Reflectance Fourier Transform Infrared Spectroscopy Research Articles

3D printed solid phase microextraction scaffolds as novel tool for sample preparation; application in antifungal drugs analysis

3D printed solid phase microextraction scaffolds as a novel sorbent were introduced for the extraction of antifungal drugs in wastewater and human plasma prior to their determination by HPLC-UV. The designed adsorbent was prepared as cubic scaffolds using fused deposition modeling (FDM) 3D printer and Polylactic acid (PLA) filament. Scaffold surface was chemically modified using alkaline ammonia solution (Alkali treatment). The application of this new design in the extraction of three antifungal drugs ketoconazole, clotrimazole and miconazole was investigated. Alkali surface modification time was optimized (0.5-5hr) and 4hr selected as the best-modification time. Morphology of the modified surface and its chemical changes were studied using Field Emission Scanning Electron Microscope (FE-SEM) and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), respectively. Surface wettability of scaffolds was measured by Water Contact Angel (WCA) and the porosity created in the scaffolds was studied by N2 adsorption/desorption studies analysis. Analytical performance of the method, under optimum conditions (extraction time: 25 min, desorption solvent: methanol, volume of desorption solvent: 2 mL, desorption time: 10 min, solution pH: 8, solution temperature: 40 °C, salt concentration: 3 mol L−1) were obtained as 3.10 and 10.0 µg L−1 for LOD and LOQ, respectively. The calibration graphs were linear in the range of 10–150 µg L−1 and 10-100 µg L−1 for wastewater and plasma, respectively.

Study of metal and organic contaminants transported by microplastics in the Lebanese coastal environment using ICP MS, GC-MS, and LC-MS

An untargeted study of multiclass contaminants associated with microplastics (MPs) in the East Mediterranean was carried out. Samples were collected in 2020–2021 from the shoreline at 14 different locations, along the Lebanese coast. Attenuated Total Reflectance (ATR) FTIR spectroscopy showed the predominant presence of polyethylene and polypropylene among plastic debris. The non-polar and polar organic compounds sorbed on the MPs were identified and quantified by GC - TOF MS and LC – electrospray MS/MS, respectively. Deconvolution of accurate GC–MS scan data allowed the identification of >130 organic pollutants, 64 of which could be confirmed by matching with the authentic standards, among which a number of previously unreported in targeted GC–MS(MS) methods. In addition to highly toxic, legacy chlorinated pollutants, high levels (average values from 0.8 to 4.0 μg g−1) of some musks, UV filters and UV absorbers were detected. Untargeted LC-MS demonstrated the persistence of several pesticides (i.e., chlorpyrifos) and pharmaceuticals, such as phenacetin and minoxidil, which were quantified. In addition, a study of metals associated with microplastics using ICP-MS confirmed the high potential of microplastics to act as a vector of, among others, toxic metals, such as Cd, Pb, Bi or Hg.

Effective Malachite Green Degradation over the Noble Metal-Doped and MOF-Coupled CsSnBr3 Nanocomposite Catalyst

Environmental protection laws require effective and green solutions to tackle water and air pollution issues. For this purpose, perovskite photocatalytic materials have proven to be a promising solution. In this study, CsSnBr3 perovskite, coupled with ZIF-67 and decorated with noble metal Au, was shown to effectively enhance the charge separation and increase the light-absorbing capacity, and thus make the photocatalytic reaction more efficient by surface plasmon resonance. Characterization results from XRD, FTIR, and UV-visible diffuse reflectance spectroscopy indicated that a mixture of cubic and tetragonal crystalline phases was found in the prepared catalyst material. XPS also revealed that in the presence of two oxidation states for tin (Sn), the Au 4f XPS peaks of Au NPs coincided with those retained in colloidal Au particles. Using malachite green as a model compound, organic pollutant photocatalytic degradation tests proved that CsSnBr3 generated good photocatalytic activity for aromatic pollutant degradation. In this research, the synthesized 4Au-7ZIF-CsSnBr3 catalyst yielded an MG degradation rate twice as high as the unpromoted CsPbBr3.

Evaluation of enzymatic stamp removal strategies on handmade (cellulose-based) and machine-made (lignin-containing) papers

Two different biocleaning techniques for stamp removal from different paper samples (handmade and machine-made) were investigated. Cellulose is the main component of handmade paper, while higher concentration of lignin is present in machine-made paper. Biocleaning methods included the direct application on paper surfaces of the extracellular enzymatic mixture (EEM) extracted from the yeast Sporidiobolus metaroseus and the recombinant protein CthediskatG of Chaetomium thermophilum var. dissitum. The produced microbial enzymes (EEM or CthediskatG) were also combined with agarose hydrogels. The effectiveness of the cleaning ability of the individual methods was determined using different spectrophotometer measurements based on colorimetric analysis and by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). Some tested samples were also subjected to microstructural and chemical analysis using Scanning Electron Microscope-Energy-Dispersive X-ray spectroscopy (SEM-EDX). The analysis showed that the EEM-based approaches were the most suitable, mainly they are less time-consuming and easy to produce, and moreover slight differences were displayed between EEM and CthediskatG during the removal of the stamp by hydrogel-enzyme approaches. Both EEM applications (direct and hydrogel) speed up the stamp removal process from real paper samples. However, for the complete elimination of the stamp smears a quick N,N-dimethylformamide post-treatment is advised too.

Low-temperature catalytic performance of toluene oxidation over Cu-Mn oxide catalysts derived from LDH precursor

A series of CuMn mixed oxides catalysts (CMO-T) were prepared by calcination of CuMn layered double hydroxides (CuMn-LDH) for catalytic oxidation of toluene. The obtained CMO-400 catalyst exhibited a high catalytic activity with T50 and T90 of 210 and 231 °C (WHSV = 30000 mL·g−1·h−1). Meanwhile, the CMO-400 exhibited high stability and durability even at 20 vol% water vapor. The effects of calcination temperature on the texture and structural properties were investigated systematically, which proved the formation of copper-manganese solid solution with abundant multiple-phase interfaces. In addition, the strong interaction between Cu and Mn could lead to more surface adsorbed oxygen due to oxidation reduction cycle of Mn3++Cu2+=Mn4++Cu+. Accordingly, for CMO-500 catalyst, the formation of spinel Cu1.5Mn1.5O4 phase prevented good dispersion of the manganese-oxide phases and weakened the reducibility and oxygen mobility. In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) revealed that the intermediates accumulated continuously were difficult to be oxidized rapidly without the replenishment gaseous oxygen. Moreover, the complete transformation of the intermediate benzoate may be the key rate-controlling step in the reaction. The Facile method of preparing mixed-metal solid solution from LDH precursor system could be widely developed for the design of transition metals in catalytic oxidation of toluene.

Reaction mechanism of NO and SO2 Co-removal by calcium hydroxide

Flue Gas simultaneous Desulfurization and Denitrification (FGDD) is expected to become a new generation of low-cost technology to achieve ultra-low emissions especially in smelting kilns and industrial boilers. The fixed bed system and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) were used to clarify the reaction mechanism of NO and SO2 co-removal by calcium hydroxide absorbent. The hydroxyl radical on the surface of calcium hydroxide was identified by Protium Nuclear Magnetic Resonance (1H NMR) and radical scavenger 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO). With synergistic effect of hydroxyl radical and oxygen, NO and SO2 are oxidized to NO2 and SO3 respectively, and then absorbed as nitrate and sulfate, according to the three-step chain reactions: SO2 +HO* →HOSO2 *, HOSO2 * +O2→SO3 +HO2 * and HO2 * +NO→HO* +NO2. The key point is the recycling of hydroxyl radical.

Quantification of Lignosulfonates and Humic Components in Mixtures by ATR FTIR Spectroscopy

The existing techniques for lignosulfonate (LS) in humate fertilizers lack selectivity to humic substances (HS) as the main component; they involve labor- and time-consuming sample preparation to separate the components at the level of detectable LS concentrations. The procedure based on attenuated total reflectance (ATR) FTIR spectroscopy with simple sample preparation for directly quantifying lignosulfonates in aqueous solutions and lignosulfonates and HS in aqueous solutions of preparations based on HS of coal origin (Sigma Aldrich, Powhumus, and Life Force) was developed. Lignosulfonate quantification is possible by exploiting the bands at 1266, 1192, 1093, and 1042 cm−1 with limits of detection of 0.4–2 g/L. Quantifying LS in a mixture with humates includes centrifugation of prepared solutions to separate interfering silicate impurities. LS quantification in the range of 10–100 g/L against HS (up to a 2-fold excess) with an error of up to 5% is possible based on the spectral absorptions at 1093 and 1042 cm−1. Simultaneous quantification of humate in the mixture with an error of up to 10% is possible by exploiting the bands at 1570 and 1383 cm−1 (carboxylates). The study shows the possibility of determining lignosulfonate against an HS background several times higher than lignosulfonate. The developed technique is applicable for analyzing fertilizers of simple composition and quality control of pure humates used for plant growth. Obtaining the most accurate results needs calibration solutions from the same brands that make up the test mixture.

Mechanism of Extracting Germanium from Ge-Containing Solution with Tannins

The process of germanium–tannin complex is the oldest form of technology for extracting germanium from Ge-containing solutions. This reaction mechanism is relatively controversial as it imposes restrictions on ideas and methods for reducing the amount of tannin. In this paper, using SEM, TEM, FT-IR, XPS, NMR, TOF-SIMS and UV diffuse reflectance spectroscopy for a deep analysis of germanium–tannin complex, the mechanism of extracting germanium from Ge-containing solutions with tannins is investigated. The results show that the theoretical tannin complex mass is 30 times that of tannin mass, and the complex rate reaches 98.84%. The changes of -OH stretching band in FT-IR spectra, the emergence of C3H3GeO7, C2H3GeO6, and C8H7GeO7 in TOF-SIMS images, and the shift of Ge and O banding energy in XPS detail spectra provided definitive evidence for the germanium–tannin complex process, highlighting that the formed complexes of tannins with germanium involve six coordinate Ge-O bonds, which are obtained through orthophenol hydroxyl groups in tannins reacting with Ge4+. Furthermore, the complex mode of germanium–tannins is layer polymerization, which finally forms an agglomeration of complex flocs. The findings of this research is innovative, and can have a profound impact on the future introduction of various methods to reduce the mass of tannins.

Metallic AgInS2 nanocrystals with sulfur vacancies boost atmospheric CO2 photoreduction under near-infrared light illumination

Unraveling the function of vacancy engineering in influencing the intrinsic CO2 photoreduction with low photon energy directly from air remains a significant challenge. Here, a metallic photocatalyst, ultrafine AgInS2 nanocrystals with sulfur vacancies (VS-AgInS2) is designed to exhibit superior atmospheric CO2 reduction performance under near-infrared (NIR) light. Theoretical calculations reveal that the presence of sulfur vacancies and metallic characteristics result in extended spectrum absorption to the NIR region and efficient separation of charge carriers. As evidenced by In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiment and theoretical calculations, the unique properties of charge delocalization around the vacancy-induced dual sites at AgInS2 nanocrystals contribute to COOH* intermediates for CO production while simultaneously inhibiting the formation of CHO* intermediates. Consequently, the metallic VS-AgInS2 nanocrystals demonstrate nearly 100% selective CO production with a rate of 8.04 μmol g−1 h−1 under NIR irradiation, even directly from atmospheric CO2 in the air.

Introduction of NiSO4 to Ni/SiO2 catalyst in hydrogenation of furfuryl alcohol: Tailoring metallic nickel sites to switch major product from tetrahydrofurfuryl alcohol to cyclopentanone

Nickel-based catalysts are widely used in hydrogenation of varied types of organics. However, the nickel catalyst, like Ni/SiO2, lacks selectivity for hydrogenation of C=C and C=O. This is undesirable in some scenarios, such as conversion of biomass-derived furfuryl alcohol (FA) to cyclopentanone (CPO), a fine chemical, in which the C=C in furan ring of FA needs to be retained. In this study, introduction of sulfur species to Ni/SiO2 catalyst via loading NiSO4 was adopted to inhibit hydrogenation of furan ring in FA, aiming to achieve conversion of FA to CPO via ring-opening route. The results indicated that NiSO4 was reduced to NixSy, which further reacted with metallic Ni, forming Ni3S2 species and introducing the acidic sites with high-strength. The co-existence of NixSy and metallic Ni species effectively hindered hydrogenation of furan ring in FA, reducing tetrahydrofurfuryl alcohol (THFA) yield from 97% over Ni/SiO2 to 0 over the NiSx/SiO2 catalysts and shifting the major product to CPO. Nonetheless, the enhanced acidic sites along with the introduction of NiSO4 catalyzed polymerization of reaction intermediates, competing with the production of CPO. The acidic sites, however, facilitated hydrogenolysis of vanillyl alcohol to selectively produce (yield: 94.3%) in hydrogenation of vanillin. Characterization of hydrogenation of FA with in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique suggested the oxygen-containing functionalities in FA, instead of furan ring, could strongly adsorb on the NiS10/SiO2 catalyst, enhancing rearrangement reaction to form CPO while suppressing hydrogenation of the furan ring.

Photothermal dual-responsive polymers for trypsin-free cell sheet harvesting

Cell sheet engineering has emerged to tackle cell therapy's bottlenecks and increase the likelihood of life-saving potentials of tissue engineering. In this study, Poly(N-isopropylacrylamide-co-spiropyran) (P(NIPAAm-co-Sp)) copolymer and Poly(N-isopropylacrylamide-co-styrene-co-spiropyran) (P(NIPAAm-co-St-co-Sp)) terpolymer were synthesized by free radical polymerization (FRP). Fourier transform infrared (FTIR) was utilized to characterize the chemical structure of the resultant polymers. The molecular weight and molecular weight distribution were measured by gel permeation chromatography (GPC). The reversible photosensitivity of the synthesized polymers was proved by ultraviolet–visible (UV–Vis) spectroscopy. Thin layers of polymers were spin-coated onto ultraviolet/ozone (UV-O3) and silane-modified glass slides. To confirm the coating process, the attenuated total reflection FTIR spectroscopy (ATR-FTIR) was used. The cross-sectional images of the spin-coated glass slides, obtained using field emission scanning electron microscopy (FESEM), showed thin layers about 300 to 400 nm thick. The roughness of the coated layers was examined by atomic force microscopy which were below 1 nm. The water contact angle (WCA) measurements showed that changes in the surface wettability of thin layers occurred in response to temperature alteration and light illumination. The spin-coated glass slides were used to culture the mouse fibroblast cell line L929. The cell culture results showed that the thickness of the thin layers was adequate for forming a confluent and integrated sheet of L929 cells. By reducing the temperature from 37 °C to 20 °C and illuminating the glass slide, fragments of the cell sheet were harvested. The use of light besides temperature reduction decreased the time needed for cell sheet detachment from 2 h to 1 h.

Electrodeposited Carbonyl Functional Polymers as Suitable Supports for Preparation of the First-Generation Biosensors.

The aim of this electrochemical study was to ascertain which type of electrochemically deposited carbonyl functionalized polymer represents the most suitable electrode substrate for direct covalent immobilization of biological catalysts (enzymes). For this purpose, a triad of amperometric biosensors differing in the type of conductive polymers (poly-vanillin, poly-trans-cinnamaldehyde, and poly-4-hydroxybenzaldehyde) and in the functioning of selected enzymes (tyrosinase and alkaline phosphatase) has been compared for the biosensing of neurotransmitters (dopamine, epinephrine, norepinephrine, and serotonin) and phenyl phosphates (p-aminophenyl phosphate and hydroquinone diphosphate). The individual layers of the polymers were electrochemically deposited onto commercially available screen-printed carbon electrodes (type C110) using repetitive potential cycling in the linear voltammetric mode. Their characterization was subsequently performed by SEM imaging and attenuated total reflectance FTIR spectroscopy. Molecules of enzymes were covalently bonded to the free carbonyl groups in polymers via the Schiff base formation, in some cases even with the use of special cross-linkers. The as-prepared biosensors have been examined using cyclic voltammetry and amperometric detection. In this way, the role of the carbonyl groups embedded in the polymeric structure was defined with respect to the efficiency of binding enzymes, and consequently, via the final (electro)analytical performance.

Manipulating drug release from 3D printed dual-drug loaded polypills using challenging polymer compositions

Combining multiple medications in a single dosage form has emerged as an important strategy for treating complex diseases and could help tackle the growing issue of polypharmacy. In this study we investigated the suitability of different dual-drug designs for achieving simultaneous, delayed and pulsatile drug release regimes using two model formulations: an immediate release erodible system of Eudragit E PO loaded with paracetamol; and an erodible swellable system of Soluplus loaded with felodipine. Both binary formulations, despite not fused deposition modelling (FDM) printable, were successfully printed using a thermal droplet-based 3D printing method, Arburg Plastic Freeforming (APF), and exhibited good reproducibility. X-ray powder diffraction (XRPD), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) were used to assess drug-excipient interaction. The printed tablets were evaluated for drug release using in vitro dissolution testing. We found the simultaneous and delayed release designs were effective at generating the intended drug release profiles, giving insight into the types of dual-drug designs which can be used to create complex release profiles. In contrast the pulsatile tablet release was non-defined, highlighting the design limitations when using erodible materials.

Promotion of glyoxylic acid penetration into human hair by glycolic acid.

Glyoxylic acid (GA) is widely used as a straight perming agent for hair care products, however, advanced GA penetration-enhancing agents are desired due to the peculiar odour and hair colour fading caused by the continuous use of GA products. Hence, it is important to develop a penetration-enhancing agent that helps minimize the GA concentration. We have found that the combined use of GA and glycolic acid (GCA) has a strong hair straightening effect. Straightening hair test was carried out to the evaluation of the effect of additives. Liquid chromatography-mass spectrometry (LC/MS) was performed to quantify the GA penetration amount into human hair. Attenuated total reflection (ATR) Fourier transform-infrared spectroscopy (FT-IR) and FT-IR microscope were implemented to estimate the localization of GA in the hair. Straightening hair tests indicated that the hair straightening effect by GA was enhanced by the presence of GCA. LC/MS results showed that the addition of GCA enhanced the amount of GA that penetrated human hair by about four times. ATR FT-IR and FT-IR microscope measurements indicated that GA was localized more in the innermost region of hair (medulla) than the cortex and cuticle. The GA accumulated in the medulla disappeared after a hair straightener treatment at 180°C due to the chemical reaction. The GA penetration-enhancing effect of GCA is worth investigating to reduce the GA concentration in products for more comfortable use.

Characterisation of coal using hyperspectral core scanning systems

Commercially available hyperspectral drill core scanning systems in the Visible and Near-Infrared (VNIR), Short-Wave Infrared (SWIR) and Long-Wave Infrared (LWIR) regions, along with a handheld spectrometer for the Middle-Wave Infrared (MWIR) region, were used to characterise a rank suite of coal samples (0.45% to 1.76% Rr) with different preparations (slabbed surface, outer core and compressed powder pellets). The samples used in this study came from Australian basins of Permian and Jurassic ages. The spectral characteristics of the coals measured using these scanning systems were compared to those obtained using well-established spectroscopy techniques that operate in the same region of the electromagnetic spectrum, such as Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. The observed spectral features of the coals changed with increasing coalification. The features occurring at 1910 nm in the SWIR region and 2940 nm in the MWIR region tended to disappear as rank increased; these features arise from OH bonds related to structural water and hence correlate with the moisture content. The CH stretching fundamentals at 3280 nm correspond to the aromatic fraction of the coal, while the spectral region between 3380 nm and 3500 nm corresponds to the CH2 and CH3 stretching fundamentals occurring in the aliphatic fraction of the coal. The ratio of the area of the aromatic absorption feature to that of the aliphatic absorption features, herein called Rank Spectral Index, displayed a strong linear correlation with coal rank parameters, such as vitrinite reflectance. Other spectral features in the SWIR and MWIR regions also correlated with coal rank parameters. In addition to rank, trends in the magnitudes of the spectral features were influenced by maceral composition, particularly in low rank samples with abundant liptinite or inertinite group macerals. The variable spectral features related to composition were mapped onto the slabbed core surface, discriminating bright and dull bands and fusain lenses enabling the classification of coal lithotypes, regardless of rank. Among the less banded lithotypes, it was established that high liptinite content coals can be distinguished by their aliphatic spectral features in core samples. Overall, this study has shown that hyperspectral drill core scanners can be used to characterise coal and non-destructively classify rank and lithotype.

ZnO Nanorod-Immobilized Pt Single-Atoms as an Ultrasensitive Sensor for Triethylamine Detection.

Triethylamine (TEA) is a flammable and highly toxic gas, and the fast, accurate, and sensitive detection of gas TEA remains greatly challenging. Herein, we report a ZnO nanorod anchored with a single-atom Pt catalyst (Pt1/ZnO) as a gas sensor for TEA detection. The sensor shows high selectivity and high response to gas TEA with a response value of 4170 at 200 °C, which is 92 times higher than that of pure ZnO. Moreover, the Pt1/ZnO sensor has very short response and recovery times of only 34 and 76 s, respectively, and also has a high response to ppb-level TEA gas (100 ppb-21.6). The gas-sensing enhancement mechanism of the Pt1/ZnO sensor to gas TEA was systematically investigated using band structure analysis, in situ diffuse reflectance infrared Fourier transformation spectroscopy, and density functional theory calculations. The results show that the oxygen vacancies on Pt1/ZnO can effectively activate the adsorbed oxygen. Moreover, chemical bonds can be formed between Pt single atoms and N atoms in TEA to achieve effective adsorption and activation of TEA molecules, facilitating the reaction between TEA and the adsorbed oxygen on Pt1/ZnO, and thereby obtaining high gas-sensing performance. This work highlights the crucial role of Pt single-atom in improving the sensing performance for gas TEA detection, paving the way for developing more advanced gas sensors.

Historical Silk: A Novel Method to Evaluate Degumming with Non-Invasive Infrared Spectroscopy and Spectral Deconvolution.

To correctly manage a collection of historical silks, it is important to detect if the yarn has been originally subjected to degumming. This process is generally applied to eliminate sericin; the obtained fiber is named soft silk, in contrast with hard silk which is unprocessed. The distinction between hard and soft silk gives both historical information and useful indications for informed conservation. With this aim, 32 samples of silk textiles from traditional Japanese samurai armors (15th-20th century) were characterized in a non-invasive way. ATR-FTIR spectroscopy has been previously used to detect hard silk, but data interpretation is challenging. To overcome this difficulty, an innovative analytical protocol based on external reflection FTIR (ER-FTIR) spectroscopy was employed, coupled with spectral deconvolution and multivariate data analysis. The ER-FTIR technique is rapid, portable, and widely employed in the cultural heritage field, but rarely applied to the study of textiles. The ER-FTIR band assignment for silk was discussed for the first time. Then, the evaluation of the OH stretching signals allowed for a reliable distinction between hard and soft silk. Such an innovative point of view, which exploits a "weakness" of FTIR spectroscopy-the strong absorption from water molecules-to indirectly obtain the results, can have industrial applications too.

Quantitative analysis of low content polymorphic impurities in canagliflozin tablets by PXRD, NIR, ATR-FITR and Raman solid-state analysis techniques combined with stoichiometry

Canagliflozin (CFZ) was a commercially new class of anti-diabetic drug, which had various anhydrate crystal forms and two hydrate crystal forms (Canagliflozin hemihydrate (Hemi-CFZ) and Canagliflozin monohydrate (Mono-CFZ) crystal form). Commercially available CFZ tablets’ active pharmaceutical ingredient (API) was Hemi-CFZ, which was easy conversion to CFZ or Mono-CFZ under the influence of temperature, pressure, humidity and other factors in tablets processing, storage, and transportation, thus affected bioavailability and efficacy of tablets. Therefore, quantitative analysis low content of CFZ and Mono-CFZ in tablets was essential to control tablets’ quality. The main objective of this study was to examine the feasibility of Powder X-ray Diffraction (PXRD), Near Infrared Spectroscopy (NIR), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Raman for quantitative analysis the low content of CFZ or Mono-CFZ in ternary mixtures. PLSR calibration models for low content of CFZ and Mono-CFZ were established by the solid analysis techniques of PXRD, NIR, ATR-FTIR and Raman combined with various pretreatments (such as Multiplicative Scatter Correction (MSC), Standard Normal Variate (SNV), Savitzky-Golay First Derivative (SG1st), Savitzky-Golay Second Derivative (SG2nd) and Wavelet Transform (WT)), and the correction models were verified. However, compared with PXRD, ATR-FTIR and Raman, NIR due to its water sensitivity was the most suitable for the quantitative analysis low content of CFZ or Mono-CFZ in tablets. Partial Least Squares Regression (PLSR) model for quantitative analysis low content of CFZ in tablets was as follow: Y = 0.0480 + 0.9928 X, R2 = 0.9986, LOD = 0.1596 %, LOQ = 0.4838 %, SG1st + WT pretreated. And that of Mono-CFZ were Y = 0.0050 + 0.9996 X, R2 = 0.9996, LOD = 0.0164 %, LOQ = 0.0498 %, MSC + WT pretreated and Y = 0.0051 + 0.9996 X, R2 = 0.9996, LOD = 0.0167 %, LOQ = 0.0505 %, SNV + WT pretreated, respectively. That can be used for quantitative analysis of impurity crystal content in drug production to ensure drug quality.

Multi-Analytical Characterization of Stone Relics from Meili Section of the Ancient Tea Horse Road in Yunnan, China

The stone relics in the Meili section of the ancient Tea Horse Road in Yunnan, China, are important for Sino-Tibetan cultural heritage. However, these relics were exposed to the risk of hydraulic erosion due to the construction of a hydroelectric power station, and thus protecting these relics is now imperative. Preliminary investigations and analyses of stone relics are crucial for their subsequent conservation and restoration. Thus, in this study, multi-analytical characterization including the microstructure, mineralogical characteristics, elements, and chemical compositions of the stone relics was conducted using optical microscopy (OM), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), polarized light microscopy, x-ray diffraction (XRD), and attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR). In addition, the contaminants and pigments on the surfaces of the stone relics were identified and analyzed by Raman spectroscopy. OM, SEM and Raman spectroscopy indicated that the surface contaminants mainly comprised of moss and soil dust, and some of the stone relics exhibited porosity and weathering. Polarized light microscopy revealed that the mineralogical morphology of stone samples mainly appeared as allotriomorphic, hypidiomorphic, and colloform structures. ATR-FTIR, and XRD confirmed that the stone relics mainly consisted of quartz, muscovite, illite, and chlorite. In addition, Raman spectroscopic analysis showed that the pigments on the relic surfaces included chalk, barium white, langite, green earth, amorphous carbon black, chrome red, and chrome yellow. The findings of this study may provide scientific support for the conservation of the stone relics.

Modification of Cotton and Leather Surfaces Using Cold Atmospheric Pressure Plasma and TiO2-SiO2-Reduced Graphene Oxide Nanopowders

Surface modification of textile fabrics and leathers is very versatile and allows the products quality improvement. In this work, cotton and leather substrates were pre-treated with cold atmospheric pressure plasma (CAPP) and further coated with TiO2-SiO2-reduced graphene oxide composites in dispersion form. By using a Taguchi scheme, this research evaluated the effect of three significant parameters, i.e., the pre-treatment with CAPP, organic dispersion coating and TiO2-SiO2-reduced graphene oxide (TS/GR) composites, that may affect the morpho-structural properties and photocatalytic activity of modified cotton and leather surfaces. The characteristics of cotton/leather surfaces were evaluated by morphological, structural, optical and self-cleaning ability using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray powder diffraction (XRD), attenuated total reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR) and UV-Vis spectroscopy. The self-cleaning performance of the obtained cotton and leather samples was evaluated by photocatalytic discoloration of berry juice surface stains under UV light irradiation for 12 h. The successfulness of coating formulations was proven by the SEM analysis and UV-Vis spectroscopy. The XRD patterns and ATR-FTIR spectra revealed the cellulose and collagen structures as dominant components of cotton and leather substrates. The CAPP treatment did not damage the cotton and leather structures. The photocatalytic results highlighted the potential of TiO2-SiO2-reduced graphene oxide composites in organic dispersion media, as coating formulations, for further use in the fabrication of innovative self-cleaning photocatalytic cotton and leather products.