Reflectance Spectroscopy Method Research Articles

PREDIKSI KANDUNGAN MINYAK DAN ASAM LEMAK BEBAS BUAH SAWIT SECARA NON-DESTRUKTIF MENGGUNAKAN NEAR-INFRARED SPECTROSCOPY DAN METODE KALIBRASI HYBRID

The study used near-infrared reflectance spectroscopy and hybrid calibration methods to predict oil and free fatty acid content of oil palm fruitlets non-destructively. The reflectance and chemical content of oil palm fruitlets were measured and the calibration between near infrared spectra and chemical content was performed using hybrid calibration methods. The developed hybrid calibration model was validated to predict oil and free fatty acid of other oil palm fruitlets. The best models to predict oil and free fatty acid of oil palm fruitlets respectively were the hybrid model of Partial Least Square-Artificial Neural Network with 25 factor components (R2 = 0.96; SEP= 2.21%, RPD = 4.79) and 19 factor components (R2 = 0.96; SEP= 0.25%, RPD = 4.24) using Savitzky-Golay first derivative spectra pre-treatment.

A two-dimensional coordination polymer bearing an Evans-Showell-type polyoxometalate: Synthesis, structure and biological insight†

An Evans-Showell-type polyoxometalate (POM) based coordination polymer (CP), [H2(Co2Mo10H4O38)2(Co3(L)3(HL)2(H2O)6)(HL)2]·14H2O (1), {L = 4,4′-bipyridine}, was synthesized under hydrothermal conditions and structurally characterized by infrared spectroscopy (IR), elemental analysis, powder X-ray diffraction (PXRD), diffuse reflectance spectroscopy (DRS) and single crystal X-ray diffraction methods. In 1, two [Co2Mo10H4O38]6− POMs are joined together via two Co-O interactions to form a dimer which is centrosymmetric. Here, the dimers act as repeating units and are expanded by another crystallographically independent Co ion in the structure. Binding of the cations to the O atoms of the POM and the N atoms of organic ligand resulted in the formation of a 2D CP structure. Compound 1 is the first example of an inorganic-organic polymer architecture constructed from Evans-Showell-type POM in which Co cations act as metal nodes. The topology of 1 can be rationalized as a 2D square lattice (sql) coordination network with point symbol {44.62} in which [Co2Mo10H4O38]6− and 4,4′-bipyridine units act as linkers and the Co cations as nodes. The cytotoxicity effects of the POM were evaluated on the cancer CT26 and normal L929 cell lines by an MTT assay from which an IC50 value of cancer CT26 cells of approximately 366 ppm was obtained, but normal L929 cells did not show significant toxicity.

Exploration of properties (crystallographic, morphological, optical) of nano cobalt aluminate synthesized by facile sol–gel method: Effects of sintering temperature

The present work reports on the facile sol–gel synthesis of CoAl2O4 nanoparticles using cobalt nitrate and aluminum nitrate as the metal salts and citric acid and glycerol as chelating agents. The consequence of sintering temperature on the structure, particle size, morphology, composition, zeta potential, color, and reflectance spectra at neutral pH condition were explored with various instrumental techniques. The CoAl2O4 nanoparticles were characterized with Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), Nanoparticle size analyzer, Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis-DRS) and CIE-Lab colorimetric method. From the data of PXRD, the crystallite size and peak profile analysis were investigated by four different models. It was found that the average crystallite size varied in the range of 28.01–320.97 nm and single-phase cubic CoAl2O4 was formed without any impurity. The average particle size of CoAl2O4 nanoparticles was discerned from the FESEM images using ImageJ software and from a nanoparticle size analyzer. The average particle sizes were increased with the increasing sintering temperature. The values of zeta potential found in all of the samples represented high dispersion stability. From the colorimetry of CoAl2O4 nanoparticles, the CIE-La*b* output illustrated high purity and brightness and the spectra.

Classification of Plenodomus lingam and Plenodomus biglobosus in Co-Occurring Samples Using Reflectance Spectroscopy

Under natural conditions, mixed infections are often observed when two or more species of plant pathogens are present on one host. Thus, the detection and characterization of co-occurring pest species is a challenge of great importance. In this study, we focused on the development of a spectral unmixing method for the discrimination of two fungi species, Plenodomus lingam and Plenodomus biglobosus, the pathogens of oilseed rape. Over 24 days, spectral reflectance measurements from Petri dishes inoculated with fungi were conducted. Four experimental combinations were used: the first two were pure fungal samples, while the other two were co-occurring fungal samples. The results of the study show the possibility of distinguishing, based on spectral characteristics, between P. lingam and P. biglobosus not only in pure but also in co-occurring samples. We observed the changes in the reflectance of electromagnetic radiation from the tested fungi over time and a strong correlation between the reflectance and changes in the areas of the mycelia on the Petri dishes. Moreover, the wavelengths most useful for spectral classification of the tested fungal mycelia were selected. Finally, a spectral unmixing model was proposed, which enables the estimation of the areas of two pathogens in co-occurring samples based on the spectral characteristics of the entire plate with an error smaller than 0.2. To our knowledge, the present study is the first report examining the use of reflectance spectroscopy methods for classifying pathogens on the same Petri dish. The study results indicate the feasibility of reflectance spectroscopy as a nondestructive sampling method for plant pathogen detection and classification.

A facile route to extend the color gamut of cochineal, Dactylopius coccus costa, natural dye on wool textiles

Color gamut of cochineal, Dactylopius coccus costa, is limited to several tones restricting its application, so, it is necessary to explore a simple and economic method to develop its color shades on textiles. To this aim, in the present study, binary combinations of eight metal salts (Al, Sn, Cr, Cu, Fe, Ni, Co, Zn) were exploited in conventional pre-mordant dyeing of wool with cochineal, afterwards, color strength, color shade, and color fastness were investigated using reflectance spectroscopy and standard test methods. Binary metal mordanting produced different sober new color shades of dark and light red, brown, magenta, purple, and black on wool with enhanced light, washing, and rubbing fastness. Interestingly, color matching of some legally restricted hazardous mordants like Cr was plausible with alternative eco-friendlier binary mordants like Fe + Zn. It was concluded that binary combination of metal mordants not only is a simple route to extend the color gamut of cochineal on wool with satisfactory color fastness but also makes natural dyeing eco-friendlier compared to conventional dyeing.

Evaluation of a Commercial Device Based on Reflection Spectroscopy as an Alternative to Resonance Raman Spectroscopy in Measuring Skin Carotenoid Levels: Randomized Controlled Trial.

Resonance Raman spectroscopy (RRS) has been used as a reference method for measuring skin carotenoid levels (SCL), which indicate vegetable and fruit intake. However, RRS is not an easy-to-use method in SCL measurement due to its complicated implementation. In this study, a commercial spectrophotometer based on reflection spectroscopy (RS), which is relatively simple and inexpensive, was evaluated to confirm usability compared with RRS in measuring SCL. To investigate the agreement between RS and RRS, eighty participants were randomly assigned to a high-carotenoid diet group (21 mg/day of total carotenoids) or a control-carotenoid diet group (14 mg/day of total carotenoids) during a 6-week whole-diet intervention period and a 4-week tracking period. Strong correlations between the RS and RRS methods were observed at baseline (r = 0.944) and the entire period (r = 0.930). The rate of SCL increase was similar during the diet intervention; however, the initiation of the SCL decrease in RS was slower than in RRS during the tracking period. To confirm the agreement of RS and RRS from various perspectives, new visualization tools and indices were additionally applied and confirmed the similar response patterns of the two methods. The results indicate that the proposed RS method could be an alternative to RRS in SCL measurements.

Portable LWNIR and SWNIR spectroscopy with pattern recognition technology for accurate and nondestructive detection of hidden mold infection in citrus

An accurate and nondestructive detection method of hidden mold infection in citrus was established based on portable near infrared diffuse reflectance spectroscopy (NIRDRS) and chemometric methods. Penetrability of NIRDRS light on the peel of Chunjian hybrid citrus was studied. The results show that NIRDRS light can penetrate the peel to a certain extent, while the penetrability of short-wave near infrared (SWNIR) was better than that of long-wave near infrared (LWNIR). The identification models of hidden mold infection were established with five pattern recognition methods combined with different wavelength bands. The results show that the identification models of LWNIR were much better than those of SWNIR. 100% identification accuracies of LWNIR were obtained with soft independent pattern classification (SIMCA), support vector machine (SVM), partial least squares discriminant analysis (PLS-DA) and the optimized pretreatment methods. In addition, the developed models were further validated by the external validation set collected one month later.

Evaluation of the photodegradation activity of bismuth oxoiodide/bismuth sub-carbonate nanocatalyst: Experimental design and the mechanism study

In this study, a binary BiOI/(BiO)2CO3 catalyst was prepared and used for sulfasalazine (SSZ) photodegradation in an aqueous phase. The semiconductors were identified by XRD, SEM-EDX, and UV–Vis diffuse reflectance spectroscopy (DRS) methods. Applying the Kubelka-Munk model on DRS results, the band gap energies of 2.09, 3.5, and 2.07 eV were obtained for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 samples. pHpzc values of 6.3, 10.1, and 8.1 were estimated for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3, respectively. After observing the boosted photocatalytic activity by the coupled system, the interaction effects of the influencing variables in SSZ photodegradation were evaluated via the response surface methodology (RSM) approach. The optimal RSM-run conditions were 8.5 ppm SSZ at pH 8, which contained 0.28 g/L of the BiOI/(BiO)2CO3 catalyst and 29 min illumination time, resulting in 87% SSZ photodegradation. The effects of some scavenging agents were also studied to elucidate the relative roles of the reactive species in the SSZ photodegradation by the proposed catalyst, that is, hydroxyl radicals ∼ photoinduced electrons > superoxide radicals ∼ photoinduced holes. The proposed catalyst retained good activity after 5 successive reusing runs.

Effect of e-Liquid on the Optical Properties of the Gingival Mucosa: Ex Vivo Studies

In this work, the change in the optical properties of the gingival mucosa in the range of 200-800 nm under the influence of liquids for electronic cigarettes (e-liquids) was studied by the method of diffuse reflectance spectroscopy. The formation of three dynamic windows of gingival optical transparency in the ultraviolet (UV) was revealed. The diffusion coefficients of e-liquids of various compositions in the gingival mucosa have been estimated, which is of practical importance in the prevention of diseases and pharmaceutical toxicity associated with vaping, as well as in enhancement of the efficiency of the oral UV therapy.

Comparison of Chemical Composition, In Vitro Digestibility, and Near Infrared Reflectance Spectroscopy in Estimating In Situ Rumen Degradable Protein of Tropical Foliage

Tropical foliage is an alternative source for protein enrichment in the dairy ration. However, due to the expensive, laborious, and time-consuming data-gathering method, its degradability database for inclusion in ration formulation is still lacking. This study aims to estimate tropical foliage's in situ protein degradability (RDP) using chemical compositions, in vitro digestibilities, and near infrared reflectance spectroscopy (NIRS) methods. The study used one hundred ten tropical foliage samples and observed chemical composition, in vitro dry and organic matter digestibility, and in situ degradation characteristics variables. NIRS spectra were collected to calibrate and validate the in situ degradation characteristics. Correlations were made prior to regression analysis. The results showed that tropical foliage varied in ash (3.02%-18.3%), crude protein (CP) (11.6%-30.7%), crude fiber (CF) (10.2%-29.8%), neutral detergent fiber (NDF) (31.0%-58.2%), acid detergent fiber (ADF) (18.7%-44.1%), dry matter digestibility (DMD) (23.9%-73.2%), organic matter digestibility (OMD) (25.6%-73.9%), and in situ RDP (21.0%-75.4%). The foliage was highly degraded (RDP > 60%) except for Calliandra calothyrsus (59%). In situ RDP significantly correlated with ash, CP, CF, DMD, and OMD with coefficient correlations (r) of 0.43, 0.60, -0.33, 0.74, and 0.76, respectively. Estimation of RDP using chemical composition and in vitro digestibility followed the equation: RDP (%)= 0.69 + 2.122 CP (%) with R²= 0.41 (p<0.01) and RDP (%)= 0.162 ash + 1.270 CP -0.104 CF + 0.489 IVOMD, with R²= 0.68, p<0.01). Calibration of NIRS using in situ RDP resulted in a regression coefficient (R²) of 0.78. It is concluded that RDP tropical foliage can be estimated more accurately using NIRS compared to in vitro digestibility and chemical composition.

PREPARATION AND PROPERTIES OF CERAMIC MATERIALS IN THE Ag6PS5I‒Ag7GeS5I SYSTEM

This work is devoted to the preparation of dense Ag+ conductive ceramic solid electrolytes in the Ag6PS5I‒Ag7GeS5I system and to the study of their electrical and optical properties. Using the non-destructive and simple method of optical diffuse reflectance spectroscopy, the value of the optical pseudogap energy of the Ag6+x(P1-xGex)S5I (x=0, 0.25, 0.5, 0.75, 1.0) solid solutions was obtained using the Kubelka-Munk function with the application of Tauc's graphic method. As a result of the performed mathematical analysis and graphic processing, it was established that the quaternary chalcohalogenides Ag6PS5I, Ag7GeS5I and solid solutions Ag6+x(P1-xGex)S5I (x=0.25, 0.5, 0.75) belong to direct-band semiconductors characterized by a forbidden optical transition . The study of electrical conductivity of Ag6+x(P1-xGex)S5I solid solutions (x=0, 0.25, 0.5, 0.75, 1.0) was carried out by the method of impedance spectroscopy, in the frequency 1×101–3×105 Hz and temperature 293–383 K ranges. For all ceramic materials prepared on the basis of Ag6+x(P1-xGex)S5I (x=0, 0.25, 0.5, 0.75, 1.0) solid solutions, an increase in the values of total electrical conductivity was observed, which is characteristic of materials with ionic electrical conductivity in the solid state.&#x0D; Keywords: argyrodites; solid solutions; ceramic; impedance spectroscopy; conductivity; optical properties; optical pseudogap.

CHARACTERIZATION OF ENERGY BAND GAP THIN FILM BaTiO3 – BaZr0.5Ti0.5O3 USING DIFUSION REFLECTANCE SPECTROSCOPY (DRS) METHOD

Ferroelectric material is a dielectric material that has a high dielectric constant value so that it can be made in the form of thin films. Its application is based on electro-optical properties, one of which is the infrared thermal switch. This paper aims to determine the bandgap energy (Eg) of a 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 thin film. The 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 thin film is a semiconductor material with the valence band and conduction band separated by an energy bandgap (Eg). Thin films of 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 were grown on FTO substrates using the sol-gel method. The films of 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 were annealed at different temperatures of 700°C, 750°C and 800°C within 1 hour. Characterization was carried out using Ultra Violet Visible (UV-Vis) spectroscopy to determine Eg using the Diffusion Reflectance Spectroscopy (DRS) method. The DRS method was found to be better for solid materials considering the scattering component. The UV-Vis characterization results show that an increase in annealing temperature causes a decrease in Eg. For example the values ​​at 700°C, 750°C and 800°C are 3.5 ± 0.01 eV; 3.3±0.01 eV and 3.2±0.01 eV. The decrease in Eg is related to the diffusion of Barium Titanate (BaTiO3) ions into the Barium Zirconium Titanate (BZT) lattice forming a new sub-gap which in turn gives BT-BZT the ability to absorb lower light. Lower light absorption means more capable optics for multilayer systems.

A porphyrin derivative with highly red shifted and intensified absorption bands immobilized into the mesopores of nanostructured amberlite: Synthesis, characterization and photocatalytic activity

The BF3 complex of meso-tetra(4-sulfonatophenyl)porphyrin (H2TPPS4), immobilized into the pores of a new nano-structured mesoporous anion exchange polymer, nanoAmbN(Me)3Cl (Amb = Amberlite IRA-410(Cl)) was used as the photosensitizer for aerobic oxidation of organic compounds. NanoAmbN(Me)3Cl, nanoAmbN(Me)3@H2TPPS4 and nanoAmbN(Me)3@H2TPPS4(BF3)2, were characterized by IR and UV–vis diffuse reflectance spectroscopy (UV–vis DRS) methods, TGA, FESEM, elemental mapping (SEM-EDX) and BET. The nanocomposite was used as photosensitizer in the aerobic oxidation of 1,5-dihydroxynaphthalene (DHN) and cyclohexene in acetonitrile. The results were compared with those obtained in the presence of the BF3 complex of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (H2TMPyP) immobilized on nanostructured amberlyst 15. The observed red shifts in the UV–vis DRS UV–vis spectrum upon the formation of nanoAmbN(Me)3@H2TPPS4(BF3)2 were much larger than those of nanoAmbSO3@H2TMPyP(BF3)2. The singlet quatum yield of nanoAmbN(Me)3@H2TPPS4 and nanoAmbN(Me)3@H2TPPS4(BF3)2 was determined by using 1,3-diphenylisobenzofuran (DPBF) and DHN as the quenchers of singlet oxygen, for the excitation of the photosensitizers in the Q and Soret band regions, respectively.

Crystal structure and spectral properties of the heterometallic 3d-4f complex of gadolinium (III) – cobalt (II) with ethylenediamine-N,N,N′,N′-tetraacetic acid

The 4f-3d heteronuclear complex Co3Gd2(EDTA)11∙9·5H2O was synthesized by the "block" synthesis method using protonated ethylenediaminetetraacetate Co(II) and Gd(III) nitrate. The complex was fully characterized by means of elemental, thermal and X-ray structural analyses, as well as by the methods of diffuse reflection spectroscopy and IR spectroscopy. The complex crystallizes in monoclinic system (space group C2) with lattice parameters a = 15.8142(3) Å, b = 14.5875(3) Å, c = 14.6808(3) Å, α = γ = 90°, β = 116.5009(10)°.The complex is a 2D coordination polymer in which each Gd(III) ion is connected to with three atoms Co(II) atoms through tridentate bridging carboxylate groups of EDTA, and each Co atom has two neighboring Gd(III) atoms. The polymer layers are packed in parallel, outer-sphere water molecules are located between the layers, forming a branched system of hydrogen bonds.

Experimental and theoretical study of synthesis and properties of Cu2O/TiO2 heterojunction for photoelectrochemical purposes

The Cu2O/TiO2 heterojunction is an attractive surface for its optoelectronic properties for developing catalysts, cells, and solar devices. However, the mechanisms involved in synthesizing an electrode using the Cu2O/TiO2 heterojunction can affect the surface properties and the surface/electrolyte interactions. In this work, we studied the formation mechanism of the Cu2O/TiO2 heterojunction by electrochemical deposition (ECD) of Cu2O molecules on TiO2 nanoparticles previously deposited on a fluorine-doped thin oxide coated glass substrate (FTO). The photoelectrochemical properties of the Cu2O/TiO2/FTO electrode were characterized by XRD, FE-SEM, TEM, EDX, UV–vis diffuse reflectance spectroscopy (DRS), Raman spectroscopy, and electrochemical methods. Theoretical methods such as ab-initio density functional theory calculations and molecular dynamics simulations were used to understand the experimental results. The analysis carried out by theoretical methods allowed us to identify the initial steps of the formation mechanism of Cu2O molecules on TiO2 nanoparticles. Theoretical calculations demonstrated that forming a Cu2O nanowire-like network on the TiO2 nanoparticle matrix favors the charge transfer at the electrolyte/semiconductor interface, promoting the behavior of the electrode as a cathode. Finally, the Cu2O/TiO2/FTO electrode synthesized was used to perform the reduction photoelectrocatalyzed of nitrate to ammonia under illumination with a Xe-Hg arc lamp and applying −0.5 V bias potential (vs Ag/AgCl sat.) to evaluate the performance of the electrode as a cathode.

Analiza comparativă a cernoziomurilor tipice din zona de nord a Moldovei după diferiți indicatori

The purpose of this presented paper is determining the main indicators of soil fertility of typical chernozems in the Northern part of Moldova, by the Near Infrared Reflectance Spectroscopy method, used as a rapid and cost-effective analytical tool for the assessment and monitoring of their quality over time. The study was carried out in the fields of 10 districts in the northern area of Republic of Moldova. For the analysis of the agrophysical and agrochemical soil properties, a total of 16 soil profiles cultivated with different agricultural crops (winter wheat, corn, winter barley, sunflower, soybean, peas, sugar beet) and a soil profile from a fallow land were taken. Data on soil texture (clay, silt and sand fractions) do not show large differences between the sampling regions and the depth of the soil layer. On average, physical clay content is 53-64%, and fine clay content is 35-44%. The humus content varies between 3.48-4.85% in the arable soil layer and between 2.69-4.80% in the 25-50 cm sub-arable layer. The total nitrogen content in the investigated soils correlates with the humus content. The higher the humus content, the higher the total nitrogen content. Total N content ranges from 0.28% (chernozem under fallow) to 0.13% (chernozem grown with maize) in the 0-50 cm soil layer. The C:N ratio is equal to 10-11 in the 0-50 cm soil layer and 8-11 in the 50-100 cm layer. The pH values vary between 5.9-7.2 in the 0-50 cm layer and 6.8-8.1 in the 50-100 cm soil layer. Carbonates are accumulated throughout the soil profile. Comparing the results previously obtained on the typical chernozems under fallow land with the results obtained on the arable chernozems investigated in this study, showed that there is a tendency of the humus content decrease by about 2%, especially in the 0-50 cm soil layer, as a result of applied agricultural practices. Simultaneously, degradation processes are amplified, especially through erosion. In this context, the main issue is the need to monitor soil fertility to assess the impact of agricultural management applied by farmers.

Preparation of a g-C3N4/Ag3PO4 composite Z-type photocatalyst and photocatalytic degradation of Ofloxacin: Degradation performance, reaction mechanism, degradation pathway and toxicity evaluation

In this study, a g-C3N4/Ag3PO4 composite Z-heterojunction photocatalyst was prepared with a simple in situ deposition method, and was first applied to the degradation of Ofloxacin (OFX). When the theoretical g-C3N4 to Ag3PO4 mass ratio was 1:10 (denoted as AC-10), the OFX degradation was optimal, and the degradation efficiency reached 71.9 % within 10 min. Steady state fluorescence emission spectroscopy (PL), electrochemical impedance spectroscopy (EIS), transient photocurrent (I-t) and N2 adsorption-desorption (BET) studies showed that AC-10 had the best charge separation efficiency and highest specific surface area. Additionally, the effects of AC-10 dosage, OFX concentration, pH value, anions, humic acid and water source on the degradation process were also studied. A cycling experiment showed that AC-10 exhibited good stability. Three-dimensional excitation-emission matrix spectroscopy (3D EEMs), LC-MS data and ECOSAR models were used to explore the process for degradation of OFX and predict the biotoxicities of byproducts, and these results indicated that the catalyst was environmentally friendly. In addition, electron spin resonance (ESR) experiments and capture of the active species showed that photogenerated holes (h+) played a major role in the reaction. Finally, the optical properties and the energy band structure of the catalyst were analyzed by UVvis diffuse reflectance spectroscopy (DRS) and Mott-Schottky (M-S) methods, and a Z-type heterojunction charge transfer mechanism was proposed.

Photocatalytic degradation of remdesivir nucleotide pro-drug using [Cu(1-methylimidazole)4(SCN)2] nanocomplex synthesized by sonochemical process: Theoretical, hirshfeld surface analysis, degradation kinetic, and thermodynamic studies

The first ultrasonic synthesis of [Cu(L)4(SCN)2] (L = 1-methylimidazole) nanocomplex was carried out under ultrasonic irradiation, and its photocatalytic performance for the degradation of remdesivir (RS) under sunlight irradiation was comprehensively investigated for the first time in this study. The physicochemical properties of the synthesized photocatalyst were examined by Fourier-transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), diffuse reflectance spectroscopy (DRS), and thermogravimetric analysis (TGA) techniques. The band gap of the synthesized [Cu(L)4(SCN)2] nanocomplex was determined to be 2.60 eV by the diffuse reflectance spectroscopy method using Kubelka-Munk formula. The photocatalytic performance of nanocomplex was examined for the removal of remdesivir under sunlight from water for which the results indicated that an amount of 0.5 gL−1 of the [Cu(L)4(SCN)2] nanocomplex was sufficient to remove more than 96% remdesivir from its 2 mg L−1 concentration within 20 min, at pH = 6. The kinetic data showed that the photodegradation onto the [Cu(L)4(SCN)2] nanocomplex has a high correlation (0.98) with the pseudo-second-order kinetic model. The decrease in chemical oxygen demand (COD) (from 70.5 mg L−1 to 36.4 mg L−1) under optimal conditions clearly confirmed the mineralization of the RS drug. The values of ΔS° (−0.131 kJ mol−1 K−1) and ΔH° (−49.750 kJ mol−1) were negative, indicating that the adsorption process was spontaneous and more favorable in lower temperatures. Moreover, the RS structure in the open shell state and the high HOMO and LUMO gaps based on the M06/6-31 + G (d) level of theory may be a confirmation of this fact. In addition, the Hirshfeld surface analysis (HSA) of the crystal packing of the prepared complex was discussed in detail to evaluate the interactions between the crystal packings. The results of this study confirm that the [Cu(L)4(SCN)2] nanocomplex can be successfully used for the photodegradation of pharmaceutical contaminants.

Solid-state synthesis of ZnMn2O4 spinel: Sequence of phase transformations, thermal stability, localization and charge state of manganese ions in the intermediate and final reaction products

This paper presents data on the solid-state synthesis of spinel ZnMn2O4, one of the leading promising materials for numerous practical applications. The evolution of the phase composition and charge state of manganese ions during the solid-state synthesis of ZnMn2O4 in air from ZnO and Mn2O3 has been studied. Using differential thermal, thermogravimetric, and X-ray diffraction analysis methods it has been established that, at a temperature of about 700 °C, an insignificant amount of ZnMn2O4 is present in the mixture with the initial oxides. During further heat treatment ZnMn2O4 interacts with Mn2O3 to form the solid solution based on ZnMn2O4. In parallel with this process, in the temperature range of 800–850 °C, ZnMn2O4 reacts with ZnO to form the compound ZnMn4+O3. It has been shown that heat treatment at 880–1180 °C leads to the formation of the final single-phase product – ZnMn2O4. Using diffuse reflectance spectroscopy, XPS, and FT-IR methods, the charge state and localization of Mn ions in the intermediate and final synthesis products have been determined. It has been shown that in the Zn1-xMn2+xMn3+2O4 solid solution Mn2+ ions are localized in the tetrahedral positions and Mn3+ ions in the octahedral positions of the structure. In the final single-phase product, ZnMn2O4, the tetrahedral positions are occupied only by zinc ions, and the octahedral positions are occupied only by Mn3+ ions. It has been established that ZnMn2O4 is stable up to 1300°С. Upon reaching this temperature, ZnMn2O4 decomposes into ZnO and Zn1-хMn2+хMn3+2O4.

Optimizing extraction solvents for deoxynivalenol analysis in maize via infrared attenuated total reflection spectroscopy and chemometric methods.

Farmers, cereal suppliers and processors demand rapid techniques for the assessment of mould-associated contamination. Deoxynivalenol (DON) is among the most important Fusarium toxins and related to human and animal diseases besides causing significant economic losses. Routine analytical techniques for the analysis of DON are either based on chromatographic or immunoanalytical techniques, which are time-consuming and frequently rely on hazardous consumables. The present study evaluates the feasibility of infrared attenuated total reflection spectroscopy (IR-ATR) for the analysis of maize extracts via different solvents optimized for the determination of DON contamination along the regulatory requirements by the European Union (EU) for unprocessed maize (1750 μg kg-1). Reference analysis was done by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The studied maize samples were either naturally infected or had been artificially inoculated in the field with Fusarium graminearum, Fusarium culmorum or Fusarium verticillioides. Principal component analysis demonstrated that water and methanol-water (70 : 30% v) were optimum solvents for differentiating DON contamination levels. Supervised partial least squares discriminant analysis resulted in excellent classification accuracies of 86.7% and 90.8% for water and methanol-water extracts, respectively. The IR spectra of samples with fungal infection and high DON contamination had distinct spectral features, which could be related to carbohydrates, proteins and lipid content within the investigated extracts.