Fructose Molecules Research Articles

Degradation mechanism of difructose dianhydride III in Blautia species.

Di-fructofuranose 1,2':2,3' dianhydride (DFA-III) is a cyclic fructo-disaccharide, which is produced by the condensation of two fructose molecules via the caramelization or enzymatic reaction of inulin fructotransferase. A strain of Blautia producta was known to utilize DFA-III as a carbohydrate source; however, the mechanisms remain unclear. In this study, we characterized the glycoside hydrolase (GH) family 91 DFA-III hydrolase (DFA-IIIase) from B. parvula NBRC 113351. Recombinant BpDFA-IIIase catalyzed the reversible conversion of DFA-III to inulobiose, which is further degraded to fructose by the cooperative action of DFA-IIIase and GH32 β-D-fructofuranosidase. DFA-III was utilized in several Blautia species with a gene cluster for DFA-III degradation (e.g., B. parvula NBRC 113351, B. hydrogenotrophica JCM 14656, and B. wexlerae JCM 35486), but not by B. wexlerae JCM 31267, which does not possess the gene cluster. Furthermore, B. hansenii JCM 14655, which cannot metabolize fructose, could not utilize DFA-III; however, it could degrade DFA-III to fructose in the presence of DFA-III-degrading enzymes. Fecal fermentation tests showed that Blautia species are important gut microbe for degrading DFA-III. KEY POINTS: • BpDFA-IIIase is the first characterized DFA-IIIase in intestinal non-pathogenic bacteria. • DFA-IIIase is widely conserved in Blautia species. • DFA-III is degraded to d-fructose through inulobiose by the cooperative action of DFA-IIIase and β-d-fructofuranosidase.

Influence of loading method on the performance of Zn/SAPO-34 catalysts and its catalytic preparation of 5-Hydroxymethylfurfural from fructose dehydration

A diverse suite of Zn-SAPO-34 catalysts was synthesized employing three distinct methodologies for the incorporation of zinc species: thermal ion exchange, wet impregnation, and physical mixing. The catalysts were characterized using various analytical techniques including XRD, FT-IR, BET, SEM, XRF, XPS, NH3-TPD, and Py-IR, to elucidate the crystal structure, morphology, surface acidity, and the presence of zinc species within the catalysts. The study showed that the method of zinc introduction markedly impacts the physicochemical properties of the catalysts. Different approaches to introducing zinc species significantly influence the acid strength and type on the catalyst surface, with variations in the existing states of zinc across the catalysts. Specifically, zinc species introduced via thermal ion exchange coexist as ZnOH+ and ZnO within the catalyst, whereas those from wet impregnation and physical mixing are individually present as either ZnOH+ or ZnO. Furthermore, the study examined the catalytic performance of these Zn-SAPO-34 catalysts in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Catalysts prepared via thermal ion exchange exhinited superior performance, achieving an remarkable HMF yield of 94.6 %. Additionally, in situ infrared technology was used to investigate the effect of zinc species introduction on the fructose dehydration process, indicating suggesting that the introduction of zinc species enhances the transformation of fructose molecules.

Natural honey helps stabilize zinc anode for dendrite-free aqueous zinc ion batteries

Aqueous zinc-ion batteries (AZIBs) have garnered significant attention as energy storage devices due to their high theoretical capacity, low cost, and superior safety. However, uncontrolled Zn dendrite growth and parasitic side reactions have hindered their practical applications. Herein, a novel low-cost and non-toxic electrolyte additive, honey, is incorporated into the typical ZnSO4 electrolyte to stabilize the Zn anode for high performance AZIBs. Both simulation and experimental results suggest that the natural honey additive can regulate the interaction of Zn2+ with SO42− and H2O molecules, thereby promoting the desolvation of Zn2+. Concurrently, glucose and fructose molecules in honey tend to absorb onto the Zn anode, facilitating the uniform deposition of Zn2+. Therefore, the honey additive can effectively inhibit the growth of Zn dendrites and side reactions. As expected, the Zn-symmetric cell with ZnSO4-honey electrolyte achieves excellent Zn stripping/plating reversibility, maintaining stable potentials over 2000 h at 1 mA cm−2 and nearly 1200 h at 5 mA cm−2. When coupling with MnO2 cathode, the full cell with the honey additive also displays improved long-term durability. Furthermore, the packaged pouch cell demonstrates surprising flexibility and satisfactory security under different harsh environments, showing practical feasibility in future wearable devices.

Application of Terahertz Time-Domain Spectroscopy to Study the Microheterogeneities of Solutions: A Case Study of Aqueous Sugar Solutions

The phenomenon of the formation of microheterogeneities (MHs) in solutions, which, according to chemical handbooks, are considered true solutions, has been known for a long time. MHs have been found in more than 100 binary solutions, many of which are used both in various scientific studies and in life. However, the nature of this phenomenon is largely unclear. It is only well-known that MHs are stable areas of increased concentration of one of the components of the solution. The main reason for the poor knowledge of MHs is the use of very few experimental methods, mainly light scattering methods. In this paper, the terahertz time-domain spectroscopy method was used for the first time to study MHs using the example of aqueous solutions of three sugars: glucose, fructose, and sucrose. This method gives the spectra of complex permittivity in the terahertz range, which are very informative when studying the hydrate shells of molecules in solutions. The idea of this study was that structuring sugar molecules with the formation of MHs changes their hydration. The characteristics of sugar hydration in solutions before and after filtration through a 20 nm filter, leading to the destruction of MHs, were compared. It has been shown that the water binding in the MHs of all three solutions is increased compared with the hydrate shells of individual sugar molecules. Also, for MHs’ fructose solution, a decrease in the number of hydrogen bonds between water molecules and an increase in the number of free water molecules was shown, which is not observed in MH glucose and sucrose solutions. This is explained by mutarotations of fructose molecules, leading to permanent significant rearrangements of the water structure in MHs. Thus, terahertz time-domain spectroscopy provides fundamentally new information about the MHs of aqueous solutions at the level of their hydration characteristics. The presence of MHs in solutions is a significant factor that has never been taken into account when studying the hydrate shells of various molecules in solutions using THz spectroscopy.

Study on spectral properties and active sites of glucose and fructose based on density functional theory

• Based on density functional theory and time-dependent density functional theory, we systematically studied the infrared spectra, ultraviolet spectra, electron hole, active sites and total transition dipole moments of glucose and fructose molecules • The optical rotation properties of glucose and fructose are explained in detail. • The theoretical study on the molecular structure and properties of glucose and fructose is of great significance for drug research and development, the preparation of biofuels and the protection of related metals. Glucose and fructose are closely related to people's life and production. Based on density functional theory, the B3LYP/6-311++G(d, p) and B3LYP/6-311 + G(d, p) levels of theory are adopted to optimize the structure and calculate the frequency of glucose and fructose molecules by adding B3LYP-D3(BJ) dispersion correction in this paper. The first 50 excited states of glucose and fructose molecules are calculated in SMD solvent model by using time-dependent density functional theory and B3LYP / def2-TZVP level of theory. It is verified that the selected method and basis set are reasonable by comparing the theoretical spectrum with the experimental spectrum. It is found that the plane structure of glucose molecule is more distorted than that of fructose molecule. The stretching vibration of C O bond of fructose is more intense than that of glucose. The absorption peak of fructose at 209.70 nm is characterized by n → σ* transition and is in the tail absorption band, other absorption peaks are all in the far ultraviolet absorption band, and it shows the transition characteristics of σ → σ*. According to the electron-hole analysis, the excitation of the 27th, 34th, 36th and 46th excited states belongs to local excitation, the excitation of the 29th excited state belongs to Rydberg excitation, and the other excited states belong to charge transfer excitation. The optical rotation mechanism of sugar molecules is explained by the direction of the transition dipole moment. O16 of glucose and O24 of fructose were electrophilic site respectively. The active product is 5-hydroxyethyl furfural (5-HMF) by oxidation of 5-hydroxymoms. This study could provide a theoretical basis for drug development, biofuel preparation and metal protection.

Photophysical and molecular docking approach on the interaction of water-soluble simple keto sugar with acridinedione dyes

Photophysical studies in association with molecular docking (MD) methods were employed in the determination of various molecular interactions existing between d-Fructose in the presence of a photoinduced electron transfer (PET) and non-PET based acridinedione (AD) dyes in water. Addition of fructose to AD dyes resulted in a decrease in the absorbance at the longest wavelength absorption maxima accompanied with the formation of an isosbestic point signifying a ground state complex formation. The ground state interaction between fructose and dye is presumably attributed to hydrogen-bonding (HB) and was authenticated by MD studies. Interestingly, the excited state characteristics of PET dye (ADR1) is found to be entirely different from that of non-PET dye (ADR2) on the introduction of fructose. A fluorescence quenching phenomenon is observed in PET dye, whereas an enhancement results in that of a non-PET dye. Fructose promotes electron transfer (ET) through space resulting in a decrease in the fluorescence intensity of ADR1 dye. On the contrary, it suppresses the PET process in ADR2 dye resulting in an increase in the quantum yield. Fluorescence lifetime studies of fructose with AD dyes results in a multi exponential lifetime with varying proportions. The presence of biexponential lifetime components justifies the existence of more than one distinguishable micro heterogenous environment in the aqueous phase containing unequal proportion of distribution of fructose and water molecules around the close vicinity of AD dyes. The local excited (LE) state of the fluorophore experiences a large variation in the excited state such that the emission intensity and fluorescence lifetime are governed by solute induced and solvent mediated HB interactions. MD studies further establish the existence of HB interaction of dye-fructose, wherein the dye acts as the HB donor and sugar as the acceptor. Docking techniques establishes clear and authentic information on the HB donor and acceptor sites in dye and sugar molecule resulting in a most stable conformer. The nature of interaction of a simple sugar molecule with water soluble fluorophores are explored in depth by fluorescence techniques in coordination with MD methods is imparted in the present study.

Macroscale liquid superlubricity achieved with mixtures of fructose and diols

Superlubricity has numerous benefits in industrial applications, but its practical applications are restrained from its heavy dependence on special atmosphere environment and the use of low-dimensional materials. This paper reports a novel and facile method to macroscale liquid superlubricity for steel tribopairs, which realizes superlow friction almost right at the start of the test. Two diols of ethylene glycol (EG) and 1,3-propanediol (13-PD) are used as the base lubricants, and fructose is dissolved into two diols at various fructose/diol weight ratios. Then the tribological properties of the prepared lubricant solutions have been investigated. Friction test results suggest that the lubricant solutions of fructose and EG with the fructose/EG weight ratio of 0.5 is capable of realizing stable and robust superlubricity combined with little wear under a certain range of testing conditions for steel tribopairs. Such desirable superlubrication state can be attributed to three main factors: (1) formation of a desirable hydrodynamic lubricant film between the tribopairs to support the load and separate the rubbing surfaces; (2) effective passivation effect to the asperity contact sites at the interface by forming robust slippery layers of fructose and diol molecules; (3) tribological polishing effect to make the contacting surfaces smooth. Lubricant solutions of fructose and 13-PD with the fructose/13-PD weight ratio of 0.3 is also found to behave near superlow friction and negligible wear, allowing it to replace fructose/EG = 0.5 in certain applications where both superlow friction and human safety are greatly concerned.

Effect of the consumption of yacon flour and energy-restricted diet on glycation markers, and association between these markers and factors linked to obesity in adults with excess body weight: A randomized, double-blind, placebo-controlled clinical trial

ObjectivesRegardless of the positive effect of yacon on metabolic markers, this food contains fructose molecules, which can originate advanced glycation end products (AGEs). High AGEs serum concentrations can contribute to excess body weight. We evaluated the effect of consuming an energy-restricted diet and yacon flour on glycation markers concentrations, and the associations between these markers and factors linked to obesity in adults with excess body weight. MethodsTwenty-six adults with excess body weight were included in this randomized, parallel, double-blind, placebo-controlled, 6-week clinical trial. Subjects were randomly allocated to the control group (n = 13) or the yacon-flour group (n = 13), and daily consumed a breakfast drink either not containing or containing 25 g of yacon flour (8.7 g of fructooligosaccharides). Energy-restricted diets were prescribed for both groups. Biochemical markers, anthropometric variables, and body composition were evaluated at baseline and the end of the study. ResultsAGEs and early glycation products did not increase in the yacon flour group. Soluble receptor for AGEs (sRAGE) decreased regardless of group. Besides, changes in AGEs were positively associated with changes in body fat (β = 0.04, P = 0.038) and in sRAGE, with insulin (β = 0.02, P = 0.035) and homeostasis model assessment index of insulin resistance (β = 0.01, P = 0.049). ConclusionsThe consumption of 25 g of yacon flour associated with an energy-restricted diet did not increase concentrations of glycation markers. Changes in glycation markers were positively associated with changes in consolidated anthropometric and biochemical markers related to being overweight. Assessing glycation markers may be a useful strategy for monitoring responses to dietary interventions in subjects with excess body weight.

Production of Sucrolytic Enzyme by Bacillus licheniformis by the Bioconversion of Pomelo Albedo as a Carbon Source.

Recently, there has been increasing use of agro-byproducts in microbial fermentation to produce a variety of value-added products. In this study, among various kinds of agro-byproducts, pomelo albedo powder (PAP) was found to be the most effective carbon source for the production of sucrose hydrolyzing enzyme by Bacillus licheniformis TKU004. The optimal medium for sucrolytic enzyme production contained 2% PAP, 0.75% NH4NO3, 0.05% MgSO4, and 0.05% NaH2PO4 and the optimal culture conditions were pH 6.7, 35 °C, 150 rpm, and 24 h. Accordingly, the highest sucrolytic activity was 1.87 U/mL, 4.79-fold higher than that from standard conditions using sucrose as the carbon source. The purified sucrolytic enzyme (sleTKU004) is a 53 kDa monomeric protein and belongs to the glycoside hydrolase family 68. The optimum temperature and pH of sleTKU004 were 50 °C, and pH = 6, respectively. SleTKU004 could hydrolyze sucrose, raffinose, and stachyose by attacking the glycoside linkage between glucose and fructose molecules of the sucrose unit. The Km and Vmax of sleTKU004 were 1.16 M and 5.99 µmol/min, respectively. Finally, sleTKU004 showed strong sucrose tolerance and presented the highest hydrolytic activity at the sucrose concentration of 1.2 M–1.5 M.

Degradation and detoxification of propranolol by a molecular intercalation bismuth oxychloride semiconductor-organic framework

In this work, the effects of different types of molecular intercalations on the morphology, photoelectrochemical performance, specific surface area and photocatalytic degradation propranolol (PRO) of BiOCl semiconductor-organic frameworks were studied by using different types of carbonate beverages (CBs) as solvents synthesized at room temperature. Interlayer organic molecules, as circuits of charge transmission can increase the strength of the electric field of the BiOCl layered structure and enhance the electronic coupling between layers. This, in turn, gives rise to narrowed bandgap energy and inhibited charge carrier recombination. Sugar (including fructose and glucose) molecules in the CB are helpful to insert into the BiOCl layer to make the thickness thinner, thus improving the specific surface area and light absorption capacity of BiOCl. Additionally, caramel molecules in CB can help broaden the light absorption and accelerate the charge transfer capacity of CB-BiOCl. The interaction of various molecules in the CB-BiOCl system significantly enhanced the photocatalytic degradation performance of PRO. Noticeably, twelve possible degradation intermediates were identified, and their toxicity decreased along with the degradation pathways. More importantly, the inhibiting effect of the degradation solution on zebrafish swimming activity weakened during the degradation process, indicating that the toxicity of the degradation solution gradually weakened. Furthermore, the mechanism of photocatalytic degradation of PRO with molecules as the circuit of charge transmission of the BiOCl semiconductor-organic framework was proposed.

Investigating the binding affinities of fructose and galactose to human serum albumin: simulation studies

ABSTRACT Human serum albumin (HSA) is abundant in blood. HSA binds a wide range of drugs, metabolites, and nutrients. A glycated HSA is also a potential diabetes biomarker. Recently, crystal structures of glucose- and fructose-bound HSA have been reported. Both cyclic and acyclic sugar forms are trapped in Sudlow site I. Galactose can also bind HSA, but no atomic detail is available. Thus, molecular dynamics simulations were employed to study the structural and dynamic properties of fructose- and galactose-bound HSA in comparison to glucose-bound HSA from previous studies. Both bound sugars promote different degrees of domain motions which can affect a drug/solute binding affinity at Sudlow site I. A large and highly water-exposed Sudlow site I allows high mobility of bound sugars. Nonetheless, more protein contacts imply a tighter binding of fructose than galactose. Although galactose and glucose are epimers, galactose forms a different interaction network which disrupts a formation of interactions with K195 and K199 resulting in the escape of galactose. In contrast, fructose molecules are anchored inside by a number of protein interactions and sugar dimer structure. These highlights the importance of protein–sugar and sugar–sugar interactions for ligand binding in large and highly water-exposed cavity.

Fructose determination in fruit juices using an electrosynthesized molecularly imprinted polymer on reduced graphene oxide modified electrode

The present work reports the development of a novel electrochemical sensor for the selective detection of fructose. The sensor was developed through electropolymerization of a molecularly imprinted polymer film on a reduced graphene oxide modified electrode. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, atomic force microscopy and RAMAN spectroscopy. Through the application of the modified electrode, the recognition of fructose molecules occurred in a concentration range of 1.0 × 10−14 to 1.0 × 10−11 mol L−1, under a Langmuir adsorption isothermal model. The sensitivity and limits of detection and quantification obtained for the sensor were 9.9 × 107 A L mol−1, 3.2 × 10−15 mol L−1 and 1.1 × 10−14 mol L−1, respectively. The analytical method used for the detection of fructose presented good reproducibility, stability and accuracy, and was successfully applied for the quantification of this sugar in orange, apple and grape juices.

Fructose-regulated ZnO single-crystal nanosheets with oxygen vacancies for photodegradation of high concentration pollutants and photocatalytic hydrogen evolution

ZnO-based photocatalysts have been widely applied to photocatalytic reactions. However, the pure phase ZnO is rarely used in degradation of refractory pollutants and photocatalytic hydrogen evolution due to its poor photo-redox ability. In this study, we develop a novel surface atom regulation strategy using fructose molecules containing hydroxyl groups to improve photo-oxidation ability of ZnO. Interestingly, the fructose-regulated ZnO nanosheets with oxygen vacancies exhibit more positive surface valence band maximum than that of pristine ZnO. The photogenerated holes with strong oxidation capacity can be formed on the fructose-regulated ZnO nanosheets. The fructose-regulated ZnO nanosheets can rapidly degrade high concentration of phenol and other organic pollutants, which is difficultly achieved by the pristine ZnO nanosheets. In addition, photocatalytic H2 production activity is also found on our pure phase ZnO. This work provides a new design strategy for modifying the surface structure of photocatalysts to improve photocatalytic performance.

Interaction of N-acetylneyraminic acid with surface of silica with fructose in aqueous solution

Quantum chemical simulation of the adsorption of N acetylneuraminic acid (NANA) on the surface of silica with the participation of the fructose molecule by the method of density functional theory B3LYP, 6-31G (d, p) was done. The influence of the solvent was taken into account in the supermolecular and continuum approximations, and a cluster approach was used for the adsorption complexes. NANA adsorption of the hydrated silica surface was considered as a process of replacement of water molecules on the silica surface by adsorbate molecules. Two schemes of influence of fructose molecule on NANA adsorption are considered. According to the first scheme, the hydrated NANA molecule interacts with the hydrated silicon-fructose adsorption complex. According to the second scheme, the cluster of hydrated silica interacts with the hydrated NANA-fructose complex. The energy of intermolecular interaction according to the scheme 1 is -9.2 kJ / mol, which is significantly lower compared to the same value with the participation of glucose or sucrose (-20.5 and -86.2 kJ / mol). Scheme 2 proved to be a thermodynamically unfavorable process, as its energy effect is +6.9 kJ / mol, in contrast to similar processes for glucose (-21.8) and sucrose (-87.7 kJ / mol). This confirms the experimental fact of the interaction of substances in a mixture of NANA with carbohydrates in relation to the interaction with silica in comparison with the interaction of substances with silica separately.

Covalent Functionalization of Graphene Oxide with Fructose, Starch, and Micro-Cellulose by Sonochemistry.

In this work, we report the synthesis of graphene oxide (GO) nanohybrids with starch, fructose, and micro-cellulose molecules by sonication in an aqueous medium at 90 °C and a short reaction time (30 min). The final product was washed with solvents to extract the nanohybrids and separate them from the organic molecules not grafted onto the GO surface. Nanohybrids were chemically characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy and analyzed by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). These results indicate that the ultrasound energy promoted a chemical reaction between GO and the organic molecules in a short time (30 min). The chemical characterization of these nanohybrids confirms their covalent bond, obtaining a grafting percentage above 40% the weight in these nanohybrids. This hybridization creates nanometric and millimetric nanohybrid particles. In addition, the grafted organic molecules can be crystallized on GO films. Interference in the ultrasound waves of starch hybrids is due to the increase in viscosity, leading to a partial hybridization of GO with starch.

Diffusion of fructose in water: a molecular dynamics study

Present work carries the molecular dynamics (MD) simulation to study the self-diffusion coefficients of fructose (C6H12O6) and SPC/E (Extended Simple Point Charge) water (H2O) along with their binary diffusion coefficients at different temperature (298.15 K, 303.15 K, 308.15 K and 312.15 K). A dilute solution of 3 molecules of fructose (solute, mole fraction 0.0018) and 1624 molecules of water (solvent, mole fraction 0.9982) has been taken for making it relevant to the previously reported experiment. The structural analysis of the mixture has been estimated by using the radial distribution function (RDF) of its constituents. Mean square displacement (MSD) and Einstein’s relation have been used to find the self-diffusion coefficients of both the solute and solvent. Furthermore, Darken’s relation finds the binary diffusion coefficients. The temperature dependence of diffusion coefficients follows the Arrhenius behavior which further calculates activation energy of diffusion. The results from the present work agree well with the previously reported experimental values.

Broadband dielectric properties of honey: effects of temperature.

Dielectric properties of jujube honey were investigated at 298-358K by broadband dielectric measurements. Four relaxation processes were observed and analyzed, which are caused by long range correlation of density fluctuation, cooperative motions of molecules, rotational polarization of bound water and collective reorientation of free water, respectively. The results of temperature dependence of dielectric parameters show that with increasing temperature, the interaction among the molecules e.g. water, fructose and glucose molecules etc. weaken, and the honey gradually forms a complete sugar solution. At a given temperature, the penetration depth at 27MHz is much greater than that at 915MHz and 2.45GHz. And based on the calculated penetration depth, dielectric heating at 27MHz seems to has more advantages for large volume of materials.

Fructose-mediated effects on gene expression and epigenetic mechanisms associated with NAFLD pathogenesis.

Nonalcoholic fatty liver disease (NAFLD) is a chronic, frequently progressive condition that develops in response to excessive hepatocyte fat accumulation (i.e., steatosis) in the absence of significant alcohol consumption. Liver steatosis develops as a result of imbalanced lipid metabolism, driven largely by increased rates of de novo lipogenesis and hepatic fatty acid uptake and reduced fatty acid oxidation and/or disposal to the circulation. Fructose is a naturally occurring simple sugar, which is most commonly consumed in modern diets in the form of sucrose, a disaccharide comprised of one molecule of fructose covalently bonded with one molecule of glucose. A number of observational and experimental studies have demonstrated detrimental effects of dietary fructose consumption not only on diverse metabolic outcomes such as insulin resistance and obesity, but also on hepatic steatosis and NAFLD-related fibrosis. Despite the compelling evidence that excessive fructose consumption is associated with the presence of NAFLD and may even promote the development and progression of NAFLD to more clinically severe phenotypes, the molecular mechanisms by which fructose elicits effects on dysregulated liver metabolism remain unclear. Emerging data suggest that dietary fructose may directly alter the expression of genes involved in lipid metabolism, including those that increase hepatic fat accumulation or reduce hepatic fat removal. The aim of this review is to summarize the current research supporting a role for dietary fructose intake in the modulation of transcriptomic and epigenetic mechanisms underlying the pathogenesis of NAFLD.

Computational and spectroscopic investigations on boronic acid based fluorescent carbohydrate sensor in aqueous solution at physiological pH 7.5

In this study, the structural and photophysical properties of 2-ethoxy-4-fluoro phenyl boronic acid (BA1) fluorescent compound was analysed using experimental spectroscopy, single crystal X-ray diffraction techniques and theoretical calculations were implemented using DFT and TD-DFT methods. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The calculated HOMO-LUMO energies shows charge transfer within the molecule and the transitions were predicted to be as п-п∗. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), UV–Vis absorption spectra and Non-linear optical properties were also studied using the same method and basis set. The BA1 compound has been tested for sugar sensing applications by absorption and emission spectroscopic analysis, to understand BA1 with sugars (D-glucose and D-fructose) complexes. The fluorescence measurements of BA1 at physiological pH 7.5, demonstrated a phenomenal quenching response to fructose and glucose molecules by having a decrease in fluorescence intensity with 3.5 fold and 1.3 fold for 0 M–0.5 M concentration of fructose and glucose, respectively, which shows strong sugar binding affinity. The association and dissociation constants were calculated by employing Stern-Volmer equation. The Job's plot and the mass spectroscopic analysis was carried to know the stoichiometry ratio of binding. The counterpoise correction method was implemented to calculate the complexation energy of the BA1-sugar complexes. The fluorescence life time of the molecule was measured in the presence and absence of sugars. The obtained lifetimes were in comparison with the theoretically calculated lifetimeusing PhotochemCAD. All these results showed that, BA1 can readily bind with sugars and could play an important role in carbohydrate sensing applications.

Silver nanoparticles for solvent-free detection of small molecules and mass-to-charge calibration of laser desorption/ionization mass spectrometry

This work aims at the utilization of nanostructured surfaces for advanced mass spectrometry [laser desorption/ionization mass spectrometry (LDI MS)]. The authors demonstrate that prepared nanostructures enable independent mass-to-charge calibration and also effectively substitute protonation agent for low-mass molecules instead of conventionally used matrices. Silver nanostructured surfaces were formed as homogeneous thin film, isolated nanoislands, and spherical nanoparticles. Besides the surface characterization, the paper focuses on the impact of LDI MS laser, irradiating the nanostructured surfaces, which results in the production of charged Ag clusters. Irradiated nanoparticle-based surfaces mostly provide single ionized species Ag+ while positive (Agn+, n ≤ 5) and negative ions (Agn−, n ≤ 7) were observed from the nanoislands film. It is shown that the ratio between particular ion line intensities can be tailored by the deposition time. The pattern of silver ions Agn (due to two natural isotopes) can be used for mass-to-charge calibration up to 1000 m/z. Additionally, the silver protonation improves the identification of small molecules. It is demonstrated on detection of sucrose (342.3 g/mol), fructose (180.2 g/mol), and creatinine (113.1 g/mol) molecules.