Infrared Spectroscopy Methods Research Articles

Influence of Talc in Polypropylene on Total Fluorine Measurements Used as an Indicator of Per- and Polyfluoroalkyl Substances (PFAS).

Increasing restrictions for chemicals of concern in plastic packaging materials have created an urgent need to accurately detect and quantify these chemicals. Total fluorine measurements have been utilized to screen for highly scrutinized per and poly-fluorinated substances (PFAS) in food packaging materials. Inorganic contributions to the total fluorine signal can result in false positive signals exceeding regulatory limits. The purpose of this study is to develop a method for determining the contribution of talc inorganic filler to the total fluorine signal. The influence of talc on total fluorine measurements of plastics was evaluated by compounding talc with virgin polypropylene (PP) then measuring the total fluorine concentration using oxidative pyrohydrolytic combustion ion chromatography. This study provides a framework to predict the contribution of talc in plastic samples to the total fluorine signal. A near infrared spectroscopy method was developed by employing the full width half height (FWHH) of the interstitial fluorine characteristic band of talc. The FWHH signal of the processed puck specimens was determined to be linearly increase with the measured total fluorine difference as a function of talc concentration (R2 = 0.9619). This study developed a method to predict contribution of talc fillers to the total fluorine signal of plastic samples. This method is critical for accurately determining the regulatory compliance of talc filled plastic samples for PFAS using total fluorine. Total fluorine is a common regulatory compliance technique as an indicator of PFAS. Talc is a common plastic filler that contains fluorine as a contaminant. The fluorine in talc contributes to the total fluorine signal, which can falsely elevate the total fluorine signal, potentially resulting in the lack of regulatory compliance. The developed method serves as a framework of how to identify the fluorine contribution of inorganic fillers in plastics.

Levels and Classification of Microplastics and Their Impact on the Wellbeing of Selected Commercially Important Fish Species in Kisumu Bay, Lake Victoria.

Microplastics (MPs) are emerging pollutants of concern in aquatic ecosystems. Fish ingest MPs accidentally during normal feeding because they resemble prey or by ingesting prey that previously consumed them. Despite severe plastic pollution in Africa, some countries, including Kenya have implemented laws to curb this pollution menace. MPs have scantly been studied in African freshwaters. This study provides empirical data and describes the levels of MPs in four commercially important fish species in Lake Victoria. A total of 95 fish samples were collected from four sampling sites (inshore-offshore waters) between March and May 2022. Microscopy and Attenuated Total Reflectance Fourier Transformed Infrared (ATR-FTIR) spectroscopy methods were used to identify MPs. In this study, 62 out of 95 (65.26%) of the gastrointestinal tracts of the sampled fish contained MPs. The four species showed different proportions of detected MPs among the sampled individuals: 75.00% (Clarias gariepinus), 75.00% (Synodontis victoriae), 71.43% (Lates niloticus), and 59.26% (Oreochromis niloticus). Polystyrene (PS) and poly (perfluorobutadiene) were the main plastic polymers in the fish samples. The condition factors estimated for O. niloticus, S. victoriae, and L. niloticus were > 1 and < 1 for C. gariepinus, respectively. Positive correlations were observed between microplastic numbers and fish length and microplastic numbers and fish weight. However, the low R2 values obtained implied no strong relationship exists between these parameters. These findings provide evidence of microplastic contamination in fish in Kisumu Bay.

Upside-Down Adsorption: The Counterintuitive Influences of Surface Entropy and Surface Hydroxyl Density on Hydrogen Spillover.

Although hydrogen spillover is often invoked to explain anomalies in catalysis, spillover remains a poorly understood phenomenon. Hydrogen spillover (H*) is best described as highly mobile H atom equivalents that arise when H2 migrates from a metal nanoparticle to an oxide or carbon support. In the 60 years since its discovery, few methods have become available to quantify or characterize H*-support interactions. We recently showed in situ infrared spectroscopy and volumetric chemisorption can quantify reversible H2 adsorption on Au/TiO2 catalysts, where adsorbed hydrogen exists as H* and interacts with titania surface hydroxyl (TiOH) groups. Here, we report parallel thermogravimetric analysis and Fourier transform infrared spectroscopy methods for systematically manipulating the surface TiOH density. We examine the role of surface hydroxylation on spillover thermodynamics using van't Hoff studies to determine apparent adsorption enthalpies and entropies at constant H* coverage, which is necessary to maintain constant H* translational entropy. Although surface TiOH groups are the likely adsorption sites, the data show removing hydroxyl groups increases spillover. This surprising finding─that adsorption increases as the adsorption site density decreases─is associated with improved thermodynamics on dehydroxylated surfaces. A strong adsorption enthalpy-entropy correlation implicates the changing surface entropy of the titania support itself (i.e., an initial state effect) is deeply intertwined with the H* configurational entropy. These effects are surprising and should apply to all low-coverage adsorbates where entropy terms dominate more traditional enthalpic considerations. Moreover, this study points toward a kinetic test for invoking spillover in a reaction mechanism: namely, in situ dehydroxylation should enhance spillover processes.

Engineered M13-Derived Bacteriophages Capable of Gold Nanoparticle Synthesis and Nanogold Manipulations

For years, gold nanoparticles (AuNPs) have been widely used in medicine and industry. Although various experimental procedures have been reported for their preparation and manipulation, none of them is optimal for all purposes. In this work, we engineered the N-terminus of the pIII minor coat protein of bacteriophage (phage) M13 to expose a novel HLYLNTASTHLG peptide that effectively and specifically binds gold. In addition to binding gold, this engineered phage could synthesize spherical AuNPs of 20 nm and other sizes depending on the reaction conditions, aggregate them, and precipitate gold from a colloid, as revealed by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM), as well as ultraviolet–visible (UV–vis) and Fourier-transform infrared (FTIR) spectroscopic methods. We demonstrated that the engineered phage exposing a foreign peptide selected from a phage-displayed library may serve as a sustainable molecular factory for both the synthesis of the peptide and the subsequent overnight preparation of AuNPs from gold ions at room temperature and neutral pH in the absence of strong reducing agents, such as commonly used NaBH4. Taken together, the results suggest the potential applicability of the engineered phage and the new, in vitro-identified gold-binding peptide in diverse biomimetic manipulations.

Molecular Aspects of the Interactions between Selected Benzodiazepines and Common Adulterants/Diluents: Forensic Application of Theoretical Chemistry Methods.

Benzodiazepines are frequently encountered in crime scenes, often mixed with adulterants and diluents, complicating their analysis. This study investigates the interactions between two benzodiazepines, lorazepam (LOR) and alprazolam (ALP), with common adulterants/diluents (paracetamol, caffeine, glucose, and lactose) using infrared (IR) spectroscopy and quantum chemical methods. The crystallographic structures of LOR and ALP were optimized using several functionals (B3LYP, B3LYP-D3BJ, B3PW91, CAM-B3LYP, M05-2X, and M06-2X) combined with the 6-311++G(d,p) basis set. M05-2X was the most accurate when comparing experimental and theoretical bond lengths and angles. Vibrational and 13C NMR spectra were calculated to validate the functional's applicability. The differences between LOR's experimental and theoretical IR spectra were attributed to intramolecular interactions between LOR monomers, examined through density functional theory (DFT) optimization and quantum theory of atoms in molecules (QTAIM) analysis. Molecular dynamics simulations modeled benzodiazepine-adulterant/diluent systems, predicting the most stable structures, which were further analyzed using QTAIM. The strongest interactions and their effects on IR spectra were identified. Comparisons between experimental and theoretical spectra confirmed spectral changes due to interactions. This study demonstrates the potential of quantum chemical methods in analyzing complex mixtures, elucidating spectral changes, and assessing the structural stability of benzodiazepines in forensic samples.

Analysis of Mineral Types, Density, and Porosity in the Lam Teuba Formation Using Infrared Spectroscopy Method

The Lam Teuba Formation is one of the local fault areas of the Seulimuem segment located in the Grand Mosque sub-district of Aceh Besar regency. The Lam Teuba Formation has several types of rocks such as basaltic andesite lava, pyrolastic flows, pyroclastic falls, and sedimentary rocks, namely claystone, limestone sandstone, agglomerate, limestone. Rocks have physical characteristics, namely density and porosity which have different values in each rock. This difference can be caused by the minerals contained in the rock. The method used to calculate the density and porosity values used the Archimedes method, and the identification of mineral types using the infrared spectroscopy method. The results of data processing obtained the highest original density value at location 1 sample 1 with a value of 3.42 and the lowest value at location 5 sample 2. The highest dry density value was in location 1 of sample 1 with a value of 3.33 and the lowest value was in location 5 of sample 2. The highest saturation density value was in location 1 of sample 1 with a value of 3.43, the lowest value was in location 5 of sample 2 with a value of 2.07. The average porosity value was the highest with a value of 5.41 in the poor quality category in sample 4, while the lowest value was 4.62 in the very bad category in sample 1. The types of minerals found in the Lam Teuba formation are illite, montmorillonite, kaolinite minerals with a mixture of smectite which is a clay mineral group and siderite minerals which are carbonate mineral groups.

What to monitor? Microplastics in a freshwater lake – From seasonal surface water to bottom sediments

Marine microplastics have received considerable attention, and efforts are underway to develop standardised methods for sampling, sample treatment, and analysis, while the observation of freshwater ecosystems remains relatively overlooked. To address this understudied environment, we present a comprehensive case study on microplastics in an urban lake from Baltic region of Northern Europe covering the seasonal dynamics of microplastics in surface water, deposition rate throughout one year in sediment traps and distribution of microplastics in dated sediment archive to determine the most representative environmental compartment for microplastic pollution monitoring. The following well-established microplastic research methods have been used: Manta trawling for surface water, trapping for assessing microplastics sedimentation rate and coring for sediments. Attenuated total reflection and micro-Fourier transform infrared spectroscopy methods were used to investigate the synthetic nature of identified particles. The sediment core chronology was based on 210Pb and Bayesian Plum model revealing sediment layers to represent even the time before the beginning of plastic mass production (approximately 1950). The surface water microplastic concentrations were higher in summer (5.71 particles/m3) and gradually decreased towards winter (0.75 particles/m3); they were almost 25 times higher in more recent (2018) sediments than in the deeper layers referring to years prior to 1890. Surprisingly, microplastic particles were found in sediments before the year 1950. The microplastic deposition rate was 9.47 particles/cm2/year or 4.31 µg/cm2/year. The most abundant polymers were polyethylene, polystyrene and polypropylene, and the prominent particle shapes were fibres in surface water and fragments in sediments. Our results provide a baseline for evaluating future contamination level changes in highly urbanized area. We recommend the combination of surface water filtering with net and sediment trapping methods for monitoring microplastics in lakes since this method requires little time and financial resources for sampling and processing and produces information on temporal microplastic occurrence and deposition.

Cyclotriphosphazenes: Pre-harvest foliar applications improve antioxidant activity by increasing phenolic compounds in Lavandula angustifolia Mill.

The versatile chemical structures of cyclotriphosphazenes (CTPs) and their derivatives make them useful for various applications, including serving as plant nutrients to enhance the production of bioactive compounds. Therefore, the effects of 30 and 60 mg/L concentrations of CTPs (Compound 4 and 5) sprayed foliar at two different stages (pre-flowering stage and full-flowering stage) on total flavonoids and phenolic content, antioxidant activity, and accumulation of phenolics in lavender (Lavandula angustifolia Mill.) were investigated. Compounds 4 and 5 were purified by using column chromatography. The structures of the compounds were verified using mass, 1H, 31P nuclear magnetic resonance (NMR) spectroscopy, and Fourier-transform infrared (FT-IR) spectroscopy methods. The highest total phenolic content and antioxidant activity were achieved with Compound 5 (60 mg/L) treatment by using Folin-Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests. The phenolic profile was determined by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Compound 4 treatment yielded a higher level of increase in total flavonoids, protocatechuic aldehyde, protocatechuic, caffeic acid, 4-OH benzoic, and salicylic acid, whereas Compound 5 treatment yielded a higher level of increase in vanillic, p-coumaric, ferulic, and rosmarinic acids. CTPs applied during the full-flowering stage resulted in significant increases, such as an 8.7-fold rise in protocatechuic acid, a 4.3-fold increase in protocatechuic aldehyde, and an 8.4-fold surge in caffeic acid. The caffeic acid was strongly and positively correlated with the 4-OH benzoic acid (,834**), vanillic acid (,955**), p-coumaric acid (,670**), and rosmarinic acid (,669**). The results showed that using a suitable cyclotriphosphazene compound(s) and selecting a suitable pre-harvest application time can significantly enhance and optimize the levels of phenolics.

Assessment of microplastics pollution level on clam farming and bathing beaches: a case study of Thanh Phu in Ben Tre, Vietnam

ABSTRACT This study focused on the investigation microplastics (MPs) with a size of ≤1.0 mm in sand samples from Thanh Phu beach, Ben Tre, Vietnam. MPs in sand from the clam beach (from 39.67 ± 6.67 to 92.00 ± 12.93 items kg−1 dried sand) were higher than those from the bathing beach (from 21.33 ± 8.76 to 51.67 ± 16.11 items kg−1 dried sand), indicating a direct contribution of MPs from coastal aquaculture. For the clam beach, MPs in surface samples (0–4 cm) were lower than in deep samples (4–6 cm). In contrast, MPs in surface samples (0–2 cm) from the bathing beach were higher than deep samples (2–5 cm). A combination of microscopy and Fourier-transform infrared spectroscopy methods confirmed that 62.5% of the representative MPs samples or 18.9% of the suspected MPs samples were plastics. Low-density polyethylene, polypropylene and polyethylene terephthalate were the largest in abundance. Further studies are needed to assess the environmental risk of MPs accumulation.

Features of the formation of cohesive and adhesive strengths by non-structured and structured polyvinyl acetate films during wood gluing

The formation of a higher number of hydrogen bonds in the structured polyvinyl acetate film compared to the unstructured one was established by means of infrared spectroscopy method. It was concluded that the structured polyvinyl acetate film has a higher cohesive strength than unstructured. It was revealed that the films subjected to moisture loads (with the amount of sorbed moisture lower than the swelling limit of the adhesive film) would show greater cohesive strength compared to the films which were not subjected to moisture loads due to the formation of a higher number of hydrogen bonds. Based on the obtained results, it was predicted that the system "structured film after moisture loads/wood substrate" would exhibit the highest adhesive strength, explained by an increase in the number of hydrogen bonds between the film components and the wood cellulose. It was theoretically predicted that in order to provide high cohesive and adhesive strengths of polyvinyl acetate adhesive joints of wood ensuring, moisture saturation should be lower than the saturation limit of the wood fiber and the adhesive film simultaneously.

Effect of Cd on Structural, Spectral, Morphological and Dielectric Properties of Sr1-xCdxZn2Fe4O11 R-type Hexaferrites Synthesized via Sol-gel Technique

Sol–gel method was used to prepare Sr1-xCdxZn2Fe4O11 (x = 0.00, 0.02, 0.06, 0.1) R-type hexaferrite. The synthesized materials were sintered at 850oC and desired phase was obtained. X-ray diffraction analysis confirms that R-type hexaferrite exists only as a single phase. Using the Scherer formula, crystallite size for all of the prepared samples was found to be in the range of 10.39–12.62 nm. Crystallite size (D), the lattice parameters (a, c), and the cell volume (Vcell), d-spacing, bulk density, X-ray density, porosity, dislocation density and micro strain were determined in structural analysis. Fourier transform infrared spectroscopy method was used to identify the metal-oxygen vibrations at different locations. FT-IR verifies the presence of the Fe–O stretching vibration band at 743 and 867 cm−1. The typical grain size in surface morphology investigation ranges from 0.56 to 0.82 μm. Dielectric response of ferrite ceramic samples replaced with Cd2+ was investigated in the frequency range of 1 MHz–3 GHz. The AC conductivity rises with an increase in frequency because they are proportional to one another. This increasing tendency is effectively described by the theory of Maxwell-Wagner and Koop. Q-values remain constant as frequency rises and behaves independently of frequency as long as frequency reaches 1.7 GHz. These types of materials are utilized in high-frequency applications including frequency filters and resonant circuits. All of the magnetic properties determined by analyzing the M − H loops, including saturation magnetization (Ms), retentivity (Mr), and coercivity (Hc), exhibit an increasing trend as the substitution of Cd2+ rises. Ms (49.76–56.38 emu/g), Mr (15.82–18.30 emu/g) and Hc range from 203.20 Oe to 215.80 Oe. Grain size decreases cause arise in coercivity, which is caused by an enhancement in magneto-crystalline anisotropy. Overall results suggest that Cd2+ replaced R-type hexagonal ferrites are a great resource for longitudinal recording media; they have the potential to be used in a wide variety of electronic applications, including resonant circuits and high-frequency filters, security, detecting and switching.

Validation of an FT-IR microscopy method for the monitorization of microplastics in water for human consumption in Portugal: Lisbon case study.

The growing anthropogenic contamination of natural water by microplastics (MPs) confirms the urgent need to preserve this precious resource. MPs are part of the group of contaminants of emerging concern, and the occurrence studies in surface water and water for human consumption (WHC) are mandatory for environmental and human health risk assessment. This study aims to optimize and validate a Fourier transform infrared spectroscopy method coupled with optical microscopy (micro-FTIR) in transmission mode to monitor MPs in WHC. Water sample (250mL; without sample pre-treatment) was filtered through 5µm silicon filters. The infrared spectra identification was performed by OMNIC mathematical correlation, using various spectra libraries for polymers (including the in-house IR spectra library), a background reading on a clean silicon filter, and an aperture of 100µm × 100µm. The validated method showed good accuracy, with an average recovery for representative polymers of 91%, a relative standard deviation of 13%, and a reporting limit (RL) of 44 MPs/L. Sixty WHC samples from the Lisbon water supply system showed MPs ranging from 0 (< RL) to 934 MPs/L, with an average value of 309 MPs/L. The most representative polymers were polyethylene (PE, 76.8%), polyethylene terephthalate (PET, 6.9%), polypropylene (PP, 6%), polystyrene (PS, 4%), and polyamide (PA,4%). In terms of size, the microplastic particles had an average length and width of 76µm and 39µm, respectively.

Determination of concentration of basic sites on oxides by IR spectroscopy

As it is commonly known, CO2 reacts simultaneously with basic O2− and basic OH sites on oxides forming carbonates and bicarbonates, which can be followed by infrared spectroscopy (IR). However, here, we succeeded to elaborate experimental conditions under which CO2 reacted solely with O2− forming CO32− for ZrO2 and CeO2, and calculated the extinction coefficients of diagnostic bands of carbonate and bicarbonate species. For the first time, the developed IR method enabled the concentrations of O2− and basic OH for ZrO2, CeO2, Al2O3 and CuO to be measured separately. Moreover, in the case of all IR studied oxides, the sum of concentrations of O−2 and basic OH basic sites was comparable with the concentration determined by pulse adsorption of CO2. Thus, the presented extinction coefficients can be applied for IR basicity studies of various basic catalysts. We also followed the effect of thermal treatment on basicity of oxides.

Microplastics removal efficiency and risk analysis of wastewater treatment plants in Oman

Microplastics (MPs) have recently been documented as an emerging pollutant that poses a critical threat to environment. Wastewater treatment plants (WWTPs) are commonly regarded as significant contributors to the presence of MPs. This study aimed to assess the MPs load of three wastewater treatment facilities in Oman using various treatments, including MBR, SBR, and CAS. Wastewater samples from influent, effluent, and sludge were collected and analyzed to determine the concentration, morphology, size, color, and polymer type of the MPs. A set of sieves with a mesh size range of 1 mm–45 μm was used to for filtration. Oxidation treatment was applied for all samples using Fenton's reagent, followed by density separation by sodium chloride solution. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR- FTIR) method was utilized to test 10% from each sampling point to confirm the polymer types of the MPs. The pollution load index (PLI) and hazard index (HI) have been employed to assess the risk associated with the chemical toxicity and concentration of detected particles. The PROMETHEE method was used to rank the risk of sampling sites based on different criteria that posed potential ecological and human health risks. The results indicate that the average concentrations of 0.99 MP/L, 1.38 MP/L, and 0.93 MP/L were detected in the final treated effluent of WWTP A, WWTP B, and WWTP C, respectively. These concentrations correspond to overall removal efficiencies of 82.5%, 77.4%, and 79.2% for WWTP A, WWTP B, and WWTP C, respectively Most MPs found in tertiary effluent were smaller particles (425 μm) and fiber-shaped. The major types of MPs were polypropylene (PP), low-density polyethylene (LDPE), polyurethane (PU), polyethylene terephthalate (PET), and Polyvinyl chloride (PVC). This study showed that treated effluent and sludge release significant MPs into the environment.

Variations of the fundamental chemical components in Moso bamboo (Phyllostachys pubescens)

ABSTRACT The utilization of bamboo as a substitute for wood or plastic signifies an imperative pathway towards achieving global sustainable development. The conduct of comprehensive and systematic research on the variations in the fundamental chemical compositions can offer scientific and theoretical guidance for the efficient and rational high-value utilization of bamboo. In this study, the variations of the content of primary chemical components in Moso bamboo (Phyllostachys pubescens) were systematically investigated by considering height and radial locations. This was achieved through using comprehensive chemical analysis and infrared spectroscopy methods, with an additional investigation into the impact of nodes on these variations. The results indicated that the fundamental chemical components of Moso bamboo consisted of cellulose, hemicelluloses and lignin. The cellulose content ranged from 36% to 40%, the hemicelluloses content ranged from 25% to 28%, and the lignin content ranged from 26% to 34%. The cellulose content decreased with increasing culm height, while it demonstrated a gradual increase during the transition from the inner to the outer layer of the wall. The cellulose content of the internodes was higher than that of the nodes. The variation in cellulose content was more pronounced in the radial direction compared to that in vertical direction. However, the hemicelluloses and lignin content in the bamboo culm showed no statistical differences. The abundant resource advantage of bamboo in China can provide a valuable resource benefit for the classification and utilization of its three fundamental chemical components. The findings derived can provide a reliable basis for establishing a scientific theoretical foundation to optimize the value-added utilization of bamboo.

Near infrared spectroscopy for determination of moisture content in lyophilized formulation

A non-invasive near infrared (NIR) spectroscopic method was developed for the quantitative moisture determination in a lyophilized injection formulation. The calibration samples were prepared by exposing lyophilized samples at different temperatures and relative humidity. The samples from different scales and different process parameters were considered for adding robustness to the model. The NIR spectra were collected using a Fourier-transform (FT) NIR with a diffuse reflectance probe and the same samples were further analyzed by the Karl Fisher (KF) method for moisture content. The pre-treated NIR spectra were used for quantitative method development for moisture content. Partial least squares regression was used to develop calibrations in the 5600-4950 cm−1 region with calibration coefficient of determination (R2) of 0.96 and root mean square error of calibration (RMSEC) of 0.149. The model was cross-validated internally using the Kernel algorithm with r2 = 0.96 and RMSECV = 0.15. The accuracy of the NIR method against the KF method, precision, and reproducibility were good and the model was robust in predicting different external validation samples. This work allowed NIR as an alternative measurement for moisture analysis as well as facilitate 100% monitoring before packaging and save the cost of sample and time of KF analysis.

An Evaluation of the Beneficial Effects of Polyamide 6's Thermal Stabilization by Ferric Chloride Complexation as a Novel Carbon Fiber Precursor

This study investigated the impact of stabilization time on pretreated polyamide 6 (PA6) fibers using various analytical techniques, including thermal analysis (TGA and DSC), infrared (IR) spectroscopy, X-ray diffraction (XRD), tensile testing, and density measurements. The two-step atmospheric air-based stabilization process for pretreated PA6 multifilament bundles involved initial thermal stabilization at 170 °C in an air atmosphere after ferric chloride impregnation, followed by a second step of thermal stabilization at 245 °C. Ferric chloride impregnation followed by thermal stabilization in an air atmosphere resulted in crucial structural transformations. The density values of the samples increased following thermal stabilization, accompanied by a decrease in tensile values. Ferric chloride pretreated and thermally stabilized PA6 fibers were found to be fully stabilized after 120 min of stabilization before the carbonization stage. The findings obtained from the DSC, XRD, and IR spectroscopy methods indicated the occurrence of disordering phases due to the scission of hydrogen bonds. The TGA findings showed significant increases in carbon yield percentages at 500 °C and 850 °C, reaching 71.4% and 63.5%, respectively, for the sample heat treated at 245 °C for 120 min. The addition of ferric chloride is expected to potentially reduce processing costs for final carbon fiber production by decreasing the time required for the thermal stabilization of PA6.

Cotton Fiber Strength Measurement and Its Relation to Structural Properties from Fourier Transform Infrared Spectroscopic Characterization

There has been an interest in understanding the relationship between textile cotton fiber strength (or tenacity) and structure for better fiber quality measurement and enhancement. This study utilized coupled Stelometer and high volume instrument (HVI) measurements with attenuated total reflection Fourier transform infrared spectroscopy methods to relate fiber strength and associated properties (Stelometer elongation and HVI micronaire) with structure properties on six Upland (as A, B, C, D, E, and F) and one Pima cultivar. Although Stelometer tenacity agreed with HVI strength in general, the Upland D cultivar (immature) was observed to show the lowest HVI strength value, while the Upland F cultivar (larger infrared crystallinity index) was found to possess the smallest Stelometer tenacity value. A few strong and significant correlations were noted, for example, between infrared crystallinity and Stelometer elongation for the Upland A fibers, between infrared maturity and Stelometer tenacity for the Upland C fibers, and between infrared maturity and HVI strength for the Upland D fibers. Furthermore, there were apparent distinctions in regressions and statistics of examined correlations between each Upland cultivar and their combined fiber set, addressing the challenge of understanding the unique response between fiber physical and structure properties from different measurements even within one cotton cultivar.

Re-engineering and regulating molecular architecture of synthetic capsaicin for enhanced water-based degradation performance

Synthetic capsaicin, also known as pelargonic acid vanillylamide (PAVA), constitutes the primary component in riot control agents. Due to the propensity of PAVA agglomerated in aqueous environments, the interaction between the active site of PAVA molecular and catalyst was restricted, consequently reducing its degradation efficiency in water-based oxidizing agents. This study used a cationic surfactant, dodecyl trimethyl ammonium chloride (DTAC), in combination with KOH for the precise regulation and arrangement of PAVA molecules, resulting in the formation of a distinctive hydrophilic structure. This approach resolved its poor solubility in aqueous solutions while the relationship between solubility and degradation rate was obtained. The frontier orbital distribution and surface electrostatic potential distribution of PAVA molecular were predicted through first-principles calculation. The mechanism of PAVA solubilization was studied by 1H NMR techniques and infrared spectroscopy methods. The results showed that KOH substitutes the phenolic hydroxyl group “–OH” of PAVA, forming potassium phenoxide “–OK”, which enhanced the solubility of PAVA in water. Additionally, KOH might reduced the surface tension in the solution. It promotes the formation of the DTAC/PAVA complex micelle structure, which exhibited the PAVA agglomerates to exposing the catalytic activation reaction sites and accelerating the catalytic oxidation.

Physical and chemical properties, hygienic quality and fatty acid profile in milk of lactating Lacaune dairy sheep

Abstract. In recent years, there has been globally increasing interest in dairy sheep breeding, including Lacaune sheep, which is supported by a high demand for sheep's milk on the market. This paper elaborates on the influence of a sheep's lactation stage on the physical and chemical properties, hygienic quality and content of fatty acids in milk produced by Lacaune sheep kept in intensive breeding. The research was conducted on 30 Lacaune sheep, which were tested in the early (60th day), middle (120th day) and late (180th day) stages of lactation. Density, freezing point and titration acidity were determined by applying the infrared spectrometry method, and indicators of the hygienic quality of milk, such as somatic cell count (SCC), were determined by the fluoro-opto-electronic method, and the total count of aerobic mesophilic bacteria (CFU) was determined by the flow cytometry method. The fatty acid profile of feed and milk was obtained by gas–liquid chromatography. Depending on the stage of lactation, results referring to the chemical composition of Lacaune sheep's milk showed a significant increase in the content of fat, protein, total dry matter and casein together with a significant decrease in the content of lactose in the late stage of lactation. There was also a significant increase confirmed for the concentration of urea and the freezing point in milk along with the lactation progress. Depending on the stage of lactation, milk yield in Lacaune sheep significantly decreased as lactation progressed. Analysis of the fatty acid composition in milk of Lacaune sheep proved a significant decrease in the concentrations of C4 : 0, C6 : 0, C11 : 0, C12 : 0, C13 : 0, C15 : 0, C17 : 1, C18 : 2n6 and C18 : 3n6 as well as the n6 concentrations and the n6 / n3 ratio. The opposite trend was observed for concentrations of C10 : 0, C14 : 1, C16 : 0, C16 : 1, C18 : 0, C20 : 2, C18 : 3n3, C20 : 3n6, C20 : 5n3 and C22 : 6n3 as well as for the n3 concentrations. When compared to the early lactation stage, the C18 : 3n6 and n6 concentrations were significantly lower in the late lactation stage, while the C20 : 2 and C20 : 5n3 concentrations were significantly lower in the middle lactation stage when compared to the late lactation stage. There were many significant positive and negative correlations determined between the researched properties of milk. The research results obtained with Lacaune sheep's milk can be compared to the results of other studies, except for the lower content of milk fat. This confirms the good adaptability of Lacaune sheep to different breeding conditions and the necessity to provide sheep with quality pastures for grazing.