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In situ FTIR reactor for monitoring gas phase products during a (photo)catalytic reaction in the liquid phase
摘要： Various catalytic and photocatalytic reactions in the liquid phase give rise to gas products. Therefore, the identification and quantification of these products are of high importance and even essential for some reactions. In this communication, a new in situ FTIR reactor is designed and used for analyzing the gas headspace of a (photo)catalytic reaction in solution. It allows the identification and quantification of the gas products of a liquid reaction under operating conditions and in real time. The new reactor has been tested in three representative photocatalytic reactions widely studied as model reactions in the liquid phase, i.e., i) decomposition of formic acid, ii) oxidation of Methylene Blue and iii) reduction of CO2. The validity of the results has been confirmed by analyzing the headspace at the end of the reaction using GC. The new reactor opens the possibility to follow on-line the (photo)catalyst activity. This is useful for ensuring the stability of the catalyst and studying the evolution of the selectivity during the reaction. The non-destructive behavior of the FTIR technique allows its coupling with other techniques for obtaining complementary results. The new reactor setup is easy to handle, to ship, and is very efficient which make it very suitable for performing fast and/or preliminary studies.
关键词： gas phase products,photocatalytic reaction,liquid phase,real-time analysis,FTIR reactor
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Synthesis and characterization of TiO2 co-polymeric hydrogel
摘要： In this study, TiO2 doped acrylic acid-co-vinyl pyrrolidone (AA-co-VP) composite co-polymeric hydrogel was synthesized by free radical polymerization technique. Titanium dioxide (TiO2) were chosen because of its superior properties such as high activity, chemical stability, low cost, non-toxicity, and stability during irradiation. TiO2 doping were carried out by varying mass ratios as 0.05%, 0.5% and 1%. Conversion, cross-linking and swelling values of each hydrogel were calculated. According to swelling behavior, while TiO2 dope ratio increase, swelling value was also increased. Chemical, morphological and thermal properties of hydrogels were specified by using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), mapping and thermogravimetric analysis (TGA-DSC) techniques. TiO2 doping provides superior properties to co-polymeric hydrogel. Hydrogels have also characteristic properties of both acrylic acid and vinyl pyrrolidone.
关键词： SEM-EDX,hydrogel,TGA-DSC,free radical polymerization,acrylic acid-co-vinyl pyrrolidone,FTIR,TiO2,swelling behavior
更新于2025-09-09 09:28:46
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Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46
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Insight into Rapid DNA-Specific Identification of Animal Origin Based on FTIR Analysis: A Case Study
摘要： In this study, a methodology has been proposed to identify the origin of animal DNA, employing high throughput extension accessory Fourier transform infrared (HT-FTIR) spectroscopy coupled with chemometrics. Important discriminatory characteristics were identified in the FTIR spectral peaks of 51 standard DNA samples (25 from bovine and 26 from fish origins), including 1710, 1659, 1608, 1531, 1404, 1375, 1248, 1091, 1060, and 966 cm?1. In particular, the bands at 1708 and 1668 cm?1 were higher in fish DNA than in bovine DNA, while the reverse was true for the band at 1530 cm?1 was shown the opposite result. It was also found that the PO2? Vas/Vs ratio (1238/1094 cm?1) was significantly higher (p < 0.05) in bovine DNA than in fish DNA. These discriminatory characteristics were further revealed to be closely related to the base content and base sequences of different samples. Multivariate analyses, such as principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were conducted, and both the sensitivity and specificity values of PLS-DA model were one. This methodology has been further validated by 20 meat tissue samples (4 from bovine, 5 from ovine, 5 from porcine, and 6 from fish origins), and these were successfully differentiated. This case study demonstrated that FTIR spectroscopy coupled with PLS-DA discriminant model could provide a rapid, sensitive, and reliable approach for the identification of DNA of animal origin. This methodology could be widely applied in food, feed, forensic science, and archaeology studies.
关键词： animal origin,PLS-DA,DNA,rapid identification,FTIR spectroscopy
更新于2025-09-09 09:28:46
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Optical and Morphological properties of environmentally benign Cu-Tin Sulphide Thin films grown by Physical Vapor Deposition Technique
摘要： Present work has set about the synthesis of Tin-Diethyl dithiocarbamate Sn (S2CN (Et) 2) n]) and Copper diethyldithiocarbamate Cu (S2CN(Et)2) complex by utilizing single source method. Sn (S2CN (Et) 2) n]) complex are further used for deposition of Tin Sulphide thin films via Physical Vapor deposition with varying concentration of copper acting as dopant specie. The fabricated doped and un-doped films were confronted to functional group detection (FTIR), optical (Uv-Vis), structural (XRD) and morphological (SEM, EDX) analysis to retrieve the hidden information. FTIR peaks of Copper and Tin complex confirmed the formation of dithiocarbamate complexes by enumerating the stretching and bending vibrational modes of bonding and metal Sulphur linkage. X-ray diffraction elucidate the predominant phase of SnS with 1:1 ratio which depicted the fabrication at high temperature. Optical investigation represented the decrease in band gap by 6% extrinsic addition while increase at 10 % doping. The enhancement in band gap is also clear from the increased absorption edge upon 10% addition. Surface morphology of films was heterogeneous along flakes with compaction of spherical particles as demonstrated by SEM. The obtained results of material (SnS) being environmentally benign were therefore discussed to assess its aptness in optoelectronic devices.
关键词： Physical vapor deposition,band gap,doping,Tin Sulphide,FTIR
更新于2025-09-09 09:28:46
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Fourier Transform Infrared Spectroscopy: Applications in Medicine
摘要： Fourier transform infrared spectroscopy (FTIR) is rapidly gaining ground in modern clinical research. This technique is useful for understanding a wide variety of applications ranging from characterization and quality control of various compounds to biomedicine. Importantly, biological materials like proteins, carbohydrates, lipids and nucleic acids have unique structures so it is possible to obtain spectral fingerprints corresponding to their functional groups. FTIR spectroscopic techniques generate an immediate appeal in the field of biology and medicine because of their fast and non-invasive nature. It allows easy visualization of cellular components based on their intrinsic properties and chemical composition. It provides a potential route to screen diagnostic markers for diseases like cancer. FTIR spectroscopy is also considered as a useful tool for analysis of the chemical composition of human calculi. Analysis of stone samples from recurrent stone formers by FTIR may provide a clue to effective prevention of stone recurrence [1]. Fourier transform infrared (FT-IR) spectroscopy has proven to be a fundamental and valuable technique in biology and medicine due to its high sensitivity to detecting changes in the functional groups belonging to tissue components such as lipids, proteins and nucleic acids [2]. Infrared spectra of human and animal tissues could provide information on the molecular structure of tissues. FT-IR has been extensively applied for the determination of a biochemical metabolite in biological fluids. Diagnosis of various types of malignancies such as lung, breast, skin, cervical and colon cancers is already reported in the literature. The spectra are analysed for changes in levels of molecules such as RNA, DNA, phosphates, and carbohydrates. Variation of the RNA/DNA ratio as measured at 1121/1020 cm-1 generally show higher ratio for malignant tissues compared to their non-malignant counterpart. Changes in the spectra of malignant samples were also observed in the symmetric and asymmetric stretching bands of the phosphodiester backbones of nucleic acids, the CH stretching region, the C-O stretching bands of the C-OH groups of carbohydrates and cellular protein residuals, and the pressure dependence of the CH2 stretching mode [3]. The changes in the FTIR spectra correlate to modification of bases and sugars, and redistribution of the H-bond network. The loss/change in the covalent bonds due to damage in the primary, secondary and tertiary structure of nucleic acids can be observed in the spectra. These changes involved the phosphate and C-O stretching bands, the CH stretch region, and the pressure dependence of the CH2 bending and C=O stretching modes. FTIR micro spectroscopy has also been used as a fast diagnostic technique to identify drugs targeting specific molecular pathways causing chronic myeloid leukaemia. Chemometric data analysis was used to assess drug compounds in ex vivo cancer cells [4]. Substantial progress has been made in incorporating advances in computational methods into the system to increase the sensitivity of the entire setup, making it an objective and sensitive technique suitable for automation to suit the demands of the medical community. FTIR spectroscopy provides the possibility of obtaining information on molecular composition and structure at the level of single cell within a time-scale of few seconds-minutes and to perform qualitative and quantitative multi-component analyses. It helps in automated pattern recognition and objective classifications of samples with minimal and label-free sample treatment. The technical improvements will progressively increase the number of potential applications of micro FT-IR to cancer research and clinical diagnosis. It may be hoped that the future pre-clinical and clinical trials will include sample evaluation utilizing this technique in order to obtain data necessary to validate the use of micro FT-IR spectroscopy in a clinical context. In fact, this appears to be the most important way to reduce the high level of skepticism of many biologists and pathologists about an old technology that has been designed and improved mainly for applications in clinical diagnosis including cancer research.
关键词： cancer research,biomedicine,clinical diagnosis,Fourier transform infrared spectroscopy,FTIR,clinical research
更新于2025-09-09 09:28:46
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VO <i> <sub/>n</sub></i> Complexes in RTA Treated Czochralski Silicon Wafers Investigated by FTIR Spectroscopy
摘要： Oxygen-vacancy complexes formed after rapid thermal annealing in silicon wafers were investigated by FTIR spectroscopy at 6 K. It was found that VO4 is the only detectable complex. The concentration of VO4 complexes increases with increasing temperature of RTA treatment in the temperature range between 1250?C and 1400?C. The concentration at maximal temperature is equal to 4.5 × 1013 cm?3. The experimental results were compared with concentrations of VOn complexes in silicon wafers obtained using ab-initio calculations combined with rate equation modelling. The simulated concentration of VO4 corresponds well to the measured concentration. The bulk microdefect density increases with increasing VO4 concentration. The vacancies stored in VOn complexes after RTA are slowly released during further annealing and enhance oxide precipitation.
关键词： VO4 complexes,silicon wafers,Rapid thermal annealing,FTIR spectroscopy,oxygen precipitation
更新于2025-09-09 09:28:46
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Effect of NO2 and NO3-/HNO3 adsorption on no photocatalytic conversion
摘要： A study was undertaken of the adsorption and photocatalytic conversion of NO, NO2 and NO3-/HNO3 using two photocatalysts (P25 and HT-ET). The HT-ET is a catalyst synthesized in our laboratory comprised only of anatase phase and with a surface area three times larger than that of the P25. In powder form, the catalyst was introduced into and extended along the length of a tube with no type of compaction on the part of the solid (pressure drops are negligible under these conditions). This tubular photoreactor arrangement operates as a continuous reactor system enabling FTIR analysis of the surface of the catalysts during the conversion process. NO adsorption was negligible, though the FTIR studies revealed the formation of nitrites on the surface after 18 h of reaction. Overall NO conversion efficiency rates were above 68% with both catalysts in that reaction time. However, selectivity to NO2 was very high with both catalysts. It was also found with both catalysts that the number of NOx moles eliminated during NO photocatalytic conversion coincided with the number of adsorbed NO2 moles observed in the adsorption studies performed with this molecule, indicating that the NO2 molecule is not efficiently converted photocatalytically. It was observed that most of the NO2 undergoes disproportionation on the surface of the catalysts, giving rise to nitrates and NO. The FTIR studies showed that a significant proportion of the NO2 interacts with surface nitrates resulting in [(NO3-)-(H2O) n-NO2] complexes which are stable on the catalyst surface in an NO atmosphere.
关键词： NO2,TiO2,NOx,Photocatalysis,Nitrates,FTIR,NO
更新于2025-09-09 09:28:46
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Bio-hydrometallurgy dynamics of copper sulfide-minerals probed by micro-FTIR mapping and Raman microspectroscopy
摘要： We report the μm-FTIR mapping and Raman microspectroscopic detection of bornite [Cu5FeS4]-, chalcocite [Cu2S]-, and covelitte [CuS]- bacterial interactions by a consortium of microorganisms consisted of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Acidithiobacillus caldus, Leptospirillum ferriphilum, Leptospirillum ferroodiazotrophum and Sulfobacillus thermosul?dooxidans. The absorption signals of amide I, K+-jarosite [KFe3(SO4)2(OH)6] and of the produced extracellular polymeric substances (EPS) from the mixed culture as a function of position on the surfaces of the bioleached bornite, chalcocite and covellite demonstrated their heterogeneity within the surface of the minerals. This reveals the high level of bio?lm, EPS, and jarosite biosynthesis on the surface of the minerals and might explain why they associate. To our knowledge this is the ?rst combined application of μm-FTIR mapping and Raman microspectroscopy for the bioleaching behaviour of bornite, chalcocite and covellite and the comparison with other bioleached systems such as chalcopyrite [CuFeS2] provides valuable information on the whole bio-hydrometallurgy Cu/Fe/S system. Both techniques provide spectrally rich, label-free, nondestructive visualizations of the bio-hydrometallurgy dynamics of copper sul?de minerals for processing and storage of large spectral data sets which are valuable for evaluation of copper containing minerals.
关键词： Micro-FTIR mapping,Copper sul?de minerals,Bio?lm formation,Jarosite biosynthesis,Raman
更新于2025-09-09 09:28:46
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Indonesian Black Tea Classification Using Fourier-Transform Near-Infrared Spectroscopy and a Principal Component Analysis
摘要： Indonesian black tea (Camellia sinensis) is processed based on several standard methods to achieve a certain grade. There are more than 25 grades produced including Dust one (D1), Fanning's (FANN) and Pekoe Fanning's (PF). In general, the physical appearances are similar to each other, which makes it difficult to be differentiated from visual observations by non-experts. During the packaging process, a tea grade can easily be packed using a bag with a different label of the grade. In the global market, such a mistake should be avoided before shipping. Since shipping usually involves a large number of bags, then rapid, accurate, and nondestructive methods are critical. This paper discusses a method for classifying tea grades rapidly, accurately and nondestructively using Fourier-transform near-infrared spectroscopy (FT-NIRS) and a principal component analysis (PCA). Sixty-nine tea samples from grade Dust one (D1), Fanning's (FANN) and Pekoe Fanning's (PF) were separated into two groups; 46 samples were used for the training sets and 30 samples for the validation sets. The analysis successfully differentiated that of 3 different grades, indicating that the method is a potential alternative for tea classification in quality control processes.
关键词： principal,FTIR,Indonesian black tea,quality control
更新于2025-09-09 09:28:46