Quartz sample chamber

Figure 4.32. Schematic of a DMA quartz sample chamber used for shrinkage measurements at 23°C.The DMA is operated in aTMA-like static mode. Typically, polymerizable samples were 0.5 mm thick and the 3.5-mm-diameter probe carried a load of 5 mN (equivalent to a pressure of 520Pa). [From Bair et al. (1998) reprinted with permission from the American Chemical Society.]...

The processed monochromatic light is then directed into a sample chamber, which can accommodate a wide variety of sample holders. Most UV-VIS measurements on biomolecules are taken on solutions of the molecules. The sample is placed in a tube or cuvette made of glass, quartz, or other transparent material. Figure 5.7 shows the design of the most common sample holders and the transmission properties of several transparent materials used in cuvette construction. 

While completing sequential assays, some residual activity might be observed. There may be some adsorbed LOX on the glass, quartz, or Teflon-coated stirrer, especially with high activities. In these cases, the sample chamber or cuvette can be washed with 0.1 % Triton X-100 or 75% methanol followed by water washes. 

Adsorption isotherms were determined on a Cahn 1000 vacuum micro-balance system, using a Leybold-Heraeus Turbotronic TMP 120 turbomolecular pump for evacuation and a variable-leak valve for adsorbate gas injection. Approximately 0.3 grams of the sodium-exchanged zeolite was placed into a 1 cm. diameter hemispherical quartz sample pan within the adsorption chamber... 

For solution phase studies the sample is usually contained in a quartz cuvette but, for most work, some form of temperature control is desirable to obtain detailed information about energy relaxation pathways. The use of a commercial cryostat to perform luminescence measurements on polymer samples in the range iT to 373 K has recently been described by Beavan and Phillips and other home built thermo-statted sample chambers have been reported in the literature (e.g. ). 

The catalysts were contained between quartz wool plugs inside a horizontal quartz tube reactor (1-cm-i.d. by 35-cm-long). The reactor was heated with a split tube furnace, and the temperatures were controlled by a feedback controller. The reactants were preheated to 175°C before entering the catalyst zone. The temperature of the product stream was maintained at 150°C to prevent condensation in the sample chamber or capillary inlet to the mass spectrometer. 

Figure 11. Raman spectra of the formic-biological system (A) shown with the vibration peaks of formic and diamond anvils used in this study. The outlined boxed region is shown at higher resolution (B) to quantify the successive decrease in the peak intensity of the C-H stretch of formic acid at pressures of 68,142, and 324 MPa. The equivalent formate concentrations (C), corresponding to each peak height change, are based on comparisons with a known calibration curve. All experiments were performed at 25°C, with diamond anvil cells with gold-lined sample chambers. Pressures were estimated using Raman shifts in quartz used as an internal calibrant.

Wickbold Decomposition. The Wickbold decomposition apparatus is shown schematically in Figure 12.2. It consists of a sample reservoir, stainless steel burner, quartz combustion chamber, and an absorber con-... 

The hangdown tube and furnace assembly used by Etter and Smith (47) is illustrated in Figure 3.31. A small platinum resistance heater located inside a relatively short quartz sample tube is used as the furnace. The temperature-sensing thermocouple is located inside the furnace chamber with entry into the chamber from the bottom. This design is similar to that of the Perkin-Elmer thermobalance. 

Figure 9.3. Schematic illustration of the heated sample holder (16). A. silver sample block and heater B. glass or quartz cover plate C. 0-ring D. thumb screw (one of four E. gas inlet to sample chamber F. gas outlet tube. G. gas inlet tube and H. connecting cable.

The experiment consists of a source of X-rays (S), a monochromator (M), a sample chamber (C) (where the temperature may be controlled), and a detector (D). The most common source of X-rays is a generator using a sealed tube, and the monochromator, made, for example, from a quartz crystal, is used to select a single wavelength from the polychromatic beam emerging from the source. The sample is placed in a chamber equipped with temperature control and facilities for alignment with a magnetic field. As for the detector, different choices can be made... 

Measurements were taken over the range from IB = 20° to IB = 44°. Temperature was measured and controlled based on a type-S thermocouple welded to the bottom of the platinum strip. At sufficiently high temperatures (t > 800°C), more accurate sample temperature measurements were possible through the use of an optical pyrometer (Optical Pyrometer, Leeds Northrup Co., Philadelphia, PA) trained on the sample surface through a quartz window in the sample chamber. 

Impressed by the information provided by Py-FIMS, another research group developed pyrolysis-molecular beam mass spectrometry (Py-MBMS) by coupling a quartz pyrolysis chamber to the inlet of a triple-quadrupole mass spectrometer. This group wished to study the organic matrix of forest soils and saw two limitations for the application of Py-FIMS to their study first, that the very small sample used in Py-FIMS might not be representative of the macro soil sample, and second, that the time required for each sample analysis by Py-FIMS was relatively long if one wished to examine and compare a large number of soil samples. 

Figure 7 Automated resistively heated filament pyrolysis using quartz sample tubes, front view, and side view of the pyrolysis chamber. 1, Quartz tubes 2, sample carousel 3, optical sensor for locating tubes 4, funnel to guide tubes into inlet valve 5, inlet valve 6, quartz chamber 7, heating filament 8, outlet valve 9, GC online valve 10, connection to GC injector.

A Cahn RG electrobalance is housed in a stainless steel case B. Polymer samples on quartz sample pans are suspended on both sides of the balance with 32-gauge nichrome wires. A strip-chart recorder is used to display portions of the electrobalance read-out. The uncross-linked and cross-linked samples of approximately equal wights are placed on the two sides of the electrobalance. A glass weighing chamber K communicates with the balance case, and a quartz spring is attached to a removable chamber cap D. An uncross-linked polymer sample is suspended on... 

Cs (T% = 2 10 years) and Cs (T = 30.1 years). Isnard et cd. [12] utilized an MC-ICP-MS unit modified to handle radioactive samples that was equipped with a PFA microconcentric nebulizer-quartz spray chamber combination for sample introduction and nine Faraday collectors. This mass region suffers from spectral interference from stable Ba, hence the Cs was purified by Hquid chromatographic methods prior to analysis. The authors noted that Cs is somewhat problematic with respect to memory effects in the sample introduction system and therefore care was taken to rinse adequately between samples. An interpolative method for determining mass bias correction factors based upon such factors determined... 

In Fig. 4.30 a sub-micrometer-thick film of a cured, unknown networkforming polymer that was adhering to an -750-pm-thick silicon wafer was placed in the TMA s quartz enclosure. The supplier reported the film s thickness after baking at 200 °C was of the order of 400 nm. An 0.8-mm-diameter quartz rod with a flat bottom was placed on top of the film with a load of approximately 10 Pa. The sample chamber was purged with helium, and a heating rate of 5 °C/min was employed. 

All measurements were made in a Perkin-Elmer DMA7e, whose sample chamber was replaced with a large quartz housing designed to allow samples held between glass shdes as wide as 4.5 cm to be placed on a flat quartz floor. In the static mode, uncured liquid or partially reacted photosensitive materials are placed between quartz plates and the probe rests with a load of 5mN on the top plate during the photoreaction and provides an accurate measure of the sample thickness perpendicular to the plane of the glass plates or in the transverse direction. 

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