Determination of mineral oil hydrocarbon contamination in Citrus essential oils by using on-line liquid-gas chromatography: critical aspects

Alessia Arena; Mariosimone Zoccali; Ivana Bonaccorsi; Monica Mondello; Peter Q Tranchida; Luigi Mondello

doi:10.1007/s00216-023-04873-7

Determination of mineral oil hydrocarbon contamination in Citrus essential oils by using on-line liquid-gas chromatography: critical aspects

Anal Bioanal Chem. 2024 Jan;416(3):801-808. doi: 10.1007/s00216-023-04873-7. Epub 2023 Jul 28.

Authors

Alessia Arena¹, Mariosimone Zoccali², Ivana Bonaccorsi¹, Monica Mondello³, Peter Q Tranchida¹, Luigi Mondello^{1

3}

Affiliations

¹ Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy.
² Department of Mathematical and Computer Science, Physical Sciences and Earth Sciences, University of Messina, Messina, Italy. mzoccali@unime.it.
³ Chromaleont s.r.l., c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy.

PMID: 37505233
DOI: 10.1007/s00216-023-04873-7

Abstract

The present manuscript reports and discusses critical issues related to the determination of mineral oil hydrocarbon contamination in Citrus essential oils (EOs); an on-line liquid-gas chromatography system equipped with a Y-interface was used (with no additional off-line step for pre-concentration). In total, eighteen samples were analyzed, specifically eleven cold-pressed (CP) and seven distilled EOs. With regard to the CP EOs, various degrees of mineral oil saturated hydrocarbon (MOSH) contamination were detected, ranging between 10.7 and 338.4 mg kg^-1 (only one sample was MOSH-free); different MOSH sub-fractions were determined, with the > C₂₅- ≤ C₃₅ sub-fraction always present, with an average concentration of 74.5 mg kg^-1. Based on the EO composition, different sample amounts were injected to avoid the overloading of the LC column and consequently the GC one, thus leading to different limits of quantification (LoQ), which were either 2 mg kg^-1 (for bergamot EO) or 5 mg kg^-1 (for all the other investigated samples). For all samples, the mineral oil aromatic hydrocarbon level was always lower than the LoQ.

Keywords: Citrus essential oils; LC-GC; Mineral oil aromatic hydrocarbons; Mineral oil saturated hydrocarbons; Multidimensional liquid-gas chromatography.