Use Of Fourier Transform Infrared Spectroscopy Research Articles

Sweet or bitter? Preliminary data on the biomechanics, physiology, and possible nutritional quality of Cretaceous gymnosperms leaves (Patagonia, Argentina)

This study provides the first data on the relationship between chemical composition and biomechanical/physiological characteristics of foliar gymnosperm compressions from the Lower Cretaceous of Santa Cruz, Argentina. Studied taxa include: Squamastrobus tigrensis, Pseudoctenis ornata, Ginkgoites tigrensis, Ruflorinia orlandoi, and Ptilophyllum micropapillosum. The properties determined include: density, tensile strength (resistance to fracture), tensile modulus of elasticity (stiffness), and leaf mass per area (metabolic cost of tissue construction). They are calculated using a 3D-multivariate model based on data obtained by Fourier transform infrared (FTIR) spectroscopy and trait relationships linking density and the properties mentioned above. Samples have a predominantly aromatic chemical composition with variable carbonyl contents. The chemical groups detected are associated with diagenetically-resistant molecules, possibly including lignins, phenylpropanoids, tannins, and resin-like compounds. The results indicate that these plant taxa may have allocated variable amounts of resources (metabolic costs) for the development of aromatic, biomechanically resistant, and relatively long-lived foliar tissues. The determined chemical, biomechanical, and physiological properties of these leaves suggest their potential as a food source for herbivores. Thus, S. tigrensis leaves might have been unpleasantly astringent, difficult to eat and digest due to their hard tissues, and possibly even hazardous. Conversely, the leaves of G. tigrensis, P. ornata, R. orlandoi, and P. micropapillosum may have been easy to eat due to their softer tissues, offering food of intermediate-high nutritional value. The use of FTIR spectroscopy proves useful to perform detailed and realistic studies on the biomechanics, physiology, and autecology of extinct plants.

Vibrational spectroscopy coupled with machine learning sheds light on the cellular effects induced by rationally designed TLR4 agonists

In this work, we present the potential of Fourier transform infrared (FTIR) microspectroscopy to compare on whole cells, in an unbiased and untargeted way, the capacity of bacterial lipopolysaccharide (LPS) and two rationally designed molecules (FP20 and FP20Rha) to activate molecular circuits of innate immunity. These compounds are important drug hits in the development of vaccine adjuvants and tumor immunotherapeutics. The biological assays indicated that FP20Rha was more potent than FP20 in inducing cytokine production in cells and in stimulating IgG antibody production post-vaccination in mice. Accordingly, the overall significant IR spectral changes induced by the treatment with LPS and FP20Rha were similar, lipids and glycans signals being the most diagnostic, while the effect of the less potent molecule FP20 on cells resulted to be closer to control untreated cells. We propose here the use of FTIR spectroscopy supported by artificial intelligence (AI) to achieve a more holistic understanding of the cell response to new drug candidates while screening them in cells.

FTIR spectroscopy for assessment of hair from lung cancer patients and its application in monitoring the chemotherapy treatment effect

Lung cancer is the most common cancer and the leading cause of death in China. The current gold standard for clinical lung cancer diagnosis is based on histopathological examination of tumors, but it has the limitation for easy operation and convenient applications. Therefore, researchers are still striving to develop other tools and methods for non-invasive and rapid assessment of the health conditions of lung cancer patients. Hair, as a reflection of the metabolism of the body, is closely related to human health conditions. In principle, Fourier-transform infrared (FTIR) spectroscopy can probe the major chemical compositions in the hair. However, as indicated by previous studies, there is still the challenge to make good use of FTIR spectroscopy for achieving reliable analysis of hair from cancer patients. In this study, hair samples from 82 lung cancer patients were collected and subjected to FTIR measurements and analysis, which showed the protein content in the hair is closely related to the protein content in the blood serum of patients, and the contents of protein and lipid are statistically lower in the lung cancer patients. Furthermore, we demonstrated that FTIR spectroscopy could be employed to monitor the hair of lung cancer patients undergoing chemotherapy, and confirmed that the FTIR spectra of the hair may reflect the resultant effect of the chemotherapy. As such, this work validates the way of using FTIR spectroscopy in hair analysis for the assistance of medical diagnosis of lung cancer as well as monitoring the conditions of the patients under the medical treatment.

Pilot study on FT-IR and GC analysis of inhalant substances (thinners and glues) for forensic purpose

Abuse of chemicals classified as inhalants, particularly volatile, for producing effects resembling those of sedatives and other CNS depressants has repeatedly been recorded from numerous locations across the world. This problem is gaining increased attention every day, just like the abuse of other potent drugs. In general, these substances, including paint thinner, glues, etc., do not carry any legal restrictions; therefore, they pose a noxious attraction for teenagers. Keeping in view the danger of such substances, the present research work was initiated in order to generate a Fourier transform infra-red spectroscopy (FT-IR) and gas chromatography (GC) database of a few frequently available inhalant type substances. Instrumental methods used in this study are common and versatile from a forensic analysis point of view. The use of FT-IR and GC has also clarified the comparative application obligation when samples are pure. The results of this study are novel and futuristically useful in forensic scientific investigation.

Monitoring a metabolic profile of wheat by using FTIR spectroscopy and chemometric methods — concept studies

Changes in plants under the influence of a variety of chemical and physical factors are reflected in metabolomic changes. To date, there are very few methods that would allow studying metabolic changes occurring in single cells. Spectroscopic methods especially combined with the chemometrics methods are a very good tool to investigate such changes in metabolomics. Tracking changes in plants is of particular importance in industry, especially when studying how the use of fertilizers affects plants. In this paper, we present preliminary research asa concept of proof to examine whether the use of FTIR (Fourier transform infrared spectroscopy) helps to monitor the changes in the metabolomic profile of the plants. For preliminary research, four species of cereals and cuckooflower were used. In this step, it was possible to verify the differences in metabolites that are produced by plants belonging to different families. Then one species of grain was selected and subjected to eleven different physical and chemical factors. Next, the research was expanded to determine the optimal concentration of hydrogen peroxide. FTIR spectra of leaves and extracts of the plants were obtained for all experimental groups and then analyzed with the use of chemometric methods: HCA (hierarchical component analysis) and PCA (Principal component analysis). Those methods were used to help in the interpretation of metabolic changes resulting in the plant in response to external factors.

Screening of Native Trichoderma Species for Nickel and Copper Bioremediation Potential Determined by FTIR and XRF

Soil pollution with heavy metals is a serious threat to the environment. However, soils polluted with heavy metals are considered good sources of native metal-resistant Trichoderma strains. Trichoderma spp. are free-living fungi commonly isolated from different ecosystems, establishing endophytic associations with plants. They have important ecological and biotechnological roles due to their production of a wide range of secondary metabolites, thus regulating plant growth and development or inducing resistance to plant pathogens. In this work we used indigenous Trichoderma strains that were previously isolated from different soil types to determine their tolerance to increased copper and nickel concentrations as well as mechanisms of metal removal. The concentrations of bioavailable metal concentrations were determined after extraction with diethylene-triamine pentaacetate (DTPA)-extractable metals (Cd, Cr, Co, Cu, Pb, Mn, Ni, and Zn) from the soil samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). Two indigenous T. harzianum strains were selected for copper tolerance, and three indigenous T. longibrachiatum strains were selected for nickel tolerance tests. Strains were isolated from the soils with the highest and among the lowest DTPA-extractable metal concentrations to determine whether the adaptation to different concentrations of metals affects the mechanisms of remediation. Mechanisms of metal removal were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray fluorescence spectroscopy (XRF), non-destructive methods characterized by high measurement speed with little or no need for sample preparation and very low costs. Increased DTPA-extractable metal content for nickel and copper was detected in the soil samples above the target value (TV), and for nickel above the soil remediation intervention values (SRIVs), for total metal concentrations which were previously determined. The SRIV is a threshold of metal concentrations indicating a serious soil contamination, thus confirming the need for soil remediation. The use of FTIR and XRF methods revealed that the presence of both biosorption and accumulation of metals in the Trichoderma cells, providing good bioremediation potential for Ni and Cu.

Classification of the Residues after High and Low Order Explosions Using Machine Learning Techniques on Fourier Transform Infrared (FTIR) Spectra.

Forensic science is a field that requires precise and reliable methods for the detection and analysis of evidence. One such method is Fourier Transform Infrared (FTIR) spectroscopy, which provides high sensitivity and selectivity in the detection of samples. In this study, the use of FTIR spectroscopy and statistical multivariate analysis to identify high explosive (HE) materials (C-4, TNT, and PETN) in the residues after high- and low-order explosions is demonstrated. Additionally, a detailed description of the data pre-treatment process and the use of various machine learning classification techniques to achieve successful identification is also provided. The best results were obtained with the hybrid LDA-PCA technique, which was implemented using the R environment, a code-driven open-source platform that promotes reproducibility and transparency.

Application of encapsulated and immobilized nano zero-valent iron for iron removal from roof-harvested rainwater

Abstract Rainwater harvesting is a viable option for dealing with the global challenge of increasing water scarcity, but heavy metal contamination often prevents it from being widely used for drinking water purposes. Harvested rainwater collected from galvanized iron (GI) and tile roofs containing iron concentration of 0.46 and 0.38 mg/L respectively, were treated by two nano sorbents, CaCO3-nZVI and PUF/CaCO3-nZVI with the intention of making the iron concentration conform to drinking quality standards. The nano sorbents were synthesized and characterized using BET (Brunauer-–Emmett–Teller surface area), SEM-EDX (Scanning Electron Microscopy-Energy-Dispersive X-ray spectroscopy, and FTIR (Fourier Transform Infrared Spectroscopy). CaCO3-nZVI achieved iron removal efficacy of 88.69% and 89.21% for harvested rainwater from GI sheet roof and tiled roof respectively and the efficiency increased to 95.65% and 95.78% when treated with PUF/CaCO3-nZVI. In addition, the nano sorbents were found to have appreciable removal efficiency for other metals (Pb, Mn, Zn, Cu, Cd and Cr) present in the collected rainwater. The use of FTIR and EDX to characterise spent nano sorbents divulged that the iron was removed through sorption process. This study thus explored the potential of CaCO3-nZVI and PUF/CaCO3-nZVI for treating heavy metal contamination in roof-harvested rainwater.

APTES-Modified Nanocellulose as the Formaldehyde Scavenger for UF Adhesive-Bonded Particleboard and Strawboard.

This work examines the possibility of applying non-modified nanocellulose and nanocellulose functionalized with 3-aminopropyltriethoxysilane (APTES) as a formaldehyde scavenger for commonly used urea-formaldehyde (UF) adhesive. The effect of silanization was determined with the use of Fourier transform infrared spectroscopy (FTIR), flame atomic absorption spectrometry (FAAS), and elemental analysis. Moreover, the ability of cellulosic nanoparticles to absorb the formaldehyde from an aqueous solution was investigated. After homogenization, cured UF adhesives were examined with the use of FTIR, energy-dispersive spectroscopy (SEM-EDS), and the perforator method to determine the content of formaldehyde. Manufactured boards made of rape straw particles and wood particles were tested in terms of their physico-mechanical properties and formaldehyde emission. Studies have shown that the applied method of silanization was effective. Furthermore, in the case of non-modified nanocellulose, no sign of formaldehyde scavenging ability was found. However, the functionalization of cellulosic nanoparticles with APTES containing an amino group led to the significant reduction of formaldehyde content in both the aqueous solution and the UF adhesive. The mechanical properties of both strawboards and particleboards were improved due to the nanocellulose reinforcement; however, no effect of silanization was found. Nevertheless, functionalization with APTES contributed to a decrease in formaldehyde emission from boards, which was not found in the case of the introduction of non-modified cellulosic nanoparticles.

Evaluation of Proteomic and Lipidomic Changes in Aeromonas-Infected Trout Kidney Tissue with the Use of FT-IR Spectroscopy and MALDI Mass Spectrometry Imaging.

Aeromonas species are opportunistic bacteria causing a vast spectrum of human diseases, including skin and soft tissue infections, meningitis, endocarditis, peritonitis, gastroenteritis, and finally hemorrhagic septicemia. The aim of our research was to indicate the molecular alterations in proteins and lipids profiles resulting from Aeromonas sobria and A. salmonicida subsp. salmonicida infection in trout kidney tissue samples. We successfully applied FT-IR (Fourier transform infrared) spectroscopy and MALDI-MSI (matrix-assisted laser desorption/ionization mass spectrometry imaging) to monitor changes in the structure and compositions of lipids, secondary conformation of proteins, and provide useful information concerning disease progression. Our findings indicate that the following spectral bands’ absorbance ratios (spectral biomarkers) can be used to discriminate healthy tissue from pathologically altered tissue, for example, lipids (CH2/CH3), amide I/amide II, amide I/CH2 and amide I/CH3. Spectral data obtained from 10 single measurements of each specimen indicate numerous abnormalities concerning proteins, lipids, and phospholipids induced by Aeromonas infection, suggesting significant disruption of the cell membranes. Moreover, the increase in the content of lysolipids such as lysophosphosphatidylcholine was observed. The results of this study suggest the application of both methods MALDI-MSI and FT-IR as accurate methods for profiling biomolecules and identifying biochemical changes in kidney tissue during the progression of Aeromonas infection.

The use of FTIR spectroscopy combined with pattern recognition and multivariate calibration for rapid authentication of Etawa goat milk from soymilk

Etawa goat milk (EGM) is valuable milk with a higher price compared to other kinds of milk. It is susceptible to being adulterated with low-priced milk for economical reasons. Therefore, the development of an analytical method for rapid authentication of EGM from soymilk (SM) is highly required. Fourier transform infrared (FTIR) spectroscopy combined with chemometrics was evaluated for rapid qualitative and quantitative analysis of SM in raw fresh EGM samples. Samples were prepared by mixing goat milk with soymilk in several concentration levels ranging from 0-100% (v/v). FTIR spectra revealed the differences between authentic and adulterated EGM samples in certain wavenumber regions. Linear discriminant analysis (LDA) at wavenumbers of 3000-750 cm-1 was successfully used for discrimination between authentic and adulterated EGM samples. The Cooman plot showed a clear classification between pure and adulterated goat milk samples. Partial least square (PLS) using wavenumber combination of 3000-2800 cm-1 and 1800-650 cm-1 as well as principal component regression (PCR) using wavenumber of 3000-750 cm-1 has been successfully used for quantification of SM in EGM. However, PLS offered a better model for quantification with higher values of R2 calibration (0.9997) and validation (0.9992) and lower values of RMSEC (0.848) and RMSEP (1.19). It can be concluded that this method is promising for the rapid authentication of goat milk s

Screening suspect pharmaceuticals for illicit designer benzodiazepines using raman, SERS, and FT-IR prior to comprehensive analysis using LC-MS

The emergence of illicit designer benzodiazepines with high dependency and no approved clinical use are of great US public health concern. Due to the increasing numbers of illicit designer benzodiazepines encountered in the US supply chain, there is a need to develop robust analytical methods that can rapidly detect these chemicals. Suspect counterfeit tablets, powders, or liquid formulations were first screened using Raman spectroscopy and surface-enhanced Raman scattering spectroscopy (SERS) for the presence of legal or illicit benzodiazepines, and then further analyzed using Fourier-transform infrared (FT-IR) spectroscopy and liquid chromatography with tandem mass spectrometric detection (LC-MS). Several microextraction procedures were developed and used to extract benzodiazepines from samples prior to SERS, FT-IR, and LC-MS analysis. Conventional Raman analyses using handheld Raman spectrometers afforded the ability to examine samples through enclosed plastic bags but were only able to detect high concentrations of various benzodiazepines in the suspect samples. The developed SERS methods were sufficient for detecting at least one benzodiazepine in the low-dose suspect samples, thereby allowing prioritization using other analytical tools that require more sample preparation and time-consuming analyses. The use of FT-IR spectroscopy coupled with extraction and spectral subtraction was found to be selective to multiple benzodiazepines and various excipients in the analyzed samples. This study demonstrated that the developed SERS and FT-IR procedures could be used in satellite laboratories to screen suspect packages at ports of entry and prioritize samples for additional laboratory-based analyses in an effort to prevent dangerous and illicit pharmaceutical products from reaching the US supply chain.

Simultaneous determination of additive concentration in rubber using ATR-FTIR spectroscopy

Using attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy for direct quantitative analysis is highly desirable for many sample systems due to advantages such as rapid spectra collection and being completely non-destructive. However, for many complex sample matrices the feasibility of direct quantitative analysis using ATR-FTIR is uncertain. The commonly used Beer–Lambert law may not be applicable for many systems in general, besides sample related complexities such as inhomogeneity, variable optical properties, or heavily overlapping absorption bands. In this study, we consider fully formulated vulcanized rubber with carbon black or silica as the primary filler as our system of interest. We developed a method to simultaneously quantify the concentration of three different antidegradents of similar chemical structure directly on rubber samples using ATR-FTIR spectra. Results show that absorbance follows the Beer–Lambert law well for the range of antidegradent concentrations considered. Despite this, a direct application of the Beer–Lambert law to deconvolute overlapping peaks between antidegradents proved insufficient. Through the application of partial least squares (PLS) multivariate analysis, remarkable prediction accuracy of within about 0.15 wt% error for all three antidegradents was achieved for both types of rubber formulations, even with high levels of carbon black. These results show the value this method has for quantitative analysis of additives in rubber. Our investigation highlights the potential usefulness of FTIR spectroscopy in general for rapid quantitative analysis directly on samples of interest without any prior chemical separation.

Identifying traumatic brain injury (TBI) by ATR-FTIR spectroscopy in a mouse model

Traumatic brain injury (TBI) is one of the most common mechanical injuries and plays a significant role in forensic practice. For cadavers, however, accurate diagnosis of TBI becomes a more and more challenging task as the level of decomposition increases. Our main purpose was to investigate whether TBI in putrefied mouse cadavers can be identified by Fourier Transform Infrared (FT-IR). The method proposed by Feeney et al. was used to establish the mouse TBI model. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) modeling were used to distinguish fresh and putrefied brain tissues. Then, we established two PLS-DA models to identify injured area samples in fresh and putrefied brain tissue samples. The accuracy of the two models were 100% and 92.5%. Our preliminary research has proved that the use of FT-IR spectroscopy combined with chemometrics can identify TBI more quickly and accurately in cadavers, providing crucial evidence for judicial proceedings.

In Vitro Assessment of Sunscreen Efficacy Using Fourier Transform Infrared (FTIR) Spectroscopy on Synthetic Skin.

Although there are several methods for assessing the sun protection factor (SPF) of sunscreen products, there is no standard and reliable in vitro method. Each test entails limitations and drawbacks. Therefore, this study aimed to assess the employability of FTIR as an alternative and quick method to evaluate the efficacy of various sunscreen formulations, their concentrations, and the timing of their application. Infrared radiation has longer wavelengths than ultraviolet, penetrates deeply into the skin, and hence enables the understanding of sunscreens' ability to block the transmission of radiation. The FTIR transmission using synthetic skin to study the effect of sunscreen agents (oxybenzone, octyl methoxycinnamate, titanium dioxide (TiO2), and zinc oxide (ZnO)) was conducted in the range 450-4000cm-1. Comparison studies were made at the peak of 805cm-1. After 2 h of sunscreen application, using the maximum concentrations, the FTIR peak at wavenumber 805cm-1 demonstrated a significant reduction of transmission from 96.55 to 60.09%, 57.59%, 32.02%, and 37.1% for oxybenzone, octyl methoxycinnamate, TiO2, and ZnO respectively (P<0.05). A significant reduction in transmission was observed (P<0.05) with increasing sunscreen concentrations after 2 h of application. Nevertheless, the upper limit of concentration showed no appreciable change from the middle level of concentration, and hence it is cost-effective to employ the middle concentration. Inorganic sunscreens showed a higher protection level than organic. Fixed-dose combinations of sunscreens showed an enhanced effect yet were not synergistic. In conclusion, the use of FTIR spectroscopy with synthetic skin is a quick and user-friendly technique that enables the assessment of the efficacy of sunscreen formulations.

Fourier Transform Infrared (FTIR) Spectroscopy to Analyse Human Blood over the Last 20 Years: A Review towards Lab-on-a-Chip Devices.

Since microorganisms are evolving rapidly, there is a growing need for a new, fast, and precise technique to analyse blood samples and distinguish healthy from pathological samples. Fourier Transform Infrared (FTIR) spectroscopy can provide information related to the biochemical composition and how it changes when a pathological state arises. FTIR spectroscopy has undergone rapid development over the last decades with a promise of easier, faster, and more impartial diagnoses within the biomedical field. However, thus far only a limited number of studies have addressed the use of FTIR spectroscopy in this field. This paper describes the main concepts related to FTIR and presents the latest research focusing on FTIR spectroscopy technology and its integration in lab-on-a-chip devices and their applications in the biological field. This review presents the potential use of FTIR to distinguish between healthy and pathological samples, with examples of early cancer detection, human immunodeficiency virus (HIV) detection, and routine blood analysis, among others. Finally, the study also reflects on the features of FTIR technology that can be applied in a lab-on-a-chip format and further developed for small healthcare devices that can be used for point-of-care monitoring purposes. To the best of the authors’ knowledge, no other published study has reviewed these topics. Therefore, this analysis and its results will fill this research gap.

Material Analysis and a Visual Guide of Degradation Phenomena in Historical Synthetic Polymers as Tools to Follow Ageing Processes in Industrial Heritage Collections.

Identifying the most vulnerable plastics and monitoring their deterioration is one of the main problems within heritage collections with historical synthetic polymers. Gathering and interpreting data about material and degradation phenomena in a collection reveals its conservation needs. A systematic survey of the collection can help towards this purpose. Surveys aiming at inspecting and documenting damages rely on several tools in order to fulfill their purpose. Firstly, objective descriptions of the damages that may appear, and secondly, the means of acquiring and interpreting material information. To address these needs, this article presents (a) a visual damage catalogue of degradation phenomena in plastic and rubber materials, and (b) the implementation of Fourier-transform infrared spectroscopy (FTIR) and pyrolysis–gas chromatography–mass spectrometry (py-GCMS) for the identification of analytically challenging rubber materials and of blooming phenomena. The damage catalogue is based solely on visual and olfactory signs, so that the assessment is independent of possible causes of damages and underlying processes, with the purpose of allowing objectivity to prime over interpretation. The limitations of the use of FTIR in the identification of heavily compounded rubbers in museum surveys is highlighted, and examples are presented. The use of py-GCMS on these cases conveniently allowed the identification of the constituting monomers of several rubber materials where FTIR could not provide a univocal classification of the material present. The study of several cases of blooming allowed the identification of diverse compositions and origins, showing that the description of a degradation phenomenon is only the first step towards its understanding. Unveiling the nature of a particular case of blooming is particularly critical when conservation treatments, such as the removal of a (potentially protecting) layer, are planned. For this purpose, attenuated total reflection-FTIR (ATR-FTIR) as a surface technique was particularly useful.

Characterization of polysaccharides from &lt;i&gt;Eremurus hissaricus&lt;/i&gt; roots by FTIR spectroscopy

The structure of water'soluble gluco' and galactomannans (GlcMan and GalMan) isolated from the roots of several Eremurus'related plant species has been studied previously. This article characterizes polysaccharides and other extraction products from the root tubers of Eremurus hissaricus by Fourier' transform infrared (FTIR) spectroscopy using an attenuated total reflectance (ATR) accessory. Polysaccharide samples were purified from protein substances with the Sevage method and discoloured through a polyamide column. In the FTIR spectra, the main peaks attributed to asymmetric and symmetric stretching vibrations of CH2 of the pyranose ring (for GluMan - 2886, 1373, 1244 cm-1; for GalGluMan - 2923, 1370, 1238 cm-1) were enhanced by purification after removing bound protein impurities. The KnownitAll and IR-Pal 2 software applications were used to examine the spectra of a sample of purified GalGluMan in the studied polysaccharides. The results show that the intensity of the absorption maximum decreased at 1732 cm-1. At the same time, at 1552.92 cm-1, a new band appeared that refers to the valence vibrations of carboxyl (CO) or nitroso (NO) groups in the purified polysaccharide. This band appeared as a result of the Maillard reaction between the protein and the reducing end of the polysaccharide unit. The intensity of the bands in the 1238-1244 cm-1 region also decreased in the purified samples, which may be due to the elimination of a small fraction of protein. The use of FTIR spectroscopy allows the process of purifying watersoluble GluMan and acid-soluble polysaccharide of GalGluMan from acrylamide impurities to be characterized timely and accurately. Additionally, this method allows a comparative estimation of functional groups in polysaccharides of the root tubers of E. hissaricus.

Use and misuse of FTIR spectroscopy for studying the bio-oxidation of plastics

Due to massive production, inefficient waste collection, and long lives, plastics have become a source of persistent pollution. Biodegradation is explored as an environmentally friendly remediation method for removing plastics from the environment. Microbial and animal biodegradation methods have been reported in the literature for various plastics. Levels of plastic oxidation are often used as an evidence of degradation and can be measured with great sensitivity by Fourier Transform Infrared (FTIR) spectroscopy. FTIR is highly sensitive to the creation of new CO, CO and OH bonds during oxidation. However, many studies reporting the use of FTIR spectroscopy to evidence plastic oxidation confused the spectral signatures of biomass contamination (CO and CO from lipids, CONH from proteins, O–H from polysaccharides) with plastic oxidation. Here, based on spectra of oxidized plastic and of probable contaminants, we make recommendations for performing and analyzing FTIR measurements properly.

FTIR Spectroscopy Detects Intermolecular \u03b2-Sheet Formation Above the High Temperature Tm for Two Monoclonal Antibodies

The temperature-dependent secondary structure of two monoclonal IgG antibodies, anti-IGF1R and anti-TSLP, were examined by transmission mode Fourier Transform Infrared (FTIR) spectroscopy. Anti-IGF1R and anti-TSLP are IgG monoclonal antibodies (mAbs) directed against human Insulin-like Growth Factor 1 Receptor for anti-tumor activity and Thymic Stromal Lymphopoietin cytokine for anti-asthma activity, respectively. Differential scanning calorimetry (DSC) clearly indicates both antibodies in their base formulations have a lower temperature protein conformational change near 70 °C (Tm1) and a higher temperature protein conformational change near 85 °C (Tm2). Thermal scanning dynamic light scatting (TS-DLS) indicates a significant particle size increase for both antibodies near Tm2 suggesting a high level of protein aggregation. The nature of these protein conformational changes associated with increasing the formulation temperature and decreasing sucrose concentration were identified by transmission mode FTIR and second derivative FTIR spectroscopy of temperature controlled aqueous solutions of both monoclonal antibodies. The transition from intra-molecular β sheets to inter-molecular β sheets was clearly captured for both monoclonal antibodies using FTIR spectroscopy. Finally, FTIR Spectroscopy was able to show the impact of a common excipient such as sucrose on the stability of each monoclonal antibody, further demonstrating the usefulness of FTIR spectroscopy for studying protein aggregation and formulation effects.