softenerconsume food in wrappers/packagingapply personal care products (sunscreen, insect repellent, etc.)use items with Teflon or PTFEDO…flush tap or water source before sample collectionensure preservatives are completely dissolvedcollect samples directly into designated containersReferences
Exploring Options for PFAS Analysis in the LabMethods and workflows available to analyze PFASby Scott D. Hanton, PhDDespite their prevalence, there are significant challenges in analyzing PFAS materials. Measurement must be precise and accurate, as PFAS are associated with environmental and hu- man health risks. This often requires instrumentation with very low detection limits, in parts per trillion ranges. Many labs have experience analyzing for trace contaminants and have the instruments, tools, and expertise to tackle PFAS analyses. In these situations, it will be important to learn from existing published methods and develop the appropri- ate methods and workflows to tackle PFAS analysis.If the lab has the right expertise and instruments and wants to start PFAS analysis, the Environmental Protection Agency has published some methods for the determination of PFAS in water. A good place to start would be EPA method 537.1 that specifies solid phase extraction and liquid chromatogra- phy with tandem mass spectrometry (LC-MS/MS) analysis of 18 different PFAS analytes. Another method to consider is ISO 21675:2019. It also highlights the use of LC-MS/MS toPFAS workflowsBefore a workflow can be determined, the lab must understand if the samples in question are to be analyzed for specific PFAS compounds through a targeted analysis method or for any detectable PFAS compounds through an untargeted analysis. Here are the steps involved in a typical PFAS workflow for a targeted analysis:If more specific PFAS workflows are required, LC and LC-MS vendors have them readily available on their websites. They also have application notes that can assist with developing methods specific to their instruments.deliver the required specificity and sensitivity. This method is focused on the linear PFAS isomers.Since PFAS have become persistent in the environment and present in a wide range of products, it can be difficult to eliminate them from the lab's work processes. Thork carefully with vendors of equipment, tools, instruments, and consum- ables to find options that are PFAS-free. All of the common items, such as isolator columns, tubing, solvent lines, fittings, and vials can be obtained from vendors that are sufficiently clean to use in highly sensitive PFAS analyses.For labs that see many PFAS analyses, lab automation can help reduce the burden of tedious sample preparation. Auto- mation can also improve the overall consistency and preci- sion of these experiments compared to having them done completely by lab staff. Thith the growing importance of PFAS analysis, new automated sample preparation tools have recently been developed that are consistent with EPA 537.1.As we learn more about the impact of PFAS on the environment and human health, the need for precise and accurate analyses grows. Thhile these analyses can be challenging, there are many resources available for labs taking on this important work.References:
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