Tricarballylic Acid Research Articles

Uranyl Tricarballylate Triperiodic and Nanotubular Species. Counterion Control of Nanotube Diameter.

Tricarballylic acid (propane-1,2,3-tricarboxylic acid, H3 tca) was reacted with uranyl nitrate hexahydrate under solvo-hydrothermal conditions and in the presence of different additional cations, yielding four complexes which have been crystallographically characterized. [(UO2)2Ba(tca)2(H2O)4] (1), isomorphous to the PbII analogue previously reported, crystallizes as a triperiodic framework in which diperiodic uranyl-tca3- subunits with the hcb (honeycomb) topology are linked by carboxylate-bound BaII cations. Triperiodic polymerization is also found in [(UO2)2(tca)2Ni(cyclam)] (2) and [(UO2)2(tca)2Cu(R,S-Me6cyclam)] (3), but here the diperiodic uranyl-tca3- subunits have the sql (square lattice) topology, and the frameworks formed through bridging by NiII or CuII cations have different topologies, tcs in 2 and xww in 3. [Co(en)3][UO2(tca)]3·2H2O (4) crystallizes as a monoperiodic coordination polymer with the hcb topology and a nanotubular geometry. In contrast to the square-section nanotubules previously found in [NH4][(UO2)2Pb(tca)2(NO3)(bipy)] (bipy = 2,2'-bipyridine), those in 4 have a hexagonal section with a width of ∼7 Å. The structure-directing role of the hydrogen bonded counterions in these nanotubular species, either NH4+ located within the nanotubule cavity or [Co(en)3]3+ located outside, is discussed. Emission spectra in the solid state display the usual vibronic fine structure for 1 and 4, while uranyl emission is quenched in 3.

Assessment of the effects of acetic, oxalic, and tricarballylic acids on struvite crystallization: characterisation and kinetic studies

ABSTRACT This work reports the characteristics and thermal decomposition kinetics of struvite crystals prepared with and without acetic acid, oxalic acid, and tricarballylic acid as additives. Firstly, the structure, functional groups, surface charge, morphology, particle size, and filtration characteristics of the crystals prepared with and without the additives were determined. All carboxylic acids used in this study were found to significantly affect the surface electrical charge, size, and morphology of the prepared struvite crystals. FTIR analysis revealed the presence of various functional groups in the struvite. With oxalic acid as the additive at a concentration of 200 ppm, the struvite was the most filterable with the lowest cake resistance and highest filtration rate. In the next step, the thermal decomposition of the crystals was examined and the obtained data were used to investigate the dehydration kinetics of the struvite based on a Coats–Redfern kinetic model. The average activation energies of struvite crystals prepared without and with acetic, oxalic, and tricarballylic acid were calculated to be 134.5, 96.3, 111.5, and 97.0 kJ/mol, respectively. Thus, the results of this work are useful for selection of a struvite morphology modifier and explaining the mechanism of the dehydration kinetics of struvite crystals.

Genetic and phenotypic characteristics of <i>Klebsiella michiganensis</i> isolates

The aim of the study was to identify an optimal research target for detection of Klebsiella michiganensis isolates, determine their genetic and phenotypic characteristics necessary for identification. Here, we examined 11 Klebsiella oxytoca strains, lacking (atypical, negative) a marker 5-aminosalicylate decarboxylase (detected by the chromogenic reaction by 5-aminosalicylic acid) unique for the genus Klebsiella bacteria. They were selected for genetic analysis subsequent to a phenotypic characterization of K. oxytoca clinical isolates, collected in within 2015–2018 period in medical institutions in St. Petersburg. Two K. oxytoca and two Raoultella ornithinolytica clinical strains displaying typical properties were used as a control. The presence of 5-aminosalicylate decarboxylase was detected by the chromogenic reaction with the “Klebsiella 5-ASK CHROME C” nutrient medium (Pasteur Institute, St. Petersburg). Substrate utilization as the sole carbon source was detected on a solid minimal synthetic medium added with 2 g/L substrate during incubation for 72 hours at 37°C. Biochemical bacteria features were studied by the microvolume method with the “Rapid-Entero” test system (Pasteur Institute, St. Petersburg). Genetic strain characterization was performed by estimating 16S rRNA, gyrA, rpoB by using a routine PCR with primer sequences described before. Two rpoB gene fragments with a total length 834 bp, 16S rRNA gene fragment — 387 bp, and gyrA gene fragment — 441 bp were amplified followed by their sequencing by Singer on an ABI 3130 automatic capillary sequencer (Applied Biosystems, USA) and subsequently determined similarity levels. Amplification pattern for pehX gene PCR fragments was performed by using a method described elsewhere with two primer pairs flanking fragment AD with a 513 bp length and 344 bp CD-long motifs. While examining 11 clinical bacterial strains identified earlier as Klebsiella oxytoca, lacking (atypical, negative) a 5-aminosalicylate decarboxylase (detected by the chromogenic reaction by 5-aminosalicylic acid) unique for the genus Klebsiella, molecular techniques identified 9 K. michiganensis strains and 1 strain highly homologous to Klebsiella kielensis based on the rpoB gene nucleotide sequence, confirming its high informative value. We used the methods for estimating a similarity level for sequenced fragments of 16S rRNA genes (fragment length 387 bp), gyrA gene (fragment length 441 bp), rpoB gene (rpoB-b and rpoB-e with a total fragments length 834 bp), and the analysis of marker amplicon patterns for pehX gene (AD, CD). It was shown that for the 4 K. oxytoca strains, 99–100% similarity to K. michiganensis was identified for all fragments in the sequenced genes. Moreover, similarity of all 9 strains detected with K. michiganensis was revealed only in the rpoB gene, hereby allowing to recommend it as the most informative approach. The pehX gene encoding polygalacturonase was verified by PCR in the majority of K. michiganensis strains, pointing that this approach is not rational for their identification (distinguish with K. oxytoca). The most informative for the phenotypic identification of K. michiganensis are were assays characterized by a common profile for the majority of strains: lack of 5-aminosalicylate decarboxylase, lack of utilized histamine, dulcitol, tricarballylic acid; positive for indole production, as well as D-melezitose and putrescine utilization.

Super porous TiO2 photocatalyst: Tailoring the agglomerate porosity into robust structural mesoporosity with enhanced surface area for efficient remediation of azo dye polluted waste water

The low surface area of TiO2 (50 m2g-1 - Degussa P25) due to randomly oriented, agglomerated nanostructures and charge carrier recombination tendency, has till date been its major limitation for photocatalytic remediation of polluted wastewater. This study presents an innovative process to design super porous TiO2 nanostructures with high effective surface area (238 m2g-1), robust, structurally ordered mesoporosity via a simple sol-gel assisted reflux method. Detailed material characterization studies suggest that the higher degree of intermolecular ligation in novel templates such as butanetetracarboxylic or tricarballylic acid modified titanium hydroxide gels resulted in retainment of the porous structure during the urea assisted combustion synthesis. The induction of robust structural porosity is accompanied by a reduction in pore size distribution, an increase in pore volume leading to significantly higher total surface area of the synthesized TiO2. Detailed investigation of dye adsorption kinetics and photocatalytic degradation kinetics, complemented by kinetic modeling analysis confirmed that the super porous TiO2 with robust mesoporous structure outperforms the rest of synthesized TiO2 catalyst (having only agglomerate porosity) in terms of its superior adsorption capacity, faster diffusion kinetics and photocatalytic activity for degradation of Amaranth dye. Thus, the super porous TiO2 shows promising potential for application in sustainable photocatalytic technology for remediation of wastewater contaminated with azo dyes.

Selective defunctionalization of citric acid to tricarballylic acid as a precursor for the production of high-value plasticizers

In presence of a solid acid H-Beta zeolite and Pd/C catalyst, citric acid was converted to tricarballylic acid via a one-pot sequential dehydration-hydrogenation process with a yield up to 85% and a selectivity exceeding 90%.

Charge-Transfer-Modulated Transparent Supercapacitor Using Multidentate Molecular Linker and Conductive Transparent Nanoparticle Assembly.

One of the most critical issues in preparing high-performance transparent supercapacitors (TSCs) is to overcome the trade-off between areal capacitance and optical transmittance as well as that between areal capacitance and rate capability. Herein, we introduce a TSC with high areal capacitance, fast rate capability, and good optical transparency by minimizing the charge transfer resistance between pseudocapacitive nanoparticles (NPs) using molecular linker- and conductive NP-mediated layer-by-layer (LbL) assembly. For this study, bulky ligand-stabilized manganese oxide (MnO) and indium tin oxide (ITO) NP multilayers are LbL-assembled through a ligand exchange reaction between native ligands and small multidentate linkers (tricarballylic acid). The introduced molecular linker substantially decreases the separation distance between neighboring NPs, thereby reducing the contact resistance of electrodes. Moreover, the periodic insertion of ITO NPs into the MnO NP-based electrodes can lower the charge transfer resistance without a meaningful loss of transmittance, which can significantly improve the areal capacitance. The areal capacitances of the ITO NP-free electrode and the ITO NP-incorporated electrode are 24.6 mF cm-2 (at 61.6% transmittance) and 40.5 mF cm-2 (at 60.8%), respectively, which outperforms state of the art TSCs. Furthermore, we demonstrate a flexible symmetric solid-state TSC that exhibits scalable areal capacitance and optical transmittance.

A molecular dynamics study of crosslinked epoxy networks: construction of atomistic models

ABSTRACTIn this paper, molecular dynamics (MD) simulations are used to construct atomistic models of crosslinked epoxy networks. An improved algorithm, which considers both the cutoff distance criterion and the orientation criterion, has been developed to construct the realistic, well-equilibrated crosslinked epoxy networks. Epoxy networks containing diglycidyl ether bisphenol-A (DGEBA) as epoxy resin and tricarballylic acid as crosslinking agent are obtained using this algorithm. The results show that this algorithm can effectively decrease the molecular configurations that have unrealistic newly formed bond angles. Some important properties such as glass transition temperature (Tg), coefficient of thermal expansion (CTE) and Young’s modulus are calculated from the equilibrated structures, which are in good agreement with existing experimental and simulated results.

Organic Surfactants Protect Dissolved Aerosol Components against Heterogeneous Oxidation.

Oxidative aging alters the composition of organic aerosols over time, in turn affecting the ability of aerosols to seed cloud formation and scatter solar radiation. Here we explore the heterogeneous photooxidation of model organic particles with and without a soluble surfactant coating. Tricarballylic acid (TCA), a proxy for α-pinene oxidation products, serves as a representative small organic solute. Sodium dodecyl sulfate (SDS) was selected as the representative soluble surfactant because its surface properties have been extensively characterized. A flow reactor and aerosol mass spectrometer were used to determine the second-order reaction rate constant ( k = (1.9 ± 0.1) × 10-11 cm3 molecule-1 s-1) and reactive uptake coefficient (γ = 3.0) for the heterogeneous photooxidation of uncoated TCA particles by gas-phase OH radicals; such a high uptake coefficient implicates radical chain reactions in the oxidation mechanism. SDS dramatically slows the disappearance of TCA: when the SDS concentration approaches monolayer coverage, the rate of reaction of TCA with OH decreases by ∼60% relative to the rate in the absence of SDS. These results indicate that small concentrations of surface-active molecules on atmospheric particles can protect organic solutes in the bulk from oxidative aging. This effect extends the environmental lifetime of dissolved pollutants.

Some New Nonionic Surfactants Based on Propane Tricarboxylic Acid as Corrosion Inhibitors for Low Carbon Steel in Hydrochloric Acid Solutions

The effect of some new nonionic surfactants namely, N1,N2,N3-tris ((14-amino-3,6,9,12-tetraazatetradecyl) carbamothioyl) propane-1,2,3-tricarboxamide (compound I) and N1,N2,N3-tris((2-hydroxyethyl) carbamothioyl) propane-1,2,3-tricarboxamide (compound II) for the corrosion of low carbon steel (LCS) in 1.0 M HCl was evaluated by electrochemical and non-electrochemical techniques. From weight loss measurements, the concentration of these compounds and the temperature of the medium have a large effect on the inhibition efficiency (IE%). The IE% reached 93% for compound (I) and 77.7% for compound (II) at 75 ppm. The behavior of these compounds obeys the Temkin isotherm with good fitting. Polarization curves of these surfactants indicate that they affect both anodic metal dissolution and cathodic H2 evolution (i.e. mixed type). The action of the addition of these compounds on the LCS was detected using scanning electron microscopy, energy disperse X-ray, Fourier-transform infra-red (FTIR) spectroscopy and atomic force microscopy (AFM) techniques. Electrochemical and non-electrochemical methods gave matched results.

Nanostructured Chitosan-Based Biomaterials for Sustained and Colon-Specific Resveratrol Release.

In the present work, we demonstrate the preparation of chitosan-based composites as vehicles of the natural occurring multi-drug resveratrol (RES). Such systems are endowed with potential therapeutic effects on inflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis, through the sustained colonic release of RES from long-lasting mucoadhesive drug depots. The loading of RES into nanoparticles (NPs) was optimized regarding two independent variables: RES/polymer ratio, and temperature. Twenty experiments were carried out and a Box–Behnken experimental design was used to evaluate the significance of these independent variables related to encapsulation efficiency (EE). The enhanced RES EE values were achieved in 24 h at 39 °C and at RES/polymer ratio of 0.75:1 w/w. Sizes and polydispersities of the optimized NPs were studied by dynamic light scattering (DLS). Chitosan (CTS) dispersions containing the RES-loaded NPs were ionically gelled with tricarballylic acid to yield CTS-NPs composites. Macro- and microscopic features (morphology and porosity studied by SEM and spreadability), thermal stability (studied by TGA), and release kinetics of the RES-loaded CTS-NPs were investigated. Release patterns in simulated colon conditions for 48 h displayed significant differences between the NPs (final cumulative drug release: 79–81%), and the CTS-NPs composites (29–34%).

Development of antibodies for N-(1-deoxy-D-fructos-1-yl) fumonisin B1 and cross-reaction with modified fumonisins

Fumonisins are a group of mycotoxins that are routinely found worldwide in commodities such as maize. The group, which has many members, is generally characterised by the presence of one or more tricarballylic acid groups esterified to a long carbon backbone. The diversity of this group of toxins is further augmented by their ability to interact with matrix components non-covalently and to form covalent products with matrix constituents, such as carbohydrates and proteins. Covalent modifications to the toxins make it more difficult to assess the total amounts that may be present in a commodity. We developed monoclonal antibodies (Mabs) against a known product of the reaction of fumonisin B1 (FB1) with glucose: N-(1-deoxy-D-fructos-1-yl) fumonisin B1 (NDFrc-FB1). Similar reactions were used to produce fructosyl-analogs of fumonisins B2 and B3, as well as galactose, maltose, and rhamnose analogs of FB1. These analogs were tested in a competitive indirect ELISA for cross-reactivity towards one of the developed antibodies (Mab 213221). All of the carbohydrate analogs cross-reacted with the Mab, at levels ranging from 75% (the FB3 analog derived from D-glucose) to 181% (the FB1 analog derived from maltose). These results suggested the assay was capable of binding to a wide variety of fumonisin-carbohydrate derivatives. The same antibody was incorporated into an immunoaffinity column that was used to isolate modified fumonisins from a sample of naturally contaminated maize. These results demonstrate the potential to isolate and detect modified fumonisins and will facilitate efforts to determine the frequency of the occurrence of these compounds in maize.

Conformation-Dependent Coordination of Carboxylic Acids with Fe3O4 Nanoparticles Studied by ATR-FTIR Spectral Deconvolution.

The coordination of valeric acid (VA), glutaric acid (GA), and tricarballylic acid (TA) with Fe-OH on the Fe3O4 nanoparticle surface has been systematically studied to elucidate the effects of COOH, molecular configuration, and ligand concentration on the coordination by the combined use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) and thermogravimetric analysis (TGA). The results show that the binding ability of the acids increases with the increase in the COOH number. Multiple conformations coexist for the dicarboxylic and tricarboxylic acid coordinated on the iron oxide NPs. Saturated coordination formed with only a one-, two-, or three-COOH conformation for VA, GA, and TA, respectively, occurs under ligand-scarce conditions, while unsaturated coordination formed with the mixture of uncoordinated, one-, and/or two-COOH conformations for VA, GA, and TA, respectively, exists under ligand-abundant conditions. The maximum coordination numbers for monolayer adsorption for VA, GA, and TA on Fe3O4 NPs are 9, 2.4, and 2.7 nm-2, respectively. This study helps us to understand the fine coordination mechanism caused by the acid molecules with different configurations and elucidates, for the first time, the fine conformational variance incurred by the surrounding ligand with different concentrations and the way in which the ligand is added.

Diverse stacked and entangled topologies in cadmium tricarballylate coordination polymers with nitrobenzene detection capability

Hydrothermal reaction of cadmium salts, tricarballylic acid (H3tca) and dipyridyl ligands resulted in generation of four coordination polymers that were characterized by single-crystal X-ray diffraction. The nature of the ancillary dipyridyl ligand plays a primary role in enforcing differing structural topologies across the series of new phases. [Cd2(tcaH)2(dpe)2]n (1, dpe = 1,2-di(4-pyridyl)ethane) displays a 2-fold interpenetrated 3D 41263pcu net based on 6-connected {Cd2(O)(OCO)} cluster nodes. [Cd(tcaH)(dpp)(H2O)]n (2, dpp = 1,2-di(4-pyridyl)propane) manifests a 1D + 1D → 3D interlocked system of loop-containing perpendicular ribbon motifs. {[Cd4(tca)2(Htca)(bpmp)5(H2O)2]·27H2O}n (3, bpmp = bis(4-pyridylmethyl)piperazine) has intersecting [Cd4(tca)2(Htca)(H2O)2]n layer, [Cd(bpmp)(H2O)]n chain, and [Cd2(bpmp)3]n ladder submotifs and forms a complicated 3,4,5-connected trinodal 3D self-penetrated network with (6.92)(42638)(42638.9310) topology. {[Cd(tcaH)(Hbpmp)](ClO4)·5.5H2O}n (4) exhibits stacked cationic bilayer (4,4) grid slabs. All compounds showed potential as potential detectors for nitrobenzene in ethanol suspension via luminescence quenching, with 1 showing the highest uptake of analyte.

Carboxylic acids as efficient corrosion inhibitors of aluminium alloys in alkaline media

The efficiency of AA5754 aluminium alloy corrosion inhibition achieved with maleic, malic, succinic, tartaric, citric, tricarballylic acids and serine in alkaline environment (pH 11) was examined. Selected corrosion inhibitors are characterized by different numbers and distribution of carbonyl and hydroxyl groups within their molecules. We have proposed and verified a novel approach for determining the adsorption isotherms based on the impedance measurements in galvanostatic mode (g-DEIS), allowing to distinguish subtle changes in the adsorption dynamics. It was shown that g-DEIS precisely determines the inhibitor concentration required for the full coverage of aluminium surface with the adsorbed inhibitor monolayer. Our approach was then cross-verified with the ellipsometry, cyclic polarization and classic EIS measurements, while the SEM and XPS analyses served to determine changes in the surface topography and chemistry. We have demonstrated that the investigated compounds significantly decelerate the corrosion rate of AA5754 at low inhibitor concentrations. Inhibition efficiency exceeds 99% at 6.9 mM for tricarballylic, 8.1 mM for citric and 12.0 mM for tartaric acid. The inhibition efficiency was primarily dependent on the high number of carbonyl groups in the molecule, while the inhibition provided by monocarboxylic amino acid (serine) was negligible, reaching 60% at 20 mM. The plotted isotherms fitted the Langmuir adsorption model, with similar values of Gibbs free energy for each studied inhibitor. The adsorption of carboxylic acids onto the surface of aluminium occurred via ligand exchange mechanism. On the basis of electrochemical and XPS studies, we claim that the role played by hydroxyl groups is secondary, while their presence slightly worsens the corrosion resistance of aluminium.

Synthesis, characterization & cytocompatibility of poly (diol-co-tricarballylate) based thermally crosslinked elastomers for drug delivery & tissue engineering applications

The aim of this study was to investigate the synthesis and in vitro characterization of thermoset biodegradable poly (diol-co-tricarballylate) (PDT) elastomeric polymers for the purpose of their use in implantable drug delivery and tissue engineering applications. The synthesis was based on thermal crosslinking technique via a polycondensation reaction of tricarballylic acid with aliphatic diols of varying chain lengths (C6-C12). PDT prepolymers were synthesized at 140 °C for 20 min. After purification, the prepolymers were molded and kept at 120 °C for 18 h under vacuum to complete the crosslinking process. PDT prepolymers were characterized by DSC, FT-IR, 1H NMR and GPC. The PDT elastomers were also subjected to thermal and structural analysis, as well as sol content, mechanical testing, in vitro degradation and cytocompatibility studies. The mechanical properties and sol content were found to be dependent on synthesis conditions and can be controlled by manipulating the crosslinking density and number of methylene groups in the chain of precursor aliphatic diol. The family of thermally crosslinked PDT biodegradable polyesters were successfully prepared and characterized; besides they have promising use in drug delivery and other biomedical tissue engineering applications.

Reversible pH-Sensitive Chitosan-Based Hydrogels. Influence of Dispersion Composition on Rheological Properties and Sustained Drug Delivery.

The present work deals with the synthesis of micro-structured biomaterials based on chitosan (CTS) for their applications as biocompatible carriers of drugs and bioactive compounds. Twelve dispersions were prepared by means of functional cross-linking with tricarballylic acid (TCA); they were characterized by Fourier transform infrared spectroscopy (FT-IR), modulated temperature differential scanning calorimetry (MTDSC) and scanning electron microscopy (SEM), and their rheological properties were studied. To the best of the authors’ knowledge, no study has been carried out on the influence of CTS concentration, degree of cross-linking and drug loading on chitosan hydrogels for drug delivery systems (DDS) and is investigated herein for the first time. The influence of dispersion composition (polymer concentration and degree of cross-linking) revealed to exert a marked impact on its rheological properties, going from liquid-like to viscoelastic gels. The release profiles of a model drug, diclofenac sodium (DCNa), as well as their relationships with polymer concentration, drug loading and degree of cross-linking were evaluated. Similar to the findings on rheological properties, a wide range of release profiles was encountered. These formulations were found to display a well-controlled drug release strongly dependent on the formulation composition. Cumulative drug release under physiological conditions for 96 h ranged from 8% to 67%. For comparative purpose, Voltaren emulgel® from Novartis Pharmaceuticals was also investigated and the latter was the formulation with the highest cumulative drug release (85%). Some formulations showed similar spreadability values to the commercial hydrogel. The comparative study of three batches confirmed the reproducibility of the method, leading to systems particularly suitable for their use as drug carriers.

Characteristics and Thermal Kinetics of Hydroxyapatite Crystals Doped with Tricarballylic Acid

AbstractHydroxyapatite (HAP) has attracted interest in many fields, e.g., catalysis, water treatment processes, and pharmaceutical industries. HAP crystallization was performed within a batch‐type crystallizer both with and without tricarballylic acid used as additive. The crystals produced in pure media and in the presence of tricarballylic acid were characterized and their thermal degradation was then accomplished in a thermal analyzer in an inert atmosphere. Experimental data was used to calculate the activation energies based on the Kissinger, Flynn‐Wall‐Ozawa, Kissinger‐Akahira‐Sunose, and Starink kinetic models. The results revealed that tricarballylic acid was adsorbed onto the crystal surface, with significant effects on crystal morphology, thermal degradation behavior, and average activation energy.

Uranyl Ion Complexes with Chiral Malic and Citramalic, and Prochiral Citric and Tricarballylic Acids: Influence of Coligands and Additional Metal Cations

Seven homo‐ or heterometallic uranyl ion complexes with R,S‐malic (H3ml), R‐citramalic (H3cml), citric (H4cit), and tricarballylic (H3tca) acids were obtained under (solvo‐)hydrothermal conditions and characterized by their crystal structures, and for five of them, by their uranyl emission spectra. All of the malate, citramalate, and citrate complexes contain the frequently observed 2:2 dimeric uranyl subunit in which the alkoxide group is bridging, these subunits being generally assembled into one‐dimensional (1D) polymeric chains by bridging carboxylate groups. Complexes [(UO2)4(ml)2(C2O4)(NMP)4] (1) and [(UO2)2Cu2(ml)2(C2O4)(phen)2] (2), which contain oxalate anions formed in situ, crystallize as two‐dimensional (2D) networks, the increase in dimensionality being provided by uranyl or copper oxalate bridges. The complex [(UO2)2Ni(cml)2(cyclam)] (3) is also a 2D species, while [(UO2)2Cd(cml)2(bipy)(H2O)2] (4) crystallizes as a three‐dimensional (3D) framework (even if CdII cations are disregarded). The complex [(UO2)2Zn(Hcit)2(bipy)2(H2O)] (5) is a 1D polymer with decorating Zn(bipy)2(H2O)2+ groups, while [(UO2)2Cd(Hcit)2(bipy)2] (6) is a 2D network. The complex [(UO2)2Pb(tca)2(H2O)4] (7), in which the three carboxylate groups are chelating and two of them are further bridging, is a 3D framework. The uranyl emission spectra of complexes 3–6 are in agreement with a previously described trend, the largest blueshift being found for the eight‐coordinate complex 7.

Detection of N-(1-deoxy-D-fructos-1-yl) Fumonisin C1, C2 and C3 in Corn Powder by LC - Orbitrap MS

Detection of N-(1-deoxy-D-fructos-1-yl) fumonisin C1, C2 and C3 (NDfrc-FCs) in a reference material of corn powder were performed with LC-Orbitrap MS. The peaks of NDfrc-FCs were eluted 0.1 ~ 0.3 min earlier than those of fumonisin C1, C2 and C3 (FCs), from the C18 column, probably due to their hydrophilic structures having the carbohydrate residues. At negative ionization mode scan with LC-MS analysis, the fragment ions of the tricarballylic acid (TCA) and characteristic fumonisin ions lacking TCA were detected at the identical retention times with those of respective parent NDfrc-FCs. Mass fragmentation patterns of NDfrc-FCs were confirmed to be almost in consistent with those of FCs. This study is the first report of natural occurrence of NDfrc-FC1, FC2, and FC3 in corn powder.

Quantification of sugars and organic acids in tomato fruits

Sugar and organic acid contents are major factors for tomato fruit flavour and are important breeding traits. Here we provide an improved protocol for accurate quantification of the main sugars, glucose and fructose, and the organic acids, citric acid and malic acid, present in tomato. The tomato extract is spiked with lactose and tricarballylic acid as internal standards and loaded onto a NH2 solid phase extraction (SPE) column. The sugars appear in the flow-through and are subsequently analysed by HPLC using a Nucleodur NH2 column and a refractive index detector. The organic acids bind to the SPE column and are eluted with 400?mM phosphoric acid. For analysis, the organic acids are separated by HPLC using a Nucleodur C18ec column and detected by UV absorption at 210?nm. The method shows excellent inter-day and intra-day reproducibility for glucose, fructose and citric acid with standard deviations of 1–5%. Quantification of citric acid by HPLC and GC–MS showed perfect agreement with a deviation of less than 3%.•Simple method for quantification of glucose, fructose, citric acid and malic acid in tomato.•Efficient removal of interfering compounds by solid phase extraction.•High intra and inter-day reproducibility.