Pulse sequencing promotes analytical capability of electro-optical ENVIR-OGT technology for compliance-level detection of PFAS in drinking water in the field
The Environmental Working Group (EWG), relying on data from the Safe Drinking Water Information System and the Department of Defense report Addressing Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA), and Department of Defense public records, estimates that at least 9,728 US locations across all 50 states and two US territories have detectable perfluoroalkyl and polyfluoroalkyl substances (PFAS) contamination.¹ Industrial-scale production of organofluorine chemicals began in the 1940s; while the carbon-fluorine bond conferred unique performance, large-scale disposal was never engineered, leaving at least 49 PFAS-contaminated Superfund sites in the United States.²
Litigation has produced billions of dollars in settlements – 3M’s $850m Minnesota settlement (2018) and $10.5–12.5bn nationwide public water systems framework (2023), DuPont/Chemours/Corteva’s $1.185bn water-systems settlement (2023), and Tyco Fire Products’ $750 million settlement (2024) – making PFAS one of the most expensive environmental liability classes in US history.³ The Environmental Protection Agency (EPA) and the National Institute for Environmental Health Sciences (NIEHS) have confirmed there is currently no instrument for real-time, field detection of individual PFAS at compliance-relevant concentrations.⁴
Scientific and regulatory context
The National Academies of Sciences, Engineering and Medicine (NASEM) has established a tiered framework and clinical guidelines for evaluation of risk of serum PFAS concentrations:
Below 2 ng/mL serum, adverse health effects are generally not expected. Within 2–20 ng/mL, potential risks exist, particularly for sensitive populations like pregnant women, infants, and diabetic individuals. Clinicians are advised to focus on reducing exposure and screening for dyslipidemia (cholesterol issues) and hypertensive disorders in pregnant females. Above 20 ng/mL, the risk of adverse effects increases further. Each doubling of serum PFAS levels is associated with a 54-70% increased risk of cancer.⁵
Almost 100% of the US population is exposed to at least one PFAS.⁶ The role of PFAS bioaccumulation for continued exposure has not been fully comprehended. PFAS drive carcinogenesis through indirect, non-mutagenic mechanisms – PPAR activation that alters lipid metabolism, endocrine disruption of estrogen/androgen/thyroid signalling, epigenetic silencing of tumour-suppressor genes, and enhanced cancer-cell motility.⁷ In July 2022, the NASEM called for expanded PFAS testing for people with a history of elevated exposure, and offers advice for clinical treatment. Testing for exposure to PFAS should be offered to patients who are likely to have a history of elevated exposure – such as those exposed to PFAS through their work or who live in areas with known PFAS contamination.5,8
In keeping with the risk of PFAS carcinogenesis and Centers for Disease Control and Prevention (CDC) monitoring critical PFAS, on 10 April, 2024, the U.S. Environmental Protection Agency (EPA) announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS.⁹ At least 39 states have introduced legislation addressing PFAS, with over 350 bills across the US. Because federal rules vary, state-level regulations are a fast-moving patchwork targeting drinking water, consumer products, firefighting foam, and industrial discharge.10 For example, the state of New Jersey’s maximum contaminant levels of perfluorononanoic acid (PFNA), PFOA, and PFOS in drinking water are 13, 14, and 13 nanograms per litre (ng/L), respectively.11
Why current tools fail regulation compliance
Although PFAS detection currently exists, detecting PFAS at nanomolar concentrations in aqueous solution is limited, costly and time-consuming because conventional, gold-standard detection instruments use a liquid chromatography electrospray-ionisation (or tandem) mass spectrometry (LC-MS/MS) based detector.12 These systems are capital-intensive, starting at approximately $590,000, with multi-year maintenance contracts adding roughly $300,000 over the instrument’s service life.13 The Wisconsin State Lab of Hygiene lists an EPA 537.1 (18 compounds, drinking water) analytical cost of $680 total with turnaround times ranging from 5-25 business days.14
The ENVIR-OGT breakthrough
The ENVIRonmental Optically Gated Transistor (ENVIR-OGT) is a non-destructive optically-gated transistor (OGT) chemical detection system. The system uses optical gating to modulate electrical current through the semiconductor in response to chemical interactions at the sensor surface.15 With the ENVIR-OGT, resultant electrical changes depend strongly on the type of chemical on the surface – measuring characteristics of functional groups, chain lengths, and isomerism of hydrocarbons and PFAS molecules.15
Fig. 1 shows the ENVIR-OGT semiconductor chip, and Fig. 2 shows the schematic illustration of the features of the ENVIR-OGT sensor. In typical field use, a utility operator can carry the device on-site and obtain a result before leaving the location. The test solution is dispensed onto the ENVIR-OGT surface adjacent to the drain electrode (contact region highlighted by the LED light circle in Fig. 1) using an adjustable-volume single-channel PFAS-free certified micropipette. Light (of specific wavelength) pulse sequences may be initiated immediately after droplet placement. Each measurement was performed on a new device. Data obtained from the measurement are saved for subsequent remote analysis.15
Remotely performed by two-way internet-enabled data traffic from the measurement site to our database at Pearlhill Technologies, and online response to the device, qualitative analysis is achieved by machine learning (ML) classifiers applied to transient-response fingerprints generated through structured pulse-sequence interrogation. This process produces the confusion matrix. Chemical identification is performed by classifiers trained to interpret chemically specific transient fingerprints, which enables identification of the trained chemicals in a mixture of PFAS – including complex or unknown mixtures. Quantitation and analytical validation are based on a calibration algorithm developed at Pearlhill based on training data from several thousand related previous measurements.15
Our algorithms will also be used to develop our future software as a service (SaaS) offering that will provide users with a robust, cloud-native architecture that combines high-performance storage, real-time data ingestion, and advanced ML pipelines for large-scale data management to support machine learning (ML) and detection. Our SaaS uses distributed databases for scalability, implements multi-tenant data isolation, and adopts automated data pipelines for continuous model training. Our SaaS model would communicate pulse-sequence interrogation protocols to the control circuitry and analyse the resulting transient-response fingerprints using stored detection models.
Competitive landscape
Table 1 shows the commercially available sensors for field detection of PFAS. It summarises publicly available information to show the advantages of Pearlhill’s ENVIR-OGT PFAS sensing platform. Most direct competitors, with different sensing technologies, have a greater focus on the PFAS remediation market.
Pearlhill’s mission is to deliver ENVIR-OGT sensor as the first-in-class portable device for regulation-concentrations detection of individual PFAS in drinking, water, groundwater and reuse water. Our outcome will accelerate biomonitoring of the population, and develop newfound understanding of their toxicity and widespread presence in water, food, and consumer products. This differentiation underpins Pearlhill’s commercial strategy.
ENVIR-OGT measurements could be used for modelling fingerprint patterns for known PFAS molecules, which could result in the future ability to identify new compounds that are not listed in current EPA Methods for analysing 55 PFAS compounds. Pearlhill is discussing our yet-to-be-published breakthroughs with the NIH programme/procurement managers and other stakeholders.
ENVIR-OGT is sensitive to the number of carbon atoms in a chain (homologs), small structural differences (isomerism), and functional group differences among analyte molecules in ultralow ppt concentrations. ML training accuracy and selectivity for ultra-low concentrations of PFBA (C4F9COOH), PFPeA (C3F7COOH), PFHxS (C6F13SO3H), PFOA (C8F17COOH), and PFOS (C8F17SO3H) measurements are achieved at 95% accuracy in pure single-sample solution and are maintained in complex real-world samples.15 We developed a machine learning model for accurate quantitation of PFAS at 1- 100 ppt and a sub-ppt minimum quantitation limit (MQL).
EPA Methods 533 (ground water and drinking water), 537.1 (drinking water), and 1633A (surface water and waste water) rely on liquid chromatography with tandem mass spectrometry (LC-MS/MS).20 A recognised limitation of electrospray ionisation is in-source fragmentation of long-chain (C6–C9) PFAS – including PFHxS, PFHpA (C7F15COOH), PFOA, and PFNA (C9F19COOH) – into C2–C4 daughter ions. These daughter ions can co-elute with native short-chain PFAS, complicating quantitation and requiring additional confirmatory analysis. ENVIR-OGT addresses this limitation through a nondestructive electro-optical measurement that resolves each PFAS molecule individually based on its intrinsic electrical response. In validation studies, ENVIR-OGT has measured C2–C4 PFAS independently of co-present C6–C9 species.15
There are analytical techniques that are ‘targeted’ and ‘untargeted’ for chemical detection. In other words, you need to tell LC-MS/MS the chemical you’re trying to find – it is targeted. Our ENVIR-OGT technique can be untargeted (like IR or NMR). One thing about LC-MS/MS is that it is very sensitive to the matrix that the sample is in. The protocols for LC-MS/MS analysis at commercial analytical laboratories cannot measure PFAS in methanol matrix below 100 ppt. The ENVIR-OGT can measure in methanol, water, and other media.15
Strategic opportunity
Building on Innovation News Network’s earlier coverage of the ENVIR-OGT breakthrough in May 2026, we have decided to introduce their readers to our business.15d
Pearlhill Technologies and Boise State University collaborated to jointly invent and patent the ENVIR-OGT through strategic collaboration in 2025.15 This invention is patent-pending, and some results from subsequent reduction to practice were published.21 Pearlhill has an exclusive license for the entire IP. The IP covers ENVIR-OGT sensing, analytical validation of measurements, and destruction of PFAS.15 The co-authors on the patent are Professor Kris A. Campbell of the Department of Electrical and Computer Engineering at Boise State University; Dr Bamidele A. Omotowa, a fluorine analytical chemist, and Dr Olaoluwa M. Omotowa, MD – both with Pearlhill Technologies LLC. Dr Bamidele Omotowa, author of this article, is co-founder and President of Pearlhill Technologies LLC, in Idaho Falls.
ENVIR-OGT can perform qualitative analysis to sub-ppt minimum detection limit (MDL), quantitative analysis with sub-ppt minimum quantitation limit (MQL), and is useful for field monitoring or real-time tracking of PFAS concentration in treatment processes. Pearlhill is working on making the prototype available to our partners sometime in 2027, and to commercialise it for field measurement and monitoring at water works, utilities, reuse facilities, and treatment plants by early 2028. Field measurements will advance epidemiological research understanding about PFAS exposure and human health, and make important contributions to advancing USEPA policy on the limit of PFAS content of drinking water.
Pearlhill is seeking new pilot partners, utility validation partnerships, and strategic investment to deploy the prototype across wider applications. We plan to test our prototype and machine learning training capability in different samples from various environments that could highlight the integrity and accuracy of ENVIR-OGT measurement in the presence of new interferences in complex samples. We seek new partnerships in water reuse, water treatment, water filter industries, utilities, groundwater around known PFAS-contamination sites, landfill leachates, and remediation operations. We already have a strategic partnership with the Pilot and Research Center (PARC) of the South Platte Renew in Englewood, CO – a water reuse facility, and another with Battelle Energy Alliance for the development of our methods for analytical validation towards compliance.
We are exploring wider collaboration with research epidemiologists, governments, and environmental monitoring companies that monitor personal exposure to complete population studies. Health professionals depend on reliable and accurate information from these sources to then develop effective policies and interventions to protect public health. We are aiming for a partnership with the National Cancer Institute’s (NCI) Division of Cancer Epidemiology and Genetics (DCEG), specifically its Occupational and Environmental Epidemiology Branch (OEEB), to identify, quantify, and correlate cardiovascular and cancer incidence with PFAS exposure in rural and urban America. We are in search of a partnership to develop personal chemical exposure monitors (PCEM) for occupational safety, and also to influence PFAS-related data on the CDC’s annual National Health Interview Survey (NHIS).
We also seek opportunities for subcontracting and deployment of ENVIR-OGT in large remediation and environmental programmes where PFAS is one contaminant among several. Our portable device could screen sites faster, sort likely positive from likely negative samples, reduce unnecessary sample transport, and focus confirmatory lab testing, for prime contractors at large DoD hazardous waste and remediation contracts, including Bavaria Hazardous Waste, United Kingdom Hazardous Waste Disposal, Anniston Hazardous Waste Removal, Puerto Rico Hazardous Waste Disposal, North Florida Regional Hazardous Waste Removal, and the Environmental Remedial Action Contract, etc.
References
https://www.ewg.org/interactive-maps/pfas_contamination/
(a) https://www.epw.senate.gov/public/index.cfm/superfund-sites-identified-by-epa-to-have-pfas-contamination; (b) https://www.epw.senate.gov/public/index.cfm/2020/5/carper-epw-democrats-ask-epa-to-share-its-plan-to-address-pfas-contamination-at-superfund-sites; (c) https://www.padilla.senate.gov/press-releases/gao-report-confirms-pfas-cleanup-cost-will-increase-significantly-calls-on-pentagon-to-release-full-cost/; (d) https://www.ewg.org/news-insights/news-release/2021/06/gao-forever-chemicals-cleanup-costs-defense-department-sites; (e) https://www.ewg.org/news-insights/news-release/spending-bill-provides-nearly-300-million-address-forever-chemicals; (f) Park, S. K.; Peng, Q.; Ding, N.; Mukherjee, B.; Harlow, S., Environ. Res. 2019, 175, 186-199; (g) FACT SHEET: Biden-Harris Administration Launches Plan to Combat PFAS Pollution | The White House; (h) https://www.federalregister.gov/documents/2024/04/26/2024-07773/pfas-national-primary-drinking-water-regulation
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(a) Pesonen, M., Vähäkangas, K., Arch Toxicol. 2024, 98, 1241-1252; (b) Ferguson, E.J., Tessmann, J.W., Zaytseva, Y.Y., Front Toxicol. 2026 11, 1768277, (c) Boyd, R.I.; Ahmad, S.; Singh, R.; Fazal, Z.; Prins, G.S.; Madak Erdogan, Z.; Irudayaraj, J.; Spinella, M.J., Cancers 2022, 14, 2919; (d) https://ysph.yale.edu/news-article/yale-study-forever-chemicals-promote-cancer-cell-migration/
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Rodriguez, K. L.; Hwang, J. H.; Esfahani, A. R.; Sadmani, A. H. M. A.; Lee, W. H., In Recent Developments of PFAS-Detecting Sensors and Future Direction: A Review, Micromachines 2020, 11, 667
Agilent 6495Triple Quadrupole MS 2023 System Cost to Stanford University. https://taggs.hhs.gov/Detail/AwardDetail?arg_AwardNum=S10OD034374&arg_ProgOfficeCode=205
Wisconsin State Laboratory of Hygiene November 1, 2025 public prices. https://www.slh.wisc.edu/environmental/pfas/
(a) Voss, K., Omotowa, B. A., Omotowa, O. M., In Environmental Chemical Detection with the Optically Gated Transistor (ENVIR-OGT), U.S. Pat. No. US2026/0063588 A1, 2025; (b) Omotowa, B. A.; Omotowa, O. M., In Electro-optical Analytical Validation Method and System Using Detection Matric for Chemical Substance Identification, U.S. Pat. pending, 2026; (c) https://www.boisestate.edu/news/2026/05/04/breakthrough-technology-detects-forever-chemicals-faster-cheaper-and-at-trace-levels-on-site/; (d) https://www.innovationnewsnetwork.com/boise-researchers-pioneer-portable-pfas-detector/69524/, (e) Pearlhill Technologies LLC/BSU Project Report for Phase I NIH STTR Award No. 1R41ES037570-01
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Please Note: This is a Commercial Profile
This article will feature in our upcoming July PFAS Special Focus Publication.
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