Infrared Spectroscopy Methods Research Articles

Preparation, characterization, and thermo-mechanical properties of poly (ε-caprolactone)-piperazine-based polyurethane-urea shape memory polymers

A series of segmented polyurethane-urea (PUU) shape memory polymers were synthesized from poly e-caprolactone (PCL)-diol, hexamethylene diisocyanate, and piperazine (PP) with different hard to soft segment ratios. Chemical structure of PUUs was characterized using hydrogen nuclear magnetic resonance and attenuated total reflective-Fourier transform infrared spectroscopy methods. The results confirmed the formation of urethane and urea groups as well as incorporation of PP ring into polymer chain. Differential scanning calorimetry and wide angle X-ray scattering analyses were conducted to study the thermal properties and crystalline morphology of PUUs. It was found that crystallization of PUUs originated from PCL crystals. The reduction in degree of crystallinity was also observed with increasing of hard segment content (HSC). Mechanical properties were examined by tensile test at two different temperatures; above and below the PCL melting temperature. It was revealed that the chemical composition and temperature greatly affect the mechanical behavior of PUUs. A correlation between mechanical properties and physical structure of PUUs was established. Shape memory properties of PUUs were studied at two different programming processes. All of the samples show shape recovery over 94 % with a broad recovery temperature ranging from 40 to 65 °C. However, the shape fixity showed a great dependence on both HSC and programming process. The reasons of this dependency were discussed.

Physical and chemical analyzis of chardonnay wine with different periods of skin contact

Aromatic precursors are precisely in the skin of grapes and nearby cells, and therefore there is a greater expression of the varietal aromas and aromatic precursors when the wine passes through this skin contact, as well as changes in product color. The aim of this study was to evaluate the physical and chemical characteristics of Chardonnay wine that has gone through different periods of skin contact. Chardonnay grapes, grown in vineyards located in the town of Bage, in Campanha Gaucha, were de-stemmed, crushed and a sulfur dioxide (50 mg/L−1 ) was addeded. The experimental design was a 4 × 3 factorial of 4 treatments with 3 repetitions: T1, the wine obtained directly from pressing machine; T2, skin contact for 2 days; T3, skin contact for 4 days and T4, skin contact for 6 days. After the end of malolactic fermentation wines went under − 2∘ C for the tartaric stabilization. There were analyzed the variables alcohol, total acidity, volatile acidity, total polyphenols, glycerol, gluconic acid and 420, 520 and 620 colors by infrared spectroscopy method by Fourier transform and the means were compared by 5% Tukey test. There was a significant differencein variables alcohol, volatile acidit, glucanic acid and color index of 420 nm (yellow).

1B32 骨密度測定における近赤外分光法とDEXA法の比較

1B32 骨密度測定における近赤外分光法とDEXA法の比較

Validation of the near Infrared Spectroscopy Method for Determining Soil Organic Carbon by Employing a Proficiency Assay for Fertility Laboratories

Current research indicates that near infrared (NIR) spectroscopy is the most promising alternative technique for the determination of soil organic carbon (SOC) in laboratories worldwide and that it may serve as a total or partial replacement for the traditional wet chemistry methods. In this research, NIR spectroscopy was developed and validated as a method for the determination of SOC aiming to promote the use of NIR technology in the soil laboratories of Brazil as a routine analysis method. To this end, multivariate calibration models were constructed from a large number of soil samples (1490 samples) that encompassed the variability of Brazilian soils. These models were validated by submitting the concentrations of soil organic matter (SOM) as determined by NIR spectroscopy to the proficiency assay for fertility laboratories, which is coordinated by the Brazilian Agricultural Research Corporation (Embrapa Soils). The proposed methodology using NIR spectroscopy received the excellence index of quality, which gives a certificate seal issued by the interlaboratory programme. Therefore, the robustness of the NIR method was proved in a conclusive way by a proficiency test programme dedicated to evaluating the reference method for SOM determination employed by over a hundred soil laboratories in Brazil.

Thermal Energy Storage Properties of Xylitol Penta Myristate and Xylitol Penta Laurate as Novel Solid-liquid Phase Change Materials

In this study, xylitol penta myristate and xylitol penta laurate were prepared as novel solid-liquid phase change material by means of esterification reaction. These esters were characterized chemically using a Fourier transform infrared spectroscopy method. By using a differential scanning calorimetry method, the melting temperatures of xylitol penta myristate and xylitol penta laurate were measured as 50.28 and 43.53°C, respectively, while their latent heat values were determined as 199.50 and 184.71 J/g, respectively. These results indicated that the synthesized esters had high latent heat of melting and suitable phase change temperatures for thermal energy storage applications. A thermal cycling test showed that the synthesized phase change materials had good thermal reliability after thermal 100 melting-freezing cycles. Thermogravimetric analysis results also revealed that the phase change materials have good thermal stability over their working temperatures.

Effects of physical treatment of hemp fibers on fiber structure and biocomposite properties

This article concerning natural cellulose fibers as reinforcement in composite materials in civil engineering. In this paper, the attention is given to industrial hemp specifically to the woody part of hemp plant called hemp hurds. The properties of natural fibers are mainly determined by the chemical and physical composition, such as structure of fibers. The objective of presented research is to characterize raw and physically treated hemp fibers using Fourier transform infrared spectroscopy method. These natural fibers were used as filler into biocomposites and MgO-cement was used as alternative binder. Physico — mechanical properties (compressive strength, thermal conductivity, absorbability) of prepared composites were determined.

Seeing Molecules in Motion in Aqueous Solutions

Hydrogen bonds play critical roles in determining the structural, thermodynamic and dynamical behavior of water and aqueous solutions. In solutions of ions in water, the hydrogen bonded network can be perturbed significantly by the presence of ions. This perturbation, in turn, changes many of the equilibrium and dynamical properties of water in the solutions compared to those in pure water. The network of hydrogen bonds is dynamic in nature. It fluctuates at a very fast rate due to breaking and reformation of hydrogen bonds. In the present article, a brief review is made of some of the recent computer simulation studies to ‘see’ these hydrogen bonded molecules in motion in aqueous solutions. Connections of the simulation results are also made to some of the recent experimental studies on aqueous solutions using the method of time dependent infrared spectroscopy.

English

This study describes the synthesis, spectra characterization using UV-Visible and Infra-Red spectroscopic methods, flavonoid profile, antioxidant activity and antifungal property of Senecio biafrae-Cu complex and Senecio biafrae. UV-Visible spectra revealed bathochromic shifts for Senecio biafrae-Cu complex in comparison with Senecio biafrae which could be due to complexation. Differences between vibration spectra of Senecio biafrae-Cu complex and Senecio biafrae showed that carbonyl oxygen and hydroxyl groups were involved in complexation because of shifts in their positions. Kaempferol; a flavonol was found to be most abundant identified in both Senecio biafrae and its complex. Senecio biafrae-Cu complex had better antioxidant and antifungal activities against free radicals and pathogenic Fusarium oxysporium, Aspergillus flavus and Fusarium solani than Senecio biafrae. This study has shown that natural vegetables such as S. biafrae can also be used for complexation. Key words: Senecio biafrae, flavonoid composition, antifungal property, inhibition, copper complex.

An infrared spectroscopy method to detect ammonia in gastric juice.

Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

Development of the device for study of the skin characteristics

The skin is the largest organ of the human body that performs many specialized functions. The main kind of the skin study is histological analysis, so the development of noninvasive methods for investigating the characteristics of the skin is very important. For a more detailed study of the skin the combined infrared spectroscopy and bioimpedance method has been proposed so that to examine the structure of the skin in more detail.

Quality Assessment of Poultry Egg Based on Visible–Near Infrared Spectroscopy and Radial Basis Function Networks

In this research the possibility of a non-destructive prediction of two main quality parameters of poultry egg using principle component analysis and radial basis function network by the transmission visible–near infrared spectroscopy method was investigated. The studied parameters include Haugh unit and air cell height as a function of a 5-week storage duration at room (25°C and 40% relative humidity) and refrigerator (5°C and 75% relative humidity) conditions. The spectra were interpreted and a radial basis function network model was developed for both storage conditions at wavelength ranges of 300–1100 nm. The developed models yielded a good prediction accuracy of Haugh unit for intact egg (R2 value 0.745 and 0.76) as well as air cell height (R2 value 0.835 and 0.844) for room and refrigerator conditions, respectively. Results of the experiment showed the developed model can be used in the prediction of egg freshness indices satisfactorily.

Bentonite hydrochar composite for removal of ammonium from Koi fish tank

The work is concerned with a bentonite hydrochar composite made from bentonite and cassava peel. Bentonite was obtained from a Ponorogo deposite, Indonesia, and cassava peel was agricultural waste. The preparation of the composite was carried out at 500°C under a flow of carbon dioxide. The sample was characterized by argon adsorption at 87K, X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy methods. The adsorption of ammonium from the solution was conducted in a batch condition at 30°C. The dynamic condition was employed in the removal of ammonium from Koi fish tank. Biochar and bentonite hydrochar composite samples had microporous structure whereas the bentonite in the composite possessed mesoporous structure. Langmuir and Freundlich adsorption isotherms were used to correlate the experimental data of adsorption of ammonium from Koi fish tank. The results indicated that the Langmuir equation described the adsorption experimental data well. Combination between van der Waals force and ion exchange increased the adsorption of ammonia onto the bentonite hydrochar composite. Adsorption of ammonia in a real aquaculture system indicated that the composite could completely remove the ammonia from the Koi fish tank within 60min.

Rapid moisture determination for cup lump natural rubber by near infrared spectroscopy

Natural rubber (Hevea brasiliensis) is an important economic crop in South-East Asia. The price paid for cup lump raw rubber depends principally on its moisture content (MC), which an examiner subjectively estimates visually and by touch. These inaccurate and subjective estimates are disputable and cause contentions. This study aimed to develop a near infrared spectroscopy (NIRS) method calibrated for rapid, accurate, inexpensive, and nondestructive moisture content determination of cup lump. We used NIRSystem 6500 to measure the reflectance spectra, and developed calibration equations for the moisture content by partial least squares (PLS) regression, restricted to that part of the spectrum known to depend on water. The calibration equation for moisture content had the coefficient of determination equal to 0.98, the standard error of calibration 1.68%, the standard error of prediction 1.48%, and an average difference between the actual and predicted value of 0.02%. The actual and the predicted values did not significantly differ at a 98% confidence level. The fitted model was then validated with a new batch of samples, by a comparison of NIR-based moisture content estimates to standard laboratory determinations. NIRS is a well-established technique for determining the moisture content in cup lump, but this study demonstrated its suitability for rapid determinations without preprocessing the samples, provided a fixed procedure is used in coagulation to form cup lump. However, the transfer of these techniques to field use will require technology development to ensure robust device performance.

Comparative analysis of the mineralogical composition of the natural chalk deposits of Ukraine

Using the methods of quantitative infrared spectroscopy and the X-ray phase analysis it is analyzed sedimentary chalk of five different domestic deposits compared to chemically precipitated and import calcite. Presence of calcite, dolomitic, aragonite in their composition is fixed. It is given a quantification of the content (for half-width within the 562-1047 cm -1 for imported calcite, 440-703 cm -1 for the national sedimentary chalk and 530 cm -1 for the chemically-deposited chalk, and the ratio of the intensities of characteristic absorption bands of carbonate anion respectively 10,38-45,33; 26,80-47,33 and 35,15) of the main structure minerals of these kinds of carbonates. It is received the data confirmation of IR spectroscopy by X-ray phase analysis of the main types of natural chalk and it is obtained quantitative structure of main content (calcite, dolomite) and extrinsic (quartz, kaolinite, iron hydroxide) minerals. According to the parameters of characteristic absorption bands in the range of 712-876 and 2512-2522 cm -1 modification of calcium carbonate - calcite – it is conducted differentiation of quantitative indicators, depending on the origin of the material. It is noted greater uniformity of mineralogical composition of import carbonates. These data allow formulate reasonable frameworks of use of domestic sedimentary chalk and assess its competitiveness compared with chemically-deposited chalk and Turkish calcite.

XAS analysis of iron and palladium bonded to a polysaccharide produced anaerobically by a strain of Klebsiella oxytoca.

Klebsiella oxytoca BAS-10 ferments citrate to acetic acid and CO2, and secretes a specific exopolysaccharide (EPS), which is able to bind different metallic species. These biomaterials may be used for different biotechnological purposes, including applications as innovative green biogenerated catalysts. In production of biogenerated Pd species, the Fe(III) as ferric citrate is added to anaerobic culture of K. oxytoca BAS-10, in the presence of palladium species, to increase the EPS secretion and improve Pd-EPS yield. In this process, bi-metallic (FePd-EPS) biomaterials were produced for the first time. The morphology of bi-metallic EPS, and the chemical state of the two metals in the FePd-EPS, are investigated by transmission electron microscopy, Fourier transform infra-red spectroscopy, micro-X-ray fluorescence, and X-ray absorption spectroscopy methods (XANES and EXAFS), and compared with mono-metallic Pd-EPS and Fe-EPS complexes. Iron in FePd-EPS is in the mineralized form of iron oxides/hydroxides, predominantly in the form of Fe(3+), with a small amount of Fe(2+) in the structure, most probably a mixture of different nano-crystalline iron oxides and hydroxides, as in mono-metallic Fe-EPS. Palladium is found as Pd(0) in the form of metallic nanoparticles with face-centred cubic structure in both bi-metallic (FePd-EPS) and mono-metallic (Pd-EPS) species. In bi-metallic species, Pd and Fe nanoparticles agglomerate in larger clusters, but they remain spatially separated. The catalytic ability of bi-metallic species (FePd-EPS) in a hydrodechlorination reaction is improved in comparison with mono-metallic Pd-EPS.

Early detection of colorectal cancer relapse by infrared spectroscopy in "normal" anastomosis tissue.

Colorectal cancer is one of the most aggressive cancers usually occurring in people above the age of 50 years. In the United States, colorectal cancer is the third most diagnosed cancer. The American Cancer Society has estimated 96,830 new cases of colon cancer and 40,000 new cases of rectal cancer in 2014 in the United States. According to the literature, up to 55% of colorectal cancer patients experience a recurrence within five years from the time of surgery. Relapse of colorectal cancer has a deep influence on the quality of patient life. Infrared (IR) spectroscopy has been widely used in medicine. It is a noninvasive, nondestructive technique that can detect changes in cells and tissues that are caused by different disorders, such as cancer. Abnormalities in the colonic crypts, which are not detectable using standard histopathological methods, could be determined using IR spectroscopic methods. The IR measurements were performed on formalin-fixed, paraffin-embedded colorectal tissues from eight patients (one control, four local recurrences, three distant recurrences). A total of 128 crypts were measured. Our results showed the possibility of differentiating among control, local, and distant recurrence crypts with more than a 92% success rate using spectra measured from the crypts' middle sites.

Spectral Investigation of Phosphorus Compounds in Spinacia Oleracea Using Fourier Transform Infrared Method

The study uses the Fourier transform infrared spectroscopy method to evaluate the influence of phosphogypsum from the soil on the growth and accumulation of nutrients in Spinacia oleracea. Attenuated total reflectance spectra of Spinacia oleracea roots and stems originated from plants cultivated on 28% to 52% phosphogypsum enriched soil have been studied in the 4000–600 cm−1 area. The structure of the infrared absorption bands for spinach roots and stems and for the soil where plants were grown was analyzed. Thus, it was observed that phosphorus–oxygen bonds contribution can be identified both in roots and stems absorption spectra. The significance of the research is the possibility to use the infrared investigation as rapid technique, particularly useful for agriculture, to study the extraction and assimilation process of the compounds containing phosphorus and nitrogen from the soil in which the spinach seedlings grew. In the case of this study, it was observed that the absorption of phosphorus in the spinach roots and stems has not the same effect. The analysis of obtained data indicated that the assimilation of phosphorus from phosphogypsum enriched soil induces changes in spinach roots structure that are most likely due to an increase synthesis of proteins, rather than to a decrease in carbohydrates quantity.

Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO2ionic liquid system

Polyethylene of fibrous morphology was obtained using Cp2VCl2 and VCl2(salenCl2) catalysts activated by AlEt2Cl and AlEtCl2 and heterogenized on a supported ionic liquid system prepared with SiO2 and 1-(3-triethoxysilyl)propyl-3-methylimidazolium chloroaluminate. The fibre length ranges from 15 to 60 µm, depending on the reaction conditions. The polyethylene is characterized by a high molecular weight ((1.1–2.4) × 106 g mol−1) and a narrow molecular weight distribution (1.4–2.5). It is a linear polymer, properly without branching. The DSC method reveals characteristic changes in melting temperature and crystallinity degree between the first and second scan heating cycles (141 °C and 136 °C, 71% and 46%, respectively). The wide angle X-ray spectroscopy and Fourier transform infrared spectroscopy methods give crystallinity degree values of 40% and 41%–51%. The influence of type of catalyst precursor, alkylaluminium activator, catalyst/activator molar ratio, reaction time and temperature is discussed. © 2015 Society of Chemical Industry

Analytical Techniques for Determination of Hydrochlorothiazide and its Combinations: A Review

Hydrochlorothiazide is chemically 6-chloro-1, 1-dioxo-3, 4-dihydro-2 H -1, 2, 4-benzothiadiazine-7-sulfonamide. Hydrochlorothiazide is a diuretic drug used for treatment of high blood pressure (hypertension) and accumulation of fluid (edema). It works by blocking salt and fluid reabsorption from the urine in the kidneys, causing increased urine output (dieresis). Hydrochlorothiazide is used to treat excessive fluid accumulation and swelling (edema) of the body caused by heart failure, cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome. It can be used alone or in conjunction with other blood pressure lowering medications to treat high blood pressure. This review focuses on the recent developments in analytical techniques for estimation of Hydrochlorothiazide alone or in combinations with other drugs in various biological media like human plasma and urine. This review will critically examine the (a) sample pretreatment method such as solid phase extraction (SPE), (b) separation methods such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), ultra performance liquid chromatography (UPLC), high performance thin layer chromatography (HPTLC), liquid chromatography coupled to tandem mass spectrometry (LC-MS) and capillary electrophoresis (CE), (c) other methods such as spectrophotometry, diffuse reflectance near infrared spectroscopy and electrochemical methods.

An evaluation of Fourier transforms infrared spectroscopy method for the classification and discrimination of bovine, porcine and fish gelatins

The objective of this research was to develop a rapid spectroscopic technique as an alternative method for the differentiation and authentication of gelatin sources in food products by using attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectra combined with chemometrics. Clear discrimination and classification of all the studied gelatin sources (bovine, porcine, and fish) were achieved by hierarchical cluster and principle component analysis (PCA). Amide-I (1700–1600cm−1) and Amide-II (1565–1520cm−1) spectral bands were used in a chemometric method. Moreover, ATR–FTIR spectral data successfully discriminated pure bovine gelatin from mixture of bovine and porcine gelatins, which is very important for the food industry. The method that we adopted could be beneficial for rapid, simple and economic determination of both gelatin presence and its origin from food products such as yogurt, ice cream, milk dessert or other gelatin containing products such as pharmaceuticals and cosmetics.