Analysis of Per- and Polyfluoroalkyl Substances in Wastewater Using EPA Method 1633 with Improved
Instrumentation
Automated EPA Method 1633: Automation of PFAS Analysis in Drinking & Wastewater
Automated EPA Method 1633 is a groundbreaking analytical approach for detecting and quantifying per- and polyfluoroalkyl substances (PFAS) in various environmental matrices, including drinking water, wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and fish tissue. The method was introduced in early 2024 to address the growing need for robust, efficient methods to monitor PFAS contamination in the environment. The automation of sample preparation and analysis within EPA Method 1633 significantly enhances the speed, accuracy, and reproducibility of PFAS detection.
PFAS are a group of human-made chemicals characterized by perfluorinated or polyfluorinated carbon chain structures, typically represented as F(CF2)n or F(CF2)n-(C2H4)n. Due to their unique properties, such as resistance to heat, water, and oil, these substances have been widely used in industrial and consumer products, including stain-resistant coatings, firefighting foams, food-contact paper products, and more.
Notable PFAS compounds like perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been detected in a wide range of environments due to their widespread use. Their persistence in the environment and potential risks to human health have led to increased regulatory scrutiny and efforts to monitor their distribution.
To support the ongoing efforts to monitor PFAS, EPA Method 1633 offers a reliable and standardized procedure for sample preparation and analysis, enabling the detection of a broad range of PFAS compounds in environmental samples. The method is part of a comprehensive effort by the EPA to address PFAS contamination, with official guidance available through resources such as the EPA 1633 Method Overview, which outlines the details of the analytical method.
As the concerns surrounding PFAS contamination in wastewater and other environmental matrices continue to grow, it’s essential to understand the sources and pathways of these substances. EPA Method 1633 plays a key role in identifying and quantifying PFAS in wastewater, a critical step in mitigating the risks posed by these substances. You can learn more about PFAS contamination in wastewater in the official EPA PFAS in Wastewater page.
The widespread use of PFAS across industries has led to their presence in wastewater, which serves as a significant source of PFAS contamination. Sources of PFAS in wastewater can be traced back to various industries, including those involved in firefighting, textile manufacturing, and food packaging. For a deeper dive into the sources and risks of PFAS contamination in wastewater, the EPA Source and Risk in Wastewater page provides valuable insights.
With the help of EPA Method 1633, the automated process for analyzing PFAS provides a more effective, efficient approach for environmental monitoring and the assessment of PFAS risks. As regulatory agencies continue to explore ways to manage PFAS contamination, the role of EPA Method 1633 in offering a standardized, automated solution is a critical advancement.
For detailed information on EPA 1633 Sample Preparation, refer to the EPA PFAS Sampling and Preparation Techniques page, which offers guidance on how to prepare samples for accurate PFAS analysis using the EPA 1633 method.
Automated Extraction System Overview
The TurboTrace® system has been designed to facilitate the extraction and analysis of wastewater. This has been accomplished using two dispensing and vacuum pumps. The vacuum pump enables the system to draw samples directly into the cartridge, while the positive pressure pump ensures precise dispensing of different solvents with an accurate flow rate and volume.
The TurboTrace® PFC SPE system automates the solid-phase extraction (SPE) process, streamlining the preparation of per- and polyfluoroalkyl substances (PFAS) from various liquid matrices, including drinking water, groundwater, wastewater, milk, and beverages. It is designed to handle sample sizes ranging from 2 mL to 8 liters, using the original sample bottle collected in the field. The modular system can process up to eight samples simultaneously, significantly improving laboratory efficiency and throughput.
Automated Extraction Steps:
- Cartridge Conditioning: The SPE cartridge is conditioned with solvents to prepare the sorbent material for optimal analyte retention.
- Sample Loading: The vacuum pump draws the sample directly into the conditioned cartridge.
- Sample Bottle Rinse & Loading to Cartridge: The system rinses the sample bottle to ensure complete analyte transfer onto the cartridge.
- Cartridge Drying: A nitrogen stream or vacuum removes residual water to prepare the cartridge for elution.
- Elution: The positive pressure pump precisely dispenses solvents for efficient elution of target analytes.
Method:
• Eight synthetic wastewater samples (500 mL) spiked with native PFAS standards and relevant internals
• Load sample bottles onto system and install cartridges
• Rinse bottles are automatically filled during procedure
• Use positive pressure (nitrogen) for pumping solvents and mixes through the system and use vacuum to load the samples
• Condition cartridges with 15 mL 1% methanolic ammonium hydroxide followed by 5 mL of 0.3M formic acid.
• Load samples across the cartridges at 5-10 mL/min (vacuum ~ 8-inch Hg).
• Sample bottles rinsed with 5 mL reagent water (twice) followed by 5 mL of 1:1 0.1M formic acid/methanol and load rinses across the cartridges.
• Dry 10 min.
• Rinse sample bottles with 5 mL 1% methanolic ammonium hydroxide.
• Load rinses across cartridges and collect in polypropylene tubes
• Cleanup over 10 mg of loose carbon
• As per the method no further concentration is carried out.
• Further relevant standards were added prior to LC/MS analysis.
Instrumentation:
• FMS Turbo Trace PFC™ System The system is modular in nature and can be
extended to a total of 4 modules for a total of 8 samples processed in parallel.
• Vacuum pump
• Agilent 6475 TripleQuad LC/MS Consumables
Consumables:
• Agilent Bond Elut PFAS WAX 150mg cartridges (# 5610-2150)
• Ultrapure DI water
• Methanol pesticide grade, Formic acid, Ammonium Hydroxide
• Relevant PFAS spiking standards
Analysis:
■ Take aliquot from final 5 mL extract (Method
1633 does not require volume reduction of final
extract)
■ Agilent 1290 Infinity II LC System
■ Agilent 6475 Triple quad LC/MS
■ Agilent Zorbax Eclipse Plus C18 column 3.0 x
50 mm, 1.8 um
■ Column temperature 40 oC
■ Injection 5.0 uL
■ Mobile phase 5 mM ammonium acetate in 95%
water, 5% acetonitrile (A) and methanol (B)
■ Gradient
0 min 98% A 2% B
0.2 min 98% A 2% B
10 min 5% a 95% B
■ Stop time 12.2 min
■ Dynamic MRM negative electrospray
■ T (gas) = 230 oC
■ T (sheath) = 355 oC