Analytical methods for the analysis of bromoform in red seaweed Asparagopsis armata and Asparagopsis taxiformis – A review

Abstract

Global warming is a significant risk to all species on this planet and is exacerbated by the release of greenhouse gases (GHG) into the atmosphere. Agricultural practices represent >20 % of the total GHG emissions with 14.6 % being ruminant livestock farming alone. The red seaweed species Asparagopsis taxiformis and Asparagopsis armata are a significant source of bioactive substances including brominated compounds that have been shown to reduce methane emission of livestock by up to 98 % when supplemented into livestock feeding regimes. Bromoform is a major contributor to the reduction in methanogenesis and can be found in remarkably high concentrations of 1–5 % in the dry mass of Asparagopsis species. The high toxicity of bromoform makes it essential for the emerging seaweed industry to accurately quantify bromoform in Asparagopsis. Bromoform quantification is normally conducted on a hyphenated gas chromatography system due to its volatility and routine quantification methods have been established for over 60 years in water and air. The complexity of the algal matrix provides a challenge for researchers and industry alike to extract and quantify bromoform in a manner that is safe, green, cost-effective and reflective of the actual concentration. This review summarises gas chromatography instrumentation and methods, non-chromatography instrumentation potentially useful for quantification, sample preparation methods, in-field analysis, and storage and stability of bromoform in seaweed.

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