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The present research is focused on the development of a cryogenically modulated (CM) comprehensive two-dimensional gas chromatography-high resolution time-of-flight mass spectrometry (GC × GC-HR ToFMS) method for the in-depth profiling of the unsaponifiable fraction of vegetable oils. Specifically, twelve vegetable oils (9 extra-virgin olive, soybean, peanut, and hazelnut oils) were subjected to analysis, with particular attention devoted to the higher molecular weight constituents (sterols, vitamin E, triterpenic alcohols). Peak assignment was carried out by using commercial unit-mass MS databases, accurate mass data, literature and on-line freely-available mass spectral information, as well as an in-lab-constructed HR ToFMS lipid database. The main objective of the work was to develop a method to define a well-characterized extra-virgin olive oil fingerprint, to be potentially exploited for vegetable oil differentiation. An additional objective of the investigation was to evaluate the performance of the HR ToFMS system (operated at a mass resolution of 25,000 FWHM) under the challenging analytical conditions of a CM GC × GC-based experiment. The HR ToFMS accurate-mass lipid database was (previously) constructed by acquiring, for the main part, the mass spectra of vegetable oil constituents, well-separated from both the matrix and column bleed background.

The present research is focused on the preliminary evaluation, in particular in relation to the advisable operational conditions, of a novel low duty cycle flow modulator. In such a respect, a fast comprehensive two-dimensional gas chromatography-mass spectrometry method is herein proposed. Applications on a C7-C30 series of alkanes, 64 fragrance allergens (plus 2 internal standards), and 5 perfumes, were carried out by using two different column sets, low-polarity + medium-polarity and low-polarity + low-polarity. In both cases, the first column was of dimensions 10 m × 0.25 mm ID × 0.25 µm df, while the second one was of dimensions 1 m × 0.10 mm ID × 0.10 µm df. A modulation period of 700 ms, with a re-injection period of 80 ms, was used in order to obtain a higher duty cycle (measured to be approx. 0.04). Absolute quantification of the allergens was carried out by using two internal standards, namely 1,4-dibromobenzene and 4,4’-dibromobiphenyl. In terms of limits of quantification the instrumental response was characterized by a wide variability, ranging between 9 ppb and 5.4 ppm for both column sets. A total number of 97 fragrance allergens were identified and quantified in five commercial perfumes.

Coal tar is a complex mixture of organic compounds obtained from the thermal treatment of coal, it contains several different chemical classes of compounds, such as polycyclic aromatic hydrocarbons, phenols and different heterocyclic compounds including sulphur derivatives. In the present research, a target analysis was carried out for the characterisation of fourteen different classes of organic sulphur compounds in coal tar by using cryogenically-modulated (CM) comprehensive two-dimensional gas chromatography-high resolution time-of-flight mass spectrometry (GC&times, GC-HR ToFMS) with the support of target analyte finding, a specific software function. Furthermore, absolute quantification data were obtained by using eight pure standard sulphur compounds, and 1-fluoronaphthalene as internal standard. Several figures-of-merit of the proposed method were measured (linearity, intra-day precision, limits of detection and quantification). Finally, the overall analytical performance of CM GC&times, GC-HR ToFMS was evaluated, in relation to MS similarities, mass accuracies, second-dimension peak widths, peak capacity and tailing factors. The approach proved itself as being a powerful analytical platform, benefiting from the high sensitivity, selectivity and resolving power, of both the GC and MS sides.

Chemical characteristics of novel seed oils, yet not investigated, from three endemic Arecaceae (palm) species from Reunion Island are described. Fatty acid profiles are performed using two-dimensional gas chromatography-mass spectrometry. Carotenoid contents are determined by high performance liquid chromatography-mass spectrometry. The results of the investigations emphasize the particular composition of the unconventional red seed oil from Hyophorbe indica. Characteristic features of this oil reveal a high degree of unsaturation (50% of polyunsaturated fatty acids, with a high content (17%) of omega-3), which is possibly a unique fatty acid composition in the Arecaceae family. The two other palm oils from Dictyosperma album and Latania lontaroides contain high level of saturated fatty acids very similar to that of the edible palm oil. H. indica oil is also very rich in valuable carotenoids; in particular, lutein, β-carotene and lycopene are detected in a high content (respectively 45, 23 and 35 mg.kg−1 in oil).

This preliminary research is focused on the task of defining an equivalent standard column set between cryogenic and flow-modulation comprehensive two-dimensional gas chromatography (GC × GC) combined with mass spectrometry (MS). Cryogenic modulation (CM) was carried out by using a loop-type device, while the flow modulator used was a seven-port wafer chip, equipped with an external accumulation loop. Initially, a common low-polarity + mid-polarity CM GC × GC column set was selected (30 m × 0.25 mm ID × 0.25 μm df + 1.5 m × 0.25 mm ID × 0.25 μm df), a method was developed, and a GC × GC-MS fingerprint was attained (on a sample of bio-oil derived from coconut fibers). After, a column set with the same stationary phases was selected for the flow modulation GC × GC-MS method (20 m × 0.18 mm ID × 0.18 μm df + 5 m × 0.32 mm ID × 0.25 μm df), with the capability to provide a-similar-as-possible separation. A side-by-side measurement of several chromatography parameters (efficiency, peak capacity, resolution, peak widths, retention factors, elution temperatures) was made.

Chemical characteristics of novel seed oils, yet not investigated, from three endemic Arecaceae (palm) species from Reunion Island are described. Fatty acid profiles are performed using two-dimensional gas chromatography-mass spectrometry. Carotenoid contents are determined by high performance liquid chromatography-mass spectrometry. The results of the investigations emphasize the particular composition of the unconventional red seed oil from

The present research is based on the use of comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-QMS), using “milder” electron ionization (EI) conditions. The term milder refers to the use of lower energy EI conditions (e.g., 20 eV), instead of the most common electron energy of 70 eV. The effects of using lower source temperatures were also evaluated. Within such an analytical context, GC × GC-QMS was applied to the analysis of a variety of different molecular-mass compounds with various polarities (sterols, linear alkanes, fatty acid methyl esters, vitamin E, squalene, a linear alcohol, and a group of fifteen pesticides). In general, the results attained indicate that milder EI conditions, and lower source temperatures, generate mass spectra with a higher relative abundance of ions at higher mass-over-charge (m/z) values, comprising the molecular ion, and reduced fragmentation at lower m/z values. The extent to which such a phenomenon occurred was obviously related to the chemical structure of each analyte. Spectral repeatability was also assessed, and was found to be satisfactory. Finally, with regard to analyte signal-to-noise ratios these were generally comparable in applications involving different electron ionization energies.

The present article contains information on current trends in the field of the hyphenated technology comprehensive two-dimensional gas chromatography-mass spectrometry, namely the most powerful analytical tool today-available for the analysis of mixtures formed of volatile compounds. The information herein reported relates mainly to a four-year time period (2014–2017). Focus is devoted to various aspects of mass spectrometry, in particular to ionization methodologies. Apart from critical considerations on past and present research, a future perspective on processes of ionization is given.