PFAS analysis

With deep expertise in chemical analysis and state-of-the art laboratories in the UK, RPS can provide PFAS analysis for soil, sediments, wastewater, food and animal tissues.

What is PFAS?

PFAS (Perfluoroalkyl-and polyfluoroalkyl substances) are a broad group of man-made chemicals that have been used in a wide variety of products and applications, due to their water repellent and non-stick properties. They are known as ‘forever chemicals’ because they do not break down in the environment. These chemicals are found in food packaging, cookware, cosmetics, carpets and mattresses and fire-fighting foams, to name just a few industrial applications.


PFAS sources

The history of PFAS analysis in the UK

PFAS rose to the public’s attention in the UK, in the aftermath of the 2005 Buncefield oil disaster. In order to bring this fire under control, PFOS (Perfluorooctane Sulfonate) was used as a key surfactant in hundreds of tons of firefighting foam. PFOS and PFOA were subsequently found to be present in the main aquifer below the site and further monitoring showed its presence in numerous water sources throughout the country.

In 2009, PFOS was added to Annex B of the Stockholm Convention on Persistent Organic Pollutants. Following this, measures were taken to restrict its production and use and further restriction was also proposed for PFAS substances containing C7 or C8 perfluorocarbon chains. 

In 2013 PFOS and its derivatives were added to Annex I of the Priority Hazardous Directive (2013/39/EC). The EU surface water annual average environmental quality standard (AA-EQS) was set to 0.65ng/L and applied in 2018.

The UK Environment Agency has published Soil Screening Values for PFOS of 0.014 mg/Kg (dry weight). Similarly, the UK Drinking Water Inspectorate (DWI) guidance places a tiered risk assessment approach with a trigger value of 10ng/L on PFOS and PFOA, above which further monitoring must be undertaken. This would be based on a list of 47 PFAS chemicals which include 19 of the 20 PFAS chemicals listed in the revised European Drinking Water directive.

Following large scale monitoring programmes such as UK Chemicals Investigation Programme (CIP) and data provided by the UK Environment Agency (EA), we know that PFAS chemicals are present in the majority of our surface water bodies. The EA state that in 470 fresh water bodies monitored since 2016, only 8% of sites had concentrations below the EQS for PFOS (from 0.053 ng/L to 84 ng/L), and only 3% of estuarine and costal waters monitored were below the EQS. Furthermore, from the CIP phase 2 monitoring programme which looked at 450 Waste Water Treatment Works, 90% of samples downstream of the discharge are exceeding the EQS. Most samples upstream of the works are already at the limit or exceeding the EQS.

Our expertise in PFAS analysis

The RPS Bedford laboratory was one of the first laboratories in the UK to gain UKAS accreditation for the analysis of a range PFAS chemicals following the monitoring required at the Buncefield oil terminal. Our laboratory team has been instrumental in providing analytical support during the extensive remediation and clean-up project and then providing routine monitoring.

Bedford Laboratories PFAS analysis

We have been providing ISO 17025 accredited analysis of both PFOS and PFOA as part of the UK Chemicals Investigation Programme for the last 12 years in line with EU AA-EQS targets and with limits of detection for both substances in water, down to 0.09ng/L. This is roughly equivalent to detecting a single drop of PFOS in 44 Olympic size swimming pools.

We carry out analysis of PFAS chemicals in line with the European Drinking Water Directive list of 20 and the UK Drinking Water Inspectorate list of 47 which we have now extended to include 54 targeted PFAS chemicals as 0.1ng/L.

As shorter chain PFASs  (<C7) are less retained by granulated activated carbon treatment systems, we have been providing analytical support to water companies, consultancies and university pilot trials in order to monitor a wide range of PFASs. This has helped our clients to evaluate their treatment options and understand the risks posed by other currently unregulated substances.

We have also been recently involved in the analysis of landfill leachate from open and closed landfill sites on behalf of the Environment Agency and the Department for Environment Food and Rural Affairs (DEFRA) to assess the potential risks of these forever chemicals from these sites. We can also provide analysis for soil, sediment, food and animal tissues.

Quality and experience

RPS has been accredited for the analysis of these chemicals since 2005 and has years of experience in the analysis of these chemicals at ultra-low levels including 12 years producing analysis data for the UK Chemical Investigation Programme as well as years of successful participation in external Performance Testing in schemes such as AQS, Aquacheck and Quasimeme.  RPS is also a member of the Environment Agency PFAS laboratory steering group which links into the wider European data sharing network.

PFAS analysis and compounds of emerging interest

RPS can also provide the analysis of compounds of emerging interests. For instance, Perfluoroethylcyclohexane Sulfonate (PFECHS) has been utilised extensively as a hydraulic fluid additive inhibit corrosion especially in aircraft systems. It has recently been identified as a likely source of this product in surface waters, fish and sediments in the proximity to airport facilities. As PFECHS is a technical mixture it contains over 13 constituents in varying ratios which can be determined by LC-MS/MS.

EU DWD PFAS 20 List analysis

In line with the new proposed EU council amendment to Directive 98/83/EC Annex I and III, which now includes 20 PFAS compounds and sets a Sum of PFASs limit of 0.1ug/l, this reflects the World Health Organisation’s recommendations.

Using LC-MS/MS RPS can detect sub nanogram levels of these PFAS compound in surface water, groundwater and treated effluents.

PFAS 20 List from Annex III

  • Perfluorobutanoic acid (PFBA)
  • Perfluoropentanoic acid (PFPA)
  • Perfluorohexanoic acid (PFHxA)
  • Perfluoroheptanoic acid (PFHpA)
  • Perfluorooctanoic acid (PFOA)
  • Perfluorononanoic acid (PFNA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluoroundecanoic acid (PFUnDA)
  • Perfluorododecanoic acid (PFDoDA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluorobutane sulfonic acid (PFBS)
  • Perfluoropentane sulfonic acid (PFPS)
  • Perfluorohexane sulfonic acid (PFHxS)
  • Perfluoroheptane sulfonic acid (PFHpS)
  • Perfluorooctane sulfonic acid (PFOS)
  • Perfluorononane sufonic acid (PFNS)
  • Perfluorodecane sulfonic acid (PFDS)
  • Perfluoroundecene sulfonic acid
  • Perfluorododecane sulfonic acid
  • Perfluorotridecane sulfonic acid


PFAS 54 suite including the DWI PFAS 47 List

The UK drinking water inspectorate as of the 31st December 2021 requires that all drinking water is monitored for a list of 47 PFAS compounds in order to gather further information on their levels and prevalence in UK supplies.  RPS has developed a targeted method to detect 54 PFAS compounds in one run to assist water companies and private supplies to meet this new regulatory requirement and have been granted UKAS accreditation for 48 of these PFAS at sub-nanogram levels in ground water, surface water, drinking water (non-regulatory), untreated sewage and treated sewage effluent.

List of 54 PFAS included in the standard analysis suite


CAS Reg No Description
PFBA 375-22-4 perfluoro-n-butanoic acid 
PFPeA 2706-90-3 perfluoro-n-pentanoic acid 
PFHxA 307-24-4 perfluoro-n-hexanoic acid 
PFHpA 375-85-9 perfluoro-n-heptanoic acid 
PFOA 335-67-1 perfluoro-n-octanoic acid 
PFNA 375-95-1 perfluoro-n-nonanoic acid 
PFDA 335-76-2 perfluoro-n-decanoic acid 
PFUnDA 2058-94-8 perfluoro-n-undecanoic acid 
PFDoDA 307-55-1 perfluoro-n-dodecanoic acid 
PFTrDA 72629-94-8 perfluoro-n-tridecanoic acid 
PFTeDA 376-06-7 perfluoro-n-tetradecanoic acid 
PFHxDA 67905-19-5 perfluoro-n-hexadecanoic acid 
PFOcDA 16517-11-6 perfluoro-n-octadecanoic acid 
PFBS 375-73-5 perfluoro-1-butanesulfonic acid 
PFPeS 2706-91-4 perfluoro-1-pentanesulfonic acid 
PFHxS 355-46-4 perfluoro-1-hexanesulfonic acid 
PFHpS 375-92-8 perfluoro-1-heptanesulfonic acid 
L-PFOS 1763-23-1 perfluoro-1-octanesulfonic acid 
br-PFOS                  perfluoro-1-octanesulfonic acid 
PFOS Sum L and br          perfluoro-1-octanesulfonic acid 
PFNS 68259-12-1 perfluoro-1-nonanesulfonic acid 
PFDS 335-77-3 perfluoro-1-decanesulfonic acid 
PFUnDS 749786-16-1 perfluoro-1-undecanesulfonic acid 
PFDoDS 79780-39-5 perfluoro-1-dodecanesulfonic acid 
PFTrDS 791563-89-8 perfluoro-1-tridecanesulfonic acid 
PFECHS 646-83-3 perfluoro-4-ethylcyclohexanesulfonic acid 
HFPO-DA/GenX 13252-13-6 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acd 
HFPO-TA 13252-14-7 perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid 
DONA 919005-14-4 dodecafluoro-3H-4,8-dioxanonanoic acid 
PFMOPA 377-73-1 perfluoro-4-oxapentanoic acid 
NFDHA 151772-58-6 perfluoro-3,6-dioxaheptanoic acid 
PFMOBA 863090-89-5 perfluoro-5-oxahexanoic acid 
3:3 FTCA 356-02-5 3-perfluoropropyl propanoic acid 
5:3 FTCA 914637-49-3 3-perfluoropentyl propanoic acid 
7:3 FTCA 812-70-4 3-perfluoroheptyl propanoic acid 
PFEESA 113507-82-7 perfluoro-(2-ethoxyethane)-sulfonic acid 
F-53B Major 756426-58-1 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid 
F-53B Minor 763051-92-9 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid 
4:2 FTSA 757124-72-4 1H,1H,2H,2H-perfluorohexane sulfonic acid 
6:2 FTSA 27619-97-2 1H,1H,2H,2H-perfluorooctane sulfonic acid 
8:2 FTSA 39108-34-4 1H,1H,2H,2H-perfluorodecane sulfonic acid 
10:2 FTSA 120226-60-0 1H,1H,2H,2H-perfluorododecane sulfonic acid 
FBSA 30334-69-1 perfluoro-1-butanesulfonamide 
FHxSA 41997-13-1 perfluoro-1-hexanesulfonamide 
PFOSA 754-91-6 perfluoro-1-octanesulfonamide 
N-AP-FHxSA 50598-28-2 N-(3-dimethylaminopropan-1-yl)perfluoro1hexanesulfonamide 
N-MeFOSAA 2355-31-9 N-methylperfluoro-1-octanesulfonamidoacetic acid 
N-EtFOSAA 2991-50-6 N-ethylperfluoro-1-octanesulfonamidoacetic acid 
N-MeFOSA 31506-32-8 N-methylperfluoro-1-octansulfonamide 
N-EtFOSA 4151-50-2 N-ethylperfluoro-1-octanesulfonamide 
MeFOSE 24448-09-7 2-(N-methylperfluoro-1-octanesulfonamido)-ethanol 
EtFOSE 1691-99-2 2-(N-ethylperfluoro-1-octanesulfonamido)-ethanol 
6:2 FTAB 34455-29-3 carboxyMeDiMe-3-[[(tridecaFlOct)sulfl]amino]prop amm hydrox 
6:2 diPAP 57677-95-9 bis(1H,1H,2H,2H-perfluorooctyl) phosphate 

On 7 December 2022, the European Commission introduced new limits for perfluoroalkyl substances in food that would apply from 1 January 2023 onwards. Foodstuffs lawfully placed on the market before this date, could remain on the market until their date of minimum durability or use-by date.

Limits would apply to a range of food matrices as outlined in the Annex to regulation (EC) No1881/2006 in the New “Section 10: Perfluoroalkyl substances. Limits have been set for PFOS, PFOA, PFNA and PFHxS with the maximum level applying to the sum of both the linear and branched stereoisomers.

RPS can now offer analysis of these perfluoroalkyl substances (PFAS) by Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-QQQ) and can also supply analysis of a larger range of other PFAS if required.

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