Determination of Tire Additive Transformation Products in Environmental Samples by LC-MS/MS

Analyzing Microplastics in the Environment
Oral Presentation

Prepared by A. Pierri1, J. Autajay2, P. Smith2
1 - Weck Laboratories, 14859 Clark Ave, Industry, CA, 91745, United States
2 - Weck Laboratories, 14859 Clark Ave., Industry, CA, 91745, United States


Contact Information: [email protected]; 626-336-2139

ABSTRACT

Globally, tire and road wear particles (TRWPs) are significant sources of microplastic pollution. In addition to the inherent physical accumulation of rubber fragments in the environment and biota, they can also cause harm by transporting potentially toxic compounds into the environment. Recently, researchers discovered that the transformation product of a common tire antioxidant exhibits significant toxicity to a variety of fish species, including coho salmon. This tire additive, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), transforms into the quinone (6PPD-quinone) and leaches out of TRWPs, finding its way into urban watersheds. Due to its acute mortality to fish, and the ubiquity of TRWPs in urban settings, 6PPD-quinone is commonly found in urban runoff, especially during storm events—resulting in a phenomenon dubbed “urban runoff mortality syndrome.” The relatively low LC50 for coho salmon of 790 ng/L means that sensitive monitoring methods are needed to quantify this emerging contaminant in urban environments.

In this work, we will present a method for the analysis of 6PPD-quinone and other common tire antioxidant transformation products in environmental samples by LC-MS/MS. We will discuss methods for analysis of aqueous samples, as well as sample preparation steps for the analysis of sediments. Utilizing highly sensitive and selective LC-MS/MS, reporting limits in the low ng/L range are achievable—several orders of magnitude lower than the determined LC50¬ for coho salmon and other game fish. We will also discuss the prevalence of these tire additive transformation products in urban watersheds around Southern California.