Search

The request for novel hyphenated instruments and techniques, capable of affording exhaustive information and results, is a focus continuously watched out. In this context, the present work aimed at the development of an integrated system combining gas chromatographic (GC) separation with mass spectrometry (MS) and (solid deposition) Fourier transform infrared spectroscopy (FTIR) detection. An external transfer line was designed in the lab for the parallel coupling of the two detectors, in such a way to obtain complementary analytical information consisting of an MS spectrum, an IR spectrum and linear retention indices (LRI), within a single analysis. The instrument performance was demonstrated for the analysis of a commercial mixture consisting of 139 hydrocarbons, comprising linear, branched, unsaturated and aromatic compounds. A 100-m poly(dimethylsiloxane) column was employed for the separation, and the outlet flow was split 95:5 between the IR and MS detectors using two uncoated capillaries. The IR spectra were acquired from solid deposits on a zinc selenide disc (-90 °C), over a spot (detector area) of about 0.1 mm 2 , in the range of 4000-700 cm -1 and at a resolution of 4 cm -1 . Final identification of the separated compounds by a library search was achieved by excluding incorrect results, sequentially using a three-filter approach (85% similarity against reference MS and IR library spectra and ±10 LRI unit tolerance). Based on these preliminary results, the GC-MS/sd-FTIR system is a promising tool for the characterization of complex matrix constituents, for which identification is cumbersome, by using only one detection technique., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Piper gaudichaudianum Kunth essential oil (EO) is a natural source of bioactive components, having multiple therapeutic applications. Its chemical composition is highly variable, and strictly depends on abiotic factors, resulting in various biological activities. The present study details the utilization of multiple gas chromatographic techniques alongside nuclear magnetic resonance (NMR) spectroscopy to characterize the essential oil of Piper gaudichaudianum Kunth from Brazil. Seventy-six components were identified using GC-MS analysis, while enantio‑selective multidimensional gas chromatography elucidated the enantiomeric distribution of eight chiral components, for the first time in the literature. Following GC-MS analysis, an unidentified component, constituting approximately 27 % of the total oil, prompted an isolation step through preparative gas chromatography. Through the combined use of nuclear magnetic resonance, GC-Fourier transform infrared spectroscopy (FTIR), and mass spectrometry (MS), the unknown molecule was structurally identified as 4-[(3E)‑dec-3-en-1-yl]phenol. Remarkably, it was identified as a known molecule, gibbilimbol B, and not previously listed in any MS database. Subsequently, the spectrum was included in a commercial library, specifically the FFNSC 4.0 MS database, for the first time., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

In this study, multiple analytical approaches, including simultaneous enantiomeric and isotopic analysis, were employed to thoroughly investigate the volatile fraction in Moscato giallo grape berries and wines. For the qualitative and quantitative profiling, a fast GC-QqQ/MS approach was successfully utilized. However, prior to isotopic analysis, the extracts underwent an additional concentration step, necessitating an assessment of isotopic fractionation during the concentration process. Once the absence of carbon isotopic fractionation was confirmed, this research aimed to develop a suitable gas chromatographic method for the simultaneous detection of both enantiomeric and isotopic ratios of target monoterpenoids in Moscato giallo samples. To address the limitations associated with a one-dimensional approach, multidimensional gas chromatography was employed to enhance separation before IRMS and qMS detections. Utilizing a Deans switch transfer device, the coupling of an apolar column in the first dimension and a chiral cyclodextrin-based stationary phase in the second dimension proved effective for this purpose. The data obtained from the analysis of Moscato giallo samples allowed for the assessment of natural isotopic and enantiomeric distributions in grapes and wines for the first time in the literature. Significant enantiomeric excesses were observed for the target terpenoids investigated. Regarding isotopic distribution, a consistent trend was observed for all detected target terpenols, including the linalool enantiomers. To date, this study represents the first investigation of simultaneous δ 13 C and chiral investigation of the main terpenoids in oenological products in the literature., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

This research aimed to support police forces in their battle against illicit drug trafficking by means of a multi-technique approach, based on gas chromatography. In detail, this study was focused on the profiling of volatile substances in narcotic Cannabis sativa L. flowering tops. For this purpose, the Scientific Investigation Department, RIS Carabinieri of Messina, provided 25 seized samples of Cannabis sativa L. The content of Δ 9 -tetrahydrocannabinol (THC), useful to classify cannabis plant as hemp (≤ 0.2 %) or as marijuana (> 0.2 %), was investigated. Essential oils of illicit drug samples were extracted using a microwave-assisted hydro-distillation (MAHD) system; GC-MS and GC-FID analytical techniques were used for the characterization of the terpenes and terpenoids fingerprint. Furthermore, the enantiomeric and carbon isotopic ratios of selected chiral compounds were investigated using a heart-cutting multidimensional GC (MDGC) approach. The latter exploited a combination of an apolar column in the first dimension, and a chiral cyclodextrin-based column in the second one, prior to parallel isotope-ratio mass spectrometry (C-IRMS) and MS detection. Finally, all the data were gathered into a statistical model, to demonstrate the existence of useful parameters to be used for the classification of seized samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Among the Moscato grapes, Moscato Giallo is a winegrape variety characterised by a high content of free and glycosylated monoterpenoids, which gives wines very intense notes of ripe fruit and flowers. The aromatic bouquet of Moscato Giallo is strongly influenced by the high concentration of linalool, geraniol, linalool oxides, limonene, α-terpineol, citronellol, hotrienol, diendiols, trans/cis -8-hydroxy linalool, geranic acid and myrcene, that give citrus, rose, and peach notes. Except for quali-quantitative analysis, no investigations regarding the isotopic values of the target volatile compounds in grapes and wines are documented in the literature. Nevertheless, the analysis of the stable isotope ratio represents a modern and powerful tool used by the laboratories responsible for official consumer protection, for food quality and genuineness assessment. To this aim, the aromatic compounds extracted from grapes and wine were analysed both by GC-MS/MS, to define the aroma profiles, and by GC-C/Py-IRMS, for a preliminary isotope compound-specific investigation. Seventeen samples of Moscato Giallo grapes were collected during the harvest season in 2021 from two Italian regions renowned for the cultivation of this aromatic variety, Trentino Alto Adige and Veneto, and the corresponding wines were produced at micro-winery scale. The GC-MS/MS analysis confirmed the presence of the typical terpenoids both in glycosylated and free forms, responsible for the characteristic aroma of the Moscato Giallo variety, while the compound-specific isotope ratio analysis allowed us to determine the carbon (δ 13 C) and hydrogen (δ 2 H) isotopic signatures of the major volatile compounds for the first time.

The present research aimed to retrieve key information about the genuineness of Sicilian lemon essential oils by evaluating simultaneously the chiral and isotopic data of target terpene components. With respect to previous literature references, where chiral recognition and isotope discrimination were performed by distinct gas chromatographic methods, this study aimed to develop a single analytical approach. To overcome limitations associated to monodimensional gas chromatographic approaches, an enantio‑selective multidimensional gas chromatographic approach coupled to isotopic ratio mass spectrometry and to parallel single quadrupole detection (Es-MDGC-C-IRMS/qMS) was developed. Thanks to the features of this system, enantiomeric excesses and target δ 13 C of the chiral and achiral components were evaluated in a single gas chromatographic run, allowing to reduce total time analysis, as well the consumption of electricity, solvents and samples. Moreover, due to the capability to baseline separate the enantiomeric couples, further considerations were done about the specific δ 13 C value of the target separated enantiomers. Dealing with the genuine lemon oils analysed, a different δ 13 C value was found between the enantiomers of the same chiral component, namely (-) and (+) of α and β-pinene, suggesting a different isotopic fractionation related to a specific biosynthetic pathway. This research aimed to evaluate the reasons behind this behaviour, paving the way to newer considerations in the field of authenticity assessment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Separation science plays a crucial role in the isolation of novel compounds contained in complex matrices. Yet their rationale employment needs preliminary structure elucidation, which usually requires sufficient aliquots of grade substances to characterize the molecule by nuclear magnetic resonance experiments. In this study, two peculiar oxa-tricycloundecane ethers were isolated by means of preparative multidimensional gas chromatography from the brown alga species Dictyota dichotoma (Huds.) Lam., aiming to assign their 3D structures. Density functional theory simulations were carried out to select the correct configurational species matching the experimental NMR data (in terms of enantiomeric couples). In this case, the theoretical approach was crucial as the protonic signal overlap and spectral overcrowding were preventing any other unambiguous structural information. Just after the identification through the density functional theory data matching of the correct relative configuration it was possible to verify an enhanced self-consistency with the experimental data, confirming the stereochemistry. The results obtained further pave the way toward structure elucidation of highly asymmetric molecules, whose configuration cannot be inferred by other means or strategies., (© 2023 Wiley-VCH GmbH.)

Recent times have witnessed an upsurge of interest in hemp and hemp-derived products, as driven by the scientific findings specific to the pharmacological properties of Cannabis sativa L. and its constituents. There has been evidence that the terpene profile, along with the cannabinoid content, produces in humans the effects associated with different strains, beyond fragrance perception. A great deal of effort has been put into developing analytical approaches to strengthen the scientific knowledge on cannabis essential oil composition and provide effective tools for ascertaining the authenticity of commercial cannabis samples. For this concern, enantio-selective-GC-C-IRMS has proven to be effective for assessing the ranges characteristic of the genuine samples and detecting any fraudulent additions. This research aimed at providing for the first time the enantiomeric and isotopic ratios of target terpenes in cannabis essential oils, obtained from microwave-assisted hydro-distillation from the fresh and dried inflorescences of different cannabis varieties. Implementing multidimensional gas chromatography separation was mandatory prior to detection, in order to obtain accurate δ 13 C values and enantiomeric data from completely separated peaks. For this purpose, a heart-cut method was developed, based on the coupling of an apolar first dimension column to a secondary chiral cyclodextrin-based stationary phase. Afterwards, the data gathered from enantio-selective-MDGC-C-IRMS/qMS analysis of a set of genuine samples were used to evaluate the quality of nineteen commercial cannabis essential oils purchased from local stores. Remarkably, the data in some cases evidenced enantiomeric ratios and δ 13 C values outside the typical ranges of genuine oils. Such findings suggest the usefulness of the method developed to ascertain the genuineness and quality of cannabis essential oils., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

The use of IRMS as a GC detector has a history going back decades, however the critical issue of wrong δ 13 C measurements resulting from impure peaks has been often underestimated. To this regard, multidimensional separation techniques are effective tools to improve the reliability of the data, with respect to those obtained after monodimensional analysis. The present research aims to draw attention to one critical issue, related to the reliability of the δ 13 C data obtained by means of monodimensional GC-C-IRMS. Although already known from the literature, such aspect has been greatly overlooked, as is reflected in the few papers reporting the use of MDGC, among the plethora of published research dealing with GC-C-IRMS applications. Hereby, a set of natural samples of complex composition were analysed to investigate the presence of minor or even undetected coelutions, and to which extent it affected the isotope ratio determination. Apart from chromatographic effects, and issues related to analytes conversion to CO 2 prior to IRMS measurement, unpredictable co-elutions with compounds, either resulting from oxidation or intentionally added in fraudulent practices, could also contribute to a shift of the δ 13 C data, up to 10‰ and higher. Last, the influence of column bleed was investigated, as affecting the determination of the δ 13 C data for compounds that were eluted at high temperatures. It was finally demonstrated by the selected key studies that implementation of MDGC separation is mandatory to prevent the aforementioned issues, aiming to guarantee accurate results. In the light of the above conclusions, and considering the level of automation of heart-cut devices nowadays available, routine practice of MDGC results highly recommendable in any IRMS applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Background: Truffles are symbiotic fungi that develop underground in association with plant roots, forming ectomycorrhizae. They are primarily known for the organoleptic qualities of their hypogeous fruiting bodies. Primarily, Tuber magnatum Pico is a greatly appreciated truffle species mainly distributed in Italy and Balkans. Its price and features are mostly depending on its geographical origin. However, the genetic variation within T. magnatum has been only partially investigated as well as its adaptation to several environments., Results: Here, we applied an integrated omic strategy to T. magnatum fruiting bodies collected during several seasons from three different areas located in the North, Center and South of Italy, with the aim to distinguish them according to molecular and biochemical traits and to verify the impact of several environments on these properties. With the proteomic approach based on two-dimensional electrophoresis (2-DE) followed by mass spectrometry, we were able to identify proteins specifically linked to the sample origin. We further associated the proteomic results to an RNA-seq profiling, which confirmed the possibility to differentiate samples according to their source and provided a basis for the detailed analysis of genes involved in sulfur metabolism. Finally, geographical specificities were associated with the set of volatile compounds produced by the fruiting bodies, as quantitatively and qualitatively determined through proton transfer reaction-mass spectrometry (PTR-MS) and gas-chromatography-mass spectrometry (GC-MS). In particular, a partial least squares-discriminant analysis (PLS-DA) model built from the latter data was able to return high confidence predictions of sample source., Conclusions: Results provide a characterization of white fruiting bodies by a wide range of different molecules, suggesting the role for specific compounds in the responses and adaptation to distinct environments.

The present research deals with the collection and structural elucidation of an unknown component, accounting for about 35% of the essential oil obtained upon distillation of the leaves of Eugenia uniflora L., harvested during summer (January, 2017) in Paraná State (Southern Brazil). A multidimensional gas chromatographic preparative system, based on the coupling of three GC systems equipped with apolar, PEG and ionic liquid-based stationary phases, was successfully applied for the isolation of the chromatographic band relative to the unknown molecule. The use of wide-bore columns allowed for an increased sample capacity compared to conventional micro-bore columns, thus the injection of a neat sample was feasible, greatly reducing the total collection time. A higher chromatographic efficiency was afforded by the use of a multidimensional approach in the heart-cut mode, exploiting the different selectivity of three stationary phases, which ensured the attainment of a highly pure fraction. In only five runs, more than 3 milligrams were collected, with an average purity greater then 95%. Finally, the unknown component was subjected to nuclear magnetic resonance spectroscopy, mass spectrometry and condensed phase Fourier-transform infrared spectroscopy, leading to the identification of 6-ethenyl-6-methyl-3,5-di(prop-1-en-2-yl)cyclohex-2-en-1-one. The presented approach has been demonstrated to be effective for the isolation and structural elucidation of unknown molecules in complex samples, which will allow for further in-depth studies, like biological evaluation or pharmacological tests.

Truffles are among the most expensive foods available in the market, usually used as flavoring additives for their distinctive aroma. The most valuable species is Tuber magnatum Pico, better known as "Alba white truffle", in which bis(methylthio)methane is the key aroma compound. Given the high economical value of genuine white truffles, analytical approaches are required to be able to discriminate between natural or synthetic truffle aroma. Gas chromatography coupled to combustion-isotope ratio mass spectrometry (GC-C-IRMS), exploiting the 13 C/ 12 C ratio abundance of the key flavorings compounds in foods, has been a recognized technique for authenticity and traceability purposes; however, a number of issues have greatly limited its widespread use so far. In the present research, a high-efficiency HS-SPME MDGC-C-IRMS with simultaneous quadrupole MS detection has been applied for the evaluation of bis(methylthio)methane, resolving the coelution occurring with other components. With the aim to minimize the effect of column bleeding on δ 13 C measurement, a medium polarity ionic liquid-based stationary phase was preferred to a polyethylene glycol one, as the secondary column. In total, 24 genuine white truffles harvested in Italy were analyzed, attaining a δ 13 C values between -42.6‰ and -33.9‰, with a maximum standard deviation lower than 0.7‰. Two commercial intact truffles and 14 commercial samples of pasta, sauce, olive oil, cream, honey, and fresh cheese flavored with truffle aroma were analyzed, and the results from δ 13 C measurement were evaluated in comparison with those of genuine "white truffle" range and commercial synthetic bis(methylthio)methane standard.

The task of lipid analysis and profiling is taking centre stage in many research fields and as a consequence, there has been an intense effort to develop suitable methodologies to discover, identify, and quantify lipids in the systems investigated. Given the high complexity and diversity of the lipidome, researchers have been challenged to afford thorough knowledge of all the lipid species in a given sample, by gathering the data obtained by complementary analytical techniques. In this research, an "omic" approach was developed to quickly fingerprint lipids in the Mediterranean mussel (Mytilus galloprovincialis), by exploiting multidimensional and hyphenated techniques. In detail, two-dimensional comprehensive hydrophilic interaction liquid chromatography coupled to reversed-phase liquid chromatography afforded both class-type separation and lipid assignment within the total lipid species in the sample, by the coupling of a 2.1-mm I.D. partially porous stationary phase in the first dimension, to a short (50 mm) monodisperse octadecylsilica secondary column; individual molecular species were afterwards identified by means of their ion trap-time of flight mass spectra obtained by electrospray ionization. More than 200 neutral and polar lipids were identified, and among the latter, phosphatydylcholine and phosphatydylethanolamine were the most represented classes, together with their mono-acylated forms, plasmanyl and plasmenyl derivatives. Subsequently, separation of the saturated and unsaturated isomers of the fatty acids (including the saturated C16:0 and the polyunsaturated C22:6) in the offline collected phospholipid fractions was accomplished by gas chromatography analysis of the corresponding methyl esters, on a 200 m × 0.25 mm, 0.2 μm d f ionic liquid column.

Cordia verbenacea D.C. (Boraginaceae, Varronia curassavica Jacq. synonym) is a medicinal plant, native from Brazil, especially the leaves are used in folk medicine. The aim of this study was to extend the characterization of the volatile fraction of the essential oil obtained from this plant, by using GC-FID, GC-MS, and chiral GC. Moreover, to further clarify the composition of the volatile fraction, preparative multidimensional-GC (prep-MDGC) was used to collect unknown compounds, followed by NMR characterization. Specifically, the chemical characterization, both qualitative and quantitative, of the volatile fraction of the essential oil obtained from Cordia verbenacea cultivated in the Minas Gerais area (central area of Brazil) was investigated for the first time. The principal components from a quantitative point of view were α-pinene (25.32%; 24.48g/100g) and α-santalene (17.90%; 17.30g/100g), belonging to the terpenes family. Chiral-GC data are reported for the enantiomeric distribution of 7 different components. Last, to obtain the complete characterization of the essential oil constituents, prep-MDGC analysis was used to attain the isolation of two compounds, not present in the principal MS databases, which were unambiguously identified by NMR investigation as (E)-α-santalal and (E)-α-bergamotenal, reported for the first time in Cordia verbenacea essential oil., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The task of lipid analysis has always challenged separation scientists, and new techniques in chromatography were often developed for the separation of lipids; however, no single technique or methodology is yet capable of affording a comprehensive screening of all lipid species and classes. This review acquaints the role of supercritical fluid chromatography within the field of lipid analysis, from the early developed capillary separations based on pure CO 2 , to the most recent techniques employing packed columns under subcritical conditions, including the niche multidimensional techniques using supercritical fluids in at least one of the separation dimensions. A short history of supercritical fluid chromatography will be introduced first, from its early popularity in the late 1980s, to the sudden fall and oblivion until the last decade, experiencing a regain of interest within the chromatographic community. Afterwards, the subject of lipid nomenclature and classification will be briefly dealt with, before discussing the main applications of supercritical fluid chromatography for food analysis, according to the specific class of lipids., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The enhanced sample collection capability of a heart-cutting three-dimensional GC-prep system is reported. In its original configuration, a highly pure component can be usually collected after the last (3D) column outlet by means of a dedicated preparative station. The latter is located after the last chromatographic column, and this poses the requirement for multiple heart cuts even for those components showing satisfactory degree of purity after the first (or second) separation dimension. The feasibility to collect pure components after each chromatographic dimension is here described, employing a three-dimension MDGC system equipped with high-temperature valves, located inside the first and second GC ovens, with the aim to improve the productivity of the collection procedure. In addition to a commercial preparative collector located at the 3D outlet, two laboratory-made collection systems were applied in the first and second dimension, reached by the effluent to be collected trough a high-temperature valve switching the heart-cut fraction between either the detector (FID), or the collector. Highly pure sesquiterpene components were collected, namely: patchouli alcohol after the first column [poly(5% diphenyl/95% dimethylsiloxane)], α-bulnesene after a second column coated with high molecular weight polyethylene glycol, and α-guaiene after an ionic-liquid based column (SLB-IL60), used as the third dimension. Purity levels ranging from 85 to 95% were achieved with an average collection recovery of 90% (n=5). The following average amounts were collected per run: 160μg for α-guaiene, 295μg for α-bulnesene, and 496μg for patchouli alcohol., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Polymethoxyflavones possess many biological properties, as lipid-lowering, hypoglycaemic, anti-inflammatory, antioxidant, and anticancer activities, therefore, they may be employed as nutraceuticals or therapeutic agents. The scarcity of pure polymethoxyflavones on the market as well as their low water solubility limited in vivo studies and the use of polymethoxyflavones as food or pharmaceutical supplements. Since mandarin peels are a rich source of polymethoxyflavones, tangeretin, nobiletin, sinensetin, tetra-O-methyl scutellarein, and heptamethoxyflavone were purified from a nonvolatile residue of a cold-pressed mandarin essential oil using a multidimensional preparative liquid chromatographic system coupled with a photodiode array detector and a single quadrupole mass spectrometer. A new prototype, consisting of a nano-liquid chromatography system coupled with an electron ionization mass spectrometer, was used for the characterization of the pure isolated molecules. Finally, due to the collection of highly pure nobiletin and tangeretin, the ability of 2-hydroxypropyl-β-cyclodextrin to enhance the water solubility of both polymethoxyflavones was evaluated by phase solubility studies and Job's plot method., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Recently the miniaturization of liquid chromatography (LC) systems and progresses in mass spectrometry instrumentation have enabled direct introduction of the effluent coming from a nanoLC column into the high-vacuum region of an electron ionization source. In the present research, a nanoLC system was directly coupled to an electron ionization mass spectrometer (EI-MS) without any interface or modification of the ion source. The advantage with respect to atmospheric pressure ionization techniques, normally coupled with LC, is major identification power because of a more extensive and reproducible fragmentation pattern, without any matrix effect or mobile-phase interference. In particular, a nanoLC/EI-MS method was developed for elucidation of the free fatty acid profile in mussel samples, avoiding a previous derivatization step, required when gas chromatographic analysis is involved. A total of 20 fatty acids were reliably identified through the comparison with commercial libraries. A quantitative determination was also carried out by using the response factors approach along with the internal standard method, allowing for quantification of 14 fatty acids. Among them, palmitic acid resulted the most abundant, followed by ω6 arachidonic acid. The quantitative data were compared with those obtained by a well-established technique, such as gas chromatography with flame ionization detection (GC-FID). Both nanoLC/EI-MS and GC-FID methods were validated and similar results were obtained in terms of limit of detection and quantification, resulting in the picomole range, and sensitivity as well was not significantly different, as demonstrated by comparing the slope values of the calibration curves (p < 0.05, from a t-test).

The evaluation of a novel medium-polarity ionic-liquid-based gas chromatography column, SLB-IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB-IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB-IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium-polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mineral oils, which are mainly composed of saturated hydrocarbons and aromatic hydrocarbons, are widespread food contaminants. Liquid chromatography coupled to gas chromatography with flame ionization detection represents the method of choice to determine these two families. However, despite the high selectivity of this technique, the presence of olefins (particularly squalene and its isomers) in some samples as in olive oils, does not allow the correct quantification of the mineral oil aromatic hydrocarbons fraction, requiring additional off-line tools to eliminate them. In the present research, a novel on-line liquid chromatography coupled to gas chromatography method is described for the determination of hydrocarbon contamination in edible oils. Two different liquid chromatography columns, namely a silica one (to retain the bulk of the matrix) and a silver-ion one (which better retains the olefins), were coupled in series to obtain the mineral oil aromatic hydrocarbons hump free of interfering peaks. Furthermore, the use of a simultaneous dual detection, flame ionization detector and triple quadrupole mass spectrometer allowed us not only to quantify the mineral oil contamination, but also to evaluate the presence of specific markers (i.e. hopanes) to confirm the petrogenic origin of the contamination., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The present research deals with the multi-collection of the most important sesquiterpene alcohols belonging to sandalwood essential oil, as reported by the international regulations: (Z)-α-santalol, (Z)-α-trans bergamotol, (Z)-β-santalol, epi-(Z)-β-santalol, α-bisabolol, (Z)-lanceol, and (Z)-nuciferol. A versatile multidimensional preparative system, based on the hyphenation of liquid and gas chromatography techniques, was operated in the LC-GC-GC-prep or GC-GC-GC-prep configuration, depending on the concentration to be collected from the sample, without any hardware or software modification. The system was equipped with a silica LC column in combination with polyethylene glycol-poly(5% diphenyl/95% dimethylsiloxane)-medium polarity ionic liquid or β-cyclodextrin based GC stationary phases. The GC-GC-GC-prep configuration was exploited for the collection of four components, by using a conventional split/splitless injector, while the LC-GC-GC-prep approach was applied for three low abundant components (<5%), in order to increase the quantity collected within a single run, by the LC injection of a high sample amount. All target compounds, whose determination is hampered by the unavailability of commercial standards, were collected at milligram levels and with a high degree of purity (>87%)., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Phthalates are a group of synthetic compounds mainly used as plasticizers, which have been classified as endocrine-disrupting chemicals and potential human-cancer causing agents. They can be found in high amounts in foods, deriving mainly from plastic packaging. The analytical determination of these compounds is very challenging since they are ubiquitous. Therefore, minimization of sample manipulation is highly desirable. The present work exploited the application of a solid-phase microextraction method for the analysis of phthalates in vegetable oil. A preliminary comparison between a polydimethylsiloxane (PDMS) and a Carbopack Z/PDMS fiber was carried out both in the headspace and direct immersion extraction modes. Before immersing the fiber, a rapid liquid-liquid extraction was performed using acetonitrile to remove the bulk of triglycerides. PDMS in the direct immersion mode showed the best performance. The method was fully validated obtaining a good linearity with a coefficient of correlation of over 0.9960 for all compounds, repeatability and accuracy values generally better than 10%, and very good limit of quantification values., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The present research is focused on the use and evaluation of a novel helium ionization detector, defined as barrier discharge ionization detector (BID), within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography (FM GC×GC). The performance of the BID device was compared to that of a flame ionization detector (FID), under similar FM GC×GC conditions. Following development and optimization of the FM GC×GC method, the BID was subjected to fine tuning in relation to acquisition frequency and discharge flow. Moreover, the BID performance was measured and compared to that of the FID, in terms of extra-column band broadening, sensitivity and dynamic range. The comparative study was carried out by using standard compounds belonging to different chemical classes, along with a sample of diesel fuel. Advantages and disadvantages of the BID system, also within the context of FM GC×GC, are critically discussed. In general, the BID system was characterized by a more limited dynamic range and increased sensitivity, compared to the FID. Additionally, BID and FID contribution to band broadening was found to be similar under the operational conditions applied. Particular attention was devoted to the behaviour of the FM GC×GC-BID system toward saturated and aromatic hydrocarbons, for a possible future use in the field of mineral-oil food contamination research., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this work, two analytical liquid chromatography methods were developed and compared for the characterization of aqueous phases from pyrolysis of lignocellulosic biomasses. NanoLC electron ionization-mass spectrometry (EI-MS) represents a novel and useful tool for both separation and identification of semi/nonvolatile and thermolabile molecules. The use of nanoscale flow rates, the highly reproducibility, and high detailed information on EI spectra are the principal advantages of this technique. On the other hand, comprehensive 2D-LC, providing a two-dimensional separation, increases the overall peak capacity lowering the occurrence of peak coelutions. Despite the use of reversed phase modes in both dimensions, a satisfactory degree of orthogonality was achieved by the employment of a smart design of gradient elution strategies in the second dimension in combination with photodiode array detection (PDA) and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS). Because of the absence of the preliminary extraction procedure, the fingerprint obtained for these samples results is independent of the extraction yield or contamination contrary to the gas chromatography-mass spectrometry (GC-MS) approach where a liquid-liquid extraction of the water phase is necessary. The main classes of identified compounds were phenols, ketones, furans, and alcohols. The synergistic information on the two powerful analytical approaches, e.g., NanoLC EI-MS and LC × LC, in the identification of such complex samples has never been investigated and fully benefit on the one hand from the superior degree of mass spectral information from EI-MS and on the other hand from enhanced LC × LC compound separation.

This study reports the recent evolution of a multidimensional GC-GC-GC preparative system, now combined with an online LC preseparation step, operated under normal phase conditions. It is herein shown that the four-dimensional instrument can collect sample components with a concentration lower than 10%, in a short time period, while maintaining a high level of analyte purity. The LC dimension allows (I) the injection of higher sample amounts, compared to "direct" GC injection; (II) a polarity-based preseparation, leading to the GC injection of simplified subsamples, and thus reducing the possibility of coelutions; (III) to eliminate the essential-oil "matrix", replacing it with the LC mobile phase (the GC system is more protected from potential contamination); (IV) the LC mobile phase is of much lower viscosity with respect to a pure, or highly concentrated essential oil, avoiding difficulties in the syringe sample withdrawal process, prior to GC injection. System optimization was performed by using standard solutions; in addition, a very complex sample, namely, vetiver essential oil, was subjected to the preparative process, with the scope of isolating two low-amount constituents (namely, α-amorphene and β-vetivone). The latter two sesquiterpenoids, which accounted for 1.7 and 4.0% of the sample (considering the volatiles), respectively, were successfully collected at the milligram level, in a one-day work period, with a purity degree in excess of 90%.

The present contribution is focused on the evaluation of a high-speed triple quadrupole mass spectrometer, carried out under moderately fast GC conditions (analysis time: 16.6 min). The mass spectrometric instrument can be operated under high-speed GC conditions, in both full-scan (maximum scan speed: 20 000 amu/s) and multiple reaction monitoring (MRM) modes (minimum dwell time: 0.01 s). Additionally, the mass spectrometric system can generate full scan and MRM information, simultaneously and rapidly. A headspace solid-phase microextraction with fast GC coupled to triple quadrupole MS approach was developed for the: (i) qualitative untargeted analysis of brewed tea volatiles, and (ii) MRM qualitative and quantitative analysis of targeted volatiles (also in brewed tea), namely 30 phytosanitary contaminants. The performance of the triple quadrupole instrument was satisfactory both for identification and quantification purposes. Furthermore, the method sensitivity was more than sufficient for the requirements of current legislation. Method validation, related to the MRM analysis, was performed considering: precision of quantification data (maximum coefficient of variation value: 12.0%) and quantification/qualification ion ratios (maximum coefficient of variation value: 14.4%), along with limits of detection (4 parts per trillion-5 parts per billion range) and quantification (14 parts per trillion-16 parts per billion range)., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The present research reports the use of a three-dimensional preparative gas chromatography (prep GC) system, equipped with three Deans-switch devices and 5%diphenyl/wax/mid-polarity ionic liquid stationary phases, for the isolation of volatile components from a complex natural source, namely wampee essential oil (derived from Clausena lansium Skeels leaves). Collection was performed by using a simple and effective lab-constructed trapping device. Initially, an unknown (and abundant) wampee oil constituent was erroneously identified as α-sinensal, through an MS database search (a low similarity match was attained), performed after a GC-quadMS experiment., The unknown compound was then the isolated by using the novel prep GC system, in a highly pure form (at the mg level), and was correctly identified by using nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS). Both FTIR and MS data were used to confirm the NMR information. The name given to the molecule was (2E,6E)-2-methyl-6-(4-methylcyclohex-3-enylidene)hept-2-enal. The results herein described will demonstrate the need for a high-resolution GC step, prior to analyte collection, in the prep GC analysis of complex samples., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The present manuscript is focused on the evaluation of a novel high-speed triple quadrupole mass spectrometer (QqQ MS), carried out under extreme GC conditions, namely those generated by a flow-modulated (FM) comprehensive two-dimensional GC (GC×GC) system. The novel QqQ MS system is capable of operation under high speed conditions, in both full-scan (maximum scan speed: 20,000 amu/s) and multiple reaction monitoring (MRM) modes. Moreover, the QqQ MS instrument can generate simultaneous full scan/MRM data, also in a very rapid manner. An FM GC × GC-MSMS method was developed for the simultaneous full-scan qualitative analysis of untargeted essential oil compounds, and MRM quali/quantitative analysis of targeted ones, namely three preservatives [o-phenylphenol (OPP), butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA)]. The QqQMS system generated a sufficient number of data points per peak, for both qualitative and quantitative purposes. The degree of sensitivity, reached through the MRM analysis, widely exceeded current-day regulations. Method validation, related to the MRM analysis, was performed considering retention time, peak area and ion ratio repeatability, limits of detection and quantification, and accuracy. Additionally, a spearmint essential oil was spiked with 5 phytosanitary compounds at the 1 ppb level, and analysed through an MRM-only GC × GC-MSMS application. Emphasis was devoted not only on sensitivity (satisfactory for all the contaminants), but also on the importance of precursor ion selection, and of the GC × GC separation process. Finally, sensitivity was compared between the MRM and SIM modes, in scan/MRM, MRM, scan/SIM and SIM analyses, performed on a mixture of 22 phytosanitary products, at a concentration level in the 50-150 ppb range., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Gas chromatography-combustion-isotope mass spectrometry was employed for the assessment of the Carbon isotope ratios of volatiles in Italian mandarin and lemon petitgrain oils. In addition, the composition of the whole oil and the enantiomeric distribution of selected chiral compounds were determined for all the samples by using gas chromatography and by multidimensional and conventional enantioselective gas chromatography. The composition of the oils was compared with previous studies. The enantiomeric distribution of lemon petitgrain oils is here reported for the first time. On the composition of mandarin petitgrain oil, the information available in literature, to date, is relative only to one sample from Egypt. Carbon isotope ratio of several terpene hydrocarbons and of their oxygenated derivatives contained in petitgrains was compared with the δ (13)C(VPDB) values of the same compounds present in the corresponding genuine Italian Citrus peel oil. The results prove that the isotopic values obtained for lemon and mandarin petitgrain oils are very close to those relative to the corresponding peel oils determined in previous studies.

The present contribution describes an investigation directed towards the use of a rapid heart-cutting multidimensional LC-GC-FID method for the analysis of mineral oil saturated hydrocarbons (MOSH), contained in different types of homogenized solid baby food (fish, meat and fruit products). The fish and meat products all contained vegetable oil (sunflower), potentially an important source of mineral-oil contamination. Sixteen commercial baby food samples were subjected to analysis, with various degrees of MOSH contamination (from 0.3mg/kg to circa 14 mg/kg) found. Hence, MOSH contamination was found not only in the meat and fish products, but also in the fruit ones. A fruit-based baby food was lab-made, using the ingredients reported on the commercial product, and was found to be contaminated. The single ingredients were then subjected to LC-GC analysis, with corn starch and sugar found to be the source of contamination. For confirmation of the analytical findings, three of the sixteen samples were analyzed in two separate laboratories, using two distinct LC-GC methods, based on different interfaces. The results were confirmed, in qualitative terms, by collecting the LC fractions, relative to some of the food samples, and subjecting them to comprehensive two-dimensional GC-quadrupole mass spectrometry. Thus, mass spectral data were attained for the saturated hydrocarbons., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In the past decades a consistent number of ionic liquids have been specifically synthesized and evaluated as stationary phase in gas chromatography. Ionic liquid, also defined as "molten salts", are a class of organic non-molecular solvents liquid at room temperature (RTILs) that satisfy most of the requirements of a GC stationary phase, among which a high viscosity, the possibility to tune the selectivity (by changing the cation-anion combination) and a high thermal stability. The choice of the proper stationary phase plays a key role in the improvement/optimization of a GC method, and although the use of IL as stationary phases is still not well-established, the general interest in their applications has greatly increased, thanks to their particular properties. The present contribution provides an overview on recent evaluations and applications of IL stationary phases, focusing in particular on the use of these novel tools in hyphenated GC-based techniques., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A novel preparative-scale triple gas chromatographic system, equipped with three Deans-switch devices, is herein described. The isolation of volatile compounds was achieved by using a lab-made collection system. Considerations are made on the possibility to inject high volumes of neat sample, maintaining, at the same time, high resolution levels. The degree of recovery of a series of compounds, characterized by a differing volatility, is also reported. In this respect, different collection conditions were evaluated, namely, the presence (or not) of packing material as well as CO(2) cooling, in various combinations. Finally, the interconnected features, that is time requirements and the isolation of "acceptable" analyte quantities (e.g., milligram level for NMR characterization), are related to parameters such as analyte concentration, injected volume, collection conditions, and number of GC runs. The results herein reported will demonstrate the need for a high-resolution GC step, prior to analyte collection, in the prep-GC analysis of complex samples.

The present contribution is focused on the main advances made in the field of heart-cutting multidimensional gas chromatography (MDGC), over approximately the last decade. Brief details on the history of classical MDGC are also given. A series of applications, carried out with modern-day commercially available instrumentation are shown, demonstrating the usefulness of the bidimensional methodology in specific analytical situations. Finally, the future prospects of MDGC are considered, within the shadow projected by a very powerful GC technique, namely comprehensive two-dimensional gas chromatography., (Copyright © 2011 Elsevier B.V. All rights reserved.)

This article focuses on the genuineness assessment of Lime oils (Citrus aurantifolia Swingle and C. latifolia Tanaka), by Multi Dimensional Gas Chromatography (MDGC) to determine the enantiomeric distribution of α-thujene, camphene, β-pinene, sabinene, α-phellandrene, β-phellandrene, limonene, linalool, terpinen-4-ol, α-terpineol and by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS) to determine the isotopic ratios of α-pinene, β-pinene, limonene, α-terpineol, neral, geranial, β-caryophyllene, trans-α-bergamotene, germacrene B. To the author's knowledge this is the first attempt to assess the authenticity and differentiate Persian Lime from Key lime oils by GC-C-IRMS. The results of the two analytical approaches were compared. The simultaneous use of the two techniques provides more reliable capability to detect adulteration in Citrus essential oils. In fact, in some circumstance only one of the two techniques allows to discriminate adulterated or contaminated oils. In cases where only small anomalies are detected by the two techniques due to subtle adulterations, their synergic use allows to express judgments. The advantage of both techniques is the low number of components the analyst must evaluate, reducing the complexity of the data necessary to deal with. Moreover, the conventional analytical approach based on the evaluation of the whole volatile fraction can fail to reveal the quality of the oils, if the adulteration is extremely subtle., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The present research is focused on the evaluation, in terms of efficiency and polarity, of a recently introduced gas chromatography (GC) column, coated with a 1,12-di(tripropylphosphonium) dodecane bis(trifluoromethansulfonyl) amide ionic-liquid stationary phase (SLB-IL59) and its application to the analysis of a complex essential oil. The ionic liquid column demonstrated very good efficiency, in terms of plate number, and a polarity close to that of the 100% poly(ethyleneglycol) stationary phase. In this preliminary evaluation, the SLB-IL59 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography/mass spectrometry (GC/MS) and, in addition, of comprehensive 2D GC. The SLB-IL59 column (30 m × 0.20 μm d(f), 0.25 mm i.d.) was then evaluated in the analysis of typical essential oil constituents, in the form of pure standard compounds. Resolution toward several analytes was measured and the results were compared to those obtained with both apolar [silphenylene polymer, equivalent to poly(5% diphenyl/95% dimethylsiloxane)] and medium-polarity [100% poly(ethyleneglycol)] stationary phases, namely, the most common columns employed in the analysis of essential oils; peak symmetry, for different essential oil constituents, was also measured and expressed through tailing factors (at 10% of peak height). The final part of the investigation was devoted to the GC/MS analysis of lemon essential oil, with GC-flame ionization detection (FID) used for quantification. Linear retention indices of all the identified compounds were determined, and the data obtained were compared to those attained on the apolar and "wax" columns. The results obtained in the present investigation reveal the great potential of this novel stationary phase, as a medium-polarity alternative, in the analysis of essential oils., (© 2011 American Chemical Society)

The bitter orange flower oil (or neroli) is an essential product, largely used in perfumery. Neroli is obtained by hydrodistillation or steam distillation, from the flowers of bitter orange (Citrus aurantium L.). Since a long time neroli production is limited and its cost on the market is considerably high. The annual production in Tunisia and Morocco is ca. 1500 Kg, representing more than 90% of the worldwide production. A small amount ofneroli is also produced in Egypt, Spain and Comorros (not exceeding 150 kg totally). Due to the high cost, the producers and the users have tried to obtain less expensive products, with odor characters close to that of neroli oil to be used as substitute and sometimes as adulterants of the genuine oil. In this study are investigated five samples of Egyptian neroli oils produced in 2008 and 2009, in the same industrial plant, declared genuine by the producer. For all the samples the composition was determined by GC/FID and by GC/MS-LRI; the samples were also analyzed by esGC to determine the enantiomeric distribution of twelve volatiles and by GC-C-IRMS for the determination of the delta13C(VPDB) values of some mono and sesquiterpene hydrocarbons, alcohols and esters. The analytical procedures allowed to quantitatively determining 86 components. In particular the variation of the composition seems to be dependent on the period of production. In fact, the amount of linalool decreases from March to April while linalyl acetate presents an opposite trend, increasing in the same period. The RSD determined for the delta13C(VPDB) are very small (max. 3.89%), ensuring the authenticity of all samples. The results are also discussed in function of the limits provided by the European Pharmacopoeia (EP) (2004), AFNOR (1995) and ISO (2002) regulations for genuine neroli oils.

The production and trade of Indian sandalwood oil is strictly regulated, due to the impoverishment of the plantations; for such a reason, Australian sandalwood oil has been evaluated as a possible substitute of the Indian type. International directives report, for both the genuine essential oils, specific ranges for the sesquiterpene alcohols (santalols). In the present investigation, a multidimensional gas chromatographic system (MDGC), equipped with simultaneous flame ionization and mass spectrometric detection (FID/MS), has been successfully applied to the analysis of a series of sandalwood oils of different origin. A detailed description of the system utilized is reported. Three santalol isomers, (Z)-α-trans-bergamotol, (E,E)-farnesol, (Z)-nuciferol, epi-α-bisabolol and (Z)-lanceol have been quantified. LoD (MS) and LoQ (FID) values were determined for (E,E)-farnesol, used as representative of the oxygenated sesquiterpenic group, showing levels equal to 0.002% and 0.003%, respectively. A great advantage of the instrumental configuration herein discussed, is represented by the fact that identification and quantitation of target analytes are carried out in one step, without the need to perform two separate analyses., (Copyright © 2010 Elsevier B.V. All rights reserved.)

A total of 92 samples of Sicilian lemon oils (Citrus limon (L.) Burm. f.) produced from September 2008 to June 2009, industrially cold-pressed by different extraction techniques (Brown Oil Extractor and Food Machinery Corporation), were analyzed by GC-flame ionization detector (FID) and GC/MS-LRI to investigate the volatile fraction; by RP-HPLC/PDA to determine the non-volatile components and by enantio-GC-FID to determine the enantiomeric ratios of 12 volatile components. This study provides a detailed investigation on the composition of Sicilian lemon essential oils industrially produced during a productive season, with the aim to recognize quality parameters for the characterization of this product. The results obtained are discussed to evaluate seasonal variation, influence of the extraction techniques, and are compared with those obtained for samples produced during different seasons.