A Direct Mass Spectrometry Method for the Rapid Analysis
of Ubiquitous Tire-Derived Toxin N‑(1,3-Dimethylbutyl)‑N′‑phenyl‑p‑phenylenediamine Quinone (6-PPDQ)
posted on 2021-10-20, 17:35authored byJoseph Monaghan, Angelina Jaeger, Alon R. Agua, Ryan S. Stanton, Michael Pirrung, Chris G. Gill, Erik T. Krogh
The oxidative transformation product
of a common tire preservative,
identified as N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone (6-PPDQ),
has recently been found to contribute to “urban runoff mortality
syndrome” in Coho salmon at nanogram per liter levels. Given
the number of fish-bearing streams with multiple stormwater inputs,
large-scale campaigns to identify 6-PPDQ sources and evaluate mitigation
strategies will require sensitive, high-throughput analytical methods.
We report the development and optimization of a direct sampling tandem
mass spectrometry method for semiquantitative 6-PPDQ determinations
using a thin polydimethylsiloxane membrane immersion probe. The method
requires no sample cleanup steps or chromatographic separations, even
in complex, heterogeneous samples. Quantitation is achieved by the
method of standard additions, with a detection limit of 8 ng/L and
a duty cycle of 15 min/sample. High-throughput screening provides
semiquantitative concentrations with similar sensitivity and a full
analytical duty cycle of 2.5 min/sample. Preliminary data and performance
metrics are reported for 6-PPDQ present in representative environmental
and stormwater samples. The method is readily adapted for real-time
process monitoring, demonstrated by following the dissolution of 6-PPDQ
from tire fragments and subsequent removal in response to added sorbents.