N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine, commonly known as 6PPD, is a chemical additive used in tire manufacturing for over six decades. This compound serves as an antioxidant and antidegradant, protecting rubber products from breaking down due to reactions with ozone and other reactive oxygen species in the air.
When 6PPD reacts with ozone in the environment, it forms a byproduct called 6PPD-quinone (6PPD-Q). This transformation has significant implications for aquatic ecosystems, particularly in urban areas where tire wear particles are prevalent.
In 2020, EPA-funded research linked 6PPD-Q to the deaths of coho salmon in urban Puget Sound streams. The chemical enters waterways through stormwater runoff, washing off parking lots and streets into streams and other bodies of water.
Recognizing the urgent need for detection and monitoring of 6PPD-Q, the U.S. Environmental Protection Agency (EPA) has developed Draft Method 1634. This analytical procedure aims to test for 6PPD-Q in surface water and storm water using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Key points about Draft Method 1634:
1. It was developed by EPA's Office of Water in collaboration with EPA Region 10 and Eurofins Environment Testing – Sacramento.
2. The method is designed to be "performance-based," allowing analysts to make modifications to improve performance and overcome interferences.
3. While not yet approved under 40 CFR Part 136, the draft method is available for widespread use by government agencies, Tribes, and other groups.
The release of Draft Method 1634 marks a significant step in addressing the 6PPD-Q issue. It provides an important tool for understanding storm water and surface water quality, enabling better protection for sensitive aquatic life.
EPA is actively engaged in further research, including:
- Investigating fate and transport of 6PPD and 6PPD-Q in air and water
- Studying ecotoxicity and potential mitigation strategies
- Developing draft screening values for 6PPD-Q and 6PPD in water
PromoChrom Technologies, a partner of Organomation, has developed an innovative approach to enhance the efficiency of testing for 6PPD-Q using automated solid phase extraction (SPE). Their SPE-03 system automates the extraction process following Draft EPA Method 1634.
Automated Efficiency: The SPE-03 system automates extraction steps for up to eight samples simultaneously, significantly reducing manual labor and increasing throughput.
High Recovery Rates: Using PromoChrom's proprietary reverse phase cartridges, the system achieves excellent recoveries of 6PPD-Q from water samples, meeting stringent accuracy criteria.
Versatile Application: The system supports both EPA Method 1634 for detecting 6PPD-Q and PFAS analysis on a single platform, demonstrating its versatility for environmental testing labs.
PromoChrom's advancements highlight how automation can streamline complex analytical processes while maintaining high precision and accuracy. Their contributions are vital in supporting regulatory efforts to monitor environmental pollutants effectively.
In a recent interview conducted by Organomation's General Manager, David Oliva, Jonathan Navarro, a graduate student of University of Buffalo, shared his insights on the environmental impact of tire-derived materials.
Samples were concentrated ahead LC/MS/MS by Organomation’s N-EVAP nitrogen blower. This discussion highlighted the crucial role of advanced analytical techniques in understanding and mitigating these impacts.
Understanding Tire-Derived Pollutants: Jonathan emphasized that tire-derived materials, such as 6PPD and its byproduct 6PPD-quinone, are significant environmental pollutants. These compounds are released into the environment through tire wear and can have detrimental effects on aquatic life.
Role of LC/MS/MS in Environmental Analysis: Jonathan discussed how Liquid Chromatography with Tandem Mass Spectrometry (LC/MS/MS) is employed to detect and quantify these pollutants in environmental samples. This method is particularly effective due to its sensitivity and specificity, allowing for accurate monitoring of 6PPD-quinone levels in water bodies.
Challenges and Future Directions: The interview also touched on the challenges faced in analyzing complex environmental matrices and the need for continuous method development. Jonathan highlighted that ongoing research and collaboration among scientists, regulatory bodies, and industry stakeholders are essential to develop more sustainable alternatives to current tire additives.
This interview underscores the importance of scientific innovation and collaboration in addressing the environmental challenges posed by tire-derived materials. As research progresses, methods like LC/MS/MS will continue to play a pivotal role in protecting aquatic ecosystems from harmful pollutants.