Vegetable oil adulteration in essential oils is a common practice to increase artificially the volume of production of these natural raw materials and reduce the production cost. With the case study of cypriol oil, an overview of the different analytical tools was established to identify the fraud. The analytical strategy implemented analytical approaches suitable for the detection of heavy compounds such as triglycerides in vegetable oils to detect at least 3% of addition. This methodology includes stable isotope analyses IRMS δ 13 C, thermogravimetric analyses, spectroscopic techniques (FTIR and NMR) and the study by GC–MS (high temperature columns and derivatization). Depending on the adulteration performed, some techniques will be more effective. δ 13 C measurement is useful for the authentication of essential oils from C 4 plants; thermogravimetric analysis is the simplest to implement and allows for a quick detection of fraud but does not allow for the identification of the adulterant, in which case a complementary spectroscopic analysis will be necessary.
Cumaru oil (Dipteryx odorata) has chemical properties that make it a sought-after input in the cosmetics, perfumery, alternative medicine and food industries. The appreciation of these essential oils, as well as other native plants, not only reinforces Brazil's position as a leader in the production and export of natural products, but also strengthens its identity on the international scene, promoting sustainability and environmental preservation. For the analysis of carbon-13 (δ¹³C), oxygen-18 (δ¹⁸O) and deuterium (δD) of the essential oil extracted from Cumaru seeds, isotope ratio mass spectrometry (IRMS) was used to determine the authenticity and quality of Cumaru oil. The results obtained allowed validating the methodology used both in the analysis and in the extraction of the essential oil, which used solvents such as ethanol and ethyl acetate, and demonstrated its ability to distinguish genuine products from fraud.
Tonka bean extract, prepared from Tonka beans, is mainly composed of Coumarin. However, due to alternative industrial procedure of production, different solvents and mixtures of solvents were tested for extraction. Investigation using HPLC-DAD-MS indicates influence of extraction procedure on compositions of main constituents. New polyphenols structures have also been found in extracts and improve the chemical analysis knowledge of these products. Waxes compositions using fatty acids methyl esters gas chromatography analysis have been determined and indicate important amounts of behenic and lignoceric acids. High polar constituents (sugars) were also pointed out with trimethyl silanization. As synthetic Coumarin addition represents the main adulteration, isotopic values of Tonka coumarin, isolated by crystallization, have also been determined using an elemental analyzer connected to an isotope ratio mass spectrometer (EA-IRMS). The delta 13C values of authentic coumarin range from - 32.88 to - 31.38%o for delta 13C, between - 113%o and - 83%o for delta 2H, and between 23.0 and 28.0%o for delta 18O. No isotopic effect was observed with different solvents extraction procedures, indicating that IRMS investigation of Coumarin is a powerful tool applied for naturalness control.
Olive mill wastewater produces a variety of potent antioxidants, including hydroxytyrosol, oleuropein, and tyrosol, that have been widely used in agriculture, pharmacy, and cosmetics. This study aims to design new poly(guanamine)s phases by polycondensation of modified triazine monomers with both petro-based and biosourced diamines, to act as stationary phases for the uptake of these phenolic molecules. Obtained polymers were characterized by NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The adsorption results showed that the newly synthesized polymers can effectively uptake the less polar phenolic compounds, ferulic acid, and caffeic acid. The isosorbide-based polymer (P6) presented the highest sorption efficiency, due to the hydrophilic properties of isosorbide associated with the proton affinity of the triazine groups. All the phenolic compounds were successfully desorbed from the P6 polymer using a minimal amount of a methanol/acetonitrile mixture. P6 polymer could be used for four successive adsorption processes without loss of efficiency.
Citronellol is a pleasant-smelling compound produced in rose (Rosa spp.) flowers and in the leaves of many aromatic plants, including pelargoniums (Pelargonium spp.). Although geraniol production has been well studied in several plants, citronellol biosynthesis has been documented only in crab-lipped spider orchid (Caladenia plicata) and its mechanism remains open to question in other species. We therefore profiled 10 pelargonium accessions using RNA sequencing and gas chromatography-MS analysis. Three enzymes from the progesterone 5β-reductase and/or iridoid synthase-like enzymes (PRISE) family were characterized in vitroand subsequently identified as citral reductases (named PhCIRs). Transgenic RNAi lines supported a role for PhCIRs in the biosynthesis of citronellol as well as in the production of mint-scented terpenes. Despite their high amino acid sequence identity, the 3 enzymes showed contrasting stereoselectivity, either producing mainly (S)-citronellal or a racemate of both (R)- and (S)-citronellal. Using site-directed mutagenesis, we identified a single amino acid substitution as being primarily responsible for the enzyme's enantioselectivity. Phylogenetic analysis of pelargonium PRISEs revealed 3 clades and 7 groups of orthologs. PRISEs from different groups exhibited differential affinities toward substrates (citral and progesterone) and cofactors (NADH/NADPH), but most were able to reduce both substrates, prompting hypotheses regarding the evolutionary history of PhCIRs. Our results demonstrate that pelargoniums evolved citronellol biosynthesis independently through a 3-step pathway involving PRISE homologs and both citral and citronellal as intermediates. In addition, these enzymes control the enantiomeric ratio of citronellol thanks to small alterations of the catalytic site.
Authentic Lavandula angustifolia (lavender) essential oil samples (n = 41) were procured from six producing countries. Essential oils were analyzed to determine physical properties and to determine profiles and related data by GC/MS, GC/FID, enantioselective GC, and GC/IRMS. The current study identified 43 volatile compounds that were detected in all authentic lavender samples (n = 41), and which can be considered authentic markers. Enantiomeric ranges for 15 volatile compounds and stable isotope ranges for four prominent compounds were determined in authentic lavender. Authentic samples and associated data were used to assess the quality of commercially available lavender essential oil samples (n = 12). 75% of the commercial samples studied were adulterated,and 17 volatile compounds were detected in these samples which can be considered markers for adulteration. This study establishes the utility and importance of using a multifaceted analytical approach to differentiate quality and determine authenticity of lavender essential oil.
In this work, four triazole-based poly(ether-pyridine)s polymers were synthesized and used as an adsorbent for the removal of phenolic compounds from aqueous solutions. For this purpose, new fluoromonomers containing 1,2,3-triazole units were prepared by the Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction and then used for the elaboration of novel poly(ether-pyridine-triazole)s (PEPTs) by direct polycondensation with isosorbide and bisphenol A. Chemical structure of fluorinated pyridinic monomers as well as resulting polymers was confirmed by H-1 and F-19 NMR spectroscopic methods. The thermal behavior of the obtained PEPTs was characterized using differential scanning calorimetry and thermogravimetric analysis. Results of sorption showed that polymers can be effectively used as a sorbent for the removal of polar organic pollutants. The isosorbide-based poly(ether-pyridine-triazole) which contains hydrophilic hydroxyl groups as pendants chains (P4) exhibited the highest sorption efficiencies (78%-100% after 1 h). In order to explain the results an adsorption mechanism mainly based on pi-pi interactions and hydrogen bonding with the pendent groups is proposed.
Natural plant extracts are primarily used as raw materials in the cosmetic and perfumery industry. However, adulterations with petrochemical products are occurring in the market, leading to non-100% natural products. Several analytical techniques such as impurity detection or enantioselective ratio assessments have been previously described as good indicators to detect any addition of synthetic products, but these techniques are ineffective with novel type of synthetic pathways such as semisynthesis. In order to improve authentication, development of advanced analytical strategies such as δ18O stable isotopic ratios assessment was tested on spearmint, cinnamon and bitter almond essential oils major metabolites (carvone, (E)-cinnamaldehyde, and benzaldehyde). Natural δ18O mean values (δ18OCarvone = 18.4‰; δ18OCinnamaldehyde = 13.9‰; δ18OBenzaldehyde = 16.5‰) were found to be higher than semisynthetic origin for the 3 studied molecules (δ18OCarvone = 9.2‰; δ18OCinnamaldehyde = 8.8‰; δ18OBenzaldehyde = 10.9‰). These measurements proved to be efficient to discriminate natural and semisynthetic origins of these components and therefore potentially lead to a novel way to authenticate natural products.
In the framework of the development of green analytical chemistry, a silica gel (SG) coated with a semi-penetrating network based on the partially biosourced poly(ethersulfone) is studied for a greener extraction process of aromatic organic pollutants. An optimized composition of the semi-penetrating network (80% of the linear polymer (LP): isosorbide-based poly(ethersulfone) and 20% cross-linking agent (XP) type bismaleimide) leads to a total adsorption of the selected aromatic pollutants, whatever their hydrophilicity. Adsorption characteristic, kinetics and isotherms of the SG-semi-INP LP80/XP20 for p-hydroxybenzoic acid and for toluic acid were studied. Langmuir model led to a better fitting of the adsorption isotherms; the adsorption of toluic acid is easier than that of p-hydroxybenzoic acid. 1/n values of benzoic acid was lower for SG-semi-INP LP80/XP20 compared to biochar and to cross-linked methacrylate resin, showing a higher adsorption efficiency.
Phenolic and substituted phenol based resoles are commonly used in the formulation of can coatings. However, migration analyses of these coatings are very little described compared to other coating technologies. While epoxy and polyester have well known migrants with defined formation mechanisms, Non-Intentionally Added Substances (NIAS) specifically related to the phenolic resin are hardly studied in the literature. The goal of the publication is to further explore the influence of the phenolic resole, used in the formulation of can coatings, on extracted NIAS's nature. Six different model polyester-phenolic can coatings were formulated each with a specific phenol, cresol or tertbutylphenol-based resole. Can coating films were extracted for 24 h at 40 °C in acetonitrile before analysis. NIAS identification was done using gas chromatography separation coupled to high resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy analyses. Cyclic polyester oligomers were found in all extracts, with oligomers found in a range of 10 μg/dm2 to 226 μg/dm2, without specific influence of the resole used in formulation. While very few or no peaks were detected from cresol- and phenol-based resoles, 48 peaks were specifically observed in coating extracts of formulas with tertbutylphenol-based resoles as well as in their respective resoles. The most intense peaks were identified as aldehyde compounds by HRMS and NMR analysis. These aldehydes were semi-quantified in similar proportions as polyester oligomers. The presence of such aldehydes has never been reported in the literature regarding NIAS in can coatings. Further study will then be needed to better understand the aldehyde formation mechanism and assess the toxicological profile of such chemicals.
The main objective of this work was to design new advanced sorbent phases, alternating copolymers, derived from isosorbide and 2,6-difluorpyridine, to be used for the removal of aromatic organic pollutants present in water at low concentrations. Six different monomers, dianhydrohexitols isomers and bisphenol derivatives, were synthesized in order to make it possible to study their hydrophilic and hydrophobic effect on the sorption efficiency of the resulting polymeric phases. Before this study, we have confirmed the chemicals structures, molecular weights, and thermal properties of the obtained polymeric phases. Sorption results show a higher adsorption efficiency of P6 co-poly(ether-pyridine) based on bisphenol substituted with pyridine units, for all tested pollutants, hydrophobic and hydrophilic ones, due to its less compact structure. Two aromatic organic pollutants, p-hydroxybenzoic acid and toluic acid, were selected as sorbates to study the adsorption characteristic, kinetics and isotherms of the co-poly(ether pyridine) P6. Langmuir model led to a better fitting of the sorption isotherms; the sorption of toluic acid is easier than of that p-hydroxybenzoic acid. Comparing 1/n values for benzoic acid was two time lower for P6 compared to that for biochar and for cross-linked methacrylate resin, showing a higher efficiency.
A greenhouse pot experiment was conducted to evaluate the impact of zinc supply (0, 1, and 2 mM Zn as ZnSO4) on morpho-physiological and biochemical parameters of caraway (Carum carvi L.). Exposure to different Zn concentrations for 12 weeks compromised severely all growth parameters (plant height, number of secondary branches, diameter of primary and secondary branches, fresh and dry weight of aerial parts and roots) yield and its components (number of umbels per primary branches and secondary branches; number of umbel per plant; number of seeds per plant; and the weight of 1000 seeds). These manifestations were intimately linked with excessive accumulation of Zn in roots and leaves, alteration of the content of photosynthetic pigments, and extended lipid peroxidation. A manifest increment of proline and soluble sugar content was also observed in response to Zn application. Lipid content in seeds was dropped in Zn-treated plants and the fatty acid profiles were profoundly affected as they were enriched with saturated fatty acids at the expense of unsaturated ones. While improving their oxidative stability as revealed by the reduced values calculated oxidizability and oxidative susceptibility, Zn treatment reduced the lipid nutritional quality of caraway seeds. Moreover, Zn treatment reduced the essential oil yield and its main component carvone while it enhanced the content of its precursor limonene. It also induced alteration of terpene metabolism as revealed in the redirection of the carbon flux to the shikimate/phenylpropanoid pathway resulting in the stimulation of the production of phenolic compounds and their subsequent antioxidant activities.
For the development of selective and sensitive chemical sensors, we have developed a new family of poly(ether-phosphoramide) polymers. These polymers were obtained with satisfactory yields by nucleophilic aromatic polycondensation using isosorbide as green resources, and bisphenol A with two novel difluoro phosphinothioic amide monomers. Unprecedented, the thiophosphorylated aminoheterocycles monomers, functionalized with two heterocyclic amine, N-methylpiperazine and morpholine were successfully obtained by nucleophilic sub-stitution reaction of P(S)-Cl compound. The resulting polymers were characterized by different analytical techniques (NMR, MALDI-ToF MS, GPC, DSC, and ATG). The resulting partially green polymers, having tertiary phosphine sulfide with P-N side chain functionalities along the main chain of polymers are the sensitive film at the surface of a gold electrode for the impedimetric detection of Cd, Ni, Pb and Hg. The bio-based poly(ether-phosphoramide) functionalized with N-methylpiperazine modified sensor showed better analytical performance than petrochemical based polymers for the detection of Ni2+. A detection limit of 50 pM was obtained which is very low compared to the previously published electrochemical sensors for nickel detection.
In this work, innovative biosourced polyimide polymers were derived from novel combinations of monomers (Isosorbide, 6-FDA and amine cardo). These polymers were obtained with satisfactory yields by polycondensation of different percentages of isosorbide and of 6-FDA (from 100% to 0%). The synthesized polyimides had number average molecular weight in the 17,600–22,000 g/mol range, and they were stable well above 451 °C (5% weight loss in N2). The glass transition temperature (Tg) were found to be in the range of 318–414 °C, depending on the composition of the copolymers. The adsorption of Water Framework Directive (WFD) heavy metals (Pb2+, Ni2+, Cd2+, Hg2+) on the biosourced polyimide films deposited on a gold electrode was monitored by the measurements of the impedance of the electrolyte/polyimide polymer/electrode interface. The adsorption isotherm of Pb2+on the different polyimide films was modeled according to a Langmuir isotherm with a best fitting. The relative adsorption capacities were higher when the isosorbide content was higher. Comparing the adsorption capacities of the different WFD heavy metals of the isosorbide based polyimide, the sequence is the following one: Pb2+ ≈ Ni2+ > Cd2+ > Hg2+. These results are within the paradigm of Pearson's HSAB principle about the metal-oxygen interaction. When isosorbide based polyimide is the sensitive part of an impedimetric sensor, the detection limit for all the WFD heavy metals is 50 pM, very lower than the environmental quality standards for these WFD priority hazardous substances.
Four Semi-Interpenetrating Networks (semi-IPN) based on polydimethylsiloxane (PDMS) were developed for the sorptive extraction of polar phenolic compounds (log Kow <= 3). Their preparation is based on the hydrosilylation crosslinking reaction of dihydrosilane terminated polydimethylsiloxane with its homologue divinyl, followed by the addition of inert various polyethylene oxide derivatives (PEO). The physico-chemical properties of the semiIPN were controlled by Differential Scanning Calorimetry (DSC), Scanning Electronic Microscopy (SEM), RAMAN spectroscopy and contact angle measurements, showing the homogeneity of the semi-IPN and their higher hydrophilicity. Under optimum extraction conditions of phenolic molecules as target analytes and using liquid chromatography as analysis techniques, the novel modified PDMS phases showed good extraction rate against polar analytes with an excellent relative recovery average (69-100 %) for phenolic molecules. The higher retention rates were obtained with 30 % interpenetrated copolymer PEO/PPO in PDMS. Moreover, five adsorption/desorption cycles led to a loss of 5.8 % of the adsorption efficiency, showing a good stability of these PDMS-based IPN phases.
Pure and natural essential oils of Allium species are primarily used in the food industry, but due to their low yield, production quantities can be difficult to achieve and thus can be highly expensive. Due to these problems, adulterations are a reality in this field. The purpose of this research is to develop a multi element stable isotope analysis methodology for authentication of the essential oils of leek, onion, shallot, and chive. Naturalness of these essential oils was achieved by assessment of compound specific δ13C and δ34S: an addition of 5% of synthetic compound can be detected. Chemometric models were undertaken to assess purity by distinction of the Allium samples according to their species origin using bulk stable and compound specific δ13C, δ2H, δ34S, and compositions of their major metabolites dipropyl disulfide, dipropyl trisulfide, methyl propyl disulfide, and methyl propyl trisulfide.
Neroli essential oil (EO), extracted from bitter orange blossoms, is one of the most expensive natural products on the market due to its poor yield and its use in fragrance compositions, such as cologne. Multiple adulterations of neroli EO are found on the market, and several authentication strategies, such as enantioselective gas chromatography (GC) and isotope ratio mass spectrometry (IRMS), have been developed in the last few years. However, neroli EO adulteration is becoming increasingly sophisticated, and analytical improvements are needed to increase precision. Enantiomeric and compound-specific isotopic profiling of numerous metabolites using multidimensional GC and GC-C/P-IRMS was carried out. These analyses proved to be efficient for geographical tracing, especially to distinguish neroli EO of Egyptian origin. In addition, δ2H values and enantioselective ratios can identify an addition of 10% of petitgrain EO. These results demonstrate that enantioselective and stable isotopic metabolite fingerprint determination is currently a necessity to control EOs.
Three new compounds, a dihydrobenzofuran (coumaran) derivative (compound 1) and two pterocarpans (compounds 2 and 3) were isolated from a root extract of Calicotome villosa growing wild in Corsica. Their structures were elucidated using 1D and 2D NMR spectroscopy and MS/MS as 2-(1-methylethenyl)-5-hydroxy-6-carbomethoxy-2,3-dihydro-benzofuran, 4,9-dihydroxy-3-methoxy-2-dimethylallylpterocarpan, and 4,9-dihydroxy-3′,3′-dimethyl-2,3-pyranopterocarpan.
In this work, innovative poly(ether pyridine) polymers obtained from bio-based monomers and pentafluoropyridine derivatives were elaborated in order to adsorb aromatic pollutants and their halogenated derivatives. These polymers were obtained with satisfactory yields by polycondensation of four pyridinium monomers (respectively based on morpholine, piperazine, dimethylamine and phenol) with isosorbide or bisphenol A. The adsorption efficiency data demonstrate that the poly(etherpyridine) based on isosorbide and morpholine-based monomer (P2) is the more efficient sorbent toward aromatic pollutants and their derivatives. Four aromatic pollutants, p-hydroxybenzoic acid, toluic acid, deisopropylatrazine, and 2,4,6-trichlorophenol, were chosen as the adsorbate to investigate the adsorption efficiency, kinetics and isotherms of the poly(ether pyridine) P2. The results demonstrate that the pseudo-second order was the best to describe the adsorption of the four target pollutants by the efficient sorbent P2 with good correlation. The experimental data of the four target pollutants adsorption were analyzed by Langmuir and Freundlich isotherms. Polymer P2 shows very high affinity (low 1/n value) for p-hydroxybenzoic acid and for 2,4,6-trichlorophenol, compared to other adsorbents. Three consecutive adsorption/desorption cycles toward eight aromatic pollutants were obtained for the efficient sorbent P2.