Improved analytical methods for hexane residue detection with lower thresholds

Analytical methods for hexane residues quantification described in the international Standards ISO 8892, 9289 and 9832 were developed respectively in 1987, 1991 and 2002, more than twenty or thirty years ago. They have failed to keep pace with advancements seen for other contaminants like PFAS, MOAH or glyphosate. While modern methods achieve detection thresholds as low as 0.1 µg/kg for glyphosate or 0.2 ng/kg for PFAS, standardized hexane analysis remains limited by outdated techniques with much higher quantification thresholds of 1 mg/kg for oil and 50 mg/kg for feed meal. In addition, they are limited to oils and meals analysis. To our knowledge, no analytical method had been published to measure hexane residue in other substrates such as milk, eggs or meat. We have validated several analytical methods on GC-MS Headspace to analyse either n-hexane or a mixture of n-hexane, 2-methylpentane, 3-methylpentane and benzene with an LOD as low as 5 µg/kg. We used these methods to analyse 54 food products bought in France and Canada (oils, fat, eggs, milk, chicken). We found residue of n-hexane in 25 samples and residue of benzene in 2 samples.

This presentation highlights the development of these advanced methods and their implications for modernizing residue analysis and enhancing consumer safety.