Development of an analytical method for the quantification of bromoform in milk using gas chromatography-mass...

Enteric methane production by ruminants contributes significantly to global greenhouse gas emissions. Seaweeds are rich in bromoform, which are known to strongly reduce methane emissions when included in animal feed. To ensure that seaweeds can be safely used for methane mitigation, there is a need to monitor bromoform residue in milk. The objective of this study was to develop and validate an analytical approach for quantifying bromoform in milk. QuEChERS-based extraction and clean-up with dispersive solid phase extraction were used followed by analysis with gas chromatography-mass spectrometry. The proposed method was validated: the limit of quantification (LOQ) was 0.21 μg L^-1, and recovery rates ranged from 86 % to 101 % with a precision <18.9 %. Twenty-two commercial milks were analyzed and contained bromoform residues at concentrations ranging from below the LOQ to 0.34 μg L^-1. This method is a reliable tool for monitoring the presence of bromoform in milk.