Attenuated Total Reflection Infrared Spectroscopy Research Articles

Characterization and radiation shielding efficiency of MWCNT/shape memory ternary blend composite films

In this study, the structural, X-ray and gamma-ray, and neutron shielding properties of shape memory ternary blend/multi-walled carbon nanotube (MWCNT) composite films were investigated. The composition of the composite films was defined as (100-x) poly (ε-caprolactone) (PCL):polyethylene glycol (PEG):polyvinyl chloride (PVC) + xMWCNT, where x = 0, 1, 3, 5% (mole percentage). The ternary blend/MWCNT composite films were characterized using Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Thermal results showed that the degradation temperatures of composite materials with two degradation curves increased with increasing MWCNT percentage. The appearance of the MWCNT signal along with the characteristic polymer signals in the XRD pattern may be evidence that MWCNT is homogeneously distributed in the polymer blend. The mass attenuation coefficients (MAC), half-value layer (HVL), mean free path (MFP), and effective atomic numbers (Z_eff) of the composite films were experimentally measured over an energy range of 8.04–383.85 keV. Additionally, the equivalent dose rates for fast neutrons were measured, and the exposure buildup factor (EBF) and fast neutron removal cross-section (Σ_R) were theoretically calculated. The proton and alpha shielding parameters of the ternary blend/MWCNT composite films were determined, revealing that the inclusion of higher amounts of MWCNTs in the composite structure significantly improved capability of the films in shielding against radiation and neutrons.

Development of a Measurement System Using Infrared Spectroscopy-Attenuated Total Reflectance, Principal Component Analysis and Artificial Intelligence for the Safe Quantification of the Nucleating Agent Sorbitol in Food Packaging.

Sorbitol derivatives and other additives are commonly used in various products, such as packaging or food packaging, to improve their mechanical, physical, and optical properties. To accurately and precisely evaluate the efficacy of adding sorbitol-type nucleating agents to these articles, their quantitative determination is essential. This study systematically investigated the quantification of sorbitol-type nucleating agents in food packaging made from impact copolymers of polypropylene (PP) and polyethylene (PE) using attenuated total reflectance infrared spectroscopy (ATR-FTIR) together with analysis of principal components (PCA) and machine learning algorithms. The absorption spectra revealed characteristic bands corresponding to the C-O-C bond and hydroxyl groups attached to the cyclohexane ring of the molecular structure of sorbitol, providing crucial information for identifying and quantifying sorbitol derivatives. PCA analysis showed that with the selected FTIR spectrum range and only the first two components, 99.5% of the variance could be explained. The resulting score plot showed a clear pattern distinguishing different concentrations of the nucleating agent, affirming the predictability of concentrations based on an impact copolymer. The study then employed machine learning algorithms (NN, SVR) to establish prediction models, evaluating their quality using metrics such as RMSE, R2, and RMSECV. Hyperparameter optimization was performed, and SVR showed superior performance, achieving near-perfect predictions (R2 = 0.9999) with an RMSE of 0.100 for both calibration and prediction. The chosen SVR model features two hidden layers with 15 neurons each and uses the Adam algorithm, balanced precision, and computational efficiency. The innovative ATR-FTIR coupled SVR model presented a novel and rapid approach to accurately quantify sorbitol-type nucleating agents in polymer production processes for polymer research and in the analysis of nucleating agent derivatives. The analytical performance of this method surpassed traditional methods (PCR, NN).

Melt processing of graphene-coated polylactide granules for producing biodegradable nanocomposite with higher mechanical strength

ABSTRACT Innovative melt processing technology is necessary for the production of biodegradable polylactide/graphene nanocomposites. In this paper, we present the aqueous spray coating method to prepare graphene-coated polylactide granules for improving the distribution of small graphene contents in polymer matrix during the melt mixing process. Three types of functionalized graphene nanosheets, including graphene oxide (GO), reduced graphene oxide (RGO) and poly(ethylene glycol)/RGO (PEG/RGO), were investigated in the formations of graphene coatings on polylactide granules and subsequent melt-processed nanocomposites. It is found that RGO nanosheets have good interfacial compatibility to form better coatings on polylactide granules. Melt processing of graphene-coated granules produced polylactide/graphene nanocomposites with higher mechanical strengths. Nanocomposite materials containing 0.1% RGO showed the best improvements of mechanical and thermal properties. As-prepared nanomaterials and nanocomposites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-Vis), attenuated total reflectance infrared spectroscopy (ATR-FTIR), tensile, flexural and impact measurements, differential scanning calorimetry (DSC) and integrated thermogravimetric analysis (TGA-DTA). In general, the innovative strategy of aqueous spray coating and melt processing is applicable for manufacturing biodegradable PLA/graphene nanocomposites in the sustainable trend of environmentally friendly development.

Laser-irradiating infrared attenuated total reflection spectroscopy of articular cartilage: Potential and challenges for diagnosing osteoarthritis

ObjectiveA prototype infrared attenuated total reflection (IR-ATR) laser spectroscopic system designed for in vivo classification of human cartilage tissue according to its histological health status during arthroscopic surgery is presented. Prior to real-world in vivo applications, this so-called osteoarthritis (OA) scanner has been tested at in vitro conditions revealing the challenges associated with complex sample matrices and the accordingly obtained sparse spectral datasets. MethodsIn vitro studies on human knee cartilage samples at different contact pressures (i.e., 0.2–0.5 ​MPa) allowed recording cartilage degeneration characteristic IR signatures comparable to in vivo conditions with high temporal resolution. Afterwards, the cartilage samples were assessed based on the clinically acknowledged osteoarthritis cartilage histopathology assessment (OARSI) system and correlated with the obtained sparse IR data. ResultsAmide and carbohydrate signal behavior was observed to be almost identical between the obtained sparse IR data and previously measured FTIR data used for sparse partial least squares discriminant analysis (SPLSDA) to identify the spectral regions relevant to cartilage condition. Contact pressures between 0.3 and 0.4 ​MPa seem to provide the best sparse IR spectra for cylindrical (d ​= ​3 ​mm) probe tips. ConclusionLaser-irradiating IR-ATR spectroscopy is a promising analytical technique for future arthroscopic applications to differentiate healthy and osteoarthritic cartilage tissue. However, this study also revealed that the flexible connection between the laser-based analyzer and the arthroscopic ATR-probe via IR-transparent fiberoptic cables may affect the robustness of the obtained IR data and requires further improvements.

Roles of extracellular polymeric substances in arsenic accumulation and detoxification by cell wall intact and mutant strains of Chlamydomonas reinhardtii

Arsenic (As) pollution seriously threatens human and ecological health. Microalgal cell wall and extracellular polymeric substances (EPS) are known to interact with As, but their roles in the As resistance, accumulation and speciation in microalgae remain unclear. Here, we used two strains of Chlamydomonas reinhardtii, namely CC-125 (wild type) and CC-503 (cell wall-deficient mutant), to examine the algal growth, EPS synthesis, As adsorption, absorption and transformation under 10–1000 µg/L As(III) and As(V) treatments for 96 h. In both strains, the As absorption increased after the EPS removal, but the growth, As adsorption, and transformation of C. reinhardtii declined. The CC-125 strain was more tolerant to As stress and more efficient in EPS production, As accumulation, and redox transformation than CC-503, irrespective of EPS presence or absence. Three-dimension excitation-emission matrix (3D-EEM) and attenuated total reflectance infrared spectroscopy (ATR-IR) analyses showed that As was bound with functional groups in the EPS and cell wall, such as -COOH, -NH and -OH in proteins, polysaccharides and amino acids. Together, this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C. reinhardtii. However, the cell wall mutant strain was more susceptible to As toxicity due to lower EPS induction and higher As absorption.

Synthesis and Characterization of Epigallocatechin Gallate-mediated Hydroxyapatite.

Hydroxyapatite is a significant material that finds its application in the field of dental and bone tissue engineering. The formulation of nanohydroxyapatite with the aid of bioactive compounds has gained importance in recent years due to the beneficial activity contributed by them. The present work focuses on the formulation of nanohydroxyapatite synthesis using epigallocatechin gallate, an active biochemical component of green tea. The prepared epigallocatechin gallate-mediated nanohydroxyapatite (epi-HAp) was nanoglobular in shape and composed of calcium, phosphorous, carbon and oxygen, which was confirmed by Scanning electron microscope- energy dispersive X-ray analysis (SEM-EDX). The Attenuated Total Reflection-Infra red spectroscopy (ATR-IR) and X-ray photoelectron spectroscopy (XPS) assured that the reduction and stabilisation of nanohydroxyapatite were mediated by epigallocatechin gallate. The epi-HAp exhibited anti-inflammatory behaviour along with nil effect on cytotoxicity. To be precise, the epi-HAp can be an effective biomaterial in bone and dental applications.

“Reagent-free determination of γ-butyrolactone in beverages”

A green partial least square (PLS) attenuated total reflectance infrared spectroscopy (ATR-FTIR) method has been developed for the prediction of the γ-butyrolactone (GBL) in all type of soft and alcoholic beverages. The method involves the use of a drop (less than 5 µL) of sample and a single calibration model based on aqueous and alcoholic solutions of GBL and beverages free from GBL. A selected wavenumber range from 1225 to 1171 cm−1 and from 999 to 972 cm−1 of the second derivative (SD) spectra of samples and standards were employed. The validation set provided root mean square error of prediction (RMSEP) of the order of 300 µg g−1 GBL with a ratio of standard error of performance to standard deviation value (RPD) of 13.4. The prediction of unknown samples not considered in the calibration nor in the validation sets offered accuracy relative errors between −1.0 and 2.9 % GBL. The proposed PLS-FTIR based method allows a fast and direct determination of GBL in all type of beverages, in less than 2 min and avoiding the use of neither reagents nor solvents, without any sample treatment required, being in agreement with the principles of Green Analytical Chemistry.

Efficient catalytic conversion of cellulose into 5-hydroxymethylfurfural by modified cerium zirconium phosphates in a biphasic system

Numerous metal phosphates have shown activity in the conversion of cellulose into 5-hydroxymethylfurfural (HMF). However, challenges persist due to low HMF yields and unclear structure-reactivity relationships. Herein, a series of zirconium-cerium phosphate-based catalysts were prepared by the co-precipitation method. These catalysts were sulfonated and loaded with tungsten to introduce Brønsted acidity. The effects of catalyst types and operating conditions on the production of HMF from cellulose using a biphasic system of tetrahydrofuran (THF) and water were systematically investigated in an autoclave reactor. The structure-reactivity relationship of these catalysts was subsequently elucidated using various catalyst characterization techniques. For an understanding of the reaction mechanism, in-situ attenuated total reflectance infrared spectroscopy (ATR-FTIR) was employed to monitor the reaction process. Experimental results revealed that the optimal HMF yield of 41.5% could be obtained using the 2W/CeZr2P + AC–SO3H–2 catalyst at 180 °C with a reaction time of 4 h. Compared to monometallic phosphate pairs of zirconium and cerium, this represents an enhancement in HMF yield by approximately 8%–20%. The enhancement could be attributed to the adequate acid amount and the balanced Brønsted/Lewis acid site ratio of this catalyst. These findings provide valuable guidance for future design and optimization of bimetallic phosphate catalysts.

Hydroxyl silicone oil grafting onto a rough thermoplastic polyurethane surface created durable super-hydrophobicity

Indwelling medical catheters are frequently utilized in medical procedures, but they are highly susceptible to infection, posing a vital challenge for both health workers and patients. In this study, the superhydrophobic micro-nanostructure surface was constructed on the surface of thermoplastic polyurethane (TPU) membrane using heavy calcium carbonate (CaCO3) template. To decrease the surface free energy, hydroxyl silicone oil was grafted onto the surface, forming a super-hydrophobic surface. The water contact angle (WCA) increased from 91.1° to 143 ± 3° when the concentration of heavy calcium CaCO3 was 20% (weight-to-volume (w/v)). However, the increased WCA was unstable and tended to decrease over time. After grafting hydroxyl silicone oil, the WCA rose to 152.05 ± 1.62° and remained consistently high for a period of 30 min. Attenuated total reflection infrared spectroscopy (ATR-FTIR) analysis revealed a chemical crosslinking between silicone oil and the surface of TPU. Furthermore, Scanning electron microscope (SEM) image showed the presence of numerous nanoparticles on the micro surface. Atomic force microscope (AFM) testing indicated a significant improvement in surface roughness. This method of creating a hydrophobic surface demonstrated several advantages, including resistance to cell, bacterial, protein, and platelet adhesion and good biosecurity. Therefore, it holds promising potential for application in the development of TPU-based medical catheters with antibacterial properties.

Improved performance of polyamide nanofiltration membrane embedded with zeolite beta

In this study, zeolite beta nanoparticles were incorporated into an interfacial polymerization procedure for the fabrication of thin film nanocomposites (TFNs). The successful introduction of zeolite beta into the polyamide (PA) selective layer was confirmed by surface attenuated total reflection infrared spectroscopy (ATR-FTIR), and x-ray photoelectron spectroscopy (XPS). The introduction of porous structured zeolite beta improved the water flux and rejection rate of the TFN membrane compared to the PA thin film composite (TFC) membrane. A quantitative performance coefficient is further proposed in this work, comprehensively considering the flux and rejection rate to evaluate the performance of TFNs. For five salt solutions, we found that the TFN0.3 membrane with 0.3 wt% of zeolite particles had a high coefficient of performance. With the help of zeolite particles, the TFN0.3 membrane achieved a high flux of 92.53 L/(m2·h) under an operating pressure of 5 bar. For ion separation from binary solutions, the TFN0.2 membrane with 0.2 wt% zeolite content was a better choice for a wide range of binary mixtures, which is because the addition of zeolite beta resulted in smaller pore sizes, the strongest zeta potential, and the thickest thickness (scanning electron microscope, SEM determined) of the TFN0.2 membrane. All these factors contribute to the selectivity of the TFN0.2 membrane. Our study provides an efficient and cost-effective method to simultaneously improve the permeability and rejection of nanofiltration membranes, facilitating the development of nanofiltration for water recovery.

Enhancing biological properties with straightforward deposition of durable heparin/chitosan surface coatings on wettable poly(ε-caprolactone)/Tween-20 electrospun fibers

Poly(ε-caprolactone) (PCL) is a hydrophobic aliphatic polyester commonly used as a biomaterial due to its cytocompatibility and biodegradability. However, PCL-based materials are hydrophobic and susceptible to bacterial adhesion and proliferation. To address these disadvantages, this study proposes a direct and practical method for functionalizing the surface and enhancing the biological properties of electrospun PCL fibers using Tween-20 surfactant, followed by the deposition of polyelectrolyte multilayers (PEMs). Tween-20, a neutral and cytocompatible surfactant, was directly incorporated into the fibers without prior surface modifications. The surfactant significantly increased the wettability of the PCL fibers, resulting in water contact angles of 0 degrees, facilitating subsequent functionalization with heparin and chitosan PEMs (with 10, 20, and 30 layers). The materials were characterized through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), water contact angle and mechanical measurements, Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The PEMs remain stable on the fiber surfaces for up to 14 days in a buffer at 37°C. The samples supported high cell viability with no observed cytotoxicity toward human adipose-derived stem cells and no hemolytic activity toward human red blood cells. Antibacterial assays (live/dead and proliferation tests) demonstrated that the coated PCL fibers inhibited the proliferation of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). The PEM coatings significantly enhanced the antimicrobial activity, resulting in a high number of damaged and dead bacterial cells attached to the coated fibers. Therefore, the heparin/chitosan PEMs on Tween-20-modified PCL fibers can prevent bacterial infections while supporting viable mammalian cells.

Elucidating the Reduction Mechanism of Lithium Bis(oxalato)borate.

Electrolyte additives are indispensable to enhance the performance of Li-ion batteries. Lithium bis(oxalato)borate (LiBOB) has been explored for many years, as it improves both cathode and anode performance. No consensus regarding its reaction mechanisms has, however, been established. A model operando study combining attenuated total reflection infrared spectroscopy (ATR-FTIR), electrochemical quartz crystal microbalance (EQCM), and online electrochemical mass spectrometry (OEMS) is herein presented to elucidate LiBOB reduction and electrode/electrolyte interphases thus formed. Reduction of the BOB- ion sets in at ∼1.8 V with solid lithium oxalate and soluble oxalatoborates as the main products. The reduced BOB- ion also reacts with itself and its environment to evolve CO2, which in turn impacts the interphase formed on the negative electrode. This study provides further insights into the reduction pathways of LiBOB and how they contribute to the interphase formation.

Development and Characterization of Gadolinium and Copper Reinforced Bioactive Glass: An In Vitro Study.

Bioactive glass, an innovative alloplastic material utilizing a matrix of silica particles combined with calcium and phosphorus, has been widely employed for the regeneration of bony defects due to its bone-forming capabilities and biocompatibility. Nevertheless, it comes with several drawbacks, including a slow degradation rate, low mechanical strength, and susceptibility to fractures. To address these issues, the present research was done to develop and characterize a novel bioactive glass incorporating gadolinium (Gd) and copper (Cu). The bioactive glass doped with Gd and Cu were synthesized and subjected to characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), and attenuated total reflectance-infrared (ATR-IR) analysis. The bioactive glass, enriched with Gd and Cu, underwent analysis using ATR-IR spectroscopy, XRD, and SEM. ATR-IR revealed characteristic silicate bands, while SEM indicated the presence of particles larger than 4 μm. XRD analysis identified the formation of Na2Ca4(PO4)2SiO4 (Silicorhenatite), Na2Ca2Si3O9 (Combeite), and wollastonite (calcium inosilicate mineral; CaSiO3). The crystalline nature of these compounds contributed to the favorable mechanical properties of the bioactive glass. In summary, the creation of the innovative Gd-Cu-incorporated bioactive glass demonstrates favorable mechanical characteristics, suggesting significant promise for augmenting bone regeneration.

Lignocellulosic Membranes Grafted with N-Vinylcaprolactam Using Radiation Chemistry: Load and Release Capacity of Vancomycin.

Radiation chemistry presents a unique avenue for developing innovative polymeric materials with desirable properties, eliminating the need for chemical initiators, which can be potentially detrimental, especially in sensitive sectors like medicine. In this investigation, we employed a radiation-induced graft polymerization process with N-vinylcaprolactam (NVCL) to modify lignocellulosic membranes derived from Agave salmiana, commonly known as maguey. The membranes underwent thorough characterization employing diverse techniques, including contact angle measurement, degree of swelling, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), nuclear magnetic resonance (CP-MAS 13C-NMR), X-ray photoelectron spectroscopy (XPS), and uniaxial tensile mechanical tests. The membranes' ability to load and release an antimicrobial glycopeptide drug was assessed, revealing significant enhancements in both drug loading and sustained release. The grafting of PNVCL contributed to prolonged sustained release by decreasing the drug release rate at temperatures above the LCST. The release profiles were analyzed using the Higuchi, Peppas-Sahlin, and Korsmeyer-Peppas models, suggesting a Fickian transport mechanism as indicated by the Korsmeyer-Peppas model.

RAPID DETECTION OF RAT MEAT ADULTERATION IN BEEF SAUSAGES USING FTIR‑ATR SPECTROSCOPY AND CHEMOMETRICS FOR HALAL AUTHENTICATION

Objective: The objective of this study was to employ Fourier Transform Infrared-Attenuated Total Reflectance (FTIR‑ATR) spectroscopy in combination with chemometrics for the analysis of rat meat adulteration in beef sausages.
 Methods: Lipid components in sausages were extracted using three extraction methods, namely Bligh and Dyer, Folch, and Soxhlet methods. The lipid components extracted were then analysed using FTIR‑ATR spectroscopy, and their spectra obtained were used as variables during chemometrics modeling. Samples were prepared by mixing beef with adulterant of rat meat in the concentration range of 0-100% of rat meat. Each sample was scanned using FTIR-Attenuated Total Reflectance (ATR) spectroscopy in three replicates at 4000-650 cm-1 wavenumber region.
 Results: The absorbance values at wavenumbers regions of 3100-700 cm-1 were used to discriminate lipid components extracted by the Bligh Dyer, Folch, and Soxhlet Method with an accuracy level of 100%. The prediction of rat sausages was successfully determined using multivariate calibrations of Partial Least Square (PLS) and Principle Component Regression (PCR) using optimised conditions.
 Conclusion: FTIR-ATR spectroscopy coupled with chemometrics is a rapid and accurate method for detecting and quantifying rat meat in beef sausages for halal authentication.

Extraction and characterisation of cuticular waxes from Physalis peruviana calyx

SummaryWaxes play an important role in maintaining fruit quality and shelf‐life extension because they are naturally effective in blocking the migration of moisture. In this work, cuticular waxes from Physalis peruviana calyx (PPC) were extracted and characterised as potentially hydrophobic materials. Extraction was carried out using the Soxhlet technique with two non‐polar solvents, hexane and petroleum ether, and one polar solvent, ethanol. The extraction yield, lipid characterisation, and hydrophobic potential of cuticular waxes from PPC were analysed and compared using thin‐layer chromatography (TLC), attenuated total reflectance‐infrared spectroscopy (ATR‐IR), GC–MS chromatogram (FAMES), and wetting contact angle. Extraction using hexane was the most efficient method (yield of 9.61 ± 0.37%) for obtaining cuticular waxes with better hydrophobic properties, characterised by a contact angle of  = 107.37 ± 1.0° and a hysteresis contact angle of 11° due mainly to the presence of functional groups desirable and characteristic of vegetable waxes. Greater texture homogeneity visualised using optical microscopy and the presence of capric acid (70.97%) as a major component of low‐molecular‐weight fatty acids were observed in this extract. Due to their biodegradable, potentially antifungal, and hydrophobic properties, cuticular waxes from PPC have the potential to replace synthetic waxes in industrial applications.

Identification of Cu(111) as Superior Active Sites for Electrocatalytic NO Reduction to NH3 with High Single‐Pass Conversion Efficiency

AbstractOpting for NO as an N source in electrocatalytic NH3 synthesis presents an intriguing approach to tackle energy and environmental challenges. However, blindly pursuing high NH3 synthesis rates and Faradaic efficiency (FE) while ignoring the NO conversion ratio could result in environmental problems. Herein, Cu nanosheets with exposed (111) surface is fabricated and exhibit a NO‐to‐NH3 yield rate of 371.89 μmol cm−2 h−1 (flow cell) and the highest FE of 93.19±1.99 % (H‐type cell). The NO conversion ratio is increased to the current highest value of 63.74 % combined with the development of the flow cell. Additionally, Crystal Orbital Hamilton Population (COHP) clearly reveals that the “σ‐π* acceptance‐donation” is the essence of the interaction between the Cu and NO as also supported by operando attenuated total reflection infrared spectroscopy (ATR‐IRAS) in observing the key intermediate of NO−. This work not only achieves a milestone NO conversion ratio for electrocatalytic NO‐to‐NH3, but also proposes a new descriptor that utilizes orbital hybridization between molecules and metal centers to accurately identify the real active sites of catalysts.

Identification of Cu(111) as Superior Active Sites for Electrocatalytic NO Reduction to NH3 with High Single-Pass Conversion Efficiency.

Opting for NO as an N source in electrocatalytic NH3 synthesis presents an intriguing approach to tackle energy and environmental challenges. However, blindly pursuing high NH3 synthesis rates and Faradaic efficiency (FE) while ignoring the NO conversion ratio could result in environmental problems. Herein, Cu nanosheets with exposed (111) surface is fabricated and exhibit a NO-to-NH3 yield rate of 371.89 μmol cm-2  h-1 (flow cell) and the highest FE of 93.19±1.99 % (H-type cell). The NO conversion ratio is increased to the current highest value of 63.74 % combined with the development of the flow cell. Additionally, Crystal Orbital Hamilton Population (COHP) clearly reveals that the "σ-π* acceptance-donation" is the essence of the interaction between the Cu and NO as also supported by operando attenuated total reflection infrared spectroscopy (ATR-IRAS) in observing the key intermediate of NO- . This work not only achieves a milestone NO conversion ratio for electrocatalytic NO-to-NH3 , but also proposes a new descriptor that utilizes orbital hybridization between molecules and metal centers to accurately identify the real active sites of catalysts.

Assessment of Beeswax Adulteration by Paraffin and Stearic Acid Using ATR-IR Spectroscopy and Multivariate Statistics-An Analytical Method to Detect Fraud.

A spectroscopic investigation of beeswax adulteration by paraffin and/or stearic acid was undertaken via Attenuated Total Reflectance Infra-Red spectroscopy (ATR-IR) combined with multivariate statistical analyses. Principal Component Analysis (PCA) was successfully applied for the first time as an exploratory tool for the differentiation among pure beeswax and adulterated beeswax by paraffin and stearic acid with detection limits (LOD) of ~5% and 1%, respectively. Partial Least Square (PLS) modelling was used to build chemometric models based on beeswax/paraffin and beeswax/stearic acid calibration mixtures and subsequently used to predict concentrations of paraffin and stearic acid on a set of unknown test samples. PLS predictions demonstrated that beeswax adulteration by paraffin is much more prominent (74%) than the one by stearic acid (26%) and that commercial beeswax products (candles, pearls, blocks, etc.) are more prone to adulteration (27%) than honeycomb-type samples (12.5%).

Valorization of bio‐calcium carbonate based Chamelea gallina shell waste fillers in shape memory polymer composites

AbstractIn recent years, the focus has been on the use of calcium carbonate‐based seashell wastes in the production of new thermoplastic and thermoset polymer materials, paving the way for their use as biofillers in polymeric composites. In this study, it is aimed to obtain a new polymeric composite material by doping Chamelea gallina shells, on polylactic acid (PLA)/polyethylene glycol (PEG) blend. Structural characterization of the obtained PLA/PEG blend/C. gallina composite films was performed with attenuated total reflection infrared spectroscopy (ATR‐IR). When the thermal properties of composite materials were examined by thermogravimetric analysis (TGA), it was determined that the thermal stability of polymeric composites increased with the addition of C. gallina. SEM images showed that the polymer blend films, which appeared to have a porous structure, filled the pores with increasing C. gallina ratio. It was observed that the biodegradability of PLA/PEG blend composite films decreased with increasing C. gallina shells addition. However, C. gallina had a positive effect on the swelling and water absorption capacities of polymeric composites. The increase in tensile strength and elongation at break values of PLA/PEG blend/C. gallina composite films with increasing C. gallina means that the mechanical properties of the polymer are improved.