The role of comprehensive two-dimensional gas chromatography in mineral oil determination

Mineral oil hydrocarbons (MOH) contain a wide structural diversity of molecules, for which the reference method of analysis is the online coupled liquid chromatography-gas chromatography with flame ionization detection (LC-GC-FID). These compounds are very heterogeneous from a toxicological viewpoint, and an accurate risk assessment when dealing with a MOH contamination can only be performed if sufficient information is available on the types of structures present (i.e., number of carbons, degree of alkylation, number of aromatic rings). Unfortunately, the separation performances of the current LC-GC-FID method are insufficient for such characterization, not even mentioning the possible coelution of interfering compounds which additionally hinder MOH determination. Comprehensive two-dimensional gas chromatography (GC x GC), while mostly used for confirmation purposes in the past, starts to prove its relevance for overcoming the weaknesses of the LC-GC method and reaching even better the analytical requirements defined in the latest EFSA opinion. The present paper therefore aims at highlighting how GC x GC has contributed to the understanding of the MOH topic, how it has developed to meet the requirements of MOH determination, and how it could play a role in the field for overcoming many of the current analytical and toxicological challenges related to the topic.

Automated summary

Mineral oil hydrocarbons (MOH) are analyzed using the online coupled liquid chromatography-gas chromatography with flame ionization detection (LC-GC-FID) method, which lacks sufficient separation performance and may result in coelution of interfering compounds. Comprehensive two-dimensional gas chromatography (GC x GC) has proven to be relevant in overcoming the weaknesses of the LC-GC method and meeting the analytical requirements. This paper highlights the contributions of GC x GC in understanding MOH, meeting the determination requirements, and overcoming analytical and toxicological challenges.