Mass Spectrometric Study of the Most Common Potential Migrants Extractible from the Inner Coatings of Metallic Beverage Cans.

Population exposure to endocrine disrupting chemical- bisphenols, which are used commonly in food containers and drinking water pipes in Europe, is above acceptable health and safety levels, according to updated research data. In order to evaluate the most abundant potential migrants in canned sweetened beverages marketed in Poland, we performed the HPLC-MS screening test of the migrants present in the can coating material. The analyzed samples represented the three top-ranked companies of the global soft drink market; it is reasonable to assume that the obtained data are of global validity. The tested can coatings and beverages contained bisphenols conjugates such as five butoxyethanol (BuOEtOH) adducts with bisphenol A diglycidyl ether (BADGE), one butoxyethanol adduct with bisphenol A monoglycidyl ether (BAMGE), and cyclo-di-BADGE. The performed HPLC-MS/MS analysis in the MRM mode enabled evaluation of the concentrations of the detected conjugates in canned beverages which were found to be very low, namely at the level of 1 µg/L. On the other hand, the high consumption of canned beverages may yield a risk associated with the presence of these compounds in the diet. The subsequent HPLC-QTOF-MS/MS experiments allowed, for the first time, a detailed determination of the fragmentation pathways of the detected migrants as well as detection of the isomers of the two migrants, namely BADGE + BuOEtOH and BADGE + BuOEtOH + HCl.

Oligoester Identification in the Inner Coatings of Metallic Cans by High-Pressure Liquid Chromatography-Mass Spectrometry with Cone Voltage-Induced Fragmentation.

The application of polyesters as food contact materials is an alternative to epoxy resin coatings, which can be a source of endocrine migrants. By using high-pressure liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS) with cone voltage-induced fragmentation in-source, a number of polyester-derived migrants were detected in the extracts of inner coatings of metallic cans. The polyester-derived migrants were detected in each inner coating of fish product-containing cans (5/5) and in one inner coating of meat product-containing can (1/5). They were not detected in the inner coatings of vegetable/fruit product-containing cans (10 samples). The respective detected parent and product ions enabled differentiation between cyclic and linear compounds, as well as unambiguous identification of diol and diacid units. Most of the detected compounds, cyclic and linear, were composed of neopentyl glycol as diol and two diacid comonomers, namely isophthalic acid and hexahydrophthalic acid. The other detected oligoesters were composed of neopentyl glycol or propylene glycol and adipic acid/isophthalic acid as comonomers. The compounds containing propylene glycol as diol were found to be exclusively linear cooligoesters. On the basis of abundances of [M+Na]+ ions, the relative contents of cyclic and linear oligoesters were evaluated.

Teaching mass spectrometry: A compilation of approaches to teaching theory and practice of mass spectrometry.

The areas of mass spectrometry applications seem to be much larger than those of any other analytical techniques. They extend from the determination of molecular mass in organic chemistry, through the analytical applications in forensic, environmental and omics sciences, the application in extra-terrestrial exploration and many others. Mass spectrometry, usually coupled with chromatographic techniques, has also found wide application in the pharmaceutical industry, forensic laboratories, laboratories of sanitary inspection or environmental inspection, etc. The growing areas of applications give rise to the demand for the comprehensive mass spectrometry education of undergraduates. This overview covers the body of literature describing various interesting ideas that can be successfully used for teaching mass spectrometry. Since mass spectrometry is a multidisciplinary field, old but dynamically developing, teaching mass spectrometry may be more problematic in comparison to teaching other analytical techniques, for example, there is the problem of position of mass spectrometry in the chemistry curriculum. On the other hand, it is obvious that the mass spectrometry community, besides difficult scientific work, does great and admirable teaching work, in order to perfectly educate undergraduates in the field of mass spectrometry and to make learning mass spectrometry as attractive as possible.

Comment on Villalva et al. Antioxidant, Anti-Inflammatory, and Antibacterial Properties of an Achillea millefolium L. Extract and Its Fractions Obtained by Supercritical Anti-Solvent Fractionation against Helicobacter pylori. Antioxidants 2022, 11, 1849.

Villalva et al. evaluated the potential utility of an Achillea millefolium (yarrow) extract in the control of H. pylori infection. The agar-well diffusions bioassay was applied to determine the antimicrobial activity of yarrow extracts. The supercritical anti-solvent fractionation process of yarrow extract was made to give two different fractions with polar phenolic compounds and monoterpenes and sesquiterpenes, respectively. Phenolic compounds were identified by HPLC-ESIMS by using the accurate masses of [M-H]- ions and the characteristic product ions. However, some of the reported product ions seem to be disputable, as described below.

Comment on Hu et al. Determination of 2-Pentanol Enantiomers via Chiral GC-MS and Its Sensory Evaluation in Baijiu. Foods 2022, 11, 2584.

Recently, Hu et al. have published a very interesting paper concerning the GC-MS analysis of 2-pentanol enantiomers in four types of Baijiu, a strong alcoholic beverage, which is of importance to Chinese social culture [...].

Extraction with Acidified Methanol-An Easy and Effective Method of Methyl Chlorogenate Formation, as Studied by ESI-MS.

Among the different Hawthorn species, Crataegus monogyna seems to be one of the most often used in herbal medicine, and is commercially available. The methanolic extract and the acidified methanol extract of an herbal medicinal product based on Crataegus monogyna inflorescences were analyzed by using high-pressure liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS). On the basis of m/z of [M-H]- ions and characteristic fragmentation patterns, a number of polyphenolic compounds, namely flavonoids and chlorogenic acids, were identified. It was found that the contents of the acid extract were enriched with methyl chlorogenates showing attractive biochemical properties. Analogous results were obtained for other plant materials, e.g., nectarine kernels. Apart from that, acid extraction had a minor influence on the polyphenolic compounds present in the plants, and thus it did not affect the natural antioxidant values of the plant extracts.

Sensitized photoreduction of selected benzophenones. Mass spectrometry studies of radical cross-coupling reactions.

The hydrogen atom transfer reaction (HAT) between selected benzophenones (benzophenone BP, 3-carboxybenzophenone 3CB, and 4-carboxybenzophenone 4CB) and 2-propanol was reinvestigated focusing on stable product analysis. As expected, the primary species of these HAT's are the respective diphenyl and dimethyl ketyl radicals that eventually undergo several radical coupling reactions leading to stable photoproducts. However, the mechanisms of these free radical reactions remain unclear and open to question. In this report, we focus on the detailed analysis of the stable photoproducts of these reactions using liquid chromatography coupled with high-resolution mass spectrometry (LC-ESI-QTOF-MS/MS). Products of photopinacolization (benzpinacol and two diastereoisomers of 4CB and 3CB dimers) and isomeric radical cross-coupling adducts of respective diphenyl and dimethyl ketyl radicals were separated chromatographically, and their structures were determined by high-resolution MS/MS, and the mechanisms of the reactions are discussed.

Comment on Tremmel et al. In Vitro Metabolism of Six C-Glycosidic Flavonoids from Passiflora incarnata L. Int. J. Mol. Sci. 2021, 22, 6566.

In recent years, growing attention has been paid to the chemical composition of aerial parts extracts and the bioavailability of active compounds from different species of Passiflora genus [...].

Laser Desorption/Ionization Mass Spectrometry as a Potential Tool for Evaluation of Hydroxylation Degree of Various Types of Titanium Dioxide Materials.

For many applications, TiO2 must have a unique surface structure responsible for its desirable physicochemical properties. Therefore the fast and easy methods of TiO2 surface characterization are of great interest. Heated TiO2 samples and dye-modified TiO2 samples were analyzed by laser desorption/ionization mass spectrometry. In the negative ion mode, two types of ions were detected, namely (TiO2)n- and (TiO2)nOH-. It has been established that the samples can be differentiated based on the relative ion abundances, especially with respect to the free hydroxyl group population. It indicates that laser desorption ionization mass spectrometry has the potential for the investigation of the surface properties of various TiO2 materials.

The Electrospray (ESI) and Flowing Atmosphere-Pressure Afterglow (FAPA) Mass Spectrometry Studies of Nitrophenols (Plant Growth Stimulants) Removed Using Strong Base-Functionalized Materials.

The functional silica-based materials functionalized with a strong nitrogen base TBD (SiO2-TBD) deposited via a linker or with a basic poly(amidoamine) dendrimer containing multiple terminal amine groups -NH2 (SiO2-EDA) and functional polymers containing a strong phosphazene base (Polymer-Phosphazene) or another basic poly(amidoamine) dendrimer (PMVEAMA-PAMAM) were tested as sorbents dedicated to a mixture of nitrophenols (p-nitrophenol and 2-methoxy-5-nitrophenol), which are analogs of nitrophenols used in plant growth biostimulants. The adsorptive potential of the studied materials reached 0.102, 0.089, 0.140, and 0.074 g of the nitrophenols g-1, for SiO2-TBD, SiO2-EDA, polymer-phosphazene, and PMVEAMA-PAMAM, respectively. The sorptive efficiency of the analytes, i.e., their adsorption on the functional materials, the desorption from the obtained [(sorbent)H+ - nitrophenolates-] complexes, and interactions with the used soil, were monitored using mass spectrometry (MS) technique with electrospray (ESI) and flowing atmosphere-pressure afterglow (FAPA) ionizations, for the analysis of the aqueous solutions and the solids, respectively. The results showed that the adsorption/desorption progress is determined by the structures of the terminal basic domains anchored to the materials, which are connected with the strength of the proton exchange between the sorbents and nitrophenols. Moreover, the conducted comprehensive MS analyses, performed for both solid and aqueous samples, gave a broad insight into the interactions of the biostimulants and the presented functional materials.

Mass Spectrometric Investigation of Organo-Functionalized Magnetic Nanoparticles Binding Properties toward Chalcones.

Chalcones are naturally occurring compounds exhibiting multiple biological functions related to their structure. The investigation of complexes formed by chalcones, namely 2',4'-dihydroxy-2-methoxychalcone (DH-2-MC) and 2',4'-dihydroxy-3-methoxychalcone (DH-3-MC), with organo-functionalized Fe3O4 magnetic nanoparticles using mass spectrometric techniques is reported. The magnetic nanoparticles were obtained by the silanization of Fe3O4 particles with 3-aminopropyltrimethosysilane, which were subsequently reacted with 3-hydroxybenzaldehyde (3-HBA) or 2-pyridinecarboxaldehyde (2-PCA), resulting in the formation of Schiff base derivatives. The formation of their complexes with chalcones was studied using electrospray (ESI) and flowing atmosphere-pressure afterglow (FAPA) mass spectrometric (MS) ionization techniques. The functional nanoparticles which were synthesized using 3-hydroxybenzaldehyde displayed higher affinity towards examined chalcones than their counterparts obtained using 2-pyridinecarboxaldehyde, which has been proved by both ESI and FAPA techniques. For the examined chalcones, two calibration curves were obtained using the ESI-MS method, which allowed for the quantitative analysis of the performed adsorption processes. The presence of Cu(II) ions in the system significantly hindered the formation of material-chalcone complexes, which was proved by the ESI and FAPA techniques. These results indicate that both mass spectrometric techniques used in our study possess a large potential for the investigation of the binding properties of various functional nanoparticles.

Ethoxylated Butoxyethanol-BADGE Adducts-New Potential Migrants from Epoxy Resin Can Coating Material.

The acetonitrile extracts of can-coating materials have been analyzed by using high-pressure liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS). On the basis of detected ions [M + H]+, [M + NH4]+, [M + Na]+ and product ions, the ethoxylated butoxyethanol-bisphenol A diglycidyl ether adducts were identified in two of the analyzed extracts. Although the oxyethylene unit-containing compounds are widely used for the production of different kinds of materials, the ethoxylated species have not been earlier detected in epoxy resin can-coatings.

Gas-phase generation of dinuclear Au(I)-Au(II) complexes by laser desorption ionization mass spectrometry.

Alkali metal chloroaurates(III) were analysed by laser desorption ionization mass spectrometry. Among a number of generated gas-phase ionic clusters, the unusual ions [MAu2Cl5]- (were M stands for Na, K, Rb, Cs) were detected. The spectra of metastable ions and quantum mechanics calculations show the presence of unprecedented Au(I)-Au(II) interactions in the clusters.

2,2-Bis(4-Hydroxyphenyl)-1-Propanol-A Persistent Product of Bisphenol A Bio-Oxidation in Fortified Environmental Water, as Identified by HPLC/UV/ESI-MS.

Biodegradation of bisphenol A in the environmental waters (lake, river, and sea) has been studied on the base of fortification of the samples taken and the biodegradation products have been analyzed using HPLC/UV/ESI-MS. Analysis of the characteristic fragmentation patterns of [M-H]- ions permitted unambiguous identification of the biodegradation products as 2,2-bis(4-hydroxyphenyl)-1-propanol or as p-hydroxyacetophenone, depending on the type of surface water source. The formation of 2,2-bis(4-hydroxyphenyl)-1-propanol was much more common than that of p-hydroxyacetophenone. Moreover, 2,2-Bis(4-hydroxyphenyl)-1-propanol has not been further biodegraded, in contrast to the p-hydroxyacetophenone, which was further mineralized. It has been proved, for the first time, that 2,2-bis(4-hydroxyphenyl)-1-propanol can be regarded as persistent product of bisphenol A biodegradation in the fortified environmental waters.

Elucidation of glycosylation sites of kaempferol di-O-glycosides from methanolic extract of the leaves of Prunus domestica subsp. syriaca.

RATIONALE: Flavonol glycosides containing the glycosylation patterns 3,4'-di-O and 4',7-di-O are rare in nature and they have not yet been studied in detail by electrospray ionization mass spectrometry (ESI-MS(+/-), in contrast to the flavonol glycosides containing the glycosylation pattern 3,7-di-O. METHOD: The leaves from Prunus domestica L. subsp. syriaca were extracted with pure methanol or, in order to perform hydrolysis and extraction simultaneously, with a 5% methanolic solution of hydrochloric acid. The high-performance liquid chromatography (HPLC)/ESI-MS(+/-) analyses were performed using a Waters model 2690 HPLC pump and a Waters/Micromass ZQ2000 mass spectrometer. RESULTS: Three kinds of kaempferol di-O-glycosides have been identified, namely kaempferol-3-O-hexoside-7-O-rhamnosides, kaempferol-3-O-pentoside-4'-O-rhamnosides and kaempferol 4',7-di-O-rhamnoside. The identification was performed on the basis of the abundances of the respective Y-type product ions. CONCLUSIONS: The abundances of [Yn 0 - H]-· , Yn 0 - and Yn 0 + product ions were of crucial importance for the determination of glycosylation patterns. The obtained results can be useful for HPLC/ESI-MS identification of rare flavonol-di-O-glycosides.

Differentiation of bisphenol F diglycidyl ether isomers and their derivatives by HPLC-MS and GC-MS-comment on the published data.

Positional isomers of bisphenol F diglycidyl ether (BFDGE) have been analyzed by high-pressure liquid chromatography-mass spectrometry and by gas chromatography-mass spectrometry (HPLC-MS, GC-MS). Positional isomers of BFDGE derivatives (BFDGEx2H2O, BFDGExH2OxHCl) have been analyzed by HPLC-MS. On the basis of the obtained fragmentation patterns, the elution order of the isomers has been unequivocally determined, in standard solutions and in the sample of liquid obtained after rinsing an empty mackerel fish can with acetonitrile. Under HPLC condition, para,para isomers are eluted first, then ortho,para isomers' elution follows, and ortho,ortho isomers are eluted last. Under GC condition, the reverse elution order has been obtained. For the first time, two ortho,para isomers of BFDGExH2OxHCl have been detected and their elution order has been determined. The obtained results are of key importance for determination of the isomer distribution of BFDGE and its derivatives in food samples.

Electrospray ionisation mass spectrometric behaviour of flavonoid 5-O-glucosides and their positional isomers detected in the extracts from the bark of Prunus cerasus L. and Prunus avium L.

INTRODUCTION: Literature data concerning the electrospray ionisation mass spectrometry (ESI-MS) behaviour of flavonoid 5-O-glycosides are poor and sometimes disputable. Therefore, we decided to analyse the compounds of this kind present in the bark of Prunus cerasus and Prunus avium by using high-performance liquid chromatography HPLC/ESI-MS. OBJECTIVE: The aim of this study is to obtain the comprehensive information about the ESI-MS(+/-) behaviour of flavonoid 5-O-glucosides, to compare their behaviour with that of their positional isomers, to confirm that the known susceptibility of flavonoid 5-O-glucosides to hydrolysis may be successfully used for their identification. METHOD: The bark from Prunus trees was extracted with pure methanol or, in order to perform hydrolysis and extraction simultaneously, with 5% methanolic solution of hydrochloric acid. The HPLC-ESI-MS analyses were performed using a Waters model 2690 HPLC pump and Waters/Micromass ZQ2000 mass spectrometer. RESULTS: Flavonoid 5-O-glycosides were completely hydrolysed under the acid conditions used, in contrast to their positional isomers. In positive ion mode, at low cone voltage, flavonoid 5-O-glycosides yield abundant Y0 + aglycone ions, in contrast to their positional isomers. In the negative ion mode, flavonoid 5-O-glycosides do not yield [Y0 - H]-· fragment ions, in contrast to their positional isomers. When aglycone contains only two hydroxyl groups, the flavonoid 5-O-glycosides can be detected in negative ion mode, whereas their positional isomers do not yield [M - H]- ions. CONCLUSION: It has been demonstrated that the susceptibility to hydrolysis of the analysed compounds, the abundances of respective fragment ions formed, and their ESI(-) response allow unambiguous identification of flavonoid 5-O-glycosides and their differentiation from their positional isomers.