Search

Rapid evaporative ionization mass spectrometry (REIMS) is a relatively recent MS technique explored in many application fields, demonstrating high versatility in the detection of a wide range of chemicals, from small molecules (phenols, amino acids, di- and tripeptides, organic acids, and sugars) to larger biomolecules, that is, phospholipids and triacylglycerols. Different sampling devices were used depending on the analyzed matrix (liquid or solid), resulting in distinct performances in terms of automation, reproducibility, and sensitivity. The absence of laborious and time-consuming sample preparation procedures and chromatographic separations was highlighted as a major advantage compared to chromatographic methods. REIMS was successfully used to achieve a comprehensive sample profiling according to a metabolomics untargeted analysis. Moreover, when a multitude of samples were available, the combination with chemometrics allowed rapid sample differentiation and the identification of discriminant features. The present review aims to provide a survey of literature reports based on the use of such analytical technology, highlighting its mode of operation in different application areas, ranging from clinical research, mostly focused on cancer diagnosis for the accurate identification of tumor margins, to the agri-food sector aiming at the safeguard of food quality and security., (© 2024 Wiley‐VCH GmbH.)

Rapid evaporative-ionization mass spectrometry (REIMS) coupled with an electroknife as a sampling device was recently employed in many application fields to obtain a rapid characterization of different samples without any need for extraction or cleanup procedures. In the present research, REIMS was used to obtain a metabolic profiling of the Kigelia africana fruit, thus extending the applicability of such a technique to the investigation of phytochemical constituents. In particular, the advantages of REIMS linked to a typical electrosurgical handpiece were applied for a comprehensive screening of this botanical species, by exploiting the mass accuracy and tandem MS capabilities of a quadrupole-time of flight analyzer. Then, 78 biomolecules were positively identified, including phenols, fatty acids and phospholipids. In the last decade, Kigelia africana (Lam.) Benth. fruit has attracted special interest for its drug-like properties, e.g., its use for infertility treatments and as anti-tumor agent, as well as against fungal and bacterial infections, diabetes, and inflammatory processes. Many of these properties are currently correlated to the presence of phenolic compounds, also detected in the present study, while the native lipid composition is here reported for the first time and could open new directions in the evaluation of therapeutic activity.

The green microalga Haematococcus pluvialis has been widely studied due to its capacity to accumulate great amounts of astaxanthin, a high-value carotenoid with biological activities. In the present work, two green compressed fluid-based processes, pressurized liquid extraction (PLE) and supercritical antisolvent fractionation (SAF), are integrated to obtain an astaxanthin-enriched extract from this microalga. PLE was carried out using pressurized ethanol as solvent, for 20 min, at 10 MPa, and 50 °C as extraction temperature. Subsequently, the obtained extract was processed by SAF to further purify the carotenoid fraction. The SAF process was optimized using a 3-level factorial experimental design and considering three experimental variables: (i) CO 2 pressure (10-30 MPa), (ii) percentage of water in the PLE extract (20-50%), and (iii) PLE extract/supercritical-CO 2 flow rate ratio (0.0125-0.05). Total carotenoid content was evaluated in both extracts and raffinates. Best results were obtained at 30 MPa, 0.05 feed/SC-CO 2 mass flow rate, and 20% (v/v) of water in the feed solution, achieving values of 120.3 mg g -1 carotenoids in extract (in the SAF extract fraction), which were significantly higher than those obtained in the original PLE extract. In parallel, a new fast two-dimensional comprehensive liquid chromatography (LC×LC) method was optimized to get the full carotenoid profile of these extracts in less than 25 min. This is the first time that the use of a C30 column is reported in an on-line LC×LC system. Graphical abstract.

Punica granatum L., commonly known as pomegranate, is an ancient fruit widely consumed all over the world as fresh fruit or juice. In addition, it is extensively used in therapeutic formulas, cosmetics and food seasonings. The fruit is native to Afghanistan, Iran, China and the Indian sub-continent. The pomegranate market has steadily grown, presumably due to the increasing demand of health-conscious consumers for products with potential beneficial effects on human health, due to the synergistic presence of a unique and complex phytochemical composition that enclose anthocyanins, phenolic acids and hydrolysable tannins. Conventionally, for their analysis liquid chromatography is employed even though it can present some drawbacks in terms of resolving power. In this contribution, as a valuable alternative, comprehensive two-dimensional liquid chromatography with "shifted gradients" in the second dimension, was applied for the characterization of three pomegranate samples, leading to the identification of 37 different polyphenolic compounds.

The topic of food analysis and safety has attracted increasing interest in recent decades owing to recent scandals concerning fraudulent activities (mislabeling, sophistication, adulteration, etc.) that can undermine human health. Among them, seafood fraud has probably the strongest relationship with food safety, an activity that goes beyond economic interests. This article explores the capabilities of an innovative instrumental setup, called the "iKnife," as a powerful tool in this specific research area, where until now genomics and proteomics have been the workhorses in analytical approaches. iKnife, which means "intelligent knife," is the name of a recent technology based on rapid evaporative ionization mass spectrometry (REIMS). REIMS is an emerging technique able to characterize different samples rapidly, affording a comprehensive profile usable as a fingerprint, without the need for preliminary extraction or cleanup procedures. In detail, a REIMS source is coupled to a high-resolution tandem mass spectrometer; such coupling allows one to maximize the amount of information (discriminant features) collected for a single analysis, as well as to focus on target analytes to achieve enhanced sensitivity and selectivity. A database was created from 18 marine species typical of the Mediterranean Sea, all caught in the very small area of the Strait of Messina, and reliable identification was achieved for each species with confidence higher than 99%. One big model and three submodels were built by principal component analysis and linear discriminant analysis for unambiguous key variable identification within each class (e.g., Cephalopoda), order (e.g., Perciformes), or family (e.g., Carangidae). Graphical abstract.

Pistachio (Pistacia vera L.) belongs to the Anacardiaceae family and it is a small tree species. It is native of the Middle East and Central Asia, but currently, it is cultivated also in California and in some Mediterranean countries, such as Greece and Italy. The most important pistachio producers are Iran, the USA, and Turkey. Besides being a delicious nut, pistachio, due to its wholesome nutritional properties, could be considered as a functional food. According to the results of several studies, pistachios have been proven to have various groups of valuable phytochemicals such as anthocyanins, flavan-3-ols, proanthocyanidins, flavonols, isoflavones, flavanones, stilbenes, and phenolic acids, possessing excellent biological activities. The most common analytical technique employed for their analysis is represented by liquid chromatography coupled to photodiode array and mass spectrometry detection. However, conventional LC can present some limits especially in terms of resolving power. In this contribution, as a powerful alternative, comprehensive two-dimensional liquid chromatography (LC×LC) was applied to the determination of the polyphenolic fraction of pistachio kernels from different geographical origins. A 150-mm micro-bore cyano column (2.7 μm d p ) and 50-mm superficially porous C18 silica column (2.7 μm d p ) in the first ( 1 D) and second ( 2 D) dimensions were employed, respectively. For boosting orthogonality, a shift 2 D gradient was investigated leading to an increase in the overall peak capacity. The newly developed LC×LC method showed satisfactory linearity, sensitivity, precision and accuracy, which was then applied to sample quantitative analysis. A total of 51 different polyphenolic compounds were determined in the four samples investigated and 18 out of them are hereby reported for the first time.

An on-line method based on the coupling of supercritical fluid extraction and supercritical fluid chromatography with triple quadrupole mass spectrometry detection (SFE-SFC-QqQ/MS) for the native carotenoids characterization and apocarotenoids detection in yellow tamarillo was developed for the first time; this is the first work reporting the application of this methodology for the apocarotenoids analysis in any matrix. An off-line liquid extraction (LE) and analysis by LC-PDA-MS, using both a conventional C30 (3 μm I.D. particles) and a novel C30 column with sub-2 micron particles were also performed. 31 compounds were extracted and identified by the developed SFE-SFC-QqQ/MS methodology in less than 18 min, including free carotenoids, carotenoids monoesters, carotenoids diesters and apocarotenoids in a very fast, and efficient way; moreover among those 31 compounds, 3 antheraxanthin monoesters and 9 apocarotenoids were detected in yellow tamarillo for the first time, namely apo-8'-zeaxanthinal, apo-10'-zeaxanthinal, apo-12'-zeaxanthinal, apo-14'-zeaxanthinal, apo-15'-zeaxanthinal, apo-12'-carotenal, apo-14'-carotenal and the two apocarotenoids esters apo-10'-zeaxanthinal-C4:0 and apo-8'-zeaxanthinal-C12:0. Further, the novel sub-2 micron particles C30 column, showed a better performance compared to the conventional C30 one. Finally a quantitative comparison of two selected carotenoids was performed by using SFE-SFC-QqQ/MS, SFC-QqQ/MS, and LC-PDA, which showed overall comparable results., (Copyright © 2018 Elsevier Inc. All rights reserved.)

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.

Amine and phenolic metabolites are important contributors to the flavor and health effects of many foods, including wine. Determination of these metabolites often involves UV detection following separation by liquid chromatography. While this is sufficient for some applications, chemical derivatization with LC-MS provides greater sensitivity and selectivity relative to LC-UV. We have developed an assay for 56 amine and phenolic metabolites in wine using benzoyl chloride derivatization and LC-MS. Isotopically labeled benzoyl chloride was used to prepare internal standards for each metabolite. Nanomolar limits of detection were achieved for all metabolites. To demonstrate the application of this assay, we compared metabolite profiles from Merlot and Cabernet Sauvignon wines from California and Australia. We found five metabolites which were significantly different when grouped by varietal, while twenty-four were different when grouped by location of production. This shows that the method can identify differences between various wines., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The present research is based on the development of an effective, environmentally-friendly and low-cost method for investigation of minor components in vegetable oils, exploiting the advantages of a miniaturized solid-phase extraction (SPE) and the potential of flow modulation (FM) comprehensive two-dimensional gas chromatography (GC×GC), coupled to a mass spectrometer (MS) and a flame ionization detector (FID). The initial sample preparation step was carried out using a miniaturized approach characterized by a SPE process in a Pasteur pipette. Then, the isolated fraction was injected into an FM GC×GC system. Tentative identification was carried out by means of MS spectral information, while quantification was carried out by using the FID data. Four different vegetable oil samples were analyzed using the proposed method, namely an extra virgin olive oil (EVO), a hazelnut oil (HO), a borage oil, and an EVO/HO mixture., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two data elaboration approaches for evaluating olive oils authenticity were compared: (I) determination of the difference between the theoretical and actual amounts of triacylglycerols with partition number 42 (ΔECN42 ⩽ |0.2|); and (II) the global method, which considers also partition numbers 44 and 46 (returning a "correct"/"not correct" result). Analysis of 31 genuine extra virgin olive oil samples was performed using different analytical methods, namely liquid chromatography (LC) coupled with a refractive index detector (RID) and LC coupled with a mass spectrometry (MS), and the results compared. Several false positives were highlighted using the ΔECN42 limit with both instrumental approaches. The global method algorithm returned "correct" results for all the samples analysed (except two that gave no results) with LC-MS; on the other hand, 10 false positives were obtained elaborating data deriving from NARP-LC-RID analysis., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In this work, ultra high performance liquid chromatography was used for the characterization of non polar lipids (triacylglycerols) in milk samples of different origin, as well as milk-derivatives. For tackling such a task, three core-shell type octadecylsilica columns were serially coupled, reaching a total stationary phase length of 45cm, using acetonitrile-isopropanol gradient elution allowing triacylglicerol separation according to increasing partition number. The employment of an ion-trap-time-of-flight detection in conjunction with atmospheric-pressure chemical ionization mass spectrometry was carried out to positively identify a number of 243 different triacylglycerols containing up to 22 fatty acids, with 2-22 carbon atom alkyl chain length, and 0-3 double bonds. This work reports an extensive characterization of the triacylglycerol fraction in milk and milk-related samples of different sources., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A non-aqueous reversed phase high performance liquid chromatography method was developed, and optimized for triacylglycerol analysis in a Brevoortia tyrannus (menhaden) oil sample. Four columns were serially coupled to tackle such a task, for a total length of 60 cm of shell-packed stationary phase, and operated under ultra high pressure conditions. As detection, positive-ion atmospheric pressure chemical ionization mass spectrometry was used to attain identification of the analyzed sample components. A number of 137 triacylglycerols containing up to 19 fatty acids, with 14-22 carbon atom alkyl chain length and 0-6 double bonds, were positively identified in the complex lipidic sample. This is the first work that reports an extensive characterization of the triacylglycerol fraction of menhaden oil., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The review, as can be deduced from the title, focuses on both theoretical and practical aspects of the use of mass spectrometry as a third, added dimension to a comprehensive LC (LC × LC) system, generating the most powerful analytical tool today for non-volatile analytes. The first part deals with the technical requirements for linkage of an LC × LC system to an MS one, including the choice of the mobile phase (buffer and salts), flow rate (splitting), type of ionization (interface); advantages and disadvantages of off-line and on-line methods are discussed, as well. A discussion of the various aspects of instrumentation is provided, both from a chromatographic and mass spectrometry standpoint, with particular emphasis directed to the choice of column sets, spatial resolution, mass resolving power, mass accuracy, and tandem-MS capabilities. The extent to which mass spectrometry may be of aid in unraveling column-outlet multicompound bands is highlighted, along with its effectiveness as a chromatographic detector of excellent sensitivity, universality yet with potential in terms of selectivity and amenability to quantitative analysis over a wide dynamic range. The following section of the review contains significant applications of comprehensive two-dimensional LC coupled to MS in different areas of research, with details on interfaces, column stationary phases, modulation and MS parameters. It is not the intention of the authors to provide a comprehensive description of the techniques, but merely to discuss only those aspects which are essential for successful applications of the LC-MS combination. The reader will be acquainted with the enormous potential of this hyphenated technique, and the factors and instrumental developments that have concurred to make it emerge to a central role in specialized fields, such as proteomics., (Copyright © 2012 Wiley Periodicals, Inc.)

Introduction: The berries of Hippophae rhamnoides Linnaeus have high nutritional and medicinal values and have been used for centuries as food both in Europe and Asia. The oleoresins represent a potential source of carotenoid esters and can be used as food additives, cosmetic ingredients or nutraceuticals., Objective: The objective of this study was to develop a HPLC-DAD-APCI-MS method, with both positive and negative ionisation modes, for the direct identification of the native carotenoid composition in fruits of Hippophae rhamnoides., Materials and Methods: Fruits of Hippophae rhamnoides, cv. Serbanesti and Victoria, were collected from an experimental field at the Fruit Research Station of Bacau, Romania. Samples were extracted using methanol:ethyl acetate:petroleum ether (1:1:1, v/v/v). The HPLC-DAD-APCI-MS analyses were carried out on a Shimadzu system using a YMC C₃₀-column and a gradient elution., Results: In total 22 compounds were detected, eight were free carotenoids, nine were xanthophylls monoesters and five were xanthophylls diesters. Differences were observed in the relative percentage composition of the identified components among the two cultivars investigated. Zeaxanthin-C16:0,C16:0 was the most abundant diester. The unsaturated palmitoleic acid was directly detected in its esterified form, in zeaxanthin-C16:0,C16:1, which is reported here for the first time. Although present in small amounts the unsaturated oleic, linoleic, linolenic, hexadecadienoic and hexadecatrienoic acids were detected in their esterified forms as lutein monoesters, the last two having been detected in Hippophae rhamnoides for the first time., Conclusion: A novel (HPLC-DAD-APCI-MS) method was developed for the direct identification of the native carotenoid composition in fruits of Hippophae rhamnoides., (Copyright © 2011 John Wiley & Sons, Ltd.)

In such a complicated field as proteomic analysis, scientists are more and more challenged in implementing separation systems capable to provide enhanced separation power, as well as sensitivity of detection for adequate identification and, to a lesser extent, quantification of the separated compounds. To address such issues, several combinations of different separation modes have been investigated in comprehensive liquid chromatographic platforms, in which the entire sample eluted from the first dimension is subjected to a secondary chromatographic separation. The different applications exploited for comprehensive LC analysis of intact or digested proteins are the focus of this review, in which advantages and disadvantages of the different columns combinations, interfaces, and operating modes are pointed out. The combination with mass spectrometry as part of the total system is stressed, and illustrated in more detail. Theoretical concerns and practical requirements will be briefly discussed, as well., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The combined use of the state-of-the-art hybrid mass spectrometers together with high efficient liquid chromatography could surely be a useful tool for such a challenging task, as phospholipids (PLs) analysis. In this research, we used hydrophilic interaction liquid chromatography (150 mm×2.1 mm I.D., 2.7 μm d.p. partially porous column) to achieve the separation of major PLs classes in cow's and donkey's milk samples. Solid-phase extraction (SPE) was performed in order to pre-concentrate minor PLs from non polar lipids (triacylglycerols) and the recovery for the extraction method was assayed on a milk sample, fortified with 5 μg/mL of SM pure standard, and analyzed in triplicate. A value of 89.99% was calculated, with a coefficient of variation (CV%) of 1.93. A 70-min long stepwise gradient of water/acetonitrile afforded baseline separation of PLs classes, at 50 μL/min flow rate. Accurate detection by an ion trap-time of flight (IT-TOF) mass spectrometer (in both positive and negative ionization mode) allowed to fully characterize the distinctive phospholipid profile and fatty acid composition of cow's and donkey's milk, the latter being analyzed for the first time. Evaporative light scattering detection was further employed to attain the quantitative evaluation of major PLs classes identified, by the external calibration method using reference material solutions in the 5-200 μg/mL concentration range. Major difference between the two analyzed samples consisted in the total PLs amount, which in cow's milk was determined as over 20-fold higher than the donkey's., (Copyright © 2011 Elsevier B.V. All rights reserved.)

LC-MS-based shotgun proteomics relies both on the power of the separation techniques and the sensitivity of detection methods. As a viable alternative to classical approaches in this field, we developed a fully automated, comprehensive 2D LC system, in which RPLC × RPLC was coupled to MS detection, for the first time, and applied for the analysis of tryptic digests obtained from α-casein and dephosphorylated α-casein. The use of a significantly different pH in the two dimensions allowed us to attain high peak capacity, despite the employment of novel identical stationary phases. Furthermore, such a combination addresses compatibility issues, thus allowing straightforward interfacing in online 2D LC configuration, as well as direct linkage to a mass spectrometer. A theoretical peak capacity of ca. 8500 was calculated for the setup, employing four serially coupled C18 columns in the first dimension (600 × 2.1 mm, 2.7 μm d.p.), operated under basic conditions, and 3 cm length of the same stationary phase (30 × 4.6 mm, 2.7 μm d.p. column), under acidic conditions, for fast second dimension analysis.

Infusions or dried leaves from Morus alba (L., Moraceae) have long been used in folk medicine for the prevention or treatment of several diseases. Despite the great interest in determining the role of phytonutrients as potential therapeutic agents, and the rising demand of natural sources with nutraceutic benefits, the antioxidant content of many foodstuffs is unknown, making accurate estimation for human dietary consumption and the correlation to human diseases difficult. The high content in polyphenols mainly accounts for in vitro and in vivo antioxidant activity of extracts obtained from this plant, and it is responsible for their preventive and therapeutic roles in a number of human diseases. In this study, we achieved full characterization and quantitation of flavonoids and other phenolic components extracted from lyophilized mulberry leaves, by maceration with ethanol. To tackle such a task, an RPLC-diode array detector-MS system was optimized, employing a partially porous octadecylsilica column as stationary phase. Identification of mulberry leaves constituents was carried out on the basis of the complementary information obtained from their migration times, diode array spectra, MS ions, and MS/MS fragments. The employment of the hybrid (IT-TOF) mass spectrometer further allowed the structural assignment of a series of structural isomers. To the best of our knowledge, 11 out of 22 identified compounds are being reported in mulberry leaves for the first time, and the relative amounts determined, in the two cultivars analyzed.

There is growing interest related to rapid screening and full characterization of the constituents of plants with medicinal properties; among these, "Mate" or Yerba Maté is a tea-like beverage widely consumed in South America, obtained from the dried leaves of Ilex paraguariensis. The high content in polyphenols accounts for in vitro and in vivo antioxidant activity of the extracts obtained from this plant; on the other hand, the high complexity of the samples extracted, depending on the method employed, may preclude complete resolution by conventional HPLC techniques. For this purpose, a comprehensive two-dimensional liquid chromatography (LC x LC) system, comprised of an RP-Amide first dimension and a partially porous octadecylsilica column in the second dimension, has been compared with a one-dimensional system. The latter was operated using a partially porous octadecylsilica column, with diode array (DAD) and electrospray/ion trap-time of flight (ESI/IT-TOF) detection for the most complex extracts. The employment of the hybrid mass spectrometer allowed unequivocal identification of several compounds in the mate extracts. Using LC x LC-MS(3), it was possible to discriminate between congeners of chlorogenic acids, along with monoacyl- and diacylchlorogenic acid esters.

The present research is focused on the offline combination of normal-phase LC to double-oven GC x GC-quadrupole MS. Initially, a diesel sample was subjected to automated LC x GC in order to define the elution windows of four fractions, viz., saturated hydrocarbons, monocyclic aromatics, dicyclic aromatics, tri- + tetracyclic aromatics; each fraction was collected exploiting the LC system in a further analysis and subjected to large-volume-injection-GC x GC analysis using an apolar-polar column combination. The GC x GC operational conditions were tuned in relation to the specific separation requirements of each heart-cut. The main benefits of what can be defined as offline LC-GC x GC were: (i) the high first-dimension LC selectivity; (ii) the injection of high sample amounts in the GC x GC system, enabling the detection and quantification of a series of low-amount diesel constituents; (iii) improved GC x GC operational conditions for each heart-cut with respect to direct GC x GC.

This study describes the development of a gas chromatography-mass spectrometry (GC-MS) library to identify optically active compounds in the flavour and fragrance field using enantioselective GC with cyclodextrin derivatives (CDs) as chiral selectors in combination with MS. The library operates on the "interactive" combination of linear retention indices (I(T) values) in parallel to MS spectra, so as to identify enantiomers reliably and to measure EE and/or ER unequivocally. Since MS is not a selective probe to discriminate optical isomers, mass spectra (or diagnostic ions in SIM mode) are used to locate the enantiomer(s) in the chromatogram, and I(T) values to identify it(them) safely and reliably in particular in complex mixtures. The library has been built up through the following steps: Some applications of the library are also reported. (a) Selection of CD derivatives able to cover a wide range of racemate separations. Four cyclodextrin derivatives were used: 2,6-di-O-methyl-3-O-pentyl-beta-CD, 2,3-di-O-methyl-6-O-tert-butyldimethylsilyl-beta-CD, 2,3-di-O-ethyl-6-AO-tert-butyldimethylsilyl-beta-CD, and 2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl-beta-CD. (b) Determination of the analytes' I(T) values and evaluation of their stability and reliability at both intra- and inter-laboratory level. (c) Determination of the range within which the I(T) of an enantiomer has to be correctly identified, i.e. determination of a common retention index allowance (RIA). (d) Construction of the library, at the moment comprising the enantiomers of 134 racemates. A record has been attributed to each enantiomer including I(T) values determined on the four CD coated columns, mass spectrum, IUPAC chemical names, CAS numbers, molecular weight, and, when separated, racemate enantiomer resolution on the CD investigated. Some applications of the library are also reported.

In the present work, a novel strategy including the use of two different comprehensive HPLC methods has been employed to study the whole carotenoid composition of mandarin essential oil. Thus, two different fully orthogonal two-dimensional HPLC methods have been used. A silica microbore column was coupled to a C(18) monolithic column to study the mandarin saponified extract, while the coupling of a cyano microbore column to a C(18) monolithic column was employed to study the intact mandarin essential oil sample in order to characterize the native carotenoid esters composition. Detection was performed by connecting a photodiode array detection (DAD) system in parallel with a MS detection system operated with an atmospheric pressure chemical ionization (APCI) interface. Thus, the carotenoid identification was carried out by combining the information provided by the DAD and MS systems and the peaks relative position in the two-dimensional chromatograms.

The present investigation describes the employment of a comprehensive 2-D HPLC system, based on the combination of a silver ion and an RP column, for the characterization of the triacylglycerol (TAG) fraction of a very complex lipidic sample: donkey milk fat. The TAGs were grouped on the resulting bidimensional contour plot according to their double bond numbers (aligned along vertical bands) and according to their partition numbers (aligned along horizontal bands). Peak assignment was supported by using atmospheric pressure chemical ionization mass spectrometric (APCI-MS) detection. The combination of the enhanced resolving power of comprehensive multidimensional LC, the formation of ordered 2-D patterns, and APCI-MS detection proved to be an effective tool for the characterization of the complex matrix, enabling the separation and identification of nearly 60 TAGs.

Triacylglycerols (TAGs), the major components in fats and oils, are a good example of natural complex mixtures. The best technique for the separation of such samples is certainly high performance liquid chromatography (HPLC). Monodimensional HPLC separations are often not sufficient to resolve all the components of interest. The present investigation reports the employment of a comprehensive LC system, based on the different separation mechanisms of silver ion (Ag) and non-aqueous reversed phase (RP) HPLC, used respectively in the first and second dimension, and applied to the analysis of plant-derived natural lipidic matrixes. The results obtained show that the approach enables both the separation of a high number of components and the attainment of structural information due to the formation of group-type patterns on the bidimensional (2D) plane. The employment of atmospheric pressure chemical ionisation (APCI) mass spectrometry as detection system was of substantial support for reliable TAG assignment, thus increasing the identification power of this comprehensive chromatographic approach.

The presence of tallow in lard is not easy to determine, due to the similarity of the composition of these two animal fats, which differ mainly in the distribution of fatty acids (FA) in the three positions of the glycerol molecule. The determination of the composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtures was investigated by HPLC in combination with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The presence of tallow in lard was determined through the study of the sn-POP/sn-PPO ratio by multidimensional HPLC. The off-line bidimensional system was attained through the coupling of non-aqueous reversed phase (NARP)-HPLC and silver ion (Ag)-HPLC. The primary column eluate was fractionated and the fraction containing POP/PPO isomers was injected onto the secondary column, allowing the separation of positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with APCI-MS spectral information. The fatty acid distribution along the glycerol backbone, determined by Ag-HPLC, was confirmed through diglyceride ion ratios derived from APCI-MS analysis. Method validation was carried out in preliminary applications on standard TAGs. The analytical results obtained show that even a 5% addition of tallow to lard modifies the distribution of positional isomers.

The triacylglycerol (TAG) profiles present in real world lipidic samples are usually quite complex and, as such, monodimensional high-performance liquid chromatographic (HPLC) techniques are inadequate when challenged with such matrices. In this respect, the complementary use of silver-ion (Ag) and non-aqueous (NA) reversed-phase (RP) HPLC can be exploited if thorough TAG separations are required. The present investigation reports the employment of a newly developed comprehensive LC (LC x LC) system, based on the different separation mechanisms of the aforementioned techniques, and applied to a rice oil sample. The approach was successful in the separation of a high number of solutes, otherwise unachievable through monodimensional LC. Furthermore, the use of atmospheric pressure chemical ionization mass spectrometry (APCI-MS), as detection system, provided a third analytical dimension boosting the identification power of the comprehensive chromatographic method.

The separation and determination of triacylglycerols (TAGs), which are the main components of naturally occurring fats and oils, in milk fat is a challenging task due to the very complex nature of this matrix. In the present study the TAG fraction of donkey milk lipids has been characterized by using high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS). HPLC in reversed phase mode has been used for TAG separation and silver ion (Ag+) HPLC has been used as a second dimension to clarify and confirm the identification. The RP-HPLC eluate was fractionated and the fractions of interest were injected onto the Ag+-HPLC column. In both cases peak assignment was carried out by combining retention data with APCI-MS spectra information. In total, 55 TAGs in donkey milk fat were identified (without considering the positional isomers) and quantified on the basis of percentage peak areas in the RP-HPLC chromatogram (without the use of correction factors). Amongst the identified triacylglycerols, POLn, POO, PPO, CaPO, POL, and PPoO proved to be the main components of the TAG fraction of donkey milk.

The determination of the triacylglycerol (TAG) profile in real world matrices is rather difficult as these compounds present a complex composition and are characterized by similar physico-chemical properties. This investigation is based on the high-performance liquid chromatography (HPLC) multidimensional determination of the TAG profile in terms of TAG species and positional isomers in a rice oil sample. The off-line bi-dimensional system was attained through the coupling of non-aqueous reversed-phase HPLC and silver ion (Ag)-HPLC. The primary column eluate was fractionated and the fractions of interest were then injected onto the secondary column, allowing the separation of several TAG positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with atmospheric pressure chemical ionisation (APCI) MS spectra information. The fatty acid distribution along the glycerol backbone, determined by Ag-HPLC, was confirmed through diglyceride ion ratios derived from APCI-MS analysis. Method validation, where both precision and accuracy were measured, was carried out in preliminary applications on standard compounds. The analytical results obtained show that rice oil TAGs follow a distribution which can be considered typical for vegetable oils.

Abstract: The research of new tyrosinase inhibitors is currently important for the development of skin whitening agents; particularly, birch leaves extracts are included in many skin cosmetic products. In this study, the potential ability of Betula pendula leaves ethanolic extract (BE) was evaluated on mushroom tyrosinase activity. Results showed that BE was capable to inhibit dose-dependently l-DOPA oxidation catalyzed by tyrosinase. The inhibition kinetics, analyzed by Lineweaver–Burk plots, showed a noncompetitive inhibition of BE towards the enzyme, using l-DOPA as substrate. The inhibitory mechanism of BE as studied by spectrophotometric analysis, demonstrated its ability to chelate copper ion in the active site of tyrosinase. In addition, BE exhibited Fe2+-chelating ability (IC50 =614.12±2.14μg/mL), reducing power and radical-scavenging properties (IC50 =137.22±1.98μg/mL). These results suggest the usefulness of birch leaves extracts in cosmetic and pharmaceutical industries for their skin-whitening and antioxidant effects. Determination of the polyphenolic compounds in BE extracts was afterward achieved by means of high-performance liquid chromatography (HPLC) with photodiode array (PDA) and mass spectrometry (MS) detection. A total of 25 compounds were positively identified, through the complementary analytical information, and are reported in such a matrix for the first time. Knowledge on the qualitative composition and contents of these natural sources in fact represents mandatory information, for rational consumption and correlation of the beneficial effects to the specific amounts. [Copyright &y& Elsevier]

Abstract: The present study was designed to define the phenolic profile and the biological potential of berries methanol extract of Juniperus drupacea Labill. from Turkey. The total phenolic content (Folin–Ciocalteau assay) was 48.06±0.99mgGAE/g extract. The HPLC-DAD-ESI-MS analysis allowed the determination of the complete phenolic profile of J. drupacea berries. Phenolic acids represented more than 60% of the total phenolics, and tyrosol was the major one (1324±0.64μg/g extract); within the flavonoids amentoflavone was detected as the main constituent (927±0.35μg/g extract). The extract exhibited good antioxidant properties, as determined by different in vitro models: DPPH test (IC50 0.38±0.02mg/mL), reducing power (12.63±0.14ASE/mL), Fe2+ chelating ability (IC50 2.26±0.06mg/mL), and TBA test (IC50 2.47±1.13μg/mL). Cytotoxicity against Artemia salina was highlighted (LC50 489.47±27.8μg/mL), and a significant decrease (p ⩽0.05; p ⩽0.01) in HepG2 cells viability was observed at the higher concentrations (5–10μg/mL). The extract displayed good antibacterial activity towards Gram-positive bacteria and in particular Staphylococcus aureus was the most susceptible strain (MIC 78.12μg/mL). [Copyright &y& Elsevier]

Abstract: Lemon liquor, commonly known as “Limoncello”, obtained from maceration of lemon peels in ethanol, water and sugar, has become a product in great demand in the international market. Scientific literature reports just a few studies on Limoncello, however, in consideration of the data available, it can be assumed that in many cases the need of industry for standard products leads to the addition of essential oils and/or related to the alcoholic syrup. Aim of this study was therefore to investigate the volatile and non volatile fraction of lemon liquors of different commercial brands, using solid phase microextraction, gas chromatography-quadrupole mass spectrometry, chiral-gas chromatography and reversed phase HPLC. [Copyright &y& Elsevier]