Anatase-Rutile Transition of Precipitated Titanium Oxide with Alcohol Rinsing

The effect of alcohol washing on the anatase-rutile transition of precipitated titanium oxide was investigated using X-ray powder diffraction, Fourier-transform IR spectroscopy, and thermogravimetry. Alcohol (butanol) rinsing accelerated the anatase-rutile transition of precipitated titanium oxide powder so that the onset temperature of transition decreased drastically from 800 degrees C for water-washed powder to 550 degrees C for alcohol-rinsed powder. Alternation of transition kinetics and mechanisms by rinsing media could be confirmed from the analysis of temperature and time dependence of rutile content. The attributability of the chemical state of anatase after crystallization, which contained H(2)O, OH, and organic residues, to the change of transition kinetics with alcohol rinsing will be discussed. Two mechanisms, the effect of residual organics and/or H(2)O(OH), could be suggested on the basis of analysis of the difference between chemical states of water-washed anatase and alcohol-rinsed powder. Copyright 2000 Academic Press.     

Effect of synthesis methods on the morphology of nanosized tin dioxide particles

The effect of precursors on the microstructure of nanocrystalline tin dioxide is studied by thermal analysis, IR spectroscopy, electron microscopy, and X-ray powder diffraction. The precursor precipitated in an optimal pH range whose dehydration and crystallization occur over a wide temperature range with low degrees of oxolation yields crystalline tin dioxide with grain sizes on the order of 16 nm upon calcination at 800°C for 2 h.     

Thermal Behaviour of a TiO2—ZrO2 Microcomposite Prepared by Chemical Coating

A microcomposite powder in the system TiO₂—ZrO₂ as a precursor of zirconium titanate (ZT) materials has been studied by thermal methods (DTA-TG) and X-ray diffraction (XRD). The microcomposite powder has been prepared by chemical processing of crystalline TiO₂ (rutile, 10 mass% anatase),as inner core, coated with in situ precipitated amorphous hydrated zirconia gel, asouter core. The morphology and chemical composition of the resultant powders has been examined by SEM-EDX (Scanning electron microscopy-energy dispersive X-ray spectroscopy). Thermal behaviour of the microcomposite powder was reported, showing the dehydration and dehydroxylation of the zirconia gel, the crystallization into metastable cubic/tetragonal zirconia at temperatures 400—470°C, and the feasibility of preparing ZT powder materials by progressive reaction of TiO₂ and ZrO₂ at higher temperatures (1400°C).This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis of titanium dioxide nanoparticles with mesoporous anatase wall and high photocatalytic activity

Mesoporous titanium dioxide nanosized powder with high specific surface area and anatase wall was synthesized via hydrothermal process by using cetyltrimethylammonium bromide (CTAB) as surfactant-directing agent and pore-forming agent. The resulting materials were characterized by XRD, nitrogen adsorption, FESEM, TEM, and FT-IR spectroscopy. The as-synthesized mesoporous TiO2 nanoparticles have mean diameter of 17.6 nm with mean pore size of 2.1 nm. The specific surface area of the as-synthesized mesoporous nanosized TiO2 exceeded 430 m2/g and that of the samples after calcination at 600 degrees C still have 221.9 m2/g. The mesoporous TiO2 nanoparticles show significant activities on the oxidation of Rhodamine B (RB). The large surface area, small crystalline size, and well-crystallized anatase mesostructure can explain the high photocatalytic activity of mesoporous TiO2 nanoparticles calcined at 400 degrees C.     

Characterisation of zeolitic materials with a HEU-type structure modified by transition metal elements: definition of acid sites in nickel-loaded crystals in the light of experimental and quantum-chemical results

Nickel-loaded HEU-type zeolite crystals have been obtained by well-known synthetic procedures and characterised by X-ray fluorescence (XRF), scanning-electron microscopy/ energy-dispersive spectroscopy (SEM-EDS), FT-IR, diffuse reflectance UV/ Vis spectroscopy (DR(UV/Vis)S) and X-ray photoelectron spectroscopy (XPS) measurements as non-homoionic and non-stoichiometric substances containing exchangeable hydrated Ni2+ ions in the micropores and nickel hydroxide phases supported on the surface. Thermogravimetric analysis/differential gravimetry (TGA/DTG) and differential thermal analysis (DTA) demonstrated that full dehydration below approximately 400 degrees C follows a clearly endothermic process, whereas at higher temperatures the zeolite is amorphised and finally partially recrystallised to Ni(Al,Si) oxides, detected by powder X-ray powder diffraction (XRD). The solid acidity of NiHEU, initially determined by temperature-programmed desorption (TPD) of ammonia to be 8.93 mgg(-1) NH3, is attributed to the weak acid sites (fundamentally Lewis sites) resolved at approximately 183 degrees C, and to the strong acid sites (essentially Br?nsted sites) resolved at approximately 461 degrees C in the TPD pattern. A more sophisticated study based on in situ/ex situ FT-IR with in situ/ex situ 27Al MAS NMR and pyridine (Py) as a probe molecule, revealed that the Lewis acid sites can be attributed primarily to Ni2+ ions, whereas the Br?nsted ones can probably be associated with the surface-supported nickel hydroxide phases. The spectroscopic measurements in conjunction with powder XRD and 29Si MAS NMR data strongly suggest that distorted Al tetrahedra are formed during the dehydration process and Py chemisorption/complexation (NiHEU-Py), whereas the crystal structure is remarkably well preserved in the rehydrated material (NiHEU-Py/R). The structural, electronic, energetic and spectroscopic properties of all possible nickel(II) aqua and dihydroxy complexes absorbed in the zeolite micropores or supported on the zeolite surface were studied theoretically by density functional theory (DFT). The computed proton affinity, found to be in the range 182.0-210.0 kcalmol(-1), increases with increasing coordination number of the aqua and dihydroxy nickel(II) complexes.     

Interaction of water with titania: implications for high-temperature gas sensing

High-temperature gas sensors based on semiconducting metal oxides show potential for optimization of combustion processes, resulting in efficient energy use and minimization of emissions. Such metal oxides can function as gas sensors because of the reaction of the sensing gas (e.g., CO) with ionosorbed oxygen species on the oxide surface with the resulting increase in conductivity. A limitation of metal oxide sensors is their difficulty of distinguishing between different gases. Designing selectivity into sensors necessitates a better understanding of the chemistry of gas-solid interactions at high temperatures. In this paper, we have used in situ infrared spectroscopy to monitor the dehydration of a hydrated anatase surface up to 600 degrees C and also to examine the hydration/dehydration of anatase held at 400 degrees C. When the O-H stretching region (3000-3800 cm(-1)) was primarily focused on, it was found that water loss from the titania surface proceeded at lower temperatures (<200 degrees C) through desorption, whereas at higher temperatures, water dissociation to terminal (approximately 3710 cm(-1)) and bridged (approximately 3660 cm(-1)) hydroxyl groups was noted. With a further increase in temperature to 600 degrees C, the bridged hydroxyl groups disappeared faster than the terminal ones. The electrical resistance of anatase at 600 degrees C was measured in the presence of moist gas streams and resulted in an increase in conductivity in the presence of water. In situ vibrational spectroscopy indicated a temporal correlation between the appearance of the bridging hydroxyl group and the change in electrical resistance. Several possible mechanisms are discussed. The chemical reaction of water with anatase at high temperatures necessitates that water be removed from the gas stream to avoid interference. A strategy involving the use of a hydrophobic microporous filter that can reject water and let gases such as CO pass unimpeded is examined. Successful use of such a concept has been demonstrated with a silicalite filter using moist CO gas streams.     

Effects of dehydration on the apolar surface energetics of inorganic paper fillers

The surface energies of various inorganic fillers including kaolin clay, titanium dioxide, and talc were examined using inverse gas chromatography (IGC). In an earlier investigation that examined calcium carbonate fillers, dehydration by heating under a dry nitrogen purge had a substantial influence on the apolar (gammaS(LW)) and polar (gammaS(AB)) components of surface energy as measured using IGC. Using the same approach, the influence of such conditioning on several inorganic fillers used in papermaking were determined using preconditioning IGC from 100 to 300 degrees C, and sequential isothermal analysis at 100 degrees C. Results from IGC analysis of titanium dioxides (rutile and anatase) were similar to precipitated calcium carbonate (PCC) for temperatures up to 200 degrees C. PCC was significantly more energetic after preconditioning at 300 degrees C, which may indicate the onset of significant thermal decomposition that titanium dioxides will not exhibit. Kaolin clay samples had relatively high apolar surface energy similar to that of the chalk samples. Calcination gave lower gammaS(LW) values that could not be accounted for by changes in the microporous structure. More likely the differences resulted from contamination of highly energetic surface sites with adsorbates other than water. Talc samples exhibited relatively high apolar surface energies that increased with preconditioning temperature. The results provided insight into the significance of water on the final adhesion properties of fillers in the sheet structure or coating layer.     

Acidity and Catalytic Activity of Phosphoric Acid Modified Titanium Oxide Surface

By refluxing the anatase form of TiO₂ powder in phosphoric acid, the surface acidity was observed to increase. The amount of acid was determined by n-butylamine titration in n-heptane media, and was found to be proportional to the reflux period in phosphoric acid. XRD patterns and IR spectra revealed that the products contained a mixture of the anatase form of TiO₂ and titanium phosphate phases. Based on the calculated acid density on the surface, part of the titrant, n-butylamine penetrated into the titanium phosphate layers. Further investigations using TGA, FT-IR and TEM techniques along with surface area measurements indicated that the titanium phosphate phase was coated over the TiO₂ phase. The surface acidity of the phosphoric acid treated anatase increased due to the substitution of Ti-OH groups by phosphate groups. Nevertheless, the chemical properties of the resultant surfaces were found to be influenced by the internal anatase phase. The kinetic data on the 2-propanol dehydration reaction, where the activation energies were found to decrease gradually with an increase in phosphate content, also support these conclusion.     

Real time observation of the hydrothermal crystallization of barium titanate using in situ neutron powder diffraction.

The hydrothermal crystallization of barium titanate, BaTiO3, has been studied in situ by time-resolved powder neutron diffraction methods using the recently developed Oxford/ISIS hydrothermal cell. This technique has allowed the formation of the ferroelectric ceramic to be followed in a noninvasive manner in real time and under genuine reaction conditions. In a first set of experiments, Ba(OD)2-8D2O was reacted with two different titanium sources, either crystalline TiO2 (anatase) or amorphous TiO2-H2O in D2O, at 100-140 degrees C and the reaction studied using the POLARIS time-of-flight neutron powder diffractometer, at the ISIS Facility. In a second series of experiments, the reaction between barium chloride and crystalline TiO2 (anatase) in NaOD/D2O was studied at temperatures between 100 and 200 degrees C and at different deuterioxide concentrations using the constant-wavelength D20 neutron powder diffractometer at the Institut Laue Langevin. Quantitative growth and decay curves were determined from analysis of the integrated intensities of Bragg reflections of starting materials and product phases. In both sets of experiments the rapid dissolution of the barium source was observed, followed by dissolution of the titanium source before the onset of crystallization of barium titanate. Using a nucleation-growth model we are able to simulate the growth curve of barium titanate at three temperatures. Our results indicate the predominance of a homogeneous dissolution-precipitation mechanism for the hydrothermal formation of barium titanate, rather than other possible mechanisms that have been discussed in the literature. Analysis of the line widths of the Bragg reflections in the neutron diffraction data indicates that the particle size of the BaTiO3 product phase prepared from the amorphous TiO2-H2O is smaller than that prepared from crystalline TiO2 (anatase).     

Crystallization of polyvinyl alcohol-water films by slow dehydration

Semicrystalline crosslinked poly(vinyl alcohol) hydrogels in the form of films were prepared by electron beam irradiation and a subsequent slow dehydration process at 25 ± 1°, using various drying agents. Nucleation and crystallization started after an induction time varying between 10 and 108 hr and proceeded very quickly, but always depending on the rate of evaporation of water. For the region of main growth of crystallites (degrees of crystallinity between 5 and 35%), the crystallization rate could be expressed by an Avrami equation; it was shown that the crystallization rate is lower for more densely crosslinked polymers under the same drying conditions.     

Crystallization behaviors of nanosized MgO particles from magnesium alkoxides

The effects of the size of the alkoxy group on the thermal decomposition behavior of magnesium alkoxides (magnesium methoxide and ethoxide) and the crystallization behavior of MgO was investigated using thermogravimetry, Fourier-transformed infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. As the size of the alkyl group increased, the decomposition temperature decreased and resultant MgO crystallization of the alkoxide precursor was enhanced. In an inert N(2) atmosphere, the decomposition temperature of magnesium ethoxide was about 260 degrees C, which was lower than that of magnesium methoxide by approximately 70 degrees C. The degree of the crystallization of MgO particles from the ethoxide was also significantly higher than that of the methoxide. This result is explained in terms of the O-R bonding strength of the alkoxide. With use of the Kissinger method, the activation energy for the thermal decomposition of magnesium alkoxide was found to be dependent on the size of the alkyl group. The activation energies were 161+/-23 and 130+/-24 kJ/mol for the magnesium methoxide and the magnesium ethoxide, respectively.     

Synthesis of highly active sulfate-promoted rutile titania nanoparticles with a response to visible light

Highly active sulfate-promoted rutile titania (SO(4)(2-)/TiO(2)) with smaller band gap was prepared by an in situ sulfation method, that is, under moderate conditions, sulfate-promoted rutile titania was directly obtained via precipitating Ti(SO(4))(2) in NaOH solution followed by peptizing in HNO(3) without the phase transformation from anatase to rutile. Thus, the negative impacts of phase transformation from anatase to rutile on the structure, surface, and photoactivity properties of the catalysts due to higher calcination temperature can be avoided. The catalysts were characterized by means of thermal analysis, Brunauer-Emmett-Teller analysis (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, FT-IR pyridine adsorption, and temperature-programmed desorption (TPD). The results show sulfate species are sensitive to the variation of calcination temperature. In the process of peptizing, sulfate species are homogeneously dispersed throughout the bulk of catalysts, allowing sulfate species to penetrate into the network of TiO(2) effectively. After being calcined at 300 degrees C, sulfate species occupy oxygen sites to form Ti-S bonds, as evidenced by XPS results. As calcination temperature is further increased to 600 degrees C or above, the active sulfate species on the catalyst surface are destroyed, and the sulfate species in the network of TiO(2) are expelled out onto the surface to form inactive sulfate species. Thus, Ti(3+) defects will be produced on the catalyst surface. Accompanying this process, surface area is decreased promptly, and crystalline size is greatly increased via two fast growth phases due to the decomposition of sulfate species with different binding forces. Most importantly, the band gap of SO(4)(2-)/TiO(2) is remarkably shifted to the visible light region due to the formation of Ti-S bonds, and with increasing calcination temperature the visible light absorption capability is reduced due to breakage of Ti-S bonds. The excellent photoactivity of 300 degrees C calcined SO(4)(2-)/TiO(2) can be explained by its small crystalline size, high surface area, loose and porous microstructure, and the generation of Br?nsted acidity on its surface.     

Pd(II) immobilized on mesoporous silica by N-heterocyclic carbene ionic liquids and catalysis for hydrogenation

In this work we synthesized Pd(II) immobilized on mesoporous silica by N-heterocyclic carbene (NHC) ionic liquids (ILs) with different alkyl chain lengths. The catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), low-angle X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen sorption. The catalysts were used for the hydrogenation of alkenes and allyl alcohol. The results indicated that the catalysts were very active, selective, and stable. The selectivity for the hydrogenation of allyl alcohol to 1-propanol increased with the increase of the alkyl chain length of the ILs. The effect of supercritical CO(2) (scCO(2)) on the hydrogenation of allyl alcohol was also studied, and it was demonstrated that scCO(2) could enhance the selectivity of the reaction considerably. The XPS study showed that the valence of Pd(II) remained unchanged under hydrogenation conditions.     

Unusual crystallization behaviors of anatase nanocrystallites from a molecularly thin titania nanosheet and its stacked forms: increase in nucleation temperature and oriented growth

Crystallization behaviors of anatase nanocrystallites from an ultrathin two-dimensional reactant composed of exfoliated titania nanosheets have been studied by monitoring the heating process of their well-organized films, with which the film thickness can be controlled from a molecularly thin monolayer to a stacked multilayer structure with a stepwise increment of approximately 1 nm. The heated products were identified by means of total reflection fluorescence X-ray absorption near-edge structure analysis and in-plane X-ray diffraction measurements using a synchrotron radiation source. The films composed of five or more layers of stacked nanosheets were transformed into anatase at 400-500 degrees C, which is a normal crystallization temperature of anatase from bulk reactants. As the film became thinner by decreasing the number of nanosheet layers to five or less, the crystallization temperature was found to increase and finally reached 800 degrees C for the monolayer film. Interestingly, preferential growth of anatase along the c-axis was strongly promoted for these ultrathin films. These unusual behaviors may be understood in terms of crystallization from the two-dimensional system of scarcely distributed reactants. The titania nanosheet crystallite is much thinner than the unit cell dimensions of anatase, and therefore, extensive atomic diffusion is required for the transformation particularly for the ultrathin films with a critical number (2-3) of stacked nanosheet layers. There is some structural similarity between anatase and titania nanosheet, which may account for the oriented growth of anatase nanocrystallites.     

Effects of microwaves on the dehydration characteristics of santite

In this paper, by using the microwave irradiation, the dehydration curves of santite (KB₅O₈·4H₂O) were obtained and modeled. By using a different mathematical model, the kinetic parameters of the dehydration process were determined. The dehydration of santite was completed at 180, 105 and 60 min for 360, 600 and 800 W, respectively. The characterization techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy were applied to the obtained santite mineral and dehydrated santite mineral. From the obtained XRD analysis, santite, its powder diffraction file number is 01-072-1688 transformed into an amorphous phase after the microwave dehydration process. From the FT-IR and Raman analyses, it can be said that partial dehydration was achieved due to the disappearance of structural H₂O bands but remaining some hydroxyl bands. For the modeling results, Verma model best fits the experimental data obtained from the dehydration and the dehydration activation energy was calculated as 11.92 kW?×?g^–1.

     

Thermal-Dependent dehydration process and intramolecular cyclization of lisinopril dihydrate in the solid state

The pathway of dehydration and intramolecular cyclization of lisinopril dihydrate in the solid state was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and a combination of thermal analyzer with Fourier transform infrared microspectroscopy (thermal FT-IR microscopic system). The results indicate that the dehydration from the solid-state lisinopril dihydrate had a two-step process from dihydrate to monohydrate at 76 degrees C and then from monohydrate to anhydrate at 99-101 approximately C, which could be clearly observed from the above three methods. Only the thermal FT-IR microscopic system could give vital information on diketopiperazine (DKP) formation via intramolecular cyclization in anhydrous lisinopril. A new peak at 1670 cm(-1) assigned to the carbonyl band of DKP formation was clearly evidenced. The water of reaction byproduct was liberated at a temperature >157 degrees C and appeared on the IR spectra near 3200-3400 cm(-1). Moreover, the peak at 1574 cm(-1) assigned to carboxylate shifted to 1552 cm(-1) due to the DKP formation. The peak at 1670 cm(-1) related to the DKP formation changed slightly in intensity from 147 degrees C and significantly near 157 degrees C. DSC and TGA methods were poor for use in supplying information on DKP formation in lisinopril. The thermal FT-IR microscopic system is useful from the view point that it can quickly and directly show the solid-state stability of drug.     

C-N-S-TiO2光催化剂的制备、表征及其性能

以钛酸四丁酯为钛源、功能生物小分子胱氨酸为掺杂剂,采用溶胶-凝胶法同步合成了C-N-S-TiO2光催化剂,利用XRD、XPS、FT-IR和DRS等测试技术对样品的结构及物化性能进行了表征。XRD和DRS分析表明,共掺杂抑制了TiO2晶粒的生长,提高了晶相转变温度,且C-N-S-TiO2样品的吸收带边明显"红移",光吸收范围一直延长至800 nm左右。XPS分析结果显示,C-N-S-TiO2样品表面产生了杂质能级,C、S元素分别取代部分晶格Ti4+以CO23-和S6+形式存在;而N峰呈宽化状态,以O—Ti—N和Ti—O—N键存在,且样品表面羟基含量明显增加。以罗丹明B染料为模型污染物,考察了该催化剂的可见光催化活性。结果表明,与P25 TiO2比较,C-N-S-TiO2光催化剂活性得到改进,C-N-S-TiO2光催化剂在470～800 nm波长下辐射120 min后对罗丹明B的降解率可高达83%。     

Paracetamol-propyphenazone interaction and formulation difficulties associated with eutectic formation in combination solid dosage forms

Polymorphic behaviours of paracetamol and propyphenazone and interaction between these two compounds were investigated using differential scanning calorimetry (DSC), X-ray powder diffraction and Fourier transform-infrared (FT-IR)-spectroscopy. Binary mixtures containing various ratios of the compounds were prepared as physical and fused mixtures and analysed by DSC to study their thermal behaviours. Phase diagrams obtained from the melting endotherms of the binary mixtures demonstrated formation of an eutectic mixture at a paracetamol-propyphenazone combination of about 35:65 (w/w) with an eutectic temperature of 56 degrees C. The FT-IR spectroscopy revealed no chemical interaction due to eutectic formation, and a lower degree of crystallinity of the eutectic mixture than individual substances was observed by X-ray powder diffraction analysis. The DSC and X-ray powder diffraction data demonstrated a polymorphic change in propyphenazone as a result of melting of the compound. Tablets, containing both paracetamol and propyphenazone in a combination formulation and prepared using standard wet granulation technology, were found to have physical instability when packed in either polyvinylchloride// aluminium or polyvinylchloride/polyvinyldienechloride// aluminium blisters and stored for one month at 40 degrees C with either 75% relative humidity or without any humidity control. The instability of the tablets was more apparent under the high humidity condition.     

Physicochemical analyses of phase transition and dehydration processes of a new oral 1beta-methylcarbapenem antibiotic agent,CS-834

The characterizations of the anhydrate (A-form), monohydrate (B1-form), and dihydrate (B2-form) of CS-834 were investigated by powder X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry-differential thermal analysis (TG-DTA), infrared spectroscopy, and Karl Fischer moisture titration. The typical DSC curve of the B2-form showed five endothermic peaks at 35.0, 46.4, 56.2, 99.2, and 190.4 degrees C and an exothermic peak at 123.4 degrees C. In TG-DTA analysis, the three peaks at 35.0, 46.4, and 56.2 degrees C had a total weight loss of 7.3%, corresponding to the release of two water molecules. From morphological observation under thermomicroscopy, the endothermic peak at 99.2 degrees C was attributed to the melting of the dehydrous crystals (B0-form) and the exothermic peak at 123.4 degrees C to the recrystallization to the A-form crystals. The endothermic peak at 190.4 degrees C was due to the melting of the A-form crystals. After incubation for 6.0 h at 35, 50, 60, and 80 degrees C, the powder X-ray diffraction patterns of the B2-form indicated that it was converted into the A-form via the B1-form and B0-form. Thus CS-834 exists in homologous hydrous crystal forms in multiple-phase transformations with the dehydration of two water molecules.     

Comparative evaluation of bioactivity of crystalline trypsin for drying by Fourier-transformed infrared spectroscopy

The purpose of this study was to evaluate the enzymatic stability of colloidal trypsin powder during heating in a solid-state by using Fourier transform infrared (FT-IR) spectra with chemoinformatics and generalized two-dimensional (2D) correlation spectroscopy. Colloidal crystalline trypsin powders were heated using differential scanning calorimetry. The enzymatic activity of trypsin was assayed by the kinetic degradation method. Spectra of 10 calibration sample sets were recorded three times with a FT-IR spectrometer. The maximum intensity at 1634 cm⁻¹ of FT-IR spectra and enzymatic activity of trypsin decreased as the temperature increased. The FT-IR spectra of trypsin samples were analyzed by a principal component regression analysis (PCR). A plot of the calibration data obtained was made between the actual and predicted trypsin activity based on a two-component model with γ² = 0.962. On the other hand, a 2D method was applied to FT-IR spectra of heat-treated trypsin. The result was consistent with that of the chemoinformetrical method. The results for deactivation of colloidal trypsin powder by heat-treatment indicated that nano-structure of crystalline trypsin changed by heating reflecting that the β-sheet was mainly transformed, since the peak at 1634 cm⁻¹ decreased with dehydration. The FT-IR chemoinformetrical method allows for a solid-state quantitative analysis of the bioactivity of the bulk powder of trypsin during drying.