Investigating chemical composition at the sea-air interface: A subsampling approach for marine surface microlayer...

Area of Science:

• Environmental Chemistry
• Oceanography
• Analytical Chemistry

Background:

• The marine surface microlayer (SML) is a critical interface regulating ocean-atmosphere exchange.
• Understanding SML chemical composition is vital due to its global impact.
• Traditional SML sampling methods are limited, requiring calm conditions and collecting thick water layers.

Purpose of the Study:

• To develop and evaluate an alternative method for SML sampling and chemical analysis.
• To enable semi-quantitative analysis of volatile and semi-volatile organic compounds (VOCs and SVOCs) in the SML.
• To overcome limitations of existing in-situ sampling techniques.

Main Methods:

• Water subsampling combined with a polycellulose-ester membrane filter for SML collection.
• Extraction of adsorbed compounds from the filter.
• Analysis using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS).

Main Results:

• The proposed method allows for semi-quantitative analysis of VOCs and SVOCs in the SML.
• Evaluated factors include sorption affinity, solute competition, and dissolved concentration vs. adsorbed load correlation.
• Demonstrated high efficiency and applicability in various sea conditions.

Conclusions:

• The developed methodology provides a more efficient and robust approach for SML chemical analysis.
• Offers lower data noise compared to traditional methods.
• Facilitates improved characterization of the SML's organic compound profile.