Cuvette cell

Bulk photolyses were carried out using a 1000-W, high pressure, Xe lamp (Model 6117, Oriel Corp., Stamford, Conn. 06902) and a UV-VIS grating monochromator. For purposes of comparison and evaluation of power, 8.5 mW of power at 425 nm is produced at the sample surface within the cuvette cell. The procedure for determining this is found elsewhere 3 ). Samples were loaded in a type 52-H 2mm light path quartz cell purchased from Precision Cells, Inc., Hicksville, NY. The amount of zeolite used was 0.3 grams. Solutions of 1.5 M isopropanol dissolved in acetonitrile were used for the bulk photolyses. 

Equal amounts (fractions) of incident radiation are absorbed by equal changes in the cuvette cell length, with the concentration of the analyte remaining constant. If we consider what happens when we have a much smaller cuvette (Figure 5.14),... 

Fig. IL6.6 Capillaiy sUt in situ UV/ s/NIR spectroelectrochemiail cells with an optically transparent electrode prepared from a metal mesh, grid, or gauze in a top cuvette cell and in a bottom flat cell with outlet allowing the solution to flow through the sUt...

Figure 5.9 depicts FUV absorption spectra of (a) an aqueous solution of AA with concentration of 1.7 wt%, (b) an aqueous solution of H2O2 with concentration of 0.2 wt%, and (c) a PAA disinfectant solution with concentrations of 0.86,0.23, and 0.22 wt% of PAA, H2O2, and AA, respectively. The spectra in Fig. 5.9 were obtained using a commercial spectrometer (Shimadzu UV-visible spectrophotometer UV-2550) and a cuvette cell of path length 10 mm. Figure 5.10 shows their second-derivative spectra. Figures 5.9 and 5.10 demonstrate that these spectra may be used for the measurement of each solute in the coexistence of their species. 

Optical Applications. Vitreous siUca is ideal for many optical appHcations because of its excellent ultraviolet transmission, resistance to radiation darkening, optical polishing properties, and physical and chemical stabiUty. It is used for prisms, lenses, cells, wiadows, and other optical components where ultraviolet transmission is critical. Cuvettes used ia scatter and spectrophotometer cells are manufactured from fused siUca and fused quart2 because of the transmissive properties and high purity (222). 

In some systems, known as continuous-flow analy2ers, the reaction develops as the sample —reagent mixture flows through a conduit held at constant temperature. In such systems, the reaction cuvettes are replaced by optical reading stations called flow cells. In most analy2ers, whether of discrete- or continuous-flow type, deterrnination of electrolyte tests, eg, sodium and potassium levels, is done by a separate unit using the technique of ion-selective electrodes (ISE) rather than optical detection. 

Let us examine some batch results. In trials in which 5 mL of a dye solution was added by pipet (with pressure) to 10 mL of water in a 25-mL flask, which was shaken to mix (as determined visually), and the mixed solution was delivered into a 3-mL rectangular cuvette, it was found that = 3-5 s, 2-4 s, and /obs 3-5 s. This is characteristic of conventional batch operation. Simple modifications can reduce this dead time. Reaction vessels designed for photometric titrations - may be useful kinetic tools. For reactions that are followed spectrophotometrically this technique is valuable Make a flat button on the end of a 4-in. length of glass rod. Deliver 3 mL of reaction medium into the rectangular cuvette in the spectrophotometer cell compartment. Transfer 10-100 p.L of a reactant stock solution to the button on the rod. Lower this into the cuvette, mix the solution with a few rapid vertical movements of the rod, and begin recording the dead time will be 3-8 s. A commercial version of the stirrer is available. 

Cuvette, Cuvette, /. bulb cell, vessel trough. 

To investigate the absorption of radiation by a given solution, the solution must be placed in a suitable container called a cell (or cuvette) which can be accurately located in the beam of radiation. The instrument is provided with a cell-carrier which serves to site the cells correctly. Standard cells are of rectangular form with a 1 cm light path, but larger cells are available when solutions of low... 

Rabbit peritoneal neutrophils were harvested and their release of p-glucuronidase was measured at 37°C, as described previously (13). For indo-1, neutrophils were washed twice in a calcium-free buffer, then loaded with 15 indo-1 acetoxymethyl ester (24) for 40 min at 37 C at a density of 5 x 10 cells/ml. The cells were then washed twice more in calcium-free buffer, resuspended to a density of 1 X 10 cells/mL, and kept on ice. Prior to fluorometry, cells were diluted 4x with the appropriate buffer at 37 C. For CTC, neutrophils were incubated with 20 pH CTC at 37°C in the spectrofluorometer cuvette. All measurements were carried out using an SLH-Aminco SPF 500C fluorospectrometer interfaced with an IBM PC microcomputer. 

Isolated chromaffin cells were maintained in suspension culture and loaded with the fluorescent calcium indicator Fura 2 as previously described (28). 2 x 10 cells/ml were added into a cuvette containing standard buffer without (dotted line) or with (full line) 2 mM calcium. At the arrow, 10" M pardaxin was added. A rise in was... 

Cuvette material Optically clean glass Electrode cell material Organic glass... 

Fluorescence spectra were recorded using an SLM 4800 spectrofluorimeter (Bioritech, Chamarande, France) fitted with a thermostat-controlled (30°C) front-surface accessory. The incidence angle of the excitation radiation was 60°. Coagulation kinetics were performed in a quartz cuvette 1 cm x 1cm. All spectra were corrected for instrumental distortions in excitation using a rhodamine cell in the reference channel. 

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