Highly purified mineral oils used for the elaboration of pharmaceutical, food and cosmetic products can contain residual mineral oil aromatic hydrocarbons (MOAH). Quantification of the MOAH level as well as detailed characterization of the aromatic species present is important for safety evaluations and for optimization of the purification process. Two comprehensive off-line silver phase liquid chromatography × gas chromatography (AgLC × GC) methods, one with flame ionization detection (FID) and another with vacuum ultraviolet detection (VUV), were developed for MOAH analysis. The methods showed a better resolution between the MOSH and MOAH groups compared to the traditional online LC-GC methods due to the different retention mechanisms employed in the two dimensions, albeit that the gain was less than seen e.g. in edible oil analysis. An important advantage of the new comprehensive AgLC × GC methods is that the use of markers to determine the MOSH/MOAH cut-point is no longer needed, because all the eluent coming from the LC separation is transferred as narrow fractions to the GC. Due to the use of silver based stationary phases in the first separation dimension, a group-type separation of the mineral oil according to the degree of aromaticity (aliphatics, mono-aromatics and poly-aromatics) was obtained. Moreover, thanks to the use of VUV detection, the new method also delivered additional structural information on the different groups of compounds present.
Bibliographical noteFunding Information:
The authors thank the Consejo Nacional de Ciencia y Tecnolog?a de M?xico (CONACyT) for the scholarship awarded to A.R. Garc?a-Cicourel (No. 410740). H.-G. Janssen was awarded an academic research grant by VUV Analytics for method development for MOSH and MOAH analysis in food products. This research did not receive any further specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
The authors thank the Consejo Nacional de Ciencia y Tecnología de México (CONACyT) for the scholarship awarded to A.R. García-Cicourel (No. 410740 ).
© 2019 The Authors
- Argentation chromatography
- Comprehensive AgLC×GC
- Mineral oil characterization