Page 6 - Shimadzu Journal vol.1

The eluted fractions were concentrated to a final volume of 100
µL to increase sensitivity, since large volume injection (LVI) was

2-3. GC×GC-MS/FID analysis GC×GC experiments were performed on a system consisting of a GC2010 gas chromatograph, and a QP2010 Ultra quadrupole mass spectrometer (Shimadzu, Kyoto, Japan). The primary column, an SLB-5ms 30 m × 0.25 mm ID × 0.25 µm df [silphenylene polymer, virtually equivalent in polarity to poly (5% diphenyl/95% methyl siloxane)], was connected to an uncoated capillary segment (1.0 m × 0.25 mm ID, used to create a double-loop), and to a 1.0 m × 0.10 mm ID × 0.10 µm df Supelcowax-10 (polyethylene glycol) segment (Supelco). The second column was connected through a capillary column splitter (SGE) to two uncoated capillaries, with these linked to the FID (0.5 m × 0.1 mm I

not used. ID) systems. 375 msec.

The GC×GC system was coupled alternatively with an MS system,
analysis of MOSH and MOAH in various foods.The pre-separation
Biedermann and Grob, who used an MS detector, along with the
The present document describes a GC×GC method,characterized
groups was achieved through off-line LC, a process necessary to
MOSH fraction), with alkylated (two- and three-ring) aromatics.
(GC×GC) analysis [26] . A pre-separation of the MOSH and MOAH
obtain both information types. A GC×GC-MS method, after an
avoid the overlapping of steranes and hopanes (present in the
Mondello and co-workers, to attain a more expanded view on
by dual MS/FID detection, for the qualitative and quantitative
additional information generated by a comprehensive 2D GC
quantification, and hence, two applications were required to
off-line LC pre-separation step, has also been exploited by
fundamental information on potential toxicity, and on the
contamination source. Such an objective was reached by
MOSH contamination in homogenized baby foods [27] .
for qualitative purposes, and with an FID system for
step was performed by using Ag-SPE. 2. Experimental 2-1. Samples and chemicals CH2Cl2 and n-hexane were purchased from Sigma-Aldrich (Milan, Italy), and distilled before use. The C7-C40 standard mixture,the paraffin oil (code 18512), AgNO3, and silica gel 60 (particle size 0.063-0.2 mm, 70-230 mesh) were purchased from Supelco and Sigma-Aldrich (Milan). Glass SPE cartridges (6 mL glass tubes with a frit) were purchased from Macherey-Nagel (Chromabond, Düren, Germany). 2-2. Samples and preparations Samples of pasta, rice and icing sugar, were purchased in a supermarket. The ground samples were extracted overnight using n-hexane, and then purified through

Food safety (50:50 v/v). 6

Food safety 5

compounds was investigated using the mass spectrometric data, and were tentatively-identified as esterified fatty acids, most probably
dual detection [flame ionization (FID) and mass spectrometric], for the simultaneous identification and quantification of mineral-oil
The present work is focused on the development/optimization of a comprehensive two-dimensional gas chromatography method, with
previously fractionated on a manually-packed silver silica solid-phase extraction (SPE) cartridge. The presence of a series of unknown
contaminants in a variety of food products. The two main classes of contaminants, namely saturated and aromatic hydrocarbons, were
on-line liquid chromatography-gas chromatography (LC-GC), with
described [11-18] . The lipid fraction can be eliminated either through
Most of the approaches reported over the last decades have been
Biedermann and co-workers exploited the separation efficiency of
have been described; with regards to packing materials, a variety
marker, using both off- and on-line techniques. Off-line methods
clear pre-separation of the MOSH from the MOAH. For example,
cartridge [15-18] . Several techniques, based on the use of glass SPE,
an LC silica column, in an on-line LC-GC system, to separate the
toxicological relevance of MOAH, work has been directed to the
a silica LC column [6,19-23] . Additionally,and in consideration of the
of solutions have been proposed, such as activated silica gel [16] ,
directed to the analysis of MOSH, exploited as a contamination
[11,12] , or directly through a prep LC silica column [13,14] , or an SPE
MOAH from the MOSH, and these from the lipidmatrix [20] . It
Considering the application of all methods, it can be affirmed
saponification, followed by silica-gel column chromatography
based on prep LC, or solid-phase extraction (SPE), have been
silica-gel SPE cartridge, have been developed for MOSH and
must also be noted that off-line SPE methods, using a Ag
without a doubt, that the most popular technique has been
non-activated silica gel [17] , or silver (Ag) silica gel [18] .
MOAH determination [24,25] . With regards to detectors, flame ionization (FID) systems have been widely employed for the reliable quantification of the humps of unresolved complex mixtures (UCM), generated in MOSH/MOAH applications; FIDs are useful because they provide virtually the same response per mass of hydrocarbons, eventhough the lack of structural information is certainly a major drawback [23] . In fact, the attainment of profound information on the composition of MOSH and MOAH constituents, can provide

global w430×h280 Analysis of MOSH and MOAH using SPE prior to GC×GC-MS analysis derived from vegetable oil based ink. Keyword:Food, MOSH, MOAH, GC×GC, Comprehensive GC, Quadrupole mass spectrometer Mineral oil products derive from crude petroleum, through distillation processes and various refining steps, and contain proportions of mineral oil saturated hydrocarbons (MOSH, including n-alkanes, isoalkanes and cycloalkanes), and mineral oil aromatic hydrocarbons (MOAH), mainly consisting of alkylated polyaromatic hydrocarbons (PAH) [1] . Mineral oil contamination in foods, deriving from a variety of sources, has been studied for quite a long time [2-4] . One of the major sources of contamination is paperboard pac

Luigi Mondello 1 Abstract 1. Introduction lacking.