KBr Disk Technique Research Articles

Corrosion Behavior Mechanism of Borosilicate Glasses Towards Different Leaching Solutions Evaluated by the Grain Method and FTIR Spectral Analysis Before and After Gamma Irradiation

Three selected borosilicate glasses of commercial applications were prepared and studied for their corrosion behavior by the accepted grain test method towards acidic and alkaline solutions and distilled water before and after gamma irradiation. The work was supplemented by investigating the FT infrared absorption spectra of the glasses after immersion through the KBr disc technique. The same IR measurements have been repeated after gamma irradiation. Experimental weight loss data reveal limited changes which vary with the type of leaching solution and its strength. Alkali hydroxide solutions cause more weight loss than acidic solutions due to their reactions with all glass constituents including silicate and borate species beside modifier ions while distilled water and acidic solutions react or attack the modifier ions through ion exchange corrosion behavior. FTIR spectral results show characteristic vibrational peaks due to combined silicate and borate groups which reveal an interconnected compact network structure within the mid region of wavenumber range 800–1400 cm−1. This is due to the presence of four structural building units consisting mainly of SiO4 beside BO3, BO4 and AlO4 groups. The vibrational spectra slightly change with the immersion media because of the strong and compact network structure usually identified in borosilicate glasses. The commercial glass of the Schott type is the most durable studied glass because of high silica content (75%) together with combined 10% B2O3 and 5% Al2O3. Gamma irradiation results indicate minor changes in the weight loss data due to the compact network structure of the three commercial borosilicate glasses studied.

Elimination of interference from water in KBr disk FT-IR spectra of solid biomaterials by chemometrics solved with kinetic modeling

Infrared analysis of proteins and polysaccharides by the well known KBr disk technique is notoriously frustrated and defeated by absorbed water interference in the important amide and hydroxyl regions of spectra. This interference has too often been overlooked or ignored even when the resulting distortion is critical or even fatal, as in quantitative analyses of protein secondary structure, because the water has been impossible to measure or eliminate. Therefore, a new chemometric method was devised that corrects spectra of materials in KBr disks by mathematically eliminating the water interference. A new concept termed the Beer-Lambert law absorbance ratio (R-matrix) model was augmented with water concentration ratios computed via an exponential decay kinetic model of the water absorption process in KBr, which rendered the otherwise indeterminate system of linear equations determinate and thus possible to solve in a formal analytic manner. Consequently, the heretofore baffling KBr water elimination problem is now solved once and for all. Using the new formal solution, efforts to eliminate water interference from KBr disks in research will be defeated no longer. Resulting spectra of protein were much more accurate than attenuated total reflection (ATR) spectra corrected using the well-accepted Advanced ATR Correction Algorithm.

Utilization of Pure Silica Extracted from Rice Husk and FTIR Structural Analysis of the Prepared Glasses

Egyptian rice husk was subjected to different chemical and thermal treatment methods, aiming to extract high pure silica. Three samples (S1, S2 and S3) were prepared applying three different chemical treatment methods. Two sets of the obtained samples were prepared, where the first set was calcinated at 600oC and the other set was calcinated at 750 oC by slow heating (starting at RT and ending at the desired calcinations temperature for 2 h).XRF was applied to identify the chemical composition and purity of the extracted silica, while XRD was applied to confirm the amorphous nature and the presence of some induced carbon black in the obtained silica. It was found that S3 slowly heated at 750 oC presents the highest silica content (98.6 %). Such sample was fed directly to the calcinations furnace at 750 oC (sudden heating for comparison) where it presents only 90.6% silica, and 3.74 % residual carbon black. However, the extracted silica from sample S3 was used to prepare glasses obeying the composition (75-x) mol% RH-silica, x mol% Bi2O3, 25 mol% Na2O, (where 0 ≤ x ≤ 20).FTIR spectroscopic analysis was applied to investigate the internal structure of the prepared glasses, where the glass networks were found to contain mainly SiO4, BiO3 and BiO6 structural groups, as well as some bridging and non-bridging oxygen anions. Also, some O-H and H-O-H groups were also detected which may be due to the used KBr disk technique.

X-Ray diffraction and Fourier transformation infrared spectroscopy studies of copper (II) thiourea chloro and sulphate complexes

Copper (II) thiourea complexes were synthesized by chemical route method. To analyze the samples, X-Ray diffraction and Fourier transformation infrared spectroscopy method have been used. XRD analysis shows that sample is crystalline in nature and having particle size in the range of nanometres. FTIR spectroscopy shows the organic and inorganic compounds present in the sample. The X-ray diffraction pattern (XRD) using Bruker D-8 advance instrument and Infrared spectra of the complexes were obtained by KBr disc technique by using VERTEX 70 (Bruker).

UV–visible and infrared absorption spectra of gamma irradiated CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses: A comparative study

Undoped and CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses were prepared. UV–visible and infrared absorption spectra of the prepared samples were measured before and after successive gamma irradiation. Experimental optical spectra of the undoped samples reveal strong UV absorption bands, which are attributed to the presence of trace iron impurities in both the lithium and zinc phosphate glasses while the lead phosphate glass exhibits broad UV bands due to combined absorption of trace iron impurities and divalent lead ions. The CuO-doped glasses reveal an extra broad visible band due to Cu 2+ ions in octahedral coordination. The effects of gamma irradiation have been analyzed for both the sharing of all constituent components including trace iron impurities. Infrared absorption spectra of the prepared samples were investigated by the KBr disk technique. The FTIR spectra reveal main characteristic absorption bands due to different phosphate groups. The IR spectra are observed to be slightly affected by the increase of CuO in the doping level (0.2–3%) indicating the stability of the main network units.

A Chemometric Method for Correcting Fourier Transform Infrared Spectra of Biomaterials for Interference from Water in KBr Discs

Mid-infrared (mid-IR) analysis of solid biomaterials by the familiar KBr disc technique is all too often frustrated by water interference in the very important protein (amide) and carbohydrate (hydroxyl) regions of their spectra. A method was therefore devised that overcomes the difficulty and corrects IR spectra of solid biomaterials in KBr discs by mathematically eliminating the interference that arises from water molecules absorbed and bound in the KBr crystal lattice. The derivation of a linear system of chemometric equations that solves the water interference problem in a rigorous objective way is presented. Infrared spectra that result after correction by the method can be used reliably for quantitative analysis as well as structure identification. A major advantage is realized in quantitative analysis as the technique permits cryogenic pulverization of the biomaterial in KBr to prevent change in chemical structure and minimize the particle size to closely approach the solid solution condition required by the Beer-Lambert law. Extensive pulverization, which produces large water absorption bands that overlap and obscure the amide and hydroxyl regions of interest, is no longer problematic. The method is illustrated by removing strong water interference to extract the spectra of corn starch and gluten in pressed KBr discs. Results of the new method are compared with attenuated total reflection (ATR) spectra of gluten corrected using the conventional advanced ATR correction algorithm.

A quantitative analysis of Zidovudine containing formulation by FT-IR and UV spectroscopy

In this study IR and UV spectroscopic procedures are describe for the quantitative determination of Zidovudine (AZT) from solid dosage form. For IR spectroscopic method (KBr disc technique) has been used and Ursodeoxycholic acid (UDCA) was used as an internal standard. The specific absorption bands at 2105 and 2931 cm−1 were chosen for AZT and UDCA respectively. In this method, beer's law was obeyed in the concentration range 0.8–2.0% w/w in KBr disc. The regression equation was found to be y = 1.088x + 1.194 with correlation coefficient 0.9819, and the assay was found to be 99.8% with RSD of 2.157%. The UV spectroscopic method was also used in the quantitative determination of AZT in solid dosage form. 266 nm was chosen as λmax. The regression equation was found to be y = 0.0434x + 0.027, and the correlation coefficient 0.9989. The assay was found to be 99.81% with RSD of 0.273% by the UV spectroscopic method.

Characterization of some glasses in the system SiO 2, Na 2O·RO by infrared spectroscopy

The structural groups arrangement of some glasses obtained in the system SiO 2. Na 2O·RO (where R is a divalent oxide: CaO, SrO, BaO, MgO, ZnO), examined by infrared absorption spectroscopy are reported. Also, some glasses of the system SiO 2, Na 2O, B 2O 3 with variable B 2O 3 content are studied. The prepared glass samples were examined by infrared spectroscopy in the range 4000–400 cm −1 by the KBr disc technique. Experimental data reveal the appearance of extended infrared absorption spectra. The mid-absorption bands (500–2000 cm −1) are related to characteristic structural building units such as SiO 4, BO 3 and BO 4 groups. Also the corrosion behavior of the glasses was studied by subjecting selected grains of the samples to the action of 0.1 M HCl solution or 0.1 M NaOH solution at 100 °C for 1 h. The results are discussed taking into consideration the current views on the corrosion mechanism of silicate glasses.

Quantitative Determination of Tenoxicam by Infrared Spectrophotometry

The purpose of this study was the quantitative determination of solid dosage forms containing tenoxicam (TNX) by IR spectrophotometry, using the KBr disc technique. Dehydrocholic acid (DHCA) was used as the internal standard. The specific absorption bands at 1420 cm−1 and 1705 cm−1 were chosen for TNX and DHCA, respectively. The concentration range between 0.15-0.35 % w/w in KBr disc showed compliance with Beer's law.

Quantitative Determination of Fluconazole by Infrared Spectrophotometry

Abstract The purpose of the study was the quantitative determination of fluconazole by IR spectrophotometry which was realized by the application of the KBr disc technique. In this study dehydrocholic acid was used as internal standard. The absorption bands at 960 and 675 cm−1 were chosen for fluconazole and 1705 cm−1 for dehydrocholic acid. The concentration range between 0.4–1.6% w/w in KBr disc showed compliance with Beer's law. Besides IR spectroscopy, UV spectroscopy and HPLC methods were also used In the quantitative determinations. In the UV spectroscopy method the absorbance value at 261 nm in MeOH was used for fluconazole. In quantitative determinations which were performed by using HPLC, ketoconazole was the internal standard. Different regression equations were applied for each method in order to complete the quantitative determination. In UV spectroscopy and HPLC methods, relative standards were found as 0.74, 1.04% and in IR spectroscopy (675, 960 cm−1) relative standards were found as 1.1 and 1.51%, respectively.

Infrared spectra of raw and chemically modified pineapple leaf fiber (annanus comosus)

AbstractInfrared spectra of raw and chemically treated pineapple leaf fibers (PALF) have been studied using the KBr disk technique. Bands due to lignin and hemicellulose in the spectra of the fibers and their changes due to chemical (NaOH and NaCIO2) treatment have been discussed.

Infrared Spectra of Alkali Treated Degummed Ramie

Infrared spectra of degummed ramie fibers (2-3% gum content) in untreated and alkali treated conditions at room temperature were observed over the frequency range 4000-300 cm -1 using the KBr disk technique. The changes in the spectra are discussed generally. The sharp change in the spectrum due to transition from cellulose I to cellulose II was observed in the concentration range 12-15% (w/w) of alkali. The transition to cellulose II was accompanied by a crimp in the fiber.

The preparation and examination of partially combusted cellulose chars

Partially combusted samples of cellulose, removed at different stages of decomposition from several thermogravimetric experiments, have been subjected to elemental analysis and IR spectroscopy. The values of maximum temperature and final mass loss for each sample have been obtained from the thermogravimetric curves. These data have been combined with values for the percentage of carbon, hydrogen and oxygen and plotted as the decline in the percentage of each of these elements with temperature. Infrared spectra of the chars have been obtained by the KBr disc technique; the mass of sample mixed in the disc was in proportion to the thermogravimetric value of the mass of sample remaining. It is shown that few changes occur to the combustion residue below 260°C. Above this temperature there is a steady increase in unsaturated groups. Under the conditions of the experiment, hydrogen and oxygen are lost in a ratio close to 2 : 1. Up to 333°C the original carbohydrate structure is retained; samples obtained from above this temperature have spectra dominated by CC and CO bonds.

Quantitative Analysis of Phenaglycodol

Abstract A procedure has been developed for the quantitative and qualitative infrared spectrophotometric analysis of phenaglycodol in tablets and capsules. The procedure consists of a liquid-liquid partition of the drug between chloroform and an aqueous alkaline phase. The quantitative measurement is made at about 9.85 μ relative to a carbon disulfide reference, using the baseline technique. Qualitative analysis employs the KBr disk technique. Five collaborators obtained a relative standard deviation of ± 1.88% for a tablet preparation and ± 1.61% for a capsule preparation. It is recommended that the method be adopted as official, first action.

Infra‐red absorption spectra of ion‐exchange resins

AbstractInfra‐red absorption spectra have been obtained by the KBr disc technique for some fifty commercial ion‐exchange resins with quaternary ammonium, tertiary and mixed amine, sulphonic, phosphonic, secondary phosphate, and carboxylic groups, as well as for a number of experimental resins, including some of the solvent‐modified type. The use of the technique in structural characterisation of ion‐exchange resins is discussed.

Infrared spectra for the identification of some inorganic anions using nitron as precipitant

Using infrared absorption spectroscopy a method has been developed which permits the identification, either singly or in admixture, of the following anions: ferrocyanide, ferricyanide, cobalticyanide, chlorate, bromate, perchlorate, periodate, nitrate, nitrite, tungstate, molybdate and chromate. The anions are precipitated by nitron, and using the KBr-disc technique characteristic bands are obtained in the near infrared.

Determination of Ethisterone by the Potassium Bromide Disk Technique

Abstract Results of determining ethisterone by the KBr disk technique are presented. Two mixtures and tablets from 2 commercial sources were analyzed by the Associate Referee and 4 collaborators. In general, the average recoveries agreed, within 4.5%, with the amounts of ethisterone which were added or declared. In most cases, the recoveries from replicate determinations agreed within 3.8%. The method is recommended for adoption as official, first action.

Quantitative I.R.-messungen an p-substituierten polystyrolen

Using the KBr disk technique we have measured the infra-red spectra of the poly( p-halogene styrenes), of poly( p-methyl styrene) and of poly( p-iso-propyl styrene). With all polymers, excepted the fluorine derivative, measurements were also made with CS 2 solutions. The absorptivities (ϵ max and ƒϵ dλ) of the following aromatic hydrogen vibrations were determined: out-of-plane vibration at about 830 cm −1, δ s (in-plane) at about 1010 cm −1, and δ as(in-plane) in the region between 1165 cm −1 and 1055 cm −1. In the case of δ s , ƒϵ dλ increases strongly from the fluorine derivative to the chlorine derivative; the absorptivities of δ as move in the opposite direction, the fluorine compound being an exception. As to the out-of-plane vibration, there are only slight differences. In the case of δ s and δ as , ƒϵ dλ and λ max depend on the molecular weight of the substituent in para position. The wave numbers of all aromatic hydrogen vibrations of the halogene derivatives increased from the iodine to the fluorine compound. Due to the non-ideal dispersion of the polymer in the KBr, ϵ max. (KBr) is always smaller than ϵ max (CS 2). The preparation technique described allows reproducible values for ϵ max (KBr). ƒϵ dλ depends little on the preparation technique. There is some evidence about an influence of the polar KBr on ϵ max.

Infra-red absorption of water of hydration in lanthanide trichlorides

The absorption spectra of the hydrated lanthanide trichlorides were examined in the region between 4000-400 cm −1 by the KBr disk technique. The major bands are assigned to vibrations characteristic of the water molecules on the basis of the consistent pattern of the observed spectra, and isotopic frequency shifts upon deuteration.

A Possible Method of Pulverizing Mica and other Flaking Materials for Spectrographic Analysis

Recently a method using the Wig-L-Bug was described for grinding wool samples to a fine powder for use in the KBr disk technique for infrared spectral study (1). The possibility of using this grinding technique for mica was investigated, as homogeneous pulverisation of mica samples for spectrographic analysis has long been a problem (2). This technique was found to be very satisfactory.