Transmission FTIR Research Articles

Operando Reactor-Cell with Simultaneous Transmission FTIR and Raman Characterization (IRRaman) for the Study of Gas-Phase Reactions with Solid Catalysts.

Raman and transmission FTIR spectroscopic techniques have been coupled in a new homemade reactor-cell designed in a joint CSIC-LCS collaboration. The setup is easily adapted to any FTIR and fiber-coupled Raman spectrometers and gas analysis techniques. It allows for simultaneous operando FTIR and Raman spectroscopic measurement, which provide complementary characterization of adsorbed species, reaction intermediates, and structural properties of the catalyst. This system was validated with the study of vanadium-based catalysts during propane oxydehydrogenation (ODH). The combined use of both spectroscopies with gas analysis techniques to measure the activity contributes to the understanding of propane ODH and the identification of the role of different oxygen species bound to vanadium sites. For example, the simultaneous characterization of the catalyst under the same conditions by IR and Raman confirms that the V═O mode has the same frequency in both spectroscopies and that bridging oxygen sites (V-O-V, V-O-Zr) present higher activity than terminal V═O bonds. These results demonstrate the high potential of the new simultaneous transmission IR-Raman operando rig to correlate the activity and the structure of catalysts, thus assisting the rational design of catalytic processes.

Effectiveness of Toothpony (Gazza minuta) protein hydrolysate on reducing oil uptake upon deep-frying

Toothpony (Gazza minuta) is not typically used for human consumption due to its small size and low meat content, which is widely used as a fish meal. It is stated to be high in protein content and may be suitable for fish protein hydrolysate (FPH) production. Deepfat fried foods contain significant amounts of fat, in some cases up to one-third of the total food weight after frying. Toothpony FPH with low oil-binding ability may reduce the amount of oil consumed by deep-fried products. The objective of this research was to measure the physicochemical properties of Toothpony FPH and its utilisation in reducing the oil intake of deep-fried food. Toothpony FPH was obtained using the enzymatic method successfully. Batter formulations are prepared by adding 0%, 2%, 4%, 6% and 8% of Toothpony FPH into the sample mixtures. The present study indicates the degree of hydrolysis of Toothpony FPH determined by trichloroacetic acid (TCA) method was found to be 98.02%. Toothpony FPH's molecular weight distributions ranged from 7 to 175kDa and FTIR's transmission spectrum indicated the presence of amide I and amide II compounds (1654 and 1535cm-1 ). Oil binding capacity of Toothpony FPH was found to be low, which was 1.9 g oil/ g protein. This study indicated that 4% of Toothpony FPH produced the optimum amount to be incorporated in batter in order to best reduce oil uptake. In sensory evaluation, deep-fat-fried squid incorporated with 8% of Toothpony FPH showed the highest acceptance in all attributes, which were colour, crispness, oiliness, taste and overall acceptability. This approach offers the potentials use of Toothpony fish FPH for the production batter formulation which is efficient in the reduction of oil uptake.

Cationic surfactant at high pH in microwave HAp synthesis

This work studies the cationic surfactant effects (CTAB) on the morphology and particle size of the hydroxyapatite (HAp), using the microwave method keeping the pH, time and temperature constant. The obtained products were characterized using transmission electron microscopy, X-ray diffraction, FT-IR and EDS spectroscopy. TEM results showed that surfactant had great impact on size of hydroxyapatite. The smallest nanorods structures with mean size of 43.17 nm in diameter and 136.52 nm in length were obtained by using 0.45w% [in proportion of Ca and P precursors] of surfactant. XRD analysis confirmed the presence of hexagonal hydroxyapatite and showed the crystallite size dimensions by Rietveld analysis. FT-IR technique corroborated the HAp presence by characteristic vibrational modes and EDS spectroscopy displayed the Ca/P ratio in all the samples. This work could be taken into account as a base for composite biomaterials development for gas sensing and biomaterial applications.

Synthesis and Biological Activity of Silver Nanoparticles from Medicinal Palm Tree Bismarckia nobilis Seeds

Silver nanoparticles (AgNPs) have received significant attention due to their distinctive antimicrobial, anticancer, catalytic and photochemical activity. The objective of this work is to amalgamate silver nanoparticles from the aqueous extract of Biamarckia nobilis seeds using green method, characterization using UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy and FTIR spectroscopy. Further, its antimicrobial and anticancer activities were evaluated. The results displayed the characteristic UV peak, cubic phase with crystalline nature, spherical in shape having average size 14 nm, prominent peaks of bio-functional groups, good antimicrobial and anticancer activities.

Hydrogen generation performance of Al–20at%Ca alloy synthesized by mechanical alloying

In this study, the Al–20at%Ca alloy was synthesized by mechanical alloy from the elemental powder mixture. Subsequently, the alloy particles were reacted at room temperature to determine the amount of hydrogen released. For these purposes, the powders reacted with different types of water, such as distilled water, tap water, and seawater, and also in the presence of NaCl and CaO additives. Both milled samples and reaction powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, and Raman spectroscopy (RS). The XRD patterns of the powders prepared show a nanocrystalline alloy consisting of a solid-cubic solution of Al and the tetragonal intermetallic phase CaAl4. Studies of XRD and SEM, as well as direct measurements of H2, indicated that the best results of H2 generation were obtained when the alloy reacts with distilled water. Both NaCl and CaO additives improve hydrogen generation, reaching 100% efficiency in distilled water and seawater, and without induction time. Samples with a combination of NaCl and distilled water showed the best reaction times to generate the entire theoretical amount of hydrogen. The XRD and DSC–TGA standards also confirmed the presence of bayerite Al(OH)3 as a secondary reaction product.

Fabrication and characterization of reduced graphene oxide by atmospheric pressure plasma jet

A low-cost and fast reduction method for the fabrication of reduced graphene oxide (r-GO) by using a dielectric barrier discharge plasma jet under atmospheric pressure has been presented. Highly reduced r-GO with the carbon atomic ratio up to 87.43% is obtained in minutes. By using diagnostic instruments like XRD, Raman, scanning electron microscopy, transmission electron microscopy, FT-IR, and X-ray photoelectron spectroscopy, the morphology, chemical, and structural properties of r-GO are analyzed. Due to the relatively high bonding energy, the functional group of C—O—C is the dominant structure in r-GO. By using N2 adsorption-desorption measurements, the specific surface area is calculated to be about 145 m2 g−1. The porosity results indicate that r-GO is a mesoporous structure with the pore size ranging from 3 nm to 4 nm.

Production and characterization of nano-polyaniline and carbonized polyaniline for potential application as energy storage devices

Polyaniline (PANI) in the nano form was prepared by a simple sol–gel method. The prepared PANI was carbonized under a direct nitrogen gas carbonization method to produce carbonized polyaniline (C-PANI). The difference in morphology and structure of the two prepared materials were studied and characterized for structure and morphological analysis by FT-IR spectrometry, X-ray diffractometry, scanning, and transmission electron microscopy. The Nano-PANI and C-PANI had a pore diameter of 84.96 and 90.86 nm which surface areas of 18.8 and 14.42 m2/g respectively. The prepared Nano-PANI was in emeraldine salt state; C-PANI was completely carbonized. The prepared materials were applied as electrode coating materials on the copper sheet which acted as a substrate and it produced a uniform smooth coating. This is promising and can further be studied for electrochemical applications. Further work is ongoing to ascertain its’ electrochemical capacitance properties. The method of preparation of the Nano-PANI and Nano C-PANI is eco-friendly and simple for the production of mass material for industrial purposes.

Microwave Assisted Green Synthesis of Silver Nanoparticles using Pomegranate Peel Extract: Characterization and Antibacterial Activity Studies

In the present work, a simple and low cost and eco-friendly technique is applied for the microwave assisted synthesis of silver nanoparticles (AgNPs) using the extract of pomegranate peel wastes, which does not require any use of external stabilizing agent. The extract of pomegranates peelings waste served as a reducing as well as capping/stabilizing agent. The synthesized silver nanoparticles were characterized by using powder X-ray diffraction (XRD), transmission eelectron microscopy (TEM), FT-IR, UV-visible spectroscopy and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX). The stability of AgNPs was analyzed by zeta potential measurements. The antibacterial activity of synthesized AgNPs was also evaluated on six Gram-positive and Gram-negative bacteria using agar well diffusion method.

Role of surface charge in enhancing antibacterial activity of fluorescent carbon dots

Herein, different surface charged carbon dots (Cdots) were synthesized by using diethylene glycol as a carbon source with various amine containing surface passivating agents. The synthesis method is very simple and fast microwave oven-based, that results in almost similar sized positive, negative and uncharged fluorescent Cdots which has been confirmed by zeta potential analysis in our case. The formation of Cdots was confirmed by characterization using fluorescence spectroscopy, transmission electron microscopy, XRD, FT-IR, and XPS spectroscopy. To find out relative bactericidal activity of these Cdots, green fluorescence protein expressing recombinant E. coli bacteria were taken as a model system. Time-dependent bacterial growth and FACS study demonstrated that both uncharged Cdots and positively charged Cdots were showing better bactericidal activity as compared to negative charged Cdots. The Cdots caused elevation of reactive oxygen species level, which is possibly leading to bacterial cell death.

Comparison of transmission FTIR and ATR spectra for discrimination between beef and chicken meat and quantification of chicken in beef meat mixture using ATR-FTIR combined with chemometrics.

Detecting meat adulteration for quality control and accurate labeling is important and needs convenient analytical methods. This study aimed to investigate and compare the application of the transmission and ATR approaches of FTIR followed by principal component analysis (PCA) to not only discriminate between chicken and beef meat but also quantizing chicken portion of mixtures. Two different approaches are presented; spectra preprocessing with focus on wavenumber region of 1700-1071cm-1, and no preprocessed where PCA was applied on the whole spectra range of mid-FTIR. The results suggest that applying PCA on specified preprocessed spectra could detect hidden relationships between variables in chicken and beef in both approaches. PCA successfully clustered these kinds of meats when applied on transmission mode spectra without any preprocessing treatment, while applying it on ATR mode's raw spectra failed to cluster them. Additionally, the preprocessed ATR-FTIR spectrum was used to prepare regression models by Partial Least Square Regression (PLS-R) and artificial neural networks (ANN) for predicting presence and percentage of chicken meat in the beef meat mixture. The results demonstrated the superiority of ANN over PLS-R in this assessment with an R2 of 0.999.

Colorimetric detection of cadmium ions using modified silver nanoparticles

Metal ion sensors are a significant and challenging area in the analytical sciences. In this study, the use of grape juice for bio-synthesizing of silver nanoparticles (AgNPs) and using it for simple and rapid colorimetric detection of Cd2+ ions is described. The as-prepared AgNPs were characterized by standard analytical techniques including UV–visible and FTIR spectroscopic methods and transmission electron microscopy (TEM). The plasmon resonance band of the silver nanoparticles was observed at 410 nm and it was found that its intensity is related to the grape juice concentration and pH. The TEM image showed the average size of 5–10 nm for AgNPs. The detection of Cd2+ ions was based on the changes of absorbance due to complex formation of the metal ion. The colorimetric detection of Cd2+ was led to a linear dynamic range from 0 to 150 µmol/L (r2 = 0.9993) and a low detection limit of 4.95 µmol/L for cadmium in aqueous solution. These results are close to or better than the previous reports. This bio-synthesized AgNPs can be used as simple alternative design for colorimetric sensing of Cd2+ in water samples.

Microwave Assisted Synthesis and Optical Properties of Highly Fluorescent N-Doped Carbon Dots

Herein, a rapid microwave assisted solid state method is reported for the synthesis of highly fluorescent N-doped carbon dots (NCDs) using citric acid as carbon source and guanidine hydrochloride as N-dopant. Synthetic parameters such as microwave power, irradiation time and reactants ratio were optimized to produce high quality N-doped carbon dots. The N-doped carbon dots were well characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), SEM-EDS, FTIR, UV-visible and fluorescence spectroscopies. N-Doped carbon dots exhibited bright emission with a quantum yield of 11 %. Detailed study of their optical properties revealed their excellent property of resistance to photo bleaching, high ionic strength and solution pH. Further they exhibited excitation dependent emission behaviour, high aqueous solubility and a long shelf life of 60 days. This strong fluorescence emission combined with high stability make N-doped carbon dots a promising fluorescent probe for wide range of applications.

Nitrogen-Doped Carbon Dots from Averrhoa carambola Fruit Extract as a Fluorescent Probe for Methyl Orange.

In this study, a simple and green hydrothermal treatment was performed to prepare nitrogen-doped carbon dots (NCDs) from Averrhoa carambola (AC) fruit extract as a carbon precursor and L-arginine (Arg) as a nitrogen dopant. The AC-NCDs were characterized by UV light, fluorescence spectroscopy, transmission electron microscopy, FTIR spectroscopy, Raman spectroscopy, UV-vis spectroscopy, and zeta potential analyzer. The AC-NCDs were spherical and the average diameter was estimated to be 6.67 nm. The AC-NCDs exhibited the maximum emission intensity at 446 nm with 360 nm excitation wavelength. The fluorescence quenching behavior of AC-NCDs after interacting with methyl orange (MO) dye was studied. The interaction of AC-NCDs and MO was achieved within 3 min and the fluorescence quenching was maintained to a fixed value even after 30 min. The linearity was obtained in the range of 1 to 25 μM MO with a 0.30 μM detection limit. Furthermore, the pH values affected the quenching behavior of the AC-NCDs/MO system where the interaction mechanisms were driven by the electrostatic interaction, π–π interaction, inner filter effect, and energy transfer. The pH 5 maintained higher quenching efficiency while other pH values slightly decreased the quenching efficiency. Incoming applications, the AC-NCDs can be used in various important fields, especially for environmental protection.

Chitosan-bacterial cellulose patch of ciprofloxacin for wound dressing: Preparation and characterization studies

Biopolymeric blends based on bacterial cellulose (BC) films modified with low molecular weight chitosan (Chi) were developed for controlled release of ciprofloxacin (Cip). Biophysical studies revealed a compatible and cooperative network between BC and Chi including deep structural changes in the BC matrix shown by spectroscopic and thermal analyses (SEM, roughness analysis, FTIR, XRD, TGA, mechanical properties and water vapor transmission rate). Incorporation of chitosan to BC matrix generated a thickening scaffold with high permeability to water vapor from 0.7 to 3.2 g mm/m2 h. Cip loaded onto the BC-Chi film showed a hyperbolic release profile with a 30% decrease in antibiotic release mediated by the presence of Chi. BC-Chi blend films containing Cip tested against Pseudomonas aeruginosa and Staphylococcus aureus showed a synergic effect of chitosan on Cip antimicrobial activity. Besides, in vitro studies revealed the lack of cytotoxicity of BC-Chi-Cip films in human fibroblasts.

Antibacterial efficacy of green synthesized α-Fe2O3 nanoparticles using Sida cordifolia plant extract

The aim of the work is to synthesize iron oxide (α-Fe2O3) nanoparticles using Sida cordifolia plant extract along with evaluation of its antibacterial activity. The presence of phytochemicals in Sida cordifolia methanolic plant extract was investigated by HPTLC and LC-MS/TOF. The probable mechanism for formation of α-Fe2O3 nanoparticles in mediation with plant extract was demonstrated. The green synthesized iron oxide nanoparticles (α-Fe2O3 NPs) were characterized by using X-ray diffraction, scanning, and transmission electronic microscopy, TG-DTA, FTIR, and UV spectroscopy. The crystallite size of prepared α-Fe2O3 nanoparticles estimated via Debye-Scherrer formula and Williamson-Hall plot was around 20 nm which is in accordance with particle size in TEM images. The S. cordifolia mediated iron-oxide nanoparticles (α-Fe2O3 NPs) hold potent antibacterial activity against various gram positive and gram negative bacteria.

Extraction of Magnetite from Millscales Waste for Ultrafast Removal of Cadmium Ions

This research was conducted to produce the magnetite (Fe3O4) nanoparticles extracted from the industrial millscale waste. Then, the micron size samples were extracted and grounded on the high energy ball milling (HEBM) at various milling time for 4, 8, 12, 16 and 20 h. The formation of nanosized single-phase hexagonal spinel has been observed with XRD analysis as early as 4 h milling time. The FTIR transmission spectrum shows the appearance of a Fe-O functional group for each sample. HRTEM images showed that all the samples had a small particle size of 5-20 nm with uniform distribution. The specific surface area of the 5 adsorbents increased after the 8 h milling time and it showed reduction after that. The magnetite adsorbents then utilized the adsorbent in Cadmium ions removal of the aqueous solution. Fe3O4 with 8 h milling time was able to remove 9.81 mg of cadmium ions with 1 g of adsorbents consume. The removal of the cadmium ions detected related to the particles size, surface areas and saturation magnetization. This research successfully revealed that the higher saturation magnetization contributed to high removal percentages in cadmium ions of aqueous solutions. Fe3O4 extraction from mill scales waste is cost-effective, the process is eco-friendly and thus, potentially to be applied for wastewater treatment.

The structural and magnetic properties of the nano-CoFe2O4 ferrite prepared by sol-gel auto-combustion technique

Single-phased nano-crystalline CoFe2O4 ferrite has been prepared using the sol-gel auto-combustion technique. The refinement analyses of X-ray diffraction patterns confirm crystallization of the sample in the (Fd3̅m) space group. The corresponding lattice constant was estimated to be aexp = 8.37 Å. Theoretical values of other structural parameters such as the ionic radii, bond lengths and the electronegativity at the tetrahedral and octahedral sites have been calculated and compared with values of other spinel systems. The cation distributions indicate that the present system is a partially inversed spinel with inversion factor 0.68. The FT-IR transmittance spectrum has been measured in the range (400–4000) cm−1. It shows the transmittance bands at (575, 1638, 2900 and 3465) cm−1. The 575 cm−1 band has been attributed to the oxygen-metal vibration at the tetrahedral sites. The Energy dispersive X-ray spectroscopy (EDXS) shows the consistency of the weight percentages of the Co and Fe ions with stoichiometric contents within 3% accuracy. Transmission electron microscopy (TEM) has been used in the estimation of the average particle size. The average particle sizes were estimated to be around 95 nm. Values of isomer shifts were found to be in the range (0.29–0.46) mm/s, which indicate that Fe3+ oxidation state is dominant and probably low percentage of ferrous Fe2+ ions. The saturation magnetization at room temperature was determined to be 69 emu/g and the reduced remanent magnetization value (Mr/Ms) was found to be 0.35. The Yafet-Kittel angle, the blocking (TB) temperature and Curie (TC) temperatures were estimated to be 33°, 724 K and 810 K respectively. The high values of TB and TC were attributed to the strength of the A-B super-exchange interactions experienced in the CoFe2O4 sample.

Bitter orange oil incorporated into chitosan nanoparticles: Preparation, characterization and their potential application on antioxidant and antimicrobial characteristics of white button mushroom

Citrus aurantium essential oil (CAEO) at different concentrations was incorporated into chitosan nanoparticles (CSNPs) by an ionic gelation technique to enhance the antioxidant activity and control of the microbial population of Agaricus bisporus during cold storage. The physicochemical properties of nanoparticles were investigated by high resolution transmission electron microscopy (HRTEM), FTIR, and dynamic light scattering (DLS). The synthesized nanoparticles showed spherical shape with an average size of 20–60 nm. The encapsulation efficiency and loading capacity of CAEO-CSNPs were between 4.51–15.33% and 2.51–5.89%, respectively. The release of CAEO from CSNPs followed Fickian diffusion model. In comparison with control treatment, a lower microbial count, decrease in POD activity and higher activity of the antioxidant enzymes, glutathione reductase (GR) and ascorbate peroxidase (APX), were observed in mushrooms packed with CAEO-CSNPs (P < 0.01). These results revealed the promising role of CSNPs as a delivery system for CAEO to improve microbial safety and antioxidant enzymes activity of white button mushroom.

Recycling Control of Histological Xylol: A Chemometric Approach

AbstractFractional distillation was applied to recycle and reuse histological xylol waste. A new sample preparation technique for analyzing liquid samples by transmission FTIR spectroscopy was developed and validated. Pressing time, sample volume, and xylol volatility were the optimized variables to acquire good quality spectra by using the KBr pellet technique. The suitability of this technique for analyzing a volatile sample, xylol, was contrasted against a non‐volatile coal sample. Semi‐quantitative IR‐derived ratios were calculated and used as input variables in principal components analysis (PCA). One‐way analysis of variance (ANOVA) test was applied to determine whether the samples of distillate, xylol waste, and commercial xylol showed significant differences among them. Unlike currently used analytical methodologies based on GC, the proposed methodology based on FTIR‐PCA‐ANOVA provided a simple way to monitor the samples (including xylol waste containing water traces and paraffin) throughout xylol recycling process. The results indicated there were no significant differences (p&gt;0.05) between commercial and recycled xylol, being comparable.

Structural analysis, molecular dynamics and docking calculations of skin protective tripeptide and design, characterization, cytotoxicity studies of its PLGA nanoparticles

The main purpose of current study is to analyze the structural behaviour of a skin protective tripeptide Gly-His-Lys (GHK) with anti-oxidant and anti-cancer properties, design and characterize its nanoformulation by experimental and spectroscopic techniques to ensure its stability and enhance bioavailability and biocompatibility. GHK is extensively used as a cosmetic products for the therapy of skin and hair deformation. In this study the calculations on GHK were performed at DFT/B3LYP level of theory with the 6–311++G (d,p) basis set to obtain optimized geometry, HOMO-LUMO energy gap, MEP analysis and vibrational wavenumbers. The spectroscopic investigation of GHK tripeptide was performed experimentally through optical spectroscopic techniques (such as FT-IR, FT-IR-ATR and Micro-RAMAN) and compared with theoretical wavenumbers. The Potantial Energy Distributions (PED) of the normal modes of vibrations were also carried out with the help of GAR2PED program. By using molecular dynamics simulation, the stability of the GHK in water and methanol mediums have been simulated. To reveal the mechanism of interaction between GHK tripeptide and Fibroblast Growth Factor, the hydrogen bonding interactions are also investigated by Molecular docking calculations. Besides, GHK-loaded Poly Lactic-co-Glycolic Acid (PLGA) nanoparticles (NPs) were synthesized with double emission (water/oil/water) method, and characterized with Zeta Sizer, UV–Vis Spectrometry, Transmission Emission Microscope and FT-IR Spectrometry. Due to the encapsulation, the shifts in the wavenumbers occurring at the characteristic peaks of GHK in histidine, peptide and carboxyl groups were also examined. The encapsulation and loading efficiencies were determined as 94% and 4%, also the in vitro release profile was performed. Peptide loaded PLGA NPs which have a spherical morphology were visualized by TEM. In vitro cell culture studies of both peptide-loaded PLGA NPs and GHK tripeptide were studied and non-toxic effect on L929 cells were found. This study is a pioneer in the development and design of products with nano-drug formulations with better effectiveness and stability, especially in cosmetic products.