Nonaqueous Titration Research Articles

Thermolytic Synthesis of Asphaltene-like Nitrogenous Bases and Study of Their Aggregative Stability

The work is devoted to the study of the influence of nitrogenous bases on the composition of oil and the structure of asphaltenes on their colloidal stability in solution. Model petroleum systems with a basic nitrogen content of 1, 2, and 3% wt. were used as objects of study. Asphaltene-like nitrogenous bases were obtained by thermolysis of model petroleum systems with different nitrogen contents. The results were obtained using elemental analysis, non-aqueous potentiometric titration, spectrophotometry, 1H NMR spectroscopy, and liquid adsorption chromatography. It was established that the content of Nbas in asphaltenes increases by 0.3–1.3% wt. with the increase in quinoline content in petroleum components. Quinoline is incorporated into the supramolecular structure of asphaltenes and increases their average molecular weight by 650 amu. and aromaticity by 2%. The aggregative stability of asphaltenes decreases by 1.5–6 times with an increase in their average molecular weight and an increase in Nbas in their composition as a component of a dispersion medium. The colloidal stability of synthetic asphaltene-like substances, on the contrary, is due to the appearance of their molecular sequence of fragments containing Nbas in aromatic rings.

Effect of Polymer Architecture and Acidic Group Density on the Degree of Salt Formation in Amorphous Solid Dispersions.

Recent work has shown that an amorphous drug-polymer salt can be highly stable against crystallization under hot and humid storage conditions (e.g., 40 °C/75% RH) and provide fast release and that these advantages depend on the degree of salt formation. Here, we investigate the salt formation between the basic drug lumefantrine (LMF) and several acidic polymers: poly(acrylic acid) (PAA), hypromellose phthalate (HPMCP), hypromellose acetate succinate (HPMCAS), cellulose acetate phthalate (CAP), Eudragit L100, and Eudragit L100-55. Salt formation was performed by "slurry synthesis" where dry components were mixed at room temperature in the presence of a small quantity of an organic solvent, which was subsequently removed. This method achieved more complete salt formation than the conventional methods of hot-melt extrusion and rotary evaporation. The acidic group density of a polymer was determined by nonaqueous titration in the same solvent used for slurry synthesis; the degree of LMF protonation was determined by X-ray photoelectron spectroscopy. The polymers studied show very different abilities to protonate LMF when compared at a common drug loading, following the order PAA > (HPMCP ∼ CAP ∼ L100 ∼ L100-55) > HPMCAS, but the difference largely disappears when the degree of protonation is plotted against the concentration of the available acidic groups for reaction. This indicates that the extent of salt formation is mainly controlled by the acidic group density and is less sensitive to the polymer architecture. Our results are relevant for selecting the optimal polymer to control the degree of ionization in amorphous solid dispersions.

Sulfonated mesoporous TUD-1: An innovative environmentally friendly solid acid catalyst for various organic transformations

TUD-1, a novel sponge-like three-dimensional mesoporous silica material, was synthesized in one-step using a hydrothermal technique and triethanolamine as a template. To enhance its acidic properties, the TUD-1 material underwent sulfonation with varying amounts of sulfonic groups (1 and 3 wt%). Structural characteristics were determined using XRD, FTIR, Raman, BET analysis, HRTEM, SEM, and XPS. Surface acidities of the catalysts were evaluated through non-aqueous potentiometric titration and FTIR analysis of chemisorbed pyridine. The performance of catalysts was assessed in various reactions, including the Pechmann reaction, Friedel-Crafts acylation reaction, and Biginelli reaction for synthesis of 7-hydroxy-4-methyl-2H-chromen-2-one, aromatic ketones and 3, 4-dihydropyrimidin-2(1H)-one. The findings confirm that the TUD-1 mesoporous structure did not undergo any significant alteration post sulfonation. The sulfonated catalysts exhibited higher surface acidities than TUD-1. A correlation between surface acidity, particularly Brönsted acid sites, and catalytic efficiency in selected reactions was evident from both catalytic testing and characterization. Under moderate conditions, TUD-1-3SO3H exhibited outstanding catalytic performance and remarkable reusability across all selected reactions.

РАЗРАБОТКА СОСТАВА И ОЦЕНКА КАЧЕСТВА КОМБИНИРОВАННОГО СРЕДСТВА ДЛЯ ПОЛОСТИ РТА

Inflammatory diseases of the oral cavity belong to the category of widespread pathologies and are characterized by a diverse etiology. For their treatment and prevention, herbal remedies that have the properties of a complex effect on the causes and nature of the development of the inflammatory process are quite often and quite reasonably used. Jujube leaves seem to be a promising source of biologically active substances (BAS) for inclusion in anti-inflammatory drugs for the oral cavity due to their significant content of flavonoids, phenolcarboxylic acids, triterpene compounds and other groups of BAS, which individually and in combination determine the target activity. In addition, according to the literature, compounds that cause an anesthetic effect in the oral cavity were found in the leaves of jujube. Free radical oxidation and subsequent disruption of the integrity of cell membranes play a significant role in the pathogenesis of oral diseases. In this regard, a promising direction in the comprehensive prevention and treatment of oral diseases is the use of antioxidant drugs, among which ethyl methylhydroxypyridine succinate (EMHPS) is quite popular in this regard. EMGPS inhibits the oxidation of biological membranes, increases the activity of antioxidant enzymes, and also participates in the regulation of metabolic activity of cells. It seemed appropriate to develop a composition and evaluate the quality of an oral product based on a complex of biologically active substances from jujube leaves and EMGPS with a predicted complex anti-inflammatory and antioxidant effect. Determination of commodity indicators of jujube leaves, dry residue, alcohol content in the alcohol extract and pH of the oral product was carried out using pharmacopoeial methods. pH was measured using a Mettler Toledo pH meter. An alcoholic extract from jujube leaves in the form of a tincture was obtained by fractional maceration using 40% ethyl alcohol, which selectively extracts flavonoids from this raw material. The quantitative content of flavonoids was determined by differential spectrophotometry using a Shimadzu UV-1800 spectrophotometer. Quantitative analysis of EMGPS was carried out titrimetrically using the non-aqueous titration method. It has been established that the developed oral product containing tincture of jujube leaves and EMGPS is characterized by satisfactory quality indicators. The proposed methods for the quantitative determination of active substances make it possible to statistically reliably control their content in the composition.

Thermal degradation studies of 2-amino 6-nitrobenzothiazole-oxamide-formaldehyde copolymer and its composites

Composites are viewed as promising advanced materials because of their superior features, including enhanced flame retardancy, density, relatively large surface areas, strength and thermomechanical/optoelectronic/magnetic capabilities. 2-amino 6-nitrobenzothiazole, oxamide, and formaldehyde has been used for the synthesis of copolymerizing polycondensation technique, and newly synthesized copolymer with activated charcoal was used to synthesize its composite. Several physicochemical techniques, and Ultraviolet-visible, SEM, TGA, and FTIR techniques, have been utilized to illustrate the produced copolymer and its composite. The non-aqueous conductometric titration was used to determine the molecular weight of the 2-amino 6-nitrobenzothiazole-oxamide-formaldehyde copolymer.based on TGA data, thermal stability of the composite is higher than copolymer, possibly because there are more carbonized residues. Based on Ea values determined by Sharp-Wentworth and Freeman-Carroll technique for copolymer and its composite, it is observed that they are in good agreement with each other. It is abundantly obvious from the results of the sequence of reaction that the decomposition reaction roughly follows a first-order kinetics. The composite's higher surface area, porous makeup, and smaller particle size may have contributed to its superior performance. The copolymer and its composite have better heat stability.

CHANGES IN THE COMPOSITION AND COLLOIDAL STABILITY OF HEAVY OIL IN THE PRESENCE OF QUINOLINE

The influence of low molecular weight nitrogenous bases (by the example of quinoline) on the composition and colloidal stability of asphaltenes in solutions and oil dispersed systems is investigated. The objects of study were model oil systems with the basic nitrogen content of 1.0-3.0 wt. %, obtained by mixing the original oil and quinoline. The content of basic nitrogen (Nbas) was determined using the method of non-aqueous potentiometric titration. Analysis of the colloidal stability of asphaltenes in solutions and oil systems was carried out by spectrophotometry. It is shown that the content of asphaltenes in oil systems is reduced by 0.22 wt. % with an increase in the content of basic nitrogen (quinoline) up to 3 wt. %. At the same time, the content of resins increases by almost 8 wt. %. With an increase in the content of quinoline in oil systems, the proportion of basic nitrogen in the asphaltenes isolated from them increases from 1.71 to 3.60 wt. %, which indicates the active participation of quinoline in the formation of supramolecular structures of asphaltenes during their precipitation with n-hexane. The presence of low molecular weight nitrogenous bases (quinoline) in oil contributes to a significant increase in the growth rate of aggregates and a decrease in the colloidal stability of oil systems.

A Quick Method for the Determination of the Fraction of Freebase Nicotine in Electronic Cigarettes.

Recently, many electronic cigarettes (ECIGs) manufacturers have begun offering e-liquids, known as "nicotine salts". These salts that have started gaining big popularity among users can be formed by adding weak acid to e-liquid mixtures consisting of propylene glycol (PG), vegetable glycerin (VG), flavors, and nicotine. The latter can exist in two forms: monoprotonated (mp) and freebase (fb) based on the pH of the matrix. Over the years, the determination of the fraction of fb was found important to policymakers as the prevalence of this form in ECIGs has been associated with the harshness sensory of inhalable aerosols. Liquid-liquid extraction (LLE), 1H NMR, and Henderson-Hasselback have been developed to deduce the fraction of fb; however, these methods were found to be time-consuming and have shown some challenges mainly due to the presence of a non-aqueous matrix consisting of PG and VG. This paper presents a quick non-aqueous pH measurement-based method that allows a quick determination of the fraction fb by just measuring the pH and the dielectric constant of the e-liquid. Then, by inputting these values into an established mathematical relationship, the fraction fb can be deduced. The relationship between pH, dielectric constant, and fb relies on knowing the values of the acidity dissociation constants of nicotine, which were determined for the first time in various PG/VG mixtures using a non-aqueous potentiometric titration. To validate the proposed method, the fraction fb was determined for commercials and lab-made nicotine salts utilizing the pH and LLE methods. The variation between the two methods was (<8.0%) for commercial e-liquids and lab-made nicotine salts containing lactic acid and salicylic acid. A larger discrepancy of up to 22% was observed for lab-made nicotine salts containing benzoic acid, which can be attributed to the stronger affinity of benzoic acid to toluene in the LLE method.

The Effect of Sample Preparation Techniques on Lignin Fourier Transform Infrared Spectroscopy.

The characterization and quantification of functional groups in technical lignins are among the chief obstacles of the utilization of this highly abundant biopolymer. Although several techniques were developed for this purpose, there is still a need for quick, cost-efficient, and reliable quantification methods for lignin. In this paper, three sampling techniques for fourier transform infrared (FTIR) spectroscopy were assessed both qualitatively and quantitatively, delineating how these affected the resultant spectra. The attenuated total reflectance (ATR) of neat powders and DMSO-d6 solutions, as well as transmission FTIR using the KBr pelleting method (0.5 wt%), were investigated and compared for eight lignin samples. The ATR of neat lignins provided a quick and easy method, but the signal-to-noise ratios in the afforded spectra were limited. The ATR of the DMSO-d6 solutions was highly concentration dependent, but at a 30 wt%, acceptable signal-to-noise ratios were obtained, allowing for the lignins to be studied in the dissolved state. The KBr pelleting method gave a significant improvement in the smoothness and resolution of the resultant spectra compared to the ATR techniques. Subsequently, the content of phenolic OH groups was calculated from each FTIR mode, and the best correlation was seen between the transmission mode using KBr pellets and the ATR of the neat samples (R2 = 0.9995). Using the titration measurements, the total OH and the phenolic OH group content of the lignin samples were determined as well. These results were then compared to the FTIR results, which revealed an under-estimation of the phenolic OH groups from the non-aqueous potentiometric titration, which was likely due to the differences in the pKa between the lignin and the calibration standard 4-hydroxybenzoic acid. Further, a clear correlation was found between the lower Mn and the increased phenolic OH group content via SEC analyses. The work outlined in this paper give complementary views on the characterization and quantification of technical lignin samples via FTIR.

Thermal Behaviour and Sorption Studies of Ion-Exchange Resin

Copolymer resin 2,4-DAPOF-II has been synthesized by condensation polymerization and its composition was determined on the basis of elemental analysis. Non-aqueous conductometric titration was used to determine the average molecular weight and the intrinsic viscosity was also determined. The formation of copolymer resin was confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopy. The semi-crystalline nature of synthesized copolymer was established by Scanning electron microscopy (SEM). Thermal degradation curve has been discussed with minute details by applying Freeman-Carroll8, Sharp-Wentworth47, Friedman and Chang equations9 to evaluate the kinetic parameters i.e. activation energy (Ea), order of reaction (n) and frequency factor (z). This copolymer is proved to be selective chelating ion exchanger for certain metal ions such as Fe3+, Co2+, Cd2+ and Pb2+. A batch equilibrium method was employed to study the selectivity of metal ion uptake involving the measurements and distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range, shaking time and in media of various ionic strengths.

Physicochemical analysis and quality assessment of Lisinopril oral formulations used in the management of hypertension

Background: Hypertension (HT) is one of the primary causes of death worldwide, accounting for 13% of all deaths. Most cardiovascular disease (CVD) outbreaks in Africa are driven by hypertension, although global detection, awareness, treatment, and control rates are low. Aim: the study aimed to analyze the physicochemical parameters and quality assessment of different brands of Lisinopril. Method: Five (5) brands of Lisinopril oral tablets (10mg) were purchased and coded LSP1, LSP2, LSP3, LSP4, and LSP5. Different test including weight uniformity, standardizations, extraction, titrimetric (aqueous and non-aqueous) analysis, and quality determination of all the brands was conducted using standard procedures outlined in the United States Pharmacopoeia (USP). Result: All brands of Lisinopril used in the analysis conformed to the weight uniformity test. LSP1 conformed to the standard purity range in aqueous titrimetric analysis (98.5%), while the other brands had a close percentage but did not fall within the stated standard with a percentage purity of 82.2% (LSP2), 75.5% (LSP3), 87.1% (LSP4), and 75.6% (LSP5), respectively. For the non-aqueous titration, LSP 1 and LSP 2, conform to the standard percentage purity outlined in the USP, with 100.65% (LSP1), and 97.55% (LSP2). The brands had a percentage purity of 72.78% (LSP3), 88.26% (LSP4), and 88.26% (LSP 5), respectively. Conclusion: the method used in this study can be easily employed in the quality assessment and physicochemical analysis of solid dosage formulations commonly utilized by patients because it is rapid, efficient, cost-effective, less technical and reproducible.

Development of a Method for the Quantitative Determination of Genisten for the Certification of a Certified Reference Material

Introduction. One of the priority directions in the development of modern pharmacy is the search for new highly effective pharmaceutical substances with a high spectrum of pharmacological action and low toxicity. As a result of studies conducted by a number of authors, positive results have been shown for the use of genistein for the prevention and treatment of cardiovascular diseases and osteoporosis in menopausal women. It exhibits hypocholesterolemic and antidiabetic effects, as well as radioprotective properties. A comparative evaluation of genistein from soybean seed cake [Glycine max (L.) Merr.] and synthesized by SPC "Pharmzashchita" and the department of chemical technology of medicinal substances, SPCPU was carried out. Studies of natural genistein by GC-MS showed the presence of an admixture of a related isoflavone, daidzein, in the sample. The synthesized genistein was assessed in terms of qualitative analysis.Aim. The aim of our study was to develop a method for the quantitative determination of genistein for its certification as a CRM.Materials and methods. The object of the study was 96 % genistein (abcr. Gute Chemie, Германия). Quantitative determination by non-aqueous titration was carried out on a laboratory pH meter F20 (METTLER TOLEDO, USA) in a reagent grade DMFA medium (JSC "EKOS-1", Russia). The HPLC study was carried out on an Agilent 1200 Series high-performance liquid chromatograph LC-20 Prominence (Shimadzu, Japan).Results and discussion. The method of non-aqueous titration in DMFA medium which recommended by the State Pharmacopoeia of the Russian Federation XIV edition, titrant 0.1 M sodium hydroxide solution, was used as the basis for the development of a method for the quantitative determination of genistein. The end point of the titration was set using thymol blue indicator. However, the difficulty in visual fixation by changing the color of the indicator was noted. It has been proposed to use a potentiometric end-point determination. For the quantitative determination of genistein in dietary supplements and drugs containing this substance a HPLC method was proposed.Conclusion. A method for non-aqueous titration of genistein with potentiometric end-point determination in DMFA medium has been developed. The integral curve is not very informative for a clear definition of the titration end point. It is recommended to use a differential curve. The validation evaluation of the obtained results showed that the method is trueness (RSD, % = 1.25), precision (RSD, % = 1.21) and intermediate precision (on the first day of RSD, % = 1.21, on the second day of RSD, % = 1.41).

A Validated Potentiometric Titration Method for Quantitative Determination of Molnupiravir from Pharmaceutical Preparation

A simple precise, rapid accurate and sensitive non-aqueous potentiometric titration method was developed for quantitative determination of molnupiravir from pharmaceutical dosage form. The titration was carried out using standardized 0.1 N perchloric acid. The proposed method was found to be precise with % RSD &lt;1 (n = 6). The method showed strict linearity (r2 &gt; 0.9999) between 10 % to 50 % w/v of 100 mg of drug substance weight. The percentage recovery of molnupiravir in the optimized method was between 99.05 to 99.81 %. The method is also found to be rugged when checked by different analysts and using different lots of reagents and different makes of titrators.

The role of phosphotungstic acid in enhancing the catalytic performance of UiO-66 (Zr) and its applications as an efficient solid acid catalyst for coumarins and dihydropyrimidinones synthesis

In recent study, we report a facile and easy technique for the synthesis phosphotungstic acid (PTA) with different weight contents (10, 25, 50 and 75 wt%) loaded on UiO-66 (Zr) as efficient and reusable catalysts for the preparation of coumarin and dihydropyrimidinones derivatives. The structural and textural properties of the prepared catalysts were characterized through XRD, FT-IR, TGA, BET, TEM, SEM, non-aqueous potentiometric titration and FT-IR of chemisorbed pyridine. 50.0 wt% of PTA/UiO-66 (Zr) catalyst showed the highest surface acidity (Ei = 578.5mV) and highest catalytic performance toward the preparation of 7-hydroxy-4-methyl coumarin (97.8%) and 3, 4-dihydropyrimidinones (94.7%).

Inner product of RGB unit vectors for detecting color transition: application to feedback-based flow ratiometric titration.

The inner product (IP) of RGB unit vectors' approach for detecting color transition has further been applied to a feedback-based flow ratiometric titration, including nonaqueous titration. While the flow ratio of titrand/titrant containing an indicator was varying, the video image of the merged solution was taken with a digital microscope downstream. The indicator's color was converted to an RGB unit vector. The change in IP between vectors was used for determining the equivalence point. The concept was successfully applied to the determinations of drug and vinegar samples with reasonable throughput rate (> 18s/titration) and precision (RSD < 4.4%).

A Validated Potentiometric Titration Method for Quantitative Determination of Favipiravir from Pharmaceutical Preparation

A simple precise, rapid accurate and sensitive non-aqueous potentiometric titration method was developed for quantitative determination of favipiravir from pharmaceutical dosage form. The titration was carried out using standardized 0.1 N perchloric acid. The proposed method was found to be precise with % RSD &lt;1 (n = 6). The method showed strict linearity (r2 &gt; 0.9999) between 10 % to 50 % w/v of 0.200 mg of drug substance weight. The percentage recovery of favipiravir in the optimized method was between 99.65 to 100.08 %. The method is also found to be rugged when checked by different analysts and using different lots of reagents and different makes of titrators.

Non-isothermal decomposition study of copolymer derived from 2-amino 6-nitrobenzothiazole, melamine, and formaldehyde

2-Amino 6-nitrobenzohiazole, melamine, and formaldehyde were utilized as a monomer in 2:1:4 M proportions to form BMF-II copolymer using polycondensation polymerization technique in presence of 2 M HCl as catalyst. In light of the essential assessment and spectrical technique like UV–Visible, FT-IR, and 1H NMR spectroscopy, the construction of the integrated copolymer not really set in stone. A non-aqueous conductometric titration approach were used to evaluate the copolymer's number average molecular weight. The surface morphology of a copolymer was concentrated on utilizing scanning electron microscopy. The The energy of activation have been evaluated from thermal methods. The four disintegration steps of the warm crumbling bend are inspected. Utilizing the Sharp-Wentworth, and Freeman-Carroll techniques the activation energy (Ea) and thermodynamic parameters were assessed. based on information from the Freeman-Carroll technique, kinetic and order of reaction, for example, entropy change (ΔS), free energy change (ΔF), evident entropy change (S*) and recurrence factor (Z) were additionally assessed. The Activation energy calculated by these methods are good in agreement with each other. It is found that the order of reaction (n) is 1.16.

Synthesis and Characterization of 2-Amino 6-Nitrobenzothiazole-Adipamide-Formaldehyde Copolymer

The copolymer ANBAF-II was made via condensation of 2-amino 6-nitrobenzothiazole, adipamide and formaldehyde in the presence of 2M HCl as a catalyst at 126 0C in a 2:1:3 molar fraction of reactants. The structure of a newly synthesized copolymer has been elucidated and demonstrated using the concept of elemental evaluation and a variety of spectrum techniques, including UV-Visible, FT-IR, and 1H NMR. The non-aqueous conductometric titration was used to determine the range of common molecular weight of the copolymer. The structure of the copolymer has been provided based on the idea of spectral and physicochemical evaluation.

Synthesis and Study of Thermal Degradation Process of 2,4-Dihydroxyacetophenone-Guanidine-Formaldehyde Copolymer

The resin DAPGF-III, in a molar ratio of 3: 1: 5 was made by heating in the presence of 2M hydrochloric acid for 5h by polycondensation of Guanidine hydrochloride and 2,4-Dihydroxyacetophenone in the presence of formaldehyde. The preliminary structure of the copolymer was evaluated by spectral methods such as elemental analysis, 1H-NMR, FTIR and UV-Visible techniques. The molecular weight of the copolymer was determined by non-aqueous conductivity titration performed by using alcoholic KOH. TGA analysis of the synthesized copolymer is carried out by non-isothermal thermogravimetric analysis, where the sample is exposed to continuous temperature rise at a heating rate of 20°C / min in an air atmosphere and is used to study the rate, decomposition and thermal stability analysis of newly synthesized copolymer at which it was executed. Thermal parameters such as apparent entropy (ΔS), frequency factor (A), change in free energy (ΔG), and rate of reaction were determined according to the methods of Freeman Carroll (FC) and Sharp Wentworth (SW). The activation energy measured by the FC method was confirmed by the SW method.

Thermal Degradation Studies of Copolymer Derived from 2,2’-Dihydroxybiphenyl, Ethylenediamine and Formaldehyde

Copolymer (2,2’-BPEDF) was synthesized with molar ratio 3:1:5 of monomer 2,2’- dihydroxybiphenyl (BP), ethylenediamine (ED) and formaldehyde (F) by condensation polymerization, in acidic medium and refluxing in oil bath at 1200C for 5 h. Composition and structure of organic copolymer have been determined by elemental analysis and molecular weight determination by non-aqueous conductometric titration method. The UV-visible, FTIR and proton nuclear magnetic resonance (1H NMR) spectra were studied to elucidate the structure. The surface features and crystalline behaviour of the copolymer was analysed by scanning electron microscope (SEM).Non isothermal thermogravimetric analysis for determination of their mode decomposition and relative thermal stability, Energy of activation, frequency factor and order of reaction have been calculated by Sharp-Wentworth (SW) and Freeman-Carroll (FC) methods. Energy of activation determined by Sharp-Wentworth and Freeman-Carroll methods are in agreement with each other. The order of reaction is found to be 0.98.

Synthesis, Characterization and Morphology of Organic Copolymer Resin-III Resulting from 1,5-Diaminonaphthalene, 2,4-Dihydroxypropiophenone and Formaldehyde

The copolymer 2,4-DHP-1,5-DANF-III has been synthesized from 2,4-dihydroxypropiophenone, 1,5-diaminonaphthalene with formaldehyde by the polycondensation method in the presence of 2M hydrochloric acid as a catalyst with 3:1:5 molar proportion of reactants. The copolymer has been characterized by various physico-chemical and spectral techniques such as elemental analysis, UV-Visible, FT-IR, 1H-NMR and non-aqueous conductometric titration. Scanning electron microscopy (SEM) has been used to establish the surface morphology. The copolymer has been found to becrystalline as well as amorphous or transition between crystalline and amorphous.