Comprehensive two‐dimensional GC after HPLC preseparation for the characterization of aromatic hydrocarbons of mineral oil origin in contaminated sunflower oil

Abstract

Many foods are contaminated with mineral oil at concentrations in the order of or above 10 mg/kg. Often, these mineral oils are of technical grade and contain around 20-30% aromatic hydrocarbons, as previously shown by an on-line HPLC-GC-flame ionization detection method for determining in foods the sum of the mineral oil aromatic hydrocarbons (ranging from 1 to at least 5 aromatic rings). Now, a comprehensive twodimensional GC (GC Â GC) method was added for characterizing these aromatics by ring number and degree of alkylation. In contrast to the polycyclic aromatic hydrocarbons originating from pyrolysis, mineral oil aromatic hydrocarbons are highly alkylated and form extremely complex mixtures. Through MS and addition of standards, sectors in the GC Â GC plots were allocated to 1 to 5 ring aromatics in order to estimate the relative abundance of each group. The quantitative composition is approximated by integration of 2nd dimension chromatograms laid as a grid over the three-dimensional hump of unresolved hydrocarbons of the GC Â GC-flame ionization detection plot. The procedure is applied to Ukrainian sunflower oils contaminated with mineral oil.

Mineral oil contents in paper and board recycled to paperboard for food packaging

“…Above the band of the highly alkylated benzenes, but still below the line separating the benzenes from the 2-ring compounds, there is a band probably representing partially hydrogenated polyaromatics with a single aromatic and up to several saturated rings. Also the 2-ring zone shows higher complexity than observed for untreated mineral oil fractions: 1,8 there are not only alkylated naphthalenes and benzothiophenes, but also partially hydrogenated structures with more than two rings.…”

“…8 Briefl y, the corresponding HPLC fractions were collected from the dismounted transfer line in a 1.5 ml autosampler vial and reconcentrated to 20-100 μl. A TRACE GC was used, equipped with a programmed temperature vaporizing (PTV) injector containing an on-column liner, a cryogenic jet modulator, a fl ame ionization detector and a DSQ II quadrupole mass spectrometer (Thermo Scientifi c).…”

“…The GC × GC-FID plots show the MOSH and MOAH fractions isolated by the HPLC of the HPLC-GC method. As discussed in Biedermann and Grob, 8 the paraffi ns form a band at low second dimension retention time, with the n-alkanes shown as dark spots with regular intervals. The gray zone above the paraffi ns represents the naphthenes, i.e.…”

A New Dimension in Separation Science: Comprehensive Two‐Dimensional Gas Chromatography

“…Most recent advances in multidimensional separation are to invoke a third chromatographic dimension to provide additional chemical selectivity, such as offline LC-GC GC, [85] LC LC CE, [86] and GC GC GC. [87] Recently, Synovec et al [88] utilized two six-port diaphragm valves as the interface between three, serially coupled capillary columns housed in a conventional GC instrument attached to an FID.…”

Theory and Practice of UHPLC and UHPLC–MS

“…), and then quantification can be easily performed if representative standard compounds are available. Biedermann and Grob (2009) used GC Â GC-FID and group-type pattern formation, for the quantification of mineral oil constituents contained in a contaminated sunflower oil. GC Â GC-FID has been used in several other application fields, such as environmental (Reddy et al, 2002;Frysinger et al, 2003) and food (Tranchida et al, 2008a;Vlaeminck et al, 2007).…”