Physicochemical Analytical Methods Research Articles

Green synthesis of copper oxide nanoparticles using genus Inula and evaluation of biological therapeutics and environmental applications

Abstract In this research, we produced copper oxide nanoparticles (CuO NPs) using extracts from the entire above-ground portion of plants of genus Inula (Inula graveolens). The synthesis of CuO NPs was verified through various physicochemical analytical methods, including UV–visible, Fourier transform infrared, and transmission electron microscopy. The CuO NPs were found to be around 20 nm in size and spherical in shape. Subsequently, the synthesized compounds were evaluated for their anticancer properties. After treating A549 cells with CuO NPs at concentrations of 15 and 30 μg, we examined their cytotoxicity, lipid peroxidation activity (malondialdehyde level), and antioxidant activity (catalase, superoxide dismutase, and glutathione levels). Additionally, we analyzed the expression of apoptotic marker genes (p53, caspase-3, and caspase-9), cytokine levels (IL-6 and TNF-α), and DNA fragmentation. Our findings demonstrated that CuO NPs enhanced the expression of apoptotic genes, suggesting that phytochemical-derived NPs from Inula extracts induce apoptosis by upregulating tumor suppressor genes and downregulating oncogenes in A549 cells. Furthermore, CuO NPs exhibited higher susceptibility toward B. subtilis and S. aureus compared to ampicillin. Using the response surface methodology, we determined that CuO NPs are effective adsorbents for removing Pb2+ ions from aqueous solutions, making them promising for environmental applications. Overall, our results indicate that CuO NPs have potential as antimicrobial, antioxidant, and anticancer agents and as efficient adsorbents.

Interactions between water quality and microbes in epiphytic biofilm and superficial sediment of lake in trophic agriculture area

Epiphytic and superficial sediment biofilm-dwelling microbial communities play a pivotal role in water quality regulation and biogeochemical cycling in shallow lakes. However, the interactions are far from clear between water physicochemical parameters and microbial community on aquatic plants and in surface sediments of lake in trophic agriculture area. This study employed Illumina sequencing, Partial Least Squares Path Modeling (PLS-PM), and physico-chemical analytical methods to explore the interactions between water quality and microbes (bacteria and eukaryotes) in three substrates of trophic shallow Lake Cyohoha North, Rwanda. The Lake Cyohoha was significantly polluted with total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3-N), and ammonia nitrogen (NH3−N) in the wet season compared to the dry season. PLS-PM revealed a strong positive correlation (+0.9301) between land use types and physico-chemical variables in the rainy season. In three substrates of the trophic lake, Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were dominant phyla in the bacterial communities, and Rotifers, Platyhelminthes, Gastrotricha, and Ascomycota dominated in microeukaryotic communities. As revealed by null and neutral models, stochastic processes predominantly governed the assembly of bacterial and microeukaryotic communities in biofilms and surface sediments. Network analysis revealed that the microbial interconnections in Ceratophyllum demersum were more stable and complex compared to those in Eichhornia crassipes and sediments. Co-occurrence network analysis (|r| > 0.7, p < 0.05) revealed that there were complex interactions among physicochemical parameters and microbes in epiphytic and sediment biofilms, and many keystone microbes on three substrates played important role in nutrients removal, food web and microbial community stable. These findings emphasize that eutrophic water influence the structure, composition, and interactions of microbes in epiphytic and surface sediment biofilms, and provided new insights into the interconnections between water quality and microbial community in presentative substrates in tropical lacustrine ecosystems in agriculturally polluted areas. The study provides useful information for water quality protection and aquatic plants restoration for policy making and catchment management.

Pysanka-Inspired Electrode Modification with Aptamer Encapsulation in ZIF-8 for Urine Creatinine Electrochemical Biosensing

Drawing inspiration from the several thousand beautiful Pysanky egg art of Ukraine, we have developed a novel material, Aptamer–Gold Nanoparticles (AuNPs)@ZIF-8, that can be used for building sensitive and highly stable POC biosensors for longitudinal health mapping. Here, we demonstrate a sensitive and specific novel electrochemical biosensor, made of a novel synthesized in situ encapsulated aptamer-AuNPs@ZIF-8 composite, for monitoring levels of creatinine (0.1–1000 μg/mL). In this work, we have reported the synthetic protocol for the first-of-a-kind in situ encapsulation of aptamer and AuNPs together in a ZIF-8 matrix, and explored the characteristic properties of this novel material composite using standard analytical techniques and its application for biosensor application. The as-synthesized material, duly characterized using various physicochemical analytical methods, portrays the characteristics of the unique encapsulation strategy to develop the first-of-a-kind aptamer and AuNP encapsulation. Non-faradaic Electrochemical Impedance Spectroscopy (EIS) and Chronoamperometry were used to characterize the interfacial electrochemical properties. The biosensor performance was first validated using artificial urine in a controlled buffer medium. The stability and robustness were tested using a real human urine medium without filtration or sample treatment. Being versatile, this Ukrainian-art-inspired biosensor can potentially move the needle towards developing the next generation of sample-in-result-out robust POC diagnostics.

The effect of the polydimethylsiloxane chain length on the properties of four-arm siloxane stars

Five low-dispersity star-shaped polydimethylsiloxanes were synthesized. The macromolecules of the polymers contain the same branching-out center, a cis-tetraphenylcyclotetrasilsesquioxane moiety, and the same number of arms, but with different lengths (n = 15, 21, 48, 75, and 123 Si(Me)2O units). Their properties were studied by a set of physicochemical analytical methods. Viscometric studies showed that the macromolecules of the Ph4-15, Ph4-21, Ph4-48, and Ph4-75 polymers are small-sized dense balls both in solution and in melt. DSC studies identified an unusual effect of the cyclic core on the thermal behavior of the Ph4-15, Ph4-21, and Ph4-48 polymers. Its incorporation suppresses the crystallization of PDMS-arms (up to n = 48 Si(Me)2O units) at concentrations four times lower than those of known modifiers and does not affect the glass transition temperature (ca. -124 °С).

Effect of erythromycin on epiphytic bacterial communities and water quality in wetlands

The occurrence of antibiotics such as erythromycin (ERY) under macrolide group, has long been acknowledged for negatively affecting ecosystems in freshwater environments. However, the effects of ERY on water quality and microbial communities in epiphytic biofilms are poorly understood. Here, Scanning Electron Microscopy (SEM), High-throughput sequencing, and physicochemical analytical methods were employed to unravel the impact of ERY on the water quality and bacterial morphology, biodiversity, composition, interaction, and ecological function in epiphytic biofilms attached to Vallisneria natans and artificial plants in mesocosmic wetlands. The study showed that ERY exposure significantly impaired the nutrient removal capacity (TN, TP, and COD) and altered the epiphytic bacterial morphology of V. natans and artificial plants. ERY did not affect the bacterial α-diversity. Notwithstanding ERY decreased the bacterial composition, but the relative abundance of Proteobacteria and Patescibacteria spiked by 62.2 % and 54 %, respectively, in V. natans, while Desulfobacteria and Chloroflexi increased by 8.9 % and 11.2 %, respectively, in artificial plants. Notably, ERY disturbed the food web structure and metabolic pathways such as carbohydrate metabolism, amino acid metabolism, energy metabolism, cofactor and vitamin metabolism, membrane transport, and signal transduction. This study revealed that ERY exposure disrupted the bacterial morphology, composition, interaction or food web structure, and metabolic functions in epiphytic biofilm. These data underlined that ERY negatively impacts epiphytic bacterial communities and nutrient removal in wetlands.

The selective synthesis of di- and cyclosiloxanes bearing several hidden p-tolyl-functionalities

This study reports the development of a selective method for the synthesis of p-tolylsiloxanes, namely, symmetrical disiloxanes and cyclotetrasiloxanes, by hydrolytic condensation of p-tolyl-containing mono(ethoxy)silanes and di(ethoxy)silanes in the presence of [Me4N]+OH–. The reaction occurs under mild and simple reaction conditions: at 30 °C, under atmospheric pressure, in 1–5 h, in acetone and ethanol medium or in the block (solvent-free), with a loading of 0.25–5 mol.% (per Si–OEt group) of [Me4N]+OH–, a commercially available and cheap catalyst. The method is well scalable and allows the target products (2a-f) to be obtained in gram amounts (up to 50 g) in 42–85% yields. The structures were confirmed using a set of physicochemical analytical methods: IR, ESI-HRMS, GPC, 3a and 4a 1H/13C/29Si NMR, and X-Ray.

SYNTHESIS OF NANOSIZED ZIRCONIUM DIOXIDE, COBALT OXIDE AND RELATED PHASES IN SUPERCRITICAL CO2 FLUID

This study is devoted to obtaining nanoscale zirconium dioxide, cobalt oxide and related phases by SAS method in supercritical carbon dioxide. The synthesized compounds were characterized by a complex of physico-chemical analytical methods: infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy. The experimental parameters for obtaining the nanoparticles were: pressure 10 MPa, temperature 40 °C, carbon dioxide supply rate 35 g/min, the initial solution supply rate 0.5 ml/min. Individual phases containing zirconium and cobalt, and also samples with zirconium to cobalt molar ratios 3:1, 2:1, 1:1, 2:1 and 1:3 were obtained. The use of zirconium and cobalt acetylacetonates as initial components leads to formation of stable products – nanoparticles of acetates of the corresponding metals in the X-ray amorphous state. When heated to 340-350 °C, the destruction of organometallic complexes to oxides occurs with formation of a continuous series of X-ray amorphous solid solutions in the ZrO2-CoO system. At temperatures above 600 °C, the phases crystallize with the decomposition of solid solutions into ZrO2 and Co3O4. When temperature is above 900 °C, further oxidation of cobalt occurs. Thus, cobalt oxide oxidation into Co3O4 proceeds in two steps, at 600 and 900 °C. For samples of zirconium dioxide with cobalt oxide admixture at a temperature of 700 °C stabilization of the cubic modification is observed which is probably due to the entry of cobalt into the cubic structure of zirconium oxide, which prevents transition to tetragonal and monoclinic modifications.

Identification of extracellular nanoparticle subsets by nuclear magnetic resonance.

Exosomes are a subset of secreted lipid envelope-encapsulated extracellular vesicles (EVs) of 50–150 nm diameter that can transfer cargo from donor to acceptor cells. In the current purification protocols of exosomes, many smaller and larger nanoparticles such as lipoproteins, exomers and microvesicles are typically co-isolated as well. Particle size distribution is one important characteristics of EV samples, as it reflects the cellular origin of EVs and the purity of the isolation. However, most of the physicochemical analytical methods today cannot illustrate the smallest exosomes and other small particles like the exomers. Here, we demonstrate that diffusion ordered spectroscopy (DOSY) nuclear magnetic resonance (NMR) method enables the determination of a very broad distribution of extracellular nanoparticles, ranging from 1 to 500 nm. The range covers sizes of all particles included in EV samples after isolation. The method is non-invasive, as it does not require any labelling or other chemical modification. We investigated EVs secreted from milk as well as embryonic kidney and renal carcinoma cells. Western blot analysis and immuno-electron microscopy confirmed expression of exosomal markers such as ALIX, TSG101, CD81, CD9, and CD63 in the EV samples. In addition to the larger particles observed by nanoparticle tracking analysis (NTA) in the range of 70–500 nm, the DOSY distributions include a significant number of smaller particles in the range of 10–70 nm, which are visible also in transmission electron microscopy images but invisible in NTA. Furthermore, we demonstrate that hyperpolarized chemical exchange saturation transfer (Hyper-CEST) with 129Xe NMR indicates also the existence of smaller and larger nanoparticles in the EV samples, providing also additional support for DOSY results. The method implies also that the Xe exchange is significantly faster in the EV pool than in the lipoprotein/exomer pool.

Validation of analytical methods for the detection of beeswax adulteration with a focus on paraffin

Beeswax adulteration in the apiculture sector represents a growing problem worldwide due to the lack of clearly defined purity criteria, the absence of official quality (authenticity) controls, and the inconsistency of the analytical methods used for adulteration detection. Although beeswax authentication is implemented in other regulatory sectors (pharmaceutical and food industry), the classical physico-chemical analytical methods used for determination of beeswax purity exhibit inconsistencies for the detection of adulterants. In this study, an inventory was made on a comprehensive set of analytical methods and the corresponding purity criteria used for the detection of the most common beeswax adulterants (paraffin, stearin and/or stearic acid) from existing legislations and scientific literature. The selected analytical methods (classical physico-chemical, and advanced instrumental, i.e. chromatographic and spectroscopic analytical techniques) were weighted by three independent experts against two criteria: feasibility and analytical performance in detecting targeted adulterants. Classical methods for which measurement data were available (melting point and acid/saponification/ester values for paraffin-adulterated vs. non-adulterated beeswax samples) were retained and further validated by a receiver operating characteristic (ROC) analysis. These methods were also validated by generating the corresponding calibration curves for paraffin detection using paraffin-beeswax mixtures containing different proportions of paraffin (ranging from 5 to 95%, w/w). The results of the ROC analysis revealed that a tentative detection of paraffin in beeswax can be achieved by a combination of at least two physico-chemical methods. However, for a reliable detection of the most common adulterants in beeswax, physico-chemical methods should be complemented with advanced analytical tools. i.e. GC-MS, HTGC-FID (MS) and/or FTIR-ATR spectroscopy, depending on the expected adulterant.

Formulation and Intracellular Trafficking of Lipid-Drug Conjugate Nanoparticles Containing a Hydrophilic Antitubercular Drug for Improved Intracellular Delivery to Human Macrophages.

Isoniazid is an important first-line antitubercular drug used in the treatment of all major clinical manifestations of tuberculosis, including both pulmonary and cerebral diseases. However, it is associated with significant drawbacks due to its inherent hydrophilic nature, including poor gut permeability and an inability to cross the lipophilic blood–brain barrier, which, in turn, limit its clinical efficacy. We hypothesized that the addition of a hydrophobic moiety to this molecule would help overcome these limitations and improve its bioavailability in the bloodstream. Therefore, we designed a stable, covalently linked lipid–drug conjugate of isoniazid with a short lipid chain of stearoyl chloride. Further, lipid–drug conjugate nanoparticles were synthesized from the bulk lipid–drug conjugate by a cold high-pressure homogenization method enabled by the optimized use of aqueous surfactants. The nanoparticle formulation was characterized systematically using in vitro physicochemical analytical methods, including atomic force microscopy, transmission electron microscopy, differential scanning calorimetry, X-ray diffraction, attenuated total reflectance, particle size, ζ-potential, and drug release studies, and the mechanism of drug release kinetics. These investigations revealed that the lipid–drug conjugate nanoparticles were loaded with an appreciable amount of isoniazid conjugate (92.73 ± 6.31% w/w). The prepared lipid–drug conjugate nanoparticles displayed a uniform shape with a smooth surface having a particle size of 124.60 ± 5.56 nm. In vitro drug release studies showed sustained release up to 72 h in a phosphate-buffered solution at pH 7.4. The release profile fitted to various known models of release kinetics revealed that the Higuchi model of diffusion kinetics was the best-fitting model (R2 = 0.9929). In addition, confocal studies showed efficient uptake of lipid–drug conjugate nanoparticles by THP-1 macrophages presumably because of increased lipophilicity and anionic surface charge. This was followed by progressive intracellular trafficking into endosomal and lysosomal vesicles and colocalization with intravesicular compartmental proteins associated with mycobacterium tuberculosis pathogenesis, including CD63, LAMP-2, EEA1, and Rab11. The developed lipid–drug conjugate nanoparticles, therefore, displayed significant ability to improve the intracellular delivery of a highly water-soluble drug such as isoniazid.

Synthesis, Characterization and Antimicrobial Activity of Cu (II), Co (II) and Ni (II) Histidine Complexes

Ternary complexes of histidine amino acid (Schiff base) were synthesized, characterized and tested against multi-drug resistant pathogens. The metal ion centers included Cu (II), Ni (II) and Co (II). These complexes were characterized using physico-chemical and spectroscopic analytical methods. All the complexes are found to be considerably soluble in both polar and non-polar solvents including methanol, ethanol, butanol, acetone, ethyl acetate, and benzene and di ethyl-ether. Electronic Absorption Studies using FT-IR spectrophotometer revealed ν (O-H), ν (C=O), ν (C=N), ν (M -N) and ν (M-O) occurred between 3410 - 3417, 1751 - 1753, 1519 – 1521, 671 – 678, 439 – 470 cm- 1 respectively in complexes and ligand. UV-Visible was further used to elucidate the complexes resulting in transitions characteristics of the ligand and complexes. The Schiff base showed no antimicrobial activity at various therapeutic concentrations. However, the metal complexes exhibited broad spectrum antibiotic activities against the multi-drug resistant pathogens at minimum inhibitory concentration (MIC ≤ 200 µg/ml). The metal complexes showed strong activity against the isolates at medium and high concentrations, the bacteria strains included E.coli , P. aeruginosa, S. typhi and S. aureus and the fungi strains of Candida albicans , Aspergillus flavus and Aspergillus niger . The bioactivity recorded against these multi drug resistant pathogens indicates the potentials of these complexes for further therapeutic studies. Keywords : Histidine complex, synthesis, characterisation, antimicrobial activity, pathogens.

A New Synthetic Route to Heteroanthracenes

In this report, we describe the synthesis of 2,3,4a,6,7,8a,9,10‐octaaza‐4,8‐dioxo‐3,4,4a,7,8,8a,9,9a,10,10a‐decahydroanthracene, an octaaza derivative of reduced anthracene, through the reaction of glyoxal bis(nitrosemicarbazone) with glyoxal bis(hydrazone) in aqueous medium at 70 °C as well as by the hydrolytic decomposition of glyoxal bis(nitrosemicarbazone) in aqueous medium at 70 °C in a one‐pot transformation. The structure of the resultant compound was confirmed by physicochemical analytical methods and X‐ray diffraction. We also obtained the first representative of the cyclic monohydrazone dimer 1,2,4,5,8,9,11,12‐octaazacyclotetradeca‐5,7,12,14‐tetraene‐3,10‐dione, which exists as lactam and lactim tautomers, through the reaction of glyoxal bis(nitrosemicarbazone) with glyoxal bis(hydrazone) in alkaline aqueous medium.

Liquid-phase synthesis and physicochemical properties of xerogels, nanopowders and thin films of the CeO2–Y2O3 system

Low-agglomerated xerogels, ultrafine oxide powders with particle sizes of 12–20 nm, and uniform thin films with particle sizes of 8–14 nm are prepared in the CeO2–Y2O3 system using liquid-phase low-temperature methods, namely via coprecipitation of hydroxides and cocrystallization of salts, sol—gel technology. A comparative characterization of the prepared xerogels and nanopowders is performed using a set of physicochemical analytical methods. A dependence of phase composition, microstructure, and particle size on synthetic parameters is elucidated.

Synthesis and study of nonionic surfactants based on propylene oxide and lauric acid

Nonionic surfactants were synthesized at various molar ratios of propylene oxide and lauric acid. Propoxylation products were identified by a number of physico-chemical analytical methods. The tensiometric method was used to measure the surface tension of aqueous solutions of the products at interface with air, find their high surface activity, and determine certain colloidal-chemical parameters (critical micelle concentration, surface pressure, maximum adsorption, minimum cross-sectional area of a molecule, change in the Gibbs free energy in micelle-formation and adsorption processes). Laboratory studies of the oil-collecting capacity of these substances were carried out for the example of a thin oil film on the surface of water with varied degree of mineralization.

Synthesis of a Bromomethylketone Based on N-Maleopimarimide and its Unusual Transformation During Preparation of Sulfonium and Phosphonium Salts

A maleopimarimide was prepared via condensation of methyl maleopimarate with alanine. Its transformations under Arndt–Eistert reaction conditions were studied. The structures of the products were proved using physicochemical analytical methods.

Hydrolytic cleavage of the pyrimidine ring in 2-aryl-[1,2,4]triazole[1,5-c]quinazolines: physico-chemical properties and the hypoglycemic activity of the compounds synthesized

It has been shown that 2-aryl-[1,2,4]triazolo[1,5-c]-quinazolines under the action of nucleophilic agents (hydrazine hydrate, sodium hydroxide, sodium methoxide, hydrochloric acid) undergo hydrolytic cleavage followed by formation of [2-(3-aryl-1H-1,2,4-triazol-5-yl)-phenyl]amines. The rational synthetic protocols for the compounds mentioned above, namely heating in the hydrochloric acid solution at 90-95°C for 60 min, have been proposed. It has been found that substituents in position 2 of the triazoloquinazoline moiety do not significantly affect duration of the reaction and the yields of products. Purity and the structure of the compounds synthesized have been proven by the corresponding physicochemical methods, namely: elemental analysis, LC-MS, 1H, 13C NMR-spectrometry and X-ray structural study. The azole-azole prototropic tautomery has been substantiated using physicochemical analytical methods. According to the data obtained in gas or DMSO medium compounds 2 exist as tautomer A or C, while in the crystal lattice the anilines mentioned exist as A-form. It has been determined that 2-(3-aryl-1H-1,2,4-triazol-5-yl)phenyl]amines (2.1, 2.8, 2.14) in the dose of 10 mg/kg are as good as reference-drugs Metformin (in the doses of 50 and 200 mg/kg) and Gliclazide (in the dose of 50 mg/kg) by their hypoglycemic activity when assessing specific pharmacological activities in oral glucose tolerance test (OGTT), rapid insulin and adrenaline test models.

Phytoecdysteroids from the Aerial Part of Silene colpophylla

The genus Silene L. includes about 700 species according to current data [1] and represents the richest source of ecdysteroids. Greater than 100 species of this genus have now been found to produce ecdysteroids [2]. Greater than 80 of the 476 identified ecdysteroids are synthesized by Silene species [3, 4]. The goal of the present work was to study the chemical composition of ecdysteroids from the aerial part of S. colpophylla Wrigley, which we recommend for the first time as a source of ecdysteroids. Ecdysteroids were isolated from the aerial part of S. colpophylla collected during flowering in 2009–2012. Starting extracts were obtained by exhaustive extraction of ground air-dried raw material by EtOH (70%). Lipophilic substances were removed by hexane. Subsequent multiple extraction by n-BuOH extracted terpenoid and phenolic compounds. The concentrated residual was fractionated successively using CHCl3–EtOH (9:1), EtOH (70%), and H2O. The CHCl3–EtOH fraction of the BuOH extract was separated by repeated chromatography over columns of silica gel. A total of 17 ecdysteroids were isolated from S. colpophylla for the first time. Six of these were identified by various physicochemical analytical methods (UV, HPLC, MS, NMR). HPLC-MS analysis was carried out on an Agilent 1200 LC with a diode-matrix detector, a hybrid quadrupole–timeof-flight micrOTOF-Q mass spectrometer (Bruker), and a Zorbax SB-C18 column (2.1 50 mm) using HCOOH–MeOH 2% eluent (linear gradient AcN content from 10 to 90% over 0–20 min) at flow rate 0.2 mL/min. The mass detector operated in chemical ionization and electrospray modes at atmospheric pressure (APCI pos. and API-ES). Positive and negative ions were scanned in the range m/z 100–3000. The drying gas (N2) flow rate was 4 mL/min at 220°C. HPLC-UV analysis was carried out on an Agilent 1100 LC with a diode-matrix detector and a Zorbax Eclipse XDB C8 chromatography column (4.6 150 mm, 5 m) using MeOH–TFA (0.1%) eluent (gradient from 2 to 100% MeOH) at flow rate 0.8 mL/min. The analytical wavelength for detecting phytoecdysteroids was max 254 nm. The principal compounds in chromatograms of the CHCl3–EtOH fraction had absorption maxima in the range 244– 252 nm and corresponded to ecdysteroids from plants of the genus Silene [2–4], the structural features of which included an , -unsaturated ketone. The following ecdysteroids were isolated for the first time. Compound 1, tR 14.00 min. UV spectrum (MeOH, max, nm): 248. Mass spectrum, m/z 497 [MH] +, 479, 461, 443, 425; 541 [M + HCOO]–, identified as integristerone A; C27H44O8 [2, 3]. Compound 2, tR 16.15 min. UV spectrum (MeOH, max, nm): 246. Mass spectrum, m/z 481 [MH] +, 463, 445, 427, 409; 525 [M + HCOO]–, identified as 20-hydroxyecdysone; C27H44O7 [2, 4]. Compound 3, tR 16.49 min. UV spectrum (MeOH, max, nm): 250. Mass spectrum, m/z 497 [MH] +, 481, 463, 445, 427; 541 [M + HCOO]–, identified as polipodine B; C27H44O8 [2, 3]. Compound 4, tR 19.08 min. UV spectrum (MeOH, max, nm): 248. Mass spectrum, m/z 465 [MH] +, 447, 429, 411; 509 [M + HCOO]–, identified as ecdysone; C27H44O6 [2, 3]. Compound 5, tR 20.03 min. UV spectrum (MeOH, max, nm): 246. Mass spectrum, m/z 465 [MH] +, 447, 429, 411, 393; 509 [M + HCOO]–, identified as 2-deoxy-20-hydroxyecdysone; C27H44O6 [3, 4].

Synthesis of (13C-Methoxy)Methacetin for Isotopic Breath Tests

Asynthesis of (13C-methoxy)methacetin, one of the most important agents for liver function diagnosis by stable-isotope breath tests, was developed. It was based on O-alkylation of phenols by alkylhalides through an intermediate potassium salt of paracetamol [N-(4-hydroxyphenyl)acetamide]. The synthesis was carried out using 13C-methyliodide in the presence of K2CO3 in one step under mild conditions (20 – 25°C) with high selectivity to isolate the product in 97.8% yield, 99.6 mass% purity, and 99.1 at% isotopic purity. The physical properties were determined. Physicochemical analytical methods for (13C-methoxy)methacetin using NMR and IR spectroscopy and ESI-MS mass spectrometry were developed and could be used for quality control of the product during preparation for its mass production.

Detection of honey adulteration of high fructose corn syrup by Low Field Nuclear Magnetic Resonance (LF 1H NMR)

The effect of honey adulteration by high fructose corn syrup in different concentrations from 0% (pure honey) to 100% (pure high fructose corn syrup) was investigated using Low Field Nuclear Magnetic Resonance spectroscopy (LF 1H NMR) and physicochemical analytical methods. The LF 1H NMR data were analyzed by bi-exponential fitting and compared with physicochemical data. The physicochemical parameters demonstrated that water content, water activity, pH and color differed significantly in honey samples adulterated with different concentrations of high fructose corn syrup. These differences were also observed by transverse relaxation (T2). Bi-exponential fitting of T2 resulted in the observation of two water populations in all samples, T21 and T22, with relaxation times in the range of 1.26–1.60ms and 3.33–7.38ms, respectively. Relaxation times increased with higher percentages of high fructose syrup in adulterated honey. Linear correlations were observed between the T2, T21 and T22 parameters and physicochemical data, suggesting that LF 1H NMR can be used to discriminate pure blossom honey from honey adulterated with high fructose corn syrup.

Quality Attributes in Shrimp Treated with Polyphosphate after Thawing and Cooking: A Study Using Physicochemical Analytical Methods and Low‐Field 1H NMR

AbstractThe effects of polyphosphate on parameters of quality in shrimp (after thawing and cooking) were investigated using physicochemical analytical methods and low‐field nuclear magnetic resonance (LF 1H NMR) spectroscopy. The NMR data were treated by bi‐exponential fitting and compared with the physicochemical data. The physicochemical parameters demonstrated that treatments with different concentrations of sodium tripolyphosphate and different time exposures influenced parameters such as cook loss, moisture, pH, color and texture. These differences were reflected in the transverse relaxation (T2) data. Bi‐exponential fitting of the T2 resulted in the observation of two water populations in all samples, T21 and T22, with relaxation times in the ranges of 24–47 and 63–120 ms, respectively. Pronounced changes in the T21 and T22 relaxation data were observed during the different treatments, with polyphosphate revealing changes in water properties. Good linear correlations were observed between the T2 parameters and physicochemical data.Practical ApplicationsShrimp processing contains various steps, such as freezing and cooking, which can lead to the denaturation or aggregation of proteins. In this context, the use of polyphosphates prior to the freezing of shrimp can improve yields, water‐holding capacity and the sensory attributes of the final product. The fish industry seeks to use polyphosphates in order to optimize production and obtain better quality products. Therefore, studies to identify the ideal phosphate concentration and contact time required for quality production in the frozen shrimp industry are important. Traditional analytical methods for physicochemical measurements are, however, time‐consuming, sample destructive and expensive. Low‐field 1H nuclear magnetic resonance is a rapid, noninvasive method to investigate water mobility within materials and foods. The method showed strong correlations with various physicochemical properties, which are important quality factors during shrimp processing. Moreover, the techniques are fast, reliable and nonsample destructive.