Thermal analysis standard apparatus

Spectroscopically pure peroxy titanium oxide was prepared by the method described in the literature, using spectrographically standardized titanium powder supplied by Johnson and Matthey, London, England. Anatase was then obtained by the thermal decomposition of the peroxy compound. Differential thermal analysis of the peroxy compound was carried out using an apparatus described by Pask and Warner 13 (fig. a). 

The standard apparatus used for thermal desorption is equally suitable for thermal extraction. Thermal extraction is used for the analysis of volatile compounds in solid samples of low moisture content (e.g. plant materials, soil, polymers, etc). In this case, a few milligrams of sample in place of the sorbent contained in a standard desorption tube is heated to a temperature below its melting or decomposition temperature. The volatile compounds released from the sample are accumulated and transferred to the column in the same way as for thermal desorption. 

Murphy CB. Differential thermal analysis. Anal Chem. May. 1960 32 168R-71R. Murphy CB. Differential thermal analysis. Anal Chem. Apr. 1962 34 298R-301R. Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded Hot-Plate Apparatus, ASTM C177, Am Soc. For Testing and Materials. Jan. 11, 2004. 

Paulik F, Paulik J, Erdey L (1958) The Derivatograph. I. An Automatic Recording Apparatus for Simultaneously Conducting Differential Thermal Analysis, Thermogravimetry, and Derivative Thermogravimetry. Z anal Chem 160 241-252. For standardization, quasi-isothermal and isobaric analyses and some example research with the Derivatograph see also (1966) Anal Chim Acta 34 419-426 Paulik F, Paulik J (1973) J Thermal Anal 5 253-270 (1975) 8 557-576. 

Infrared spectrometers may also be combined with thermal analysis instrumentation. Thermal analysis methods provide information about the temperature-dependent physical properties of materials. However, it is not always possible to gain information about the chemical changes associated with changes in temperature by using standard thermal analysis equipment. It is possible to combine thermal analysis apparatus with an infrared spectrometer in order to obtain a complete picture of the chemical and physical changes occurring in various thermal processes [11, 12]. 

The extent of dehydration during temperature treatment of tin(IV)oxide powder is Mcertained by thermogravimetry (Simultaneous Thermal Analysis STA 409, Netzsch). Surface are l8 are determined by nitrogen adsorption using a standard volumetric BET apparatus. The tin(IV)oxide content of the loaded crtrriers and the catalysts is quantified gravimetrically. The platinum content of the catalysts is obtained by a spectrophotometric method which has been described elsewhere (11). 

As was mentioned earlier, distillation and subsequent solvent extraction remains popular in the aroma research area Q). In this method for aroma analysis, the Likens-Nickerson apparatus has been a standard for over 20 years (17, 18). The primary limitation of the Likens-Nickerson distillation/ extraction procedure has been its operation at reduced pressure. It is desirable to operate the system under vacuum in order to reduce the sample boiling point to minimize the formation of thermally induced artifacts. The fact that the solvent side of the distillation-extraction apparatus is also under vacuum makes it difficult to retain the solvent in the apparatus. Even modifications of the apparatus to include a dry ice/acetone condenser followed by a liquid nitrogen trap do not permit easy operation under vacuum. Problems arise in that the solvent or aqueous vapors reach the cryogenic traps, thereby eventually blocking the exit of the condenser. The need to minimize exposure of the sample to heat has resulted in the more frequent use of two step procedures. Very often, the sample is simply placed in a flash evaporator, a certain volume of distillate collected and the distillate is solvent extracted via either separatory funnel or a continuous extractor. In this manner, the distillation process and solvent choice are not conflicting processes. 

The optimal calcination method for zeolite beta was established by thermogravimetric analysis using a PL-Thermal Sciences STA 1500 apparatus. Chemical compositions of the zeolites were determined by atomic absorption spectroscopy on a Varian AAIO spectrometer after dissolution of the samples in hydrofluoric acid. The structure was confirmed by x-ray diffraction on a Siemens D-5000 diffractometer and with infrared spectroscopy on a Mattson Instruments Galaxy 2000 spectrometer. Total surface area, micropore area and micropore volume of the samples were determined by argon adsorption on a Micromeritics ASAP 200M volumetric analyzer using standard techniques. Crystal diameters were determined by scanning electron microscopy. 

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