Fast and Sensitive Measurement of Off-Flavors in Recirculating Aquaculture Systems

Area of Science:

• Analytical Chemistry
• Aquaculture Science
• Environmental Monitoring

Background:

• Geosmin and 2-methylisoborneol (2-MIB) cause earthy off-flavors in fish.
• These off-flavors are a significant quality concern in recirculating aquaculture systems (RAS).
• Extremely low odor thresholds necessitate rapid and sensitive detection methods.

Purpose of the Study:

• To develop a novel analytical method for detecting geosmin and 2-MIB in aquaculture water.
• To achieve rapid and highly sensitive detection of these off-flavor compounds.
• To enable objective monitoring relevant to sensory perception.

Main Methods:

• Static headspace sampling combined with proton transfer reaction-mass spectrometry (PTR-MS).
• Optimized sample preparation using sodium chloride for enhanced salting out.
• Incubation at 90 °C and maximized headspace injection speed for improved sensitivity.

Main Results:

• Achieved detection limits of 19 ng·L⁻¹ for geosmin and 4 ng·L⁻¹ for 2-MIB.
• Total sample screening time of less than 10 minutes.
• Detection limits align with sensory odor thresholds, enabling quantification at relevant concentrations.

Conclusions:

• The PTR-MS method offers rapid and sensitive objective detection of geosmin and 2-MIB in aquaculture water.
• The method is suitable for routine monitoring in RAS to prevent off-flavors.
• Potential for application to other volatile compounds and aqueous analyses.