Study by thermal methods on the materials obtained by dye removal from waste waters with beech flour

The study is devoted to the characterization by both TG-DTG analysis and FTIR spectroscopy of beech flour, dyes and the sorbent-dyes products obtained through retention of the dyes from aqueous solution on the beech flour, to the aim of obtaining information on the nature of dyes’ retention, thermal behavior of the sorbent-dye materials as well as on their possible upgrading as fuel. Thermal analysis led to the conclusion that the mechanism of thermo-oxidative degradation is specific and the retention of dyes occurs on cellulose from beech flour. The nature of the bonds involved in dyes’ retention is also investigated by FTIR analysis, which evidences that dyes retention on cellulose is realized through hydrogen bonding between the NH and, respectively, OH groups from dye molecule and the oxygen atoms from cellulose. Involvement of the non-participating electrons of the nitrogen and, respectively, oxygen atoms of these groups in the extended electronic conjugation with aromatic nuclei strongly influences the capacity of the amino and, respectively, hydroxyl groups of forming hydrogen bonds, thus achieving dyes fixation on the sorbent. DTA analysis led to the conclusion that an improvement in the quality of the sorbent-dye materials as fuels is possible, as compared to untreated beach flour, as a result of the modification of the cellulosic fibers in the process of dyes retention.     

红外光谱法研究苯胺和环氧丙烷的共聚机理及共聚物的表征

采用原位红外光谱技术对苯胺和环氧丙烷的电化学共聚机理进行了研究, 研究结果表明, 环氧丙烷能在苯胺及其低聚物阳离子自由基的催化作用下发生α位开环, 与苯胺发生电化学共聚, 生成了含有芳香-脂肪醚结构的共聚物. 采用显微红外成像技术研究苯胺和环氧丙烷共聚物在电极表面的生长特点发现, 该共聚物能在电极表面从中间向两侧有规律地生长.     

Biohydrolysis of nylon 6,6 fiber with different proteolytic enzymes

In recent years, the textile industry must go towards sustainable technologies and developing environmentally safer methods for textiles processing. One way is the processing with enzymatic system, rather than conventional chemical methods. The aim of this work was to investigate the changes induced on nylon 6,6 fiber by enzymatic system using different proteolytic enzymes. Technical measurements were studied including Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal, dyeability, and fastness properties. For this purpose, nylon 6,6 fabrics were first treated separately with different concentrations of four protease enzymes. The dyeing process was then carried out on the treated fabrics with two reactive and acid dyes. The intensity of major peaks in FTIR spectra of the protease treated samples is in favor of chemical changes of the polypeptide functional groups in fabric. Thermal studies also show significant decrease in thermal degradation temperature of the treated polymer. Reactive and acid dyes showed higher dyebath exhaustion on the enzyme treated samples compared to raw material. The results of color measurements showed that the more concentration of enzyme used, the darker the color of dyed sample is. Interesting results were obtained in the studied topic.     

A simple,rapid, and robust “on-the-go” identity testing of biotherapeutics using FTIR spectroscopy

The stunning rise of biotherapeutics as successful treatments of complex and hard-to-treat diseases, in particular cancer, has necessitated the development of a rapid analytical method capable of differentiating these otherwise significantly similar antibody-based products. The existing methods for product identification pose significant drawbacks in terms of the consumption of time and labor. Here, we present an FTIR spectroscopy-based simple, rapid, and robust method that is capable of differentiating between the biotherapeutics (both innovator products and biosimilars). The proposed approach uses partial least-squares-discriminant analysis to pinpoint subtle differences in the FTIR spectra of the samples, enabling us to not only identify the product but also calculate its concentration. This FTIR-based method can be used to fulfill the identity testing requirement of a pharmaceutical drug in its final packaged form set by the US Food and Drug Administration. Along with this, identity testing can also be deployed at multiple steps in the manufacturing process and can also be used by the appropriate regulatory or government agency for tackling counterfeits of biotherapeutic products.     

Application of an HPLC-FTIR modified thermospray interface for analysis of dye samples.

Previously, we developed a reversed-phase HPLC method compatible to high performance liquid chromatography diffuse reflectance Fourier-transform infrared (HPLC-FTIR) thermospray interface for the analysis of dyes. Dye separation achieved with a mixed-mode (SCX-ODS) column using a small gradient (90 to 80% water with acetic acid) and pH 3.25; 10 to 20% acetonitrile was considered to be suitable for HPLC-FTIR. A constant-voltage setting for the thermospray temperature (227 degrees C) was successfully used for this gradient condition. The HPLC-separated components deposited as a series of concentrated spots on a moving tape were scanned by specially developed HPLC-FTIR software. Excellent repeatability of the thermospray deposition FTIR chromatograms and IR spectra was obtained. The interface-derived spectra of the separated components of formulated and purified reactive dyes were compared and differences in spectral features were observed.     

抚顺烟煤及其抽出物的FTIR光谱结构表征

用富立叶变换红外光谱(FTIR)对抚顺烟煤的有机组分进行了测定。通过对谱图的解析,指出抚顺烟煤及其吡啶抽出物和抽提残煤在结构上的异同。以及抽出物各色谱馏分中存在的官能团和官能团之间极性的差异,对原煤整体结构提供了精细的结构信息。     

Application of FTIR imaging to detect dietary induced biochemical changes in brown and white adipocytes

Fourier Transform Infrared microspectroscopy Imaging (FTIR imaging) has powerful advantages when used as a complementary technique to histopathological investigations. The common histopathological investigations use a number of chemical fixatives and deparaffinizing agents that alter lipid profiles of biological tissues, particularly in lipid-rich adipose tissues. An infrared image is made of a multitude of pixels. For each pixel, identified by its (x,y) coordinates, corresponds an FTIR spectrum that reveals the chemical composition at this specific location. As a result, it allows biochemical analysis in selective locations within samples. Moreover, functional group distribution maps can be used as a staining free technique for spatial characterization of different biomolecules. Though FTIR imaging has been reported as a powerful approach to characterize adipose tissues, the biochemical heterogeneity within adipose tissues has not been acknowledged. This study shows relative changes in brown and white adipose tissues of mice due to consumption of high-fat diet. In particular, we report cryosectioning of adipose tissues, image acquisition, and different image analysis methods to evaluate dietary induced changes in lipids stored in brown and white adipocytes. Since biochemical changes in adipocytes constitute an important component in obesity investigations, this study shows the potential use of FTIR imaging to compare relative biochemical changes associated with dietary interventions.     

Review of FTIR microspectroscopy applications to investigate biochemical changes in C. elegans

Caenorhabditis elegans nematode has emerged as a model organism paving the ways for multidisciplinary research in biomedical, environmental toxicology, aging, metabolism, obesity, and drug discovery. The wide range of applications of this model organism are attributed to C. elegans’ unique features: C. elegans are inexpensive, easy to grow and maintain in a laboratory, has a short lifespan, and has a small body size. With this increased interest, the need for analytical techniques to assess the biochemical information on intact worms continues to grow. Fourier Transform Infrared (FTIR) microspectroscopy is considered as a powerful technique that can be used to determine the chemical structure and composition of various materials, including biological samples. Furthermore, the development of focal plane array detectors has made this technique attractive to study complex biological systems such as whole nematodes. This review focuses on the use of FTIR microspectroscopy to study C. elegans. The first published work on the use of FTIR microspectroscopy to study a complex whole animal was reported in 2004. Since then, very few other studies were carried out. The objective of this review is to summarize work conducted to date using FTIR microspectroscopy to study nematodes and to discuss the information that can be gained by using this technique. This could allow scientists to add this technique to the arsenal of techniques already in use for C. elegans studies.     

Real time observation of microwave-enhanced reactions via fast FTIR spectroscopy

Microwave-enhanced reactions are very fast in comparison to thermal reactions. The determination of optimal end point often fails because conventional analytical methods are too slow. Therefore, we established a fast method using FTIR spectroscopy. The result of the reaction control analysis is obtained within less than 1 min.     

人参种类鉴别的傅里叶变换红外光谱法

用傅里叶变换红外光谱法对白参、高丽参、西洋参、红参、野山参等不同种类的人参进行了鉴别；结果表明，不同种类的人参都具有类同的人参皂苷吸收峰，根据红外指数I值、特定位置的吸收峰峰形以及峰位偏移情况可以很好地鉴别人参的种类；该法简便、实用、可靠。     

Infrared detection in flow analysis - developments and trends (review)

Flow analysis offers an inexpensive and versatile means for the automation of analytical procedures and hence it has been incorporated in many different techniques. However, the use of infrared detection in flow analysis systems is not common. Whereas Fourier transform infrared (FTIR) spectroscopic detection has been routinely used in gas chromatography (GC), its use for liquid chromatography, and now for flow analysis, flow injection analysis, or sequential injection analysis, is not frequent. The most prominent reasons are probably: (i) the strong absorption of most of the common solvents, specially water, (ii) the relative poor sensibility compared to UV–vis, fluorescence, etc. (iii) FTIR is normally not even considered a valuable detection technique, (iv) problems arising from obtaining adequate information from transient IR signals from the injected samples, and (v) only a few analytical chemist uses routinely the FTIR technique. This practice neglects that IR spectroscopy offers some unique features that now, using modern FTIR instrumentation, can be exploited in an advantageous manner. It is important to realize that each sample (analyte/matrix) represents a special and unique analytical problem; which defines the mode of operation and implementation of the IR technique. Flow analysis–IR techniques – as well as all techniques – has a number of shortcomings to solve these problems. In this article, most of these strategies such as the use of: baseline correction, derivative spectroscopy, stopped flow systems, reverse flow systems, multiparametric calibrations, etc., will be discussed. Additionally, recent developments in on-line gas phase generation–FTIR and hydride generation–FTIR spectrometry, as well as the principles of the HPLC–FTIR and capillary electrophoresis–FTIR hyphenation are also discussed. This review aims to provide an account of the state of the art, of these relatively new techniques. Its beginning, developments, applications and new trends, basically in the MID–IR, and by using transmission cells.     

Influence of temperature on FTIR spectra of various organic compounds analyzed by on-line carbon dioxide SFC/FTIR

The development of an on-line SFC-FTIR method with supercritical carbon dioxide as mobile phase requires information about the nature of the FTIR spectrum of a solute dissolved in supercritical or liquid CO₂. The wavenumber of maximum absorbance of the carbonyl stretching vibration was quantitatively studied versus temperature and CO₂ density. FTIR spectra recorded in supercritical or liquid CO₂ have been compared to their vapor-phase and condensed-phase spectra for various solutes.     

An automated FTIR method for the routine quantitative determination of moisture in lubricants: An alternative to Karl Fischer titration

An accurate primary Fourier transform infrared (FTIR) method for the determination of moisture in mineral and ester based lubricants has been developed based on the extraction of moisture into dry acetonitrile. FTIR evaluation of acetonitrile extracts from new and used lubricants as well as common lubricant additives and contaminants which might co-extract indicated that phenolic constituents interfered significantly with moisture measurements. By measuring moisture at 3676 cm⁻¹ on the shoulder of the asymmetric OH stretching band, spectral interferences from extracted phenolic constituents were minimized. The spectra of calibration standards (0-2100 ppm), prepared by gravimetric addition of water to dry acetonitrile, were recorded in a 1000-μm CaF₂ transmission flow cell and produced linear standard curves having an S.D. of ∼±20 ppm. Lubricant sample preparation involved the vigorous shaking (20 min) of a 1:1.5 (w/v) mixture of lubricant and dry acetonitrile, centrifugation to separate the phases, acquisition of the FTIR spectrum of the upper acetonitrile layer, and subtraction of the spectrum of the dry acetonitrile used for extraction. A Continuous Oil Analyzer and Treatment (COAT^®) FTIR system was programmed to allow the automated analysis of acetonitrile extracts, and the methodology was validated by analyzing 58 new and used oils, independently analyzed by the Karl Fischer (KF) method. Linear regression of FTIR versus KF results for these oils produced a linear plot with a between-method S.D. of ±80 ppm. As implemented on the COAT^® system, this FTIR method is capable of analyzing 72 acetonitrile extracts/h and provides a high-speed alternative to the KF titrimetric procedures for the determination of water in lubricants.     

On the Protein Fibrillation Pathway: Oligomer Intermediates Detection Using ATR-FTIR Spectroscopy

Oligomeric intermediates on the pathway of amyloid fibrillation are suspected as the main cytotoxins responsible for amyloid-related pathogenicity. As they appear to be a part of the lag phase of amyloid fibrillation when analyzed using standard methods such as Thioflavin T (ThT) fluorescence, a more sensitive method is needed for their detection. Here we apply Fourier transform infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode for fast and cheap analysis of destabilized hen-egg-white lysozyme solution and detection of oligomer intermediates of amyloid fibrillation. Standard methods of protein aggregation analysis— Thioflavin T (ThT) fluorescence, atomic force microscopy (AFM), and 8-anilinonaphthalene-1-sulphonic acid (ANS) fluorescence were applied and compared to FTIR spectroscopy data. Results show the great potential of FTIR for both, qualitative and quantitative monitoring of oligomer formation based on the secondary structure changes. While oligomer intermediates do not induce significant changes in ThT fluorescence, their secondary structure changes were very prominent. Normalization of specific Amide I region peak intensities by using Amide II peak intensity as an internal standard provides an opportunity to use FTIR spectroscopy for both qualitative and quantitative analysis of biological samples and detection of potentially toxic oligomers, as well as for screening of efficiency of fibrillation procedures.     

Towards the identification of plant and animal binders on Australian stone knives

There is limited information regarding the nature of plant and animal residues used as adhesives, fixatives and pigments found on Australian Aboriginal artefacts. This paper reports the use of FTIR in combination with the chemometric tools principal component analysis (PCA) and hierarchical clustering (HC) for the analysis and identification of Australian plant and animal fixatives on Australian stone artefacts. Ten different plant and animal residues were able to be discriminated from each other at a species level by combining FTIR spectroscopy with the chemometric data analysis methods, principal component analysis (PCA) and hierarchical clustering (HC). Application of this method to residues from three broken stone knives from the collections of the South Australian Museum indicated that two of the handles of knives were likely to have contained beeswax as the fixative whilst Spinifex resin was the probable binder on the third.     

Role of coordinated metal ions on the orientation of phthalocyanine based coatings

In the present work, we have investigated the molecular orientation of phthalocyanine films deposited on polycrystalline gold. Three films built from the following molecules are investigated: phthalocyanine (H(2)Pc), cobalt phthalocyanine (CoPc) and copper phthalocyanine (CuPc). The films are prepared by spin coating and drop casting methods. Orientation analysis has been performed using polarization dependent Fourier transform infrared (FTIR) spectroscopy using transmission and grazing angle reflectance mode. The FTIR study suggests that each phthalocyanine film contains both alpha- and beta-phases. H(2)Pc based films demonstrate deposition method dependence on the molecular orientation, while the CuPc and CoPc films preserve their molecular orientation independent of deposition method. Grazing angle analysis also suggests that CoPc films show negligible preferred orientation irrespective of film deposition methods. In literature, the band at 878cm(-1) in CuPc has been assigned to out-of-plane bending of C-H. Our grazing angle experiments suggest that this band cannot be assigned to out-of-plane bending vibrations of C-H. Accurate band assignments are also described here for the phthalocyanine system.     

分析测试新成果(238~242)电线塑料护套的傅立叶变换红外光谱分析

采用傅立叶变换红外光谱法对21个5种不同颜色的电线塑料护套样品进行了分析.从红外光谱图中可观察到样品特征峰的峰数、峰位、相对峰面积比均有差异,但可以归纳为两大类.其中同种颜色的不同样品在红外谱图中又反映出了不同的信息,这表明在外观颜色十分相近的情况下,采用此方法能够有效的为刑事案件现场遗留的各种塑料制品提供鉴别与比对.     

傅里叶变换红外光谱结合模式识别法快速鉴别食用油的真伪

采用傅里叶变换红外光谱(FTIR)结合簇类独立软模式识别技术(SIMCA)建立了真伪食用油的快速鉴别方法. 该方法依据FTIR 的指纹特性, 收集并分析了53 个合格食用油和13 个伪造食用油的FTIR 谱图; 通过对谱图取二阶导数和标准化处理, 主成分分析(PCA)提取特征变量; 采用SIMCA 方法分别随机选取43 个合格食用油和9 个伪食用油样品的FTIR 谱图组成训练集, 构建得到真伪食用油的SIMCA 分类模型. 该模型经过剩余10 个合格食用油和4 个伪食用油的验证, 正确识别率达到了100%. 说明FTIR 结合SIMCA 可能成为快速鉴别食用油真伪的一种新方法.     

Reactive Dyeing of Electrospun Cellulose Nanofibers by Pad-steam Method

Based on the functional properties of electrospun cellulose nanofibers(CNF), scientists are showing substantial interest to enhance the aesthetic properties. However, the lower color yield has remained a big challenge due to the higher surface area of nanofibers. In this study, we attempted to improve the color yield properties of CNF by the pad-steam dyeing method. Neat CNF was obtained by deacetylation of electrospun cellulose acetate(CA) nanofibers. Three different kinds of reactive dyes were used and pad-steam dyeing parameters were optimized. SEM images revealed smooth morphology with an increase in the average diameter of nanofibers. FTIR results showed no change in the chemical structure after dyeing of CNF. Color fastness results demonstrated excellent ratings for reactive dyes, which indicate good dye fixation properties and no color loss during the washing process. The results confirm that the pad-steam dyeing method can be potentially considered to improve the aesthetic properties of CNF, which can be utilized for functional garments, such as breathable raincoats and disposable face masks.     

Estimation of the Number of Scans Required per Hard-to-Clean Location and Establishing the Limit of Quantification of a Partial Least Squares Calibration Model When the FTIR Is Used for Pharmaceutical Cleaning Verification

This study aims to identify two critical components required for pharmaceutical cleaning verification when an FTIR is used: (a) the number of scans required per hard-to-clean location, and (b) the limit of quantification (LOQ) of the FTIR instrument when measuring the surface contamination. The current practice in pharmaceutical manufacturing does not require multiple samples as it is standard practice to collect a single swab sample from a 25 × 25 cm area from a difficult-to-reach area of the manufacturing equipment. However, since the FTIR will only scan a tiny portion of the surface compared to the swab, a sufficient number of samples (data points) are required to provide enough confidence to ensure that the measurement results are close to the true value with a maximum degree of certainty. Similarly, calculating the LOQ for a linear regression could be straightforward. However, complexity arises when the experimental data are complex; in this case, the complexity arises due to the nature of the measurement and the lack of the defined peak in the pre-processed spectra. Therefore, this study uses the practical approach of calculating the sample size and the LOQ.