Analysis Of Fourier Transform Infrared Spectra Research Articles

Preparation and study of attapulgite reinforced PVA fiber with cross‐linking of boric acid

AbstractPolyvinyl alcohol (PVA) fibers were manufactured by gel spinning with reinforcing of attapulgite (ATT) and cross‐linking of boric acid (PVA/B/ATT fibers), in order to improve the mechanical properties. Furthermore, the final fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), powder x‐ray diffraction (XRD) and tensile strength tester. In addition, when ATT amount was no more than 2.0 wt%, FTIR analyses suggested that the degrees of cooperation combining of ATT and boric acid with PVA macromolecules were enhanced. SEM images indicated that PVA/B/ATT fibers had smooth surfaces. DSC, TGA and XRD results illustrated that the melting temperatures and maximum thermal decomposition temperatures first increased and then dropped as the content of ATT increased. Moreover, mechanical properties results indicated that the optimal ATT amount was 2.0 wt%, and the tensile strength of PVA/B/ATT‐2 fiber reached the highest of 14.2 ± 0.3 cN/dtex. It was largely because that the cooperation combining of boric acid and ATT with PVA molecules improved the mechanical properties of PVA/B/ATT fibers.

Microbial Activity of TiO2 NPs via Two Phases Synthesized by The Sol-Gel Method

TiO2 titanium dioxide nano phases of anatase and rutile were controlled only by temperature control of the calcination process, which is a cheap technical technique, and were organized using a sol-gel process, which involved mixing titanium tetrachloride (TiCl4) with ethanol as starting materials, as well as heating at various temperatures (650, 850 ℃ ). The fundamental properties of the as-prepared nanomaterials were investigated using Fourier transform infrared spectra (FTIR). The antibacterial activity of TiO2 was next investigated using two strains of E. coli, Staphylococcus aureus, and Streptococcus bacteria. The TiO2 structure has a dominating phase of 650 °C in addition to rutile at 850 °C, with an average volume of crystalline (D) of 21.9 nm for the anatase phase and 30.41 nm for the rutile phase. According to XRD data, the spherical shape of the rutile phase is clearly evident in the TEM of TiO2 NPs, the tetragonal shape is clearly seen in the anatase, and the calcination process had a major effect on the crystal size. According to FTIR analysis, the majority of peaks are seen between 400 and 700 cm-1 as a result of bending and oscillation lengthening. The studies demonstrated that TiO2, in both protease and rutile forms, is a highly efficient antibacterial that can be used as a self-cleaning exterior to exterior surfaces (windows) as well as in bio-penetration places like hospitals and medical clinics.

Detection of Verticillium infection in cotton leaves using ATR-FTIR spectroscopy coupled with machine learning algorithms

Verticillium wilt (VW) is a soil-borne vascular disease that affects upland cotton and is caused by Verticillium dahliae Kleb. A rapid and user-friendly early diagnostic technique is essential for the preventing and controlling VW disease. In this study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) technology was used to detect VW infection in cotton leaves. About 1800 FTIR spectra were obtained from 348 cotton leaves. The cotton leaves were collected from three categories: VW group, infected group and control group (non-infected). The vibrational peak of chitins at 1558 cm−1 was identified through mean and differential analysis of FTIR spectra as a criterion to differentiate the VW or infected group from the control group. Classification models were constructed using various machine learning algorithms. The support vector machines (SVM) model exhibited the highest predictive accuracy (>96 %) in each group and a total accuracy (>97 %) for the three groups. These results provide a new approach for detecting Verticillium infection in cotton leaves and shows a promising potential for the future applications of the method in plant science.

Ultrafast and Highly Efficient Laser Extraction of Matrine and Oxymatrine from Sophora flavescens for the Anticancer Activity.

Matrine and oxymatrine are mainly obtained from Sophora flavescens using the high-temperature and prolonged solvent extraction methods currently employed in industries. In this study, an ultrafast and highly efficient method for extracting matrine and oxymatrine from S. flavescens at room temperature using laser technology, specifically, laser extraction, was demonstrated. The laser extraction rates for matrine and oxymatrine from S. flavescens at room temperature for 1 min were 266.40 and 936.80 mg(g·h)-1, respectively. These rates were 1400 times higher than those achieved with conventional solvent extraction. These results mean that 1 min of laser extraction is equivalent to 24 h of solvent extraction. The reason for such a high efficiency is that laser-induced cavitation can accelerate the rapid release of alkaloid molecules in plant cells. Mass spectrum, nuclear magnetic resonance, and Fourier-transform infrared spectrum analyses of the extracted matrine and oxymatrine compounds confirmed that they are the same as the products of solvent extraction. Furthermore, it was found that the anticancer activity of laser-extracted compounds is slightly better than that of conventionally solvent-extracted ones, likely due to the slight change in the microstructure or conformation of these compounds under laser irradiation. These findings demonstrated that the laser extraction method was ultrafast and highly efficient, unveiling a novel approach to alkaloid extraction. This discovery will have significant implications for the extraction and utilization of alkaloids from plants.

New molecular and macroscopic understandings of novel green chemicals based on Xanthan Gum and bio-surfactants for enhanced oil recovery

This research investigates the interactions between a novel environmentally friendly chemical fluid consisting of Xanthan gum and bio-based surfactants, and crude oil. The surfactants, derived from various leaves using the spray drying technique, were characterized using Fourier-transform infrared (FTIR) spectroscopy, zeta potential analysis, Dynamic light scattering, and evaluation of critical micelle concentration. Static emulsion tests were conducted to explore the emulsification between crude oil and the polymer-surfactant solution. Analysis of the bulk oil FTIR spectra revealed that saturated hydrocarbons and light aromatic hydrocarbons exhibited a higher tendency to adsorb onto the emulsion phase. Furthermore, the increased presence of polar hydrocarbons in emulsion phases generated by polar surfactants confirmed the activation of electrostatic forces in fluid–fluid interactions. Nuclear magnetic resonance spectroscopy showed that the xanthan solution without surfactants had a greater potential to adsorb asphaltenes with highly fused aromatic rings, while the presence of bio-based surfactants reduced the solution's ability to adsorb asphaltenes with larger cores. Microfluidic tests demonstrated that incorporating surfactants derived from Morus nigra and Aloevera leaves into the xanthan solution enhanced oil recovery. While injection of the xanthan solution resulted in a 49.8% recovery rate, the addition of Morus nigra and Aloevera leaf-derived surfactants to the xanthan solution increased oil recovery to 58.1% and 55.8%, respectively.

Structural and electrical conductivity studies of Polyaniline - WO3 hybrid nanocomposites for gas sensing applications

Abstract Conducting polymer – metal oxide based hybrid nanocomposites are a fascinating class of materials for miniaturized and flexible gas sensor devices. They exhibit enhanced physiochemical properties such as sensitivity, selectivity towards various volatile and hazardous chemical and bioanalytes. Our study focuses on conducting polyaniline (PANI) and WO3 nanocomposites, where different weight percentages (wt.%) of WO3 nanoparticles are embedded within the conducting PANI matrix using an in-situ oxidation polymerization synthesis technique. The surface morphology analysis indicated that the WO3 nanoparticles with an average grain size of ~200 nm are homogeneously distributed within the PANI nanofibers. The Fourier Transform Infra-Red (FTIR) spectrum analysis showed that the absorption peaks at 1111,1291, 1385, 1474, and 1560 cm−1 are typical of the conducting PANI emeraldine phase. We attribute the additional broad peak ranging between 840 to 720 cm−1 in the spectrum to WO3 phase, wherein, the intensity of the peak increases with WO3 content in case of hybrid composites. Current-voltage (I-V) characteristics for all our samples showed linear behaviour up to 1.2 volts. Temperature-dependent DC electrical conductivity (σ) studies measured from room temperature to 120°C for pure PANI, and PANI-WO3 composites showed an enhanced electrical conductivity of values up to 0.12 S/cm for PANI as compared to WO3 with σ ~ 1.4 x 10−3 S/cm. Pure PANI exhibits semiconducting behavior with an increase in electrical conductivity with temperature due to the charge carrier delocalization within the dispersed PANI backbone. The addition of higher concentrations of WO3 in composites leads to a metallic-like behavior, characterized by a decrease in electrical conductivity with temperature. These observations are attributed to the field-assisted band bending effects at the interfaces of PANI and WO3. Our composites show desired electrical characteristics suitable for gas sensing applications.

Discovery of Delirium Biomarkers through Minimally Invasive Serum Molecular Fingerprinting.

Delirium presents a significant clinical challenge, primarily due to its profound impact on patient outcomes and the limitations of the current diagnostic methods, which are largely subjective. During the COVID-19 pandemic, this challenge was intensified as the frequency of delirium assessments decreased in Intensive Care Units (ICUs), even as the prevalence of delirium among critically ill patients increased. The present study evaluated how the serum molecular fingerprint, as acquired by Fourier-Transform InfraRed (FTIR) spectroscopy, can enable the development of predictive models for delirium. A preliminary univariate analysis of serum FTIR spectra indicated significantly different bands between 26 ICU patients with delirium and 26 patients without, all of whom were admitted with COVID-19. However, these bands resulted in a poorly performing Naïve-Bayes predictive model. Considering the use of a Fast-Correlation-Based Filter for feature selection, it was possible to define a new set of spectral bands with a wider coverage of molecular functional groups. These bands ensured an excellent Naïve-Bayes predictive model, with an AUC, a sensitivity, and a specificity all exceeding 0.92. These spectral bands, acquired through a minimally invasive analysis and obtained rapidly, economically, and in a high-throughput mode, therefore offer significant potential for managing delirium in critically ill patients.

Harnessing nature's potential: Alpinia galanga methanolic extract mediated green synthesis of silver nanoparticle, characterization and evaluation of anti-neoplastic activity.

With the advent of nanotechnology, the treatment of cancer is changing from a conventional to a nanoparticle-based approach. Thus, developing nanoparticles to treat cancer is an area of immense importance. We prepared silver nanoparticles (AgNPs) from methanolic extract of Alpinia galanga rhizome and characterized them by UV-Vis spectrophotometry, Fourier transform Infrared (FTIR) spectroscopy, Zetasizer, and Transmission electron Microscopy (TEM). UV-Vis spectrophotometry absorption spectrum showed surface plasmon between 400 and 480nm. FTIR spectrum analysis implies that various phytochemicals/secondary metabolites are involved in the reduction, caping, and stabilization of AgNPs. The Zetasier result suggests that the particles formed are small in size with a low polydispersity index (PDI), suggesting a narrow range of particle distribution. The TEM image suggests that the particles formed are mostly of spherical morphology with nearly 20-25nm. Further, the selected area electron diffraction (SAED) image showed five electron diffraction rings, suggesting the polycrystalline nature of the particles. The nanoparticles showed high anticancer efficacy against cervical cancer (SiHa) cell lines. The nanostructures showed dose-dependent inhibition with 40% killing observed at 6.25µg/mL dose. The study showed an eco-friendly and cost-effective approach to the synthesis of AgNPs and provided insight into the development of antioxidant and anticancer agents.

Novel LiFePO4/very-few-layer-graphene (LFP/VFLG) composites to improve structural and electrochemical properties of lithium-ion battery cathode

LiFePO4/Very-few-layer-graphene (LFP/VFLG) composites have been prepared using the sol-gel method for lithium-ion battery cathode. VFLG dominated by 1∼3 layers was obtained from an economical and environmentally benign process. Structural properties of LFP/VFLG composites were studied using Fourier-transform infrared spectra (FTIR) spectroscopy, X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy, while the electrochemical performance was measured using galvanostatic discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests. The FTIR analysis confirmed that incorporating VFLG neither affected the chemical structure of LiFePO4 nor initiated any side reactions during the LiFePO4 formation reaction. The XRD results showed that LFP/VFLG composites had better lattice parameters, crystallinity, and phase purity than LiFePO4 without VFLG addition. The Raman spectroscopy analysis indicated that LFP/VFLG composites had a lower disorder in the carbon arrangement. HRTEM results indicated that a VFLG was successfully wrapped around the LFP particle offers a versatile way to enhanced electrochemical performance of LFP/VFLG composites. The galvanostatic discharge profiles showed an enhancing specific discharge capacity of up to 58.3% after incorporating VFLG. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests revealed that LFP/VFLG delivered small polarization, low inner resistance, high electrochemical reaction reversibility, and high lithium-ion diffusion coefficient. VFLG is a promising additive to improve the structural and electrochemical properties of the LiFePO4 cathode of lithium-ion batteries.

Adsorption of Ammonium, Nitrate, and Phosphate on Hydrochars and Biochars

Biochar (BC) and hydrochar (HC) have attracted considerable attention owing to their versatile characteristics and proven effectiveness in diverse technical fields. Solid BC is generated as a result of the dry carbonisation process of pyrolysis, in contrast to the slurry HC, which is produced during the hydrothermal carbonisation process. In this study, we evaluated the adsorption potential of two hydrochar samples (HCs) and three biochar samples (BCs) produced from sugar cane bagasse. The adsorption capacity of these samples was tested for ammonium, nitrate, and phosphate ions under various conditions. The BCs and HCs were subjected to characterisation using a CHNS/O analyser, the zeta potential, and Fourier transform infrared (FTIR). Elevating the pyrolysis temperature of the biochar resulted in changes in the fixed carbon and ash contents, while the volatile matter and H/C and O/C atomic ratios decreased. As the residence time increased, the H/C ratio and volatile matter content of the hydrochars (HCs) decreased. However, the fixed carbon content, ash content, and O/C and C/N ratios exhibited an increase. Thermodynamics, adsorption isotherms, and pH were also taken into consideration. The FTIR spectra analysis indicated that the carboxyl and ester functional groups present in both the BCs and HCs displayed reduced peak intensities subsequent to the adsorption of the three ions. While the adsorption was exothermic, we noticed that the adsorption capacity increased with temperature. The results indicate that sorption was homogenous across all binding sites, as evidenced by the optimal fit to the Langmuir isotherm. The research findings indicate that the adsorption capacity of various BC and HC adsorbents is significantly influenced by the surface area of the adsorbents in the case of nitrate and phosphate, but in the case of ammonia, adsorption is dictated by the functional polar groups present on the adsorbent surface.

Magnesium-Doped Nano-Hydroxyapatite/Polyvinyl Alcohol/Chitosan Composite Hydrogel: Preparation and Characterization.

Polyvinyl alcohol/Chitosan hydrogel is often employed as a carrier because it is non-toxic, biodegradable, and has a three-dimensional network structure. Meanwhile, Magnesium-doped nano-hydroxyapatite(Mg-nHA) demonstrated high characterization to promote the osteogenic differentiation of bone marrow derived mesenchymal stem cell(BMSCs). Therefore, in order to develop a porous hydrogel scaffold for the application of bone tissue engineering, an appropriate-type Mg-nHA hydrogel scaffold was developed and evaluated. A composite hydrogel containing magnesium-doped nano-hydroxyapatite (Mg-nHA/PVA/CS) was developed using a magnetic stirring-ion exchange method and cyclic freeze-thaw method design, with polyvinyl alcohol and chitosan as the main components. Fourier transform infrared spectra (FTIR), electron energy dispersive spectroscopy (EDS), X-ray photoelectron spectrometer (XPS) and scanning electron microscopy (SEM) were employed to analyze the chemical structure, porosity, and elemental composition of each hydrogels. The equilibrium swelling degree, moisture content, pH change, potential for biomineralization, biocompatibility, the osteogenic potential and magnesium ion release rate of the composite hydrogel were also evaluated. SEM analysis revealed a well-defined 3D spatial structure of micropores in the synthesised hydrogel. FTIR analysis showed that doping nanoparticles had little effect on the hydrogel's structure and both the 5% Mg-nHA/PVA/CS and 10% Mg-nHA/PVA/CS groups promoted amide bond formation. EDS observation indicated that the new material exhibited favourable biomineralization ability, with optimal performance seen in the 5% Mg-nHA/PVA/CS group. The composite hydrogel not only displayed favourable water content, enhanced biocompatibility, and porosity (similar to human cancellous bone), but also maintained an equilibrium swelling degree and released magnesium ions that created an alkaline environment around it. Additionally, it facilitated the proliferation of bone marrow mesenchymal stem cells and their osteogenic differentiation. The Mg-nHA/PVA/CS hydrogel demonstrates significant potential for application in the field of bone repair, making it an excellent composite material for bone tissue engineering.

Mimicking Natural Antioxidant Systems for Improved Photostability in Wide-Band-Gap Perovskite Solar Cells.

Fostered by the top power conversion efficiencies (PCEs) of lab-scale devices, industrialization of perovskite solar cells is underway. Nevertheless, the intrinsically poor stability of these materials still represents a major concern. Herein, inspired by Nature, the use of β-carotene in perovskite solar cells is proposed to mimic its role as a protective pigment, as occurs in natural photosynthesis. Laser-mediated photostability (LMPS) assessment, Fourier-transform infrared spectra analysis acquired in attenuate total reflectance (ATR-FTIR), spectroscopy ellipsometry (SE), and time-resolved photoluminescence (TRPL) measurements under stress conditions prove that the inclusion of a thin β-carotene interlayer promotes a high improvement in the photostability of the perovskite films against photooxidation. Importantly, this is accompanied by an improvement of the solar cell PCE that approaches 20% efficiency with no hysteresis, which is among the highest values reported for a mixed halide (I-Br) perovskite with a band gap of 1.74 eV, relevant for coupling with silicon in tandem cells.

Biogenic synthesis of silver nanoparticles using essential oil of aerial part of cyclospermum leptophyllum and their application in colorimetric determination of metallic ions

The focus of this research was to synthesize biogenic silver nanoparticles (AgNPs) using the essential oil of the aerial part of Cyclospermum leptophyllum (CLEO) and investigate their colorimetric determination of metallic ions. In the synthesis of CLEO mediated AgNPs (CLEO-AgNPs), the one-factor-at-a-time method was used to optimize the reaction parameters. Ultraviolet-visible (UV-Vis) peak of CLEO-AgNPs was determined at 426 nm. Fourier transform-infrared (FTIR) spectra analysis identified the functional groups participating in the bio-reducing, capping, and stabilizing processes in the CLEO-AgNPs synthesis. Scanning electron microscope (SEM) image demonstrated the predominately spherical shape and the average size of 70.86+1.80 nm of CLEO-AgNPs. Energy dispersive X-ray spectroscopy (EDX) peak profile depicted the presence of Ag elements in CLEO-AgNPs. The X-ray diffraction (XRD) peaks observed at 38.5°, 44°, 65°, and 77° which represent Ag(111), Ag(200), Ag(220), and Ag(311) lattice faces, respectively. The average zeta nanosize, zeta potential, and polydispersity index of CLEO-AgNPs were determined as 69.70 nm, -43.5 mV, and 0.256, respectively. The stability test exhibited the prolonged storage stability of CLEO-AgNPs for over six months at room temperature. CLEO-AgNPs demonstrated the potential colorimetric detection of K+, Mg2+, Al3+, Cr6+, Mn2+, Fe3+, Ni2+, Cu2+, Zn2+, Hg2+, Pb2+, and Cd2+ ions in the real samples.
 KEY WORDS: Cyclospermum leptophyllum, Essential oil, Biogenic silver nanoparticles, Bio-reductants, Colorimetric detection 
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 213-228. DOI: https://dx.doi.org/10.4314/bcse.v38i1.16

Investigations on growth, XRD, strain, FTIR, UV–Vis NIR, photoluminescence, SHG, and Z-scan analyses of L-cysteine picrate single crystal for NLO and optical limiting applications

Organic single crystal of L-cysteine picrate (LCP), an efficient NLO material for frequency conversion, optoelectronic, and optical limiting applications has been grown within 20 days by Slow Evaporation Solution Technique (SEST). PXRD analysis shows that the LCP is subjected to the noncentrosymmetric space group of P21 with a monoclinic crystal system. The very low strain value depicts that the level and dislocations of the defect in the lattice of LCP crystal are very low. The various functional group assignments were investigated by using Fourier-Transform Infrared (FTIR) spectrum analysis with the range of 4000–400 cm−1. The optical analysis (UV–Visible) confirmed that the crystal has a lower cut-off wavelength of 250 nm and very low absorption in the entire visible region. Photoluminescence (PL) spectrum analysis confirmed that the material exhibits blue emission and is suitable for LED device fabrication. The SHG efficiency for LCP crystal is established to be 1.7 times higher than KDP material. Z-scan measurement determined the LCP exhibits two-photon absorption-induced optical limiting action with a nonlinear absorption coefficient of 0.70 × 10−10 m/W and onset limiting threshold of 2.36 × 1012 W/m2 which indicates that it can be used in making laser protection gadgets.

Structure, thermal and crystallization behavior of lead-bismuth silicate glasses

Lead-bismuth silicate glasses were synthesized using a standard melt-quenching technique, varying the compositions within the range of (80-x-y)PbO–(10+x)Bi2O3–(10+y)SiO2, where x and y were between 0 and 20 wt%. The glasses were subjected to comprehensive analysis, including X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and dilatometry, to investigate their crystallization behavior, thermal properties, and structure. The obtained glass samples were confirmed to be amorphous through X-ray diffraction and scanning electron microscopy. Fourier-transform infrared spectra analysis indicated that the glasses consisted mainly of PbO4, BiO6, and SiO4 structural units. Differential thermal analysis curves were used to estimate the glass transition, crystallization, and melting temperatures, and the results showed increased thermal stability and decreased crystallization tendency with increasing SiO2 content in the glass. X-ray diffraction analysis was utilized to identify the specific crystalline phases that were formed after the glass was subjected to heat treatment. Dilatometric measurements demonstrated that the investigated glasses possess a wide range of coefficient of thermal expansion values (6.8–11.1 ppm/°C), a low glass transition temperature (335–475°С), and a low dilatometric softening temperature (355–505°С). These results have significant implications for developing oxide glasses with specific thermal characteristics suitable for a wide range of applications.

Insights into the mechanisms of L. salivarius CECT5713 resistance to freeze-dried storage

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits. However, it is sensitive to freeze-drying and storage in the dried state, thus limiting its commercial exploitation. Our objective was to identify markers of cell resistance by applying multiscale characterization to L. salivarius CECT5713 cell populations exhibiting different resistance to freeze-dried storage. Cells were produced under two different sets of production conditions differing in the culture parameters (temperature, neutralizing solution, and harvesting time) and the protective formulation composition. The culturability, membrane integrity, and cell biochemical composition assessed by Fourier transform infrared (FTIR) micro-spectroscopy were evaluated after freezing, freeze-drying, and subsequent storage at 37 °C. Membrane properties (fatty acid composition, membrane fluidity, and phospholipid organization), as well as matrix physical properties (glass transition temperature and water activity), were determined. The most resistant cells to freeze-dried storage exhibited the highest cyclic fatty acid content and the most rigid membrane. Freeze-drying and storage induced damage to membrane integrity, proteins, nucleic acids, and constituents of the peptidoglycan cell wall. From the FTIR spectra analysis, we propose the minimization of the variations of the 1058 and 1714 cm−1 vibration bands (that arise mainly from symmetric C–O–C stretching and CO stretching, respectively) induced by the freeze-drying process as a marker of storage stability. We confirmed that a matrix with a glass transition temperature at least 50 °C higher than the storage temperature is crucial for L. salivarius CECT5713 storage stability. In addition, this work explored promising FTIR methods for a better understanding of the protection mechanisms involved.

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy for Forensic Screening of Long-Term Alcohol Consumption from Human Nails.

Fourier transform infrared (FT-IR) spectroscopy is used throughout forensic laboratories for many applications. FT-IR spectroscopy can be useful with ATR accessories in forensic analysis for several reasons. It provides excellent data quality combined with high reproducibility, with minimal user-induced variations and no sample preparation. Spectra from heterogeneous biological systems, including the integumentary system, can be associated with hundreds or thousands of biomolecules. The nail matrix of keratin possesses a complicated structure with captured circulating metabolites whose presence may vary in space and time depending on context and history. We developed a new approach by using machine-learning (ML) tools to leverage the potential and enhance the selectivity of the instrument, create classification models, and provide invaluable information saved in human nails with statistical confidence. Here, we report chemometric analysis of ATR FT-IR spectra for the classification and prediction of long-term alcohol consumption from nail clippings in 63 donors. A partial least squares discriminant analysis (PLS-DA) was used to create a classification model that was validated against an independent data set which resulted in 91% correctly classified spectra. However, when considering the prediction results at the donor level, 100% accuracy was achieved, and all donors were correctly classified. To the best of our knowledge, this proof-of-concept study demonstrates for the first time the ability of ATR FT-IR spectroscopy to discriminate donors who do not drink alcohol from those who drink alcohol on a regular basis.

Chemometrics Approach Based on Wavelet Transforms for the Estimation of Monomer Concentrations from FTIR Spectra.

Fourier-transform infrared (FTIR) spectroscopy can detect the presence of functional groups and molecules directly from a mixed solution of organic molecules. Although it is quite useful to monitor chemical reactions, quantitative analysis of FTIR spectra becomes difficult when various peaks of different widths overlap. To overcome this difficulty, we propose a chemometrics approach to accurately predict the concentration of components in chemical reactions, yet interpretable by humans. The proposed method first decomposes a spectrum into peaks with various widths by the wavelet transform. Subsequently, a sparse linear regression model is built using the wavelet coefficients. Models by the method are interpretable using the regression coefficients shown on Gaussian distributions with various widths. The interpretation is expected to reveal the relation of broad regions in spectra to the model prediction. In this study, we conducted the prediction of monomer concentration in copolymerization reactions of five monomers against methyl methacrylate by various chemometric approaches including conventional methods. A rigorous validation scheme revealed that the proposed method overall showed better predictive ability than various linear and non-linear regression methods. The visualization results were consistent with the interpretation obtained by another chemometric approach and qualitative evaluation. The proposed method is found to be useful for calculating the concentrations of monomers in copolymerization reactions and for the interpretation of spectra.

Facile synthesis of fluorinated graphene for surface self-assembly of aluminum hydride

A facile method, refluxing with hydrothermal process, was used to synthesize the fluorinated graphene sheets (FGS) with high F/C ratio. Then, the surface of aluminum hydride (AlH3) was coated with FGS by means of liquid self-assembly process. The structure and performance of FGS were characterized through fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM) and elemental analyzer. FTIR spectra show that the FGS have obvious absorption peak of CF bond. Raman spectra display many defects on FGS. XPS spectra and elemental analysis also prove the existence of CF bond, and the content of fluorine is more than 25%. From SEM photos we can see that FGS have thin layers with some curled wrinkles. TEM photos demonstrate intuitively the FGS has a few layers. At last, the aluminum hydride (AlH3) was coated with FGS by means of liquid self-assembly process, and AlH3 samples before and after treated were characterized through hydrogen content (H%) analysis, X-ray diffraction (XRD), FTIR, SEM and differential thermal analysis (DTA), ect. The results demonstrate that there is only a little FGS on the surface of AlH3, which won't affect the effective H% and release efficiency of hydrogen. AlH3@FGS also reduces the mechanical sensitivity of solid propellant with AlH3, which will remarkably promote the application of AlH3 in the novel high-energy solid propellant.

Effect of NaOH-catalyzed organosolv pretreatment on the co-production of ethanol and xylose from poplar

NaOH-catalyzed organosolv pretreatment was proposed to degrade lignin, retain cellulose and hemicellulose in poplar, and the pretreated substrates was used to produce ethanol and xylose simultaneously. After the organosolv pretreatment conducted at 205 ºC for 20 min with 1.2% NaOH, the optimal ethanol concentration and xylose yield reached 30.1 g/L and 10.3 g/100 g raw material after 48 h, respectively, and the xylose yield was positively correlated with the ethanol concentration (R2 =0.934). The alteration in chemical composition and structure enhanced the ethanol concentration and xylose yield, which was revealed by Scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectrum (FT-IR), Thermogravimetric (TG), and correlation analysis. In addition, their capacity for generating ethanol and xylose during three fermentation processes was comprehensively compared. The results indicated that SSF was beneficial to improve ethanol concentration, and SHF was in favour of enhancing xylose and ethanol yields to 95.4% and 85.3% based on retained xylan after pretreatment and the fermentable glucose, respectively. The NaOH enhanced organosolv pretreatment exhibited excellent performance in converting poplar into energy and chemicals, which presented a new idea for biomass refining.