Fourier Transform Infrared Spectroscopy Spectroscopy Research Articles

An Advanced Surface Treatment Technique for Coating Three-Dimensional-Printed Polyamide 12 by Hydroxyapatite

Polymer 3D printing has is used in a wide range of applications in the medical field. Polyamide 12 (PA12) is a versatile synthetic polymer that has been used to reconstruct bony defects. Coating its surface with calcium phosphate compounds, such as hydroxyapatite (HA), could enhance its bonding with bone. The aim of this study was to coat 3D-printed polyamide 12 specimens with hydroxyapatite by a simple innovative surface treatment using light-cured resin cement. Polyamide 12 powder was printed by selective laser sintering to produce 80 disc-shaped specimens (15 mm diameter × 1.5 mm thickness). The specimens were divided randomly into two main groups: (1) control group (untreated), where the surface of the specimens was left without any modifications; (2) treated group, where the surface of the specimens was coated with hydroxyapatite by a new method using a light-cured dental cement. The coated specimens were characterised by both Fourier transform infrared spectroscopy (FTIR) and Transmission Electron Microscopy (TEM), (n = 10/test). The control and treated groups were further randomly subdivided into two subgroups according to the immersion in phosphate-buffered saline (PBS). The first subgroup was not immersed in PBS and was left as 3D-printed, while the second subgroup was immersed in PBS for 15 days (n = 10/subgroup). The surfaces of the control and treated specimens were examined using an environmental scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA) before and after immersion in PBS. Following the standard American Society for Testing and Materials (ASTM D3359), a cross-cut adhesion test was performed. The results of the FTIR spectroscopy of the coated specimens were confirmed the HA bands. The TEM micrograph revealed agglomerated particles in the coat. The SEM micrographs of the control 3D-printed polyamide 12 specimens illustrated the sintered 3D-printed particles with minimal porosity. Their EDXA revealed the presence of carbon, nitrogen, and oxygen as atomic%: 52.1, 23.8, 24.1 respectively. After immersion in PBS, there were no major changes in the control specimens as detected by SEM and EDXA. The microstructure of the coated specimens showed deposited clusters of calcium and phosphorus on the surface, in addition to carbon, nitrogen, and oxygen, with atomic%: 9.5, 5.9, 7.2, 30.9, and 46.5, respectively. This coat was stable after immersion, as observed by SEM and EDXA. The coat adhesion test demonstrated a stable coat with just a few loose coating flakes (area removed <5%) on the surface of the HA-coated specimens. It could be concluded that the 3D-printed polyamide 12 could be coated with hydroxyapatite using light-cured resin cement.

Synthesis and Characterization of Gold Nanoparticles and Gold Nanoparticles Loaded with Bromelain

The production and use of nanometallic elements, such as gold, have received a lot of attention lately due to their distinctive features and wide range of uses. Most of these studies have employed the Turkevich approach. This research employed the Turkevich technique to produce gold nanoparticles (AuNPs). AuNPs and bromelain-loaded AuNPs were characterised using a variety of methods, including ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and zeta potential (ZP) measurements. The UV-Vis spectra of Bromelain, AuNPs, and AuNPs-Bromelain each had a peak at 276, 534, and 550 nm wavelengths, respectively. The FE-SEM and TEM studies revealed the presence of spherical particles with a smooth surface. The diameters of the AuNPs ranged from 49.32 to 77.29 nm; the diameters of the Bromelain-AuNPs ranged from 46.39 to 75.66 nm, as determined by the FE-SEM analysis. The TEM analysis indicated that the particles' sizes ranged from 7.40 to 15 nm for AuNPs and 14.51 nm for AuNPs-Bromelain. The XRD patterns revealed numerous diffraction peaks, indicating the crystal structure of the synthesised nanoparticles. FTIR spectrometry was employed to identify the functional groups in the synthesised nanoparticles. Zeta potential (ZP) measurements revealed that AuNPs had a zeta potential value of +0.1±0.4, and the zeta potential value for AuNPs-Bromelain was +1.2±3.0 mV.

Novel poly(2-ethyl-2-oxazoline) and poly(diallyldimethylammonium chloride) polymer functionalized montmorillonite: Physicochemical aspects and near-IR study of hydration properties

The novel functionalized montmorillonites (Mts) with non-ionic poly(2-ethyl-2-oxazoline) (PEtOx) and cationic poly(diallyldimethylammonium) (PDDA) were created via an intercalation method with different loading ratio of both polymers. A comprehensive investigation into their physicochemical properties was conducted using Carbon analysis (CA), Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), Simultaneous thermal analysis (TGA/DSC) and BET-N2 adsorption analysis. The impact of hydration on PEtOx-Mts and PDDA-Mts was assessed through gravimetric analysis and near-infrared spectroscopy (NIR) spectroscopy. PXRD analysis revealed a significant increase in 001 diffraction of PDDA-Mt corresponding to a PDDA interlayer with a basal spacing ranging from 1.47 to 1.49 nm. Conversely, the basal spacing exceeding 2 nm for PEtOx suggested, that the PEtOx polymer was intercalated in a larger amount and packed in a less compact manner compared to PDDA. After modification of Na-Mt with PEtOx polymer, FTIR spectroscopy confirmed the presence of the carbonyl CO group (3265 and 1641 cm-1) and the stretching (2982, 2942 and 2883 cm-1) and bending (1480–1200 cm-1) vibrations of the CH2 and CH3 groups. The vibrations of CH groups were further verified following PDDA modification. NIR spectroscopy also confirmed the vibrational bands attributed to both modifiers after intercalation of PEtOx and PDDA. The results of BET-N2 adsorption revealed a significant decrease in the specific surface area (SSA) after intercalation with a non-ionic PEtOx polymer. On the contrary, in the case of saturation of Na-Mt with polycation PDDA, SSA increased slightly in two instances. TGA analysis confirmed greater weight loss for PEtOx-Mts compared to PDDA-Mts. Derivative thermogravimetry (DTG) revealed the release of physisorbed bound water around 100 °C, decomposition of the organic phase within the 250–550 °C range and dehydroxylation of OH groups around 550–800 °C in both cases. The results obtained from the gravimetry and NIR analysis indicated a greater hydrophobic nature for PEtOx-Mts compared to PDDA-Mts. These findings hold substantial potential for enhancing the properties of novel organo-montmorillonites, thereby facilitating their application as adsorbents for pollutants, surface coatings, biodegradable materials, fillers in polymer nanocomposites, drug carriers, anticancer agents and various other significant applications.

Metal-based compounds: Synthesis and characterization of new thiazole-based iridium and palladium complexes with potential anticancer and other biological activities

Thiazoles and their derivatives are one of the most active classes of compounds known for their wide spectrum of bioactivity. Metal complexes, based on them, show antitumor potential that is attractive for investigations. Herein, we report 6 new biologically active thiazole-based complexes have been synthesized. The iridium- and palladium-based coordination compounds obtained by the precipitation method were characterized using elemental analysis (EA), Fourier-transform infrared spectroscopy (FTIR), magnetic measurements, thermogravimetric analysis coupled with mass spectrometry (TGA-MS), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Spectroscopic data helped to propose the formulas of the complexes and indicated that all ligands acted in a monodentate manner. Water molecules were identified by thermal analysis and FTIR spectroscopy. Mathematical analysis and evaluation of thermodynamic parameters including entropy (ΔS), Gibbs free energy (ΔG), and activation energy (E) were performed using the Coats–Redfern method for all complexes. The biological potential (anticancer, antibacterial, and antifungal properties) of compounds was analyzed by biological evaluation studies. Investigated CT-DNA studies revealed that the prepared compounds were intercalatively bound to the DNA. Cytotoxicity analyses showed that complexation with Ir(III) increased the toxicity of L2 towards both tested cell lines (LN-229 and MDA-MB-231), while complexation of L3 with Pd(II) significantly increased cytotoxic activity against LN-229. Due to this, the further biological studies, such as apoptosis/necrosis detection, cell cycle analysis and JC-1 fluorescence measurements were performed on this pair of compounds.

The application of vibrational spectroscopy in forensic analysis of biological evidence.

Vibrational spectroscopy is a powerful analytical domain, within which Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy stand as exemplars, offering high chemical specificity and sensitivity. These methodologies have been instrumental in the characterization of chemical compounds for an extensive period. They are particularly adept at the identification and analysis of minute sample quantities. Both FTIR and Raman spectroscopy are proficient in elucidating small liquid samples and detecting nuanced molecular alterations. The application of chemometrics further augments their analytical prowess. Currently, these techniques are in the research phase within forensic medicine and have yet to be broadly implemented in examination and identification processes. Nonetheless, studies have indicated that a combined classification model utilizing FTIR and Raman spectroscopy yields exceptional results for the identification of biological fluid-related information and the determination of causes of death. The objective of this review is to delineate the current research trajectory and potential applications of these two vibrational spectroscopic techniques in the detection of body fluids and the ascertainment of causes of death within the context of forensic medicine.

Synthesis of nanoscale spinel aluminates powder and studies of their optical and structural properties

In this research, Manganese aluminate (MA), Nickel aluminate (NA), and Zinc aluminate (ZA) nanocrystallites were synthesized using the combustion method at a temperature of 1173 K. This technique was selected for its effectiveness in producing nanocrystalline materials with high purity and precise compositional control. The synthesized nanocrystallites underwent extensive characterization to understand their structural and optical properties. Techniques such as UV–visible spectrophotometry (UV–vis), Fourier-transform infrared spectroscopy (FT-IR), and x-ray diffraction (XRD) were utilized to examine the impact of different cations (Mn2+, Ni2+, Zn2+) on the optical bandgap, binding energy, and crystallographic parameters of the materials. The optical bandgap values (Eg), determined using Tauc’s formula, were 4.121 eV for manganese aluminate, 3.819 eV for nickel aluminate, and 3.771 eV for zinc aluminate. FT-IR spectroscopy identified fundamental absorption peaks within the range of 450 to 750 cm−1, confirming the formation of aluminate spinel structures. XRD analysis confirmed the presence of a cubic spinel-type structure in all three prepared samples. The results revealed that the average crystallite sizes ranged from 23.890 nm to 45.100 nm, cell volumes varied between 521.47 Å3 and 548.68 Å3, lattice constants spanned from 8.258 Å to 8.049 Å, and inter-planar spacing ranged from 2.4268 nm to 2.4532 nm. These variations were observed as the cation transitioned from nickel to manganese passing through zinc element. Additionally, Rietveld refinements were performed to further analyze and refine the crystal structures based on XRD data. This comprehensive study aimed to elucidate the relationship between the synthesis conditions and the resultant properties of the nanocrystallites, providing insights into their potential applications in fields such as optoelectronics and photocatalysis.

Early identification of the nosocomial spread of vancomycin-resistant Enterococcus faecium by Fourier-transform infrared spectroscopy and performance comparison with PFGE and WGS

ABSTRACT Early detection of disseminating vancomycin-resistant Enterococcus faecium (VREfm) in ICU wards is crucial for outbreak identification and the implementation of prompt infection control measures. Genotypic methods like pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) are costly and time-consuming, hindering rapid response due to batch dependency. Fourier-transform infrared spectroscopy (FT-IR) offers the potential for real-time outbreak detection and reliable strain typing. We utilized FT-IR to identify clonal VREfm dissemination and compared its performance to PFGE and WGS. Between February through October 2023, an unusually high number of VREfm were recovered at a tertiary hospital in Barcelona. Isolates were examined for antimicrobial susceptibility, carriage of vanA/vanB genes and clonality was also studied using FT-IR, PFGE, and WGS. Routine FT-IR inspections revealed recurring VREfm clustering during the outbreak's initial weeks. In total, 104 isolates were recovered from 75 patients and from multiple wards. However, only one isolate was recovered from an environmental sample, suggesting the absence of environmental reservoirs. An ST80 vancomycin-resistant (vanA) E. faecium strain was the main strain responsible for the outbreak, although a few additional VREfm strains were also identified, all belonging to CC17. PFGE and cgMLST (WGS) yielded identical clustering results to FT-IR, and WGS confirmed vanA/vanB gene carriage in all VREfm isolates. Infection control measures led to a rapid decline in VREfm isolates, with no isolates detected in November. FT-IR spectroscopy offers rapid turnaround times, sensitivity, and reproducibility, comparable to standard typing methods. It proved as an effective tool for monitoring VREfm dissemination and early outbreak detection.

Fundamental structural study of hexagonal boron nitride (h-BN) and boron nitride nanotube (BNNT) at low and high temperatures

The molecular structure stability at low and high temperature is important for an industrial application. The boron nitride-based materials, such as hexagonal boron nitride (h-BN) and boron nitride nanotubes (BNNTs), have been interested due to their high oxidation resistance and thermal stability. In this study, ex-situ and in-situ characterization techniques (e.g., Raman spectroscopy, X-ray Diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR)) were applied to investigate the structural change of BNNT and h-BN at high (up to 800 °C) and low (down to -50 °C) temperatures. The Raman spectroscopy results showed that at high temperatures (800 °C), h-BN exhibited a significant red shift under both inert and oxidizing conditions, while BNNT showed no peak shift, indicating its more stable structural resistance compared to h-BN. Both h-BN and BNNT showed no peak shift after cooling to low temperatures (-50 °C). Stability of h-BN and BNNT up to a high temperature of 800 °C was revealed from the thermogravimetric analysis (TGA) and FTIR spectroscopy results. The FTIR results also indicate that under oxidizing conditions, heating h-BN results in the formation of more hydroxyl groups compared to BNNT. The in-situ XRD results showed a greater magnitude of lower 2θ shift with increasing temperatures for h-BN compared to BNNT. Additionally, there was a more significant increase in FWHM values with respect to temperatures for h-BN than BNNT regardless of the sample under inert or oxidizing conditions. The characterization results from this study indicate that BN-based materials, especially BNNT, are suitable candidates for high temperature chemical reaction applications.

Kinetics, products and mechanisms of the OH radicals and Cl atoms reactions with trans-2-octene and cycloheptene

Relative rate coefficients for the gas-phase reactions of OH radicals and Cl atoms with trans-2-octene (k1-OH and k2-Cl) and cycloheptene (k3-OH and k4-Cl) have been determined by in situ Fourier Transform Infrared Spectroscopy (FTIR). The experiments were carried out at 298 ± 2 K and atmospheric pressure (760 ± 10) Torr using synthetic air as bath gas. The following rate coefficients (in units of cm3 molecule−1 s−1) were obtained for the reactions of trans-2-octene and cycloheptene with OH radicals and Cl atoms: k1-OH = (8.51 ± 1.86) × 10−11, k2-Cl = (4.47 ± 1.09) × 10−10, k3-OH = (7.84 ± 1.78) × 10−11, k4-Cl = (5.46 ± 1.01) × 10−10, respectively. This is the first kinetic study for the reactions of trans-2-octene with Cl atoms and the first rate coefficient determination for the title reactions by in situ FTIR spectroscopy. The kinetic data were compared with previously reported values for similar compounds and reactivity trends were developed. Complementary, products identification studies were performed in similar conditions to the kinetic experiments by the in situ FTIR and Gas Chromatography coupled to mass spectrometry (GC-MS). The atmospheric chemical mechanisms were postulated for the first time for both unsaturated compounds. In addition, the atmospheric implications of these reactions were assessed through the estimation of the tropospheric lifetimes, Photochemical Ozone Creation Potential (POCP) and fates of these compounds in the troposphere.

Quantitative analysis of molecular structure characterization of different liptinite-rich coals using FTIR spectroscopy

As one of the important components in low-rank coals, liptinite plays an indispensable role in the formation and utilization of coal, thus, understanding the occurrence and structures of liptinite-rich coals provides a theoretical basis for the origin and clean utilization of coals. In this study, the occurrence of liptinite and the functional groups and molecular structure of different liptinite-rich coals were quantitatively characterized by using optical microscope and Fourier transform infrared spectroscopy (FTIR), respectively. The results showed that the sample JS-7 from Yunnan Province mainly enriched sporinite and bituminite, the sample JS-15 from Yunnan Province is rich in dispersed resin and the amber-rich coal from Liaoning Province mainly contains bulk resin. The FTIR results indicated that the amber-rich coal, the sample JS-7 and pure amber (Liaoning Province) consist mainly of trisubstituted benzene. The sample JS-7 has the highest content of trisubstituted benzene (63.4%) due to the high content of sporinite and bituminite. The sample JS-15 is mainly composed of tetrasubstituted and pentasubstituted benzene, which may be relevant to the cyclization of aliphatic chains and the decarboxylation reaction of benzene rings. The CC group has not been detected in the sample JS-7 and pure amber. The FTIR structural parameters indicate that the pure amber has the lowest maturity, the lowest degree of aromatization, but the highest hydrocarbon generation potential. The highest CH2/CH3 group value (14.69) and the lowest A factor value (0.36) of the sample JS-15 indicate a well-developed aliphatic chain structure and lowest hydrocarbon generation potential, respectively, which probably caused by the low content of CO group.

Application of two dimensional correlation Fourier Transform Infrared spectroscopy (2D-COS-FTIR) to the quantification of carbohydrates in milk powder

The importance of milk and its products accelerated their adulteration as well as their characterization in term of techniques used, composition determination and adulteration quantification. Fourier Transform Infrared spectroscopy (FTIR) is one of the most widely used and increasingly developed methods to identify chemical contaminations and determine their concentrations. This study employs FTIR and two dimensional correlation (2D-COS) spectroscopies to detect milk powder adulteration with sucrose, lactose and starch in the concentrations range from 0.0 % to 6.0 % w/w. With the help of synchronous 2D-COS-FTIR spectra, the FTIR regions from 830 to 930 and 930–1200 cm−1 were determined as the qualified regions for the detection and carrying out quantitative analysis of milk adultered carbohydrates. Based on the area beneath the corresponding region or the height of a specific band limits of detection were determined as 0.25, 1.2 and 1.5 % for sucrose, starch and lactose respectively. The method was applied on commercial milk powder samples and one sample was assigned to have been adultered with 4 % sucrose. FTIR spectroscopy combined with 2D-COS offers an advanced tool for rapid screening and quantification of milk adulteration.

Characterization of cellulose nanocrystals from Zhombwe (Neorautanenia brachypus (harms) CA Sm.) bagasse.

Increased awareness of environmental pollution has changed focus to the use of biodegradable materials because they lack persistence in the environment. This article focused on the production of cellulose nanocrystals from Zhombwe, Neorautanenia brachypus (Harms) CA Sm. bagasse using steam explosion, alkaline treatment, bleaching, purification, and acid hydrolysis. The chemical composition after the treatments was determined using TAPPI standards. Further characterization was done using x-ray Diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The nanoscale dimensions and morphology of the extracted nanocrystals was determined through field emission scanning electron microscopy (FE-SEM). FTIR spectroscopy and DSC confirmed the removal of noncellulosic compounds. XRD revealed that N. brachypus bagasse contained cellulose type I, which partly endured morphological change to polymorph II after purification and hydrolysis. FE-SEM revealed elliptical to rod-shaped structures after acid hydrolysis, which had a mean length and width of 1103 nm and 597 nm respectively. TAPPI tests revealed that successive chemical treatments increased crystallinity by 29.7%, enriched cellulose content by 74.2%, reduced lignin content by 21.7%, and reduced hemicellulose to less than 1%. The semicrystalline nature of the material produced in our work is a promising candidate for swelling hydrogel applications in areas such as wound dressing, heavy metal removal, controlled drug delivery, agriculture, and sanitary products. Future studies may focus on surface modification of nanocrystals to improve their thermal stability and therefore expand their range for potential industrial applications.

Exploring the Anticonvulsant Properties of a Celecoxib-Phospholipid Conjugate: Synthesis, Activation, and Evaluation of Cytotoxicity.

Epilepsy poses a significant global health challenge, particularly in regions with limited financial resources hindering access to treatment. Recent research highlights neuroinflammation, particularly involving cyclooxygenase-2 (COX-2) pathways, as a promising avenue for epilepsy management. This study aimed to develop a Cyclooxygenase-2 inhibitor with potential anticonvulsant properties. A promising drug candidate was identified and chemically linked with phospholipids through docking analyses. The activation of this prodrug was assessed using phospholipase A2 (PLA2)-mediated hydrolysis studies. The conjugate's confirmation and cytotoxicity were evaluated using Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), and Sulphoramide B (SRB) assays. Docking studies revealed that the Celecoxib-Phospholipid conjugate exhibited a superior affinity for PLA2 compared to other drug-phospholipid conjugates. FT-IR spectroscopy confirmed the successful synthesis of the conjugate, while DSC analysis confirmed its purity and formation. PLA2-mediated hydrolysis experiments demonstrated selective activation of the prodrug depending on PLA2 concentration. SRB experiments indicated dose-dependent cytotoxic effects of Celecoxib, phospholipid non-toxicity, and efficient celecoxib-phospholipid conjugation. This study successfully developed a Celecoxib-phospholipid conjugate with potential anticonvulsant properties. The prodrug's specific activation and cytotoxicity profile makes it a promising therapeutic candidate. Further investigation into underlying mechanisms and in vivo studies is necessary to assess its translational potential fully.

FT-IR Characterization and Phylogenetic Analysis of Patchouli Oil from West Aceh and Aceh Jaya using PCA and HCA

This study aims to characterize and compare the chemical composition of patchouli oil from various regions in Aceh, Indonesia, using Fourier-transform Infrared Spectroscopy (FT-IR) combined with Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). Patchouli oil samples from five distinct locations within West Aceh and Aceh Jaya Regencies were analyzed, focusing on the 1800-500 cm⁻¹ range. The FT-IR spectra revealed significant chemical markers, with notable absorption bands corresponding to aliphatic C-H, C=O, and C=C stretching vibrations. Multivariate analyses showed distinct clustering patterns, with four samples (POSM, POSP, POT, and POW) exhibiting high chemical similarity and clustering together, while one sample (POP) formed a separate cluster, indicating a lower degree of similarity. PCA analysis of the original spectra in the 1800-500 cm⁻¹ range yielded a cumulative PC1 and PC2 value of 89%. The HCA dendrogram highlighted a significant relative distance of 10 between the POP sample and the other four samples, indicating minimal relatedness, with the closest relatedness observed between POSM and POSP, having a relative distance of 1.1. This study demonstrates the effectiveness of FT-IR spectroscopy combined with PCA and HCA in distinguishing chemical profiles of patchouli oil from different regions, providing insights into geographical and varietal influences on oil composition. The findings are crucial for quality control and standardization in the patchouli oil industry, with further molecular studies recommended to corroborate and enhance understanding of genetic diversity among patchouli varieties in Aceh.

Green synthesis of silver nanoparticles and their application for colorimetric detection of L-cysteine: a spectroscopic investigation

In this study, we report an eco-friendly synthesis of silver nanoparticles (AgNPs) using banana peel extract (BPE), along with their use for colorimetric detection of L-cysteine and investigation of the mechanisms involved in these processes. Transmission electron microscopy (TEM) and UV–Vis spectroscopy were used to confirm the formation of silver particles at the nanoscale (∼20 nm). TEM images also showed the presence of BPE-derived organic material enveloping the nanoparticles. The nature and role of this capping material were investigated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Visual inspection and UV–Vis spectroscopy revealed that the insertion of L-cysteine into the AgNPs solutions induced discernible color changes. pH variations in the solutions and FTIR spectroscopy were also employed to study the molecular dynamics underlying the formation of AgNPs, the capping material and the detection of L-cysteine. Studies concerning different amino acids in AgNPs solutions confirmed the selectivity for L-cysteine. The overall spectroscopic results, particularly those from FTIR spectroscopy, shed light on the crucial role of carboxylate ions (COO–) of BPE in the formation of AgNPs and their interaction with L-cysteine. Finally, the importance of the thiol group of L-cysteine in the colorimetric detection process was also reinforced by this study.

A novel multi-model estimation of phosphorus in coal and its ash using FTIR spectroscopy

The level of phosphorus must be carefully monitored for proper and effective utilization of coal and coal ash. The phosphorus content needs to be assessed to optimize combustion efficiency and maintenance costs of power plants, ensure quality, and minimize the environmental impact of coal and coal ash. The detection of low levels of phosphorus in coal and coal ash is a significant challenge due to its complex chemical composition and low concentration levels. Effective monitoring requires accurate and sensitive equipment for the detection of phosphorus in coal and coal ash. X-ray fluorescence (XRF) is a commonly used analytical technique for the determination of phosphorus content in coal and coal ash samples but proves challenging due to their comparatively weak fluorescence intensity. Fourier Transform Infrared spectroscopy (FTIR) emerges as a promising alternative that is simple, rapid, and cost-effective. However, research in this area has been limited. Until now, only a limited number of research studies have outlined the estimation of major elements in coal, predominantly relying on FTIR spectroscopy. In this article, we explore the potential of FTIR spectroscopy combined with machine learning models (piecewise linear regression—PLR, partial least square regression—PLSR, random forest—RF, and support vector regression—SVR) for quantifying the phosphorus content in coal and coal ash. For model development, the methodology employs the mid-infrared absorption peak intensity levels of phosphorus-specific functional groups and anionic groups of phosphate minerals at various working concentration ranges of coal and coal ash. This paper proposes a multi-model estimation (using PLR, PLSR, and RF) approach based on FTIR spectral data to detect and rapidly estimate low levels of phosphorus in coal and its ash (R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^2$$\\end{document} of 0.836, RMSE of 0.735 ppm, RMSE (%) of 34.801, MBE of − 0.077 ppm, MBE (%) of 5.499, and MAE of 0.528 ppm in coal samples and R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^2$$\\end{document} of 0.803, RMSE of 0.676 ppm, RMSE (%) of 38.050, MBE of − 0.118 ppm, MBE (%) of 4.501, and MAE of 0.474 ppm in coal ash samples). Our findings suggest that FTIR combined with the multi-model approach combining PLR, PLSR, and RF regression models is a reliable tool for rapid and near-real-time measurement of phosphorus in coal and coal ash and can be suitably modified to model phosphorus content in other natural samples such as soil, shale, etc.

A Study of the Association between Primary Oral Pathologies (Dental Caries and Periodontal Diseases) Using Synchrotron Molecular FTIR Spectroscopy in View of the Patient's Personalized Clinical Picture (Demographics and Anamnesis).

In this exploratory study, we searched for associations between the two most common diseases of the oral cavity-dental caries and periodontal diseases-taking into account additional factors, such as personalized clinical pictures (the individual risk factors of the patient), based on the method of a multivariate data analysis of the molecular changes in the composition of human gingival crevicular fluid (GCF). For this purpose, a set of synchrotron Fourier-transform infrared spectroscopy (FTIR) spectra of gingival crevicular fluid samples from patients with different demographics, levels of dental caries development and periodontal diseases, and the presence/absence of concomitant chronic diseases were obtained and analyzed. Using a set of techniques (v-, F-, Chi-square tests; a principal component analysis (PCA); and the hierarchical clustering of principal components (HCPCs)) implemented in the R package FactoMineR allowed us to assess the relationship between the principal components (PCs) and characteristics of the respondents. By identifying the features (vibrational modes in the FTIR spectra) that contribute most to the differentiation of the spectral dataset, and by taking into account the interrelationships between the patients' characteristics, we were able to match specific biological markers (specific molecular groups) to the two factors of interest-two types of oral pathologies. The results obtained show that the observed changes in the quantitative and qualitative composition of the modes in the infrared (IR) spectra of the GCF samples from patients with different dental caries developments and periodontal diseases present confirm the difficulty of identifying patient-specific spectral information. At the same time, different periodontal pathologies are more closely associated with other characteristics of the patients than the level of their caries development. The multivariate analysis performed on the spectral dataset indicates the need to take into account not only the co-occurrence of oral diseases, but also some other factors. The lack of this consideration (typical in lots of studies in this area) may lead to misinterpretations and consequently to a loss of data when searching for biological markers of certain oral diseases.

Morphology-transforming AuNPs-based fluorescent probe for ultra-low sensitive detection of levofloxacin in urine samples at pH 7.0 through excimer formation

Fluorescent metal nanoparticles (MNPs) have garnered considerable interest in the realm of healthcare applications. Within this domain, we present a novel fluorescent sensor: Pamoic acid (PA) functionalized excitation-dependent gold nanoparticles (PA@AuNPs), designed to ascertain levofloxacin (LF) concentrations in human urine samples under pH 7.0 conditions. The synthesis of PA@AuNPs was achieved via a chemical reduction method employing PA as both a reducing and stabilizing agent. Validation of the successful synthesis of PA@AuNPs was conducted utilizing a suite of analytical techniques including X-ray diffraction (XRD), ultraviolet–visible absorption spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Microscopic examination via field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) elucidated the spherical morphology of PA@AuNPs, with an average diameter ranging from 10 to 15 nm. Furthermore, atomic force microscopy (AFM) revealed an average surface roughness of 20.72 nm for PA@AuNPs. Thermal analysis results divulge that PA@AuNPs are highly stable up to 370 °C. The PA@AuNPs have shown more than 10-fold higher selectivity for LF in comparison with other commercially available antibiotics. The fluorescence emission intensity of PA@AuNPs (quantum yield (ΦF) 3.36 %) has shown enhanced redshift (436 → 497 nm; ∼61 nm) (λex 353 nm) upon the sequential addition of LF (0 → 100 µM) and achieved a lower detection limit (LoD = 36 nM; LoQ = 121 nM; Ka = 1.0457 × 104 M−1) with increased ΦF 18.96 %. This radiative process and fluorescence enhancement were confirmed by time-correlated single photon counting (TCSPC) measurement (4.89 → 5.36 ns). Interestingly, upon sensing LF, PA@AuNPs changed their morphology from spherical to octahedron and displayed an excimer formation through intermolecular π-π stacking. Furthermore, the stability of the complex, PA@AuNPs•LF which formed through coordination, by restoring the fluorescence intensity of PA@AuNPs•LF (turn on) in the presence of ethylenediamine tetraacetic acid (EDTA) (turn off) is demonstrated. The formation of the PA@AuNPs•LF complex was further confirmed by XRD analysis and FTIR spectroscopy. The HRTEM and FESEM validate that PA@AuNPs•LF have octahedral morphology with an average size of 20–30 nm, and the obtained moiré fringes in TEM images are due to the overlap of LF on the surface of PA@AuNPs. The AFM analysis divulges that PA@AuNPs•LF had a larger surface roughness (Sa = 26.91 nm). The experimentally attained zeta potential of PA@AuNPs (–12.6 mV) was further decreased (–17.6 mV) in the presence of LF, which confirms the interaction between PA@AuNPs and LF. The cell viability (82 %) in L929 Fibroblast cells augmented the biological applications of PA@AuNPs. The practicability of the fluorescent sensor probe was demonstrated in human urine samples with recovery ranges from 97.56 to 104.38 %.

#749 Components in blood collection tubes interfere with the spectral signatures of patients with kidney disease: analysis by infrared microspectroscopy

Abstract Background and Aims Kidney disease is a worldwide public health problem, affecting between 8%-16% of the global population. Chronic Kidney Disease (CKD) is a silent disease and its detection is often late, making the treatment difficult. Considering the emerging Fourier-Transform Infrared spectroscopy (FTIR) as a biophotonic resource for the biomedical sciences, we aimed to identify spectral signatures related to biomarkers of CKD in human blood serum using the microscopy FTIR option. Method Blood serum samples from 17 healthy in comparison to 33 CKD patients were analyzed by micro-reflectance FTIR spectroscopy. The first aspect to be addressed refers to the possible influence of components present in the container tube. Here we showed that separator gel in VACUETTE® tubes is a relevant source of spectral interference which could decrease the accuracy of discrimination from 85% to 65%. Acquiring a diluted gel signal as a background would improve the discrimination performance in spite of some gel bands still present in sample data. Results In this case, our results indicated that vibrations associated with galactose-4-sulfate, CH2 bending of the methylene chains, C=C in lipids and fatty acids, C=N stretching, CH bending vibration from the phenyl rings, N-H bending vibration coupled to C-N stretching and β-sheet of Amide II and ring base are modulated in blood serum samples of chronic kidney disease patients compared to healthy patients. Urinary trypsin inhibitors, fatty acids, phenolic derivatives, tryptophan, and plasminogen were the biomolecules related to these assignments were the biomolecules related to these assignments. Conclusion In conclusion, FTIR is a viable option for fast diagnosis of chronic kidney disease being also a powerful tool for monitoring the disease. Due to its capability of large batch analysis, the micro-FTIR would be an eligible technology for clinical laboratories in healthcare facilities. However, for direct clinical applications, ATR-FTIR would be the option of choice.

CARACTÉRISATION ET ÉVALUATION IN VITRO DE L’ACTIVITÉ ANTIBACTÉRIENNE DE NANOPARTICULES D’OXYDE DE ZINC PRÉPARÉES À BASE DE L’EXTRAIT AQUEUX DES FEUILLES DE CHROMOLAENA ODORATA (L.) R. M. KING & H. ROBINSON (ASTERACEAE)

In the present study, zinc oxide nanoparticles were prepared using the aqueous extract of the leaves of Chromolaena odorata. These biosynthesized nanocrystals were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results on the prepared powder confirmed the presence of ZnO, with an estimated mean size of 24 nm. The SEM and TEM images indicated that the synthesized nanoparticles were spherical in shape with good particle dispersion. FTIR spectroscopy also confirmed the presence of ZnO in the synthesized powder through to the presence of the band localized between 800-500 cm-1, which is characteristic of the (Zn−O) bonds in zinc oxide. The antimicrobial activity of the prepared nanopowders against the bacterial strains E. coli and S. aureus demonstrated significant inhibitory effects. These inhibitory effects were more pronounced on E. coli than on S. aureus with maximum inhibition zones of 16 and 14 mm, respectively. It appears that this method can be used for the rapid and environmentally-friendly biosynthesis of stable zinc oxide nanoparticles having antimicrobial properties.