Quartz cells

Fourier-transform infrared (IR) spectra (resolution 2 cm- ) were recorded with a Perkin Elmer 1750 instrument in a quartz cell connected to grease-free evacuation and gas manipulation lines. The self-supporting disk technique was used. Before recording the spectra, the samples were treated with O2 at 450°C (Ih), then cooled down to r.t. before evacuating the O2. The sample was then evacuated at 400°C. Evacuation at higher temperatures lead to a drastic cut off of IR trasparency. All reactants were purified prior to the adsorption experiments. Due to the better resolution of the spectra, only results for Sb V=1.0 are reported here, however the IR data for Sb V=3.0 were not significantly different. 

Absorption curves of the colored solutions were run on a Beckman spectrophotometer using 1.00-cm. quartz cells. A typical curve, shown in Figure 1, has an absorption maximum at about 515 millimicrons. The Coleman Junior spectrophotometer was used for routine determinations of Compound 118 throughout this study. 

In our laboratory, ECD spectra provide important auxiliary data for the proteins and peptides we study. ECD spectra are usually obtained for more dilute samples using strain-free quartz cells having various sample path lengths from 0.2 to 10 mm for concentrations of 0.1-1 mg/ml. To test if concentration effects cause a difference in the interpretation of data from the two techniques, which can be very important for study of unfolded proteins and peptides, we also can use IR cells and samples directly in the ECD spectrometer (Baumruk et al., 1994 Yoder, 1997 Yoder et al., 1997b Silva et al., 2000b). 

Burdick and Jackson). All solutions were photolyzed to less than 5% conversion in a standard 3 ml capacity, 1-cm path length quartz cell. Samples were irradiated with a 450-Watt medium pressure, Hanovla mercury lamp focused through an appropriate band-pass filter (280 nm or 254 nm) onto the 1-cm quartz cell with the requisite solution. Test solutions could be purged with either helium or oxygen using a needle valve assembly attached to the tapered quartz cell neck. The loss of carbamate due to photolysis and the amounts of known photoproducts were determined quantitatively by GC using eicosane as an internal standard. The columns were 6 stainless steel containing Carbowax 20M on chromosorb G. 

Liu [51] developed a simple and rapid UV spectrophotometric method for determination of niclosamide. The drug, with or without purification by chromatography on a silica gel plate, was dissolved in anhydrous ethanol and the solution or standard was placed in a 1-cm quartz cell and analyzed at 335 nm by spectrophotometry. 

Note Catalyst, 1 g (Ti02 0.3 g) water, 350 mL Na2C03, optimum quantity. An inner irradiation-type quartz cell, high-pressure Hg lamp (400 W) from Arakawa, H. and Sayama, K., Photocatalysis, Science and Technology, Kodansha/Springer, Berlin, 2002. 

Cuculic and Branica [788] applied differential pulse anodic stripping voltammetry to a study of the adsorption of cadmium, copper, and lead in seawater onto electrochemical glass vessels, quartz cells, and Nalgene sample bottles. Nalgene was best for sample storage and quartz was best for electroanalytical vessels. 

Figure 12. Spectral change of the annealed film by moisture treatment, (a) CgAzoCioN+Br film was sealed in a quartz cell with 62% humidity after annealing. The type V spectrum (broken line) immediately moved to the type VI spectrum and then shifted to the type I absorption, (b) Humidity effect on time courses of the spectral change. Ao and A, are absorbance of 370 nm immediately and l min after stored in a sealed quartz cell, respectively.

The IR spectra of this new resist films on silicon substrates were measured with a Shimadzu FTIR-4000 Fourier transform spectrometer. The UV spectra of 4,4 -diazidodiphenyl methane in a quartz cell and the films of poly(styrene-co-maleic acid half ester) and the new resist on quartz substrates were measured with a Shimadzu UV-265FS double-beam spectrometer. 

Procedure Weigh accurately about 20 mg of stilbosterol in sufficient ethyl alcohol to produce 100 ml and dilute 10 ml of this solution to 100 ml with ethyl alcohol. To 25 ml of the resulting solution add 25 ml of dispotassium hydrogen phosphate solution, transfer a portion of the mixture to a 1-cm closed quartz cell, place the cell 10 cm from a 15 watt short-wave UV-lamp, and subject it to irradiation for 10 minutes. Now, measure the extinction of the irradiated solution at the maximum at about 418 nm as described earlier. 

Let us now describe in more detail the main components of a photoacoustic calorimeter and later use this account to illustrate how an experiment can be done. There are several designs of photoacoustic calorimeter, but the most important variations concern the cell. For instance, the cells built by Lynch and Endicott [294] and by Arnault et al. [295] are quite different from the rather simple (and commercially available) flow-through quartz cell used by Griller and co-workers [296]. This type of cell was also adopted in the instrument outlined in figure 13.6. 

IR spectra of the samples with and without pyridine were recorded on an FT-IR spectrometer (PE 430) with a resolution of 1 cm. In order to measure the pyridine adsorption, the samples were pressed into thin pellets, and placed into a quartz cell with CaF2 windows. The sample pellets were evacuated at 400°C for 2 h (< 10 Torr). After cooling down to room temperature, the pellets were exposed to pyridine environment (10 Torr) at 25°C. IR spectra were recorded after adsorption of pyridine for 1 h and evacuation at 150, 250, 350, and 450°C for 1 h. 

The absorbance measurements were performed with an Agilent 8453 UV-Vis Spectrophotometer, using 1,00 cm quartz cells, PLS-1 was applied with an in-house program written according to the algorithm given by Martens and Naes [23],... 

Laser pulses of 265 nm and 20 ns duration were delivered into a quartz cell through which a solution of dearated 0.2 mM [Co(NH3)5Cl]Cl2 in 5 mM HCl was flowing. Both spectral and conductivity changes could be monitored. The very fast absorbance change at 340 nm (only a slight conductivity increase) and the slower conductivity changes (no absorbance changes) are shown in Fig. 2. The absorbance at the end of (a) corresponds to Cl. Interpret the results. 

Kinetics. The reaction of N-dodecyl 3-carbamoyl pyridinium bromide (I) with cyanide ion in the microemulsions was observed by following the 340 nm absorption maximum of the 4-cyano adduct (II). See equation (1). Following the work of Bunton, Romsted and Thamavit in micelles ( ), a 5/1 mole ratio of KCN to NaOH was employed to prevent cyanide hydrolysis. The pH of each reaction mixture was measured on a Coleman 38A Extended Range pH meter to insure that the system was sufficiently basic to allow essentially complete ionization of the cyanide. The appropriate amounts of cyanide and hydroxide were added to the mlcroemulslon sample within 10 minutes of running a reaction. Cyanide concentration varied between 0.02 and 0.08 M with respect to the water content. Substrate was Injected via a Unimetrics model 1050 syringe directly into a known volume of the yE-nucleophlle mixture in a 1.0 cm UV quartz cell. Absorbance at 340 nm was followed as a function of time on a Perkln-Elmer model 320 spectrophotometer at 25.0 + 0.3 C. Since the Initial bulk concentration of substrate was 10 M, cvanide was always present in considerable excess. 

When nitrobenzene, with nitrogen as a carrier gas, was passed through a quartz cell and irradiated by two 220-volt arcs, nitrosobenzene and 4-nitrophenol formed as the major products (Hastings and Matsen, 1948). A rate constant of 1.4 x 10cmVmolecule-sec was reported for the gas-phase reaction of nitrobenzene and OH radicals in air (Witte et ah, 1986). 

Industrial wastewater may be colored and color removal may be required to comply with regulation. Coque et al. describe how various discoloration methods were studied with standard azo dyes solutions and an industrial wastewater from the paper industry as model systems. The liquids were recirculated between the photochemical discoloration reactor and an at-line spectrophotometer (Suprasil quartz cell, path length 2 or 10mm, resp.). A discoloration yield x was calculated in CIE L a b space, which permitted monitoring the process and determining completion in an easily implemented manner. 

The sample was placed in a quartz cell in a thermostated holder (25 + 0.5 °C). The laser line was focused by a lens and mirror system and the scattored light... 

Circular Dichroism Measurements. Circular dichroism measurements were carried out by using a Cary model 6002 spectro-polarimeter calibrated with d-10 camphor sulfonic acid. All measurements were run at room temperature in the same 1 cm, quartz cell over the near-ultraviolet region (250-330 nm). 

Catalyst. (0.3 wt% Pt/Ti02), 0.3 g yf catalyst suspended in 350 ml of water placed in an inner irradiator quartz cell Irradiated with high-pressure mercnry lamp (400 W)... 

For the in situ Raman studies the Mo03/Si02 samples were pressed into wafers at 21 MPa. The pressed wafers were placed in a rotatable sample holder that was enclosed in a quartz cell equipped with an oven. The samples were oxidized at 773 K for 1 hour in O2 to minimize sample fluorescence, then were cooled to 343 K in flowing helium. The adsorbates were introduced through an injection port of the cell at 343 K with flowing helium, and the spectra were recorded at the same tenq>erature. 

The polymer sample (35 mg) was pyrolyzed in a quartz cell which was directly attached to the inlet flange of a quadrupole mass spectrometer. Gases evolved from the pol3raier compound were dynamically sampled via a 1.0-mm diameter orifice, formed into a modulated molecular beam, and mass analyzed. Information was obtained on the total yield of volatile products, product composition, and individual product yields as a function of temperature. 

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