Analysis of 6PPD-Quinone in Salmon: A Simplified Sample Prep

Significance of the Topic

Monitoring 6PPD-Q in salmon is critical due to its acute toxicity in spawning streams impacted by urban runoff. Tire rubber additives oxidize to form 6PPD-Q which accumulates in waterways and has been linked to high mortality rates in coho salmon.

Aims and Study Overview

This study presents a simplified workflow for extracting and quantifying 6PPD-Q in salmon tissue. The objective was to reduce matrix interference and improve sensitivity using a streamlined sample preparation and LC MS MS analysis.

Methodology

Salmon fillet was homogenized and 2 g was extracted twice with cold acetonitrile. Extracts were combined, diluted with water, and passed through a Captiva EMR Lipid cartridge under gravity. A rinse with 80 20 acetonitrile water was collected, dried, and reconstituted in mobile phase starting conditions.

Used Instrumentation

• Agilent 1290 Infinity II UHPLC binary pump and multisampler
• Agilent thermostatted column compartment
• Agilent 6475 triple quadrupole mass spectrometer with JetStream ESI source
• Agilent Poroshell 120 EC C18 column 2.1 x 50 mm 1.9 µm
• Captiva EMR Lipid 300 mg 3 mL SPE cartridges

Major Results and Discussion

The EMR Lipid cleanup removed over 90 percent of phospholipid background compared to solvent only workflows. Using acetonitrile alone eliminated additional interference observed with ethyl acetate. A limit of detection of 3.1 pg g was achieved with 11.4 percent RSD at low levels. Calibration from 10 to 1000 pg g yielded linearity with R2 of 0.9987.

Benefits and Practical Applications of the Method

• Rapid sample preparation with gravity driven lipid removal
• Reduced matrix suppression for trace level analyte detection
• Sensitivity suitable for environmental monitoring of 6PPD-Q in aquatic tissues
• Scalable to routine high throughput analysis

Future Trends and Opportunities

• Multiplexing sample introduction via StreamSelect flow selector
• Automation of extraction and cleanup for increased throughput
• Adaptation to other tissue matrices and contaminants of emerging concern

Conclusion

The simplified acetonitrile extraction combined with Captiva EMR Lipid cleanup and Agilent LC MS MS provided a sensitive robust method for quantifying 6PPD-Q in salmon. The approach minimizes phospholipid interference, achieves low pg g detection, and is adaptable for higher throughput workflows.

References

• Brinkmann M et al Acute Toxicity of the Tire Rubber Derived Chemical 6PPD quinone to Four Fishes of Commercial Cultural and Ecological Importance Environmental Science Technology Letters 2022 9 4 333 338
• Tian Z et al 6PPD Quinone Revised Toxicity Assessment and Quantification with a Commercial Standard Environmental Science Technology Letters 2022 9 2 140 146