Spectrophotometer scanning

Visible-spectrum studies of the course of the dye reduction were performed on a Beckmann Model 25 Ultraviolet-Visible Spectrophotometer scanning the region of 750-350 nm. 

The stained gel is shown below the graph. A spectrophotometer scan of the dye peaks is shown on the graph, and a profile of measured pH is plotted. Each dark band of stained protein gives an absorbance peak. The instrument that measures absorbance as a function of position along the gel is called a densitometer. 

Conventional spectrophotometers scan through a spectrum one wavelength at a time. Newer instruments record the entire spectrum at once in a fraction of a second. One application of rapid scanning is chromatography, in which the full spectrum of a compound is recorded in seconds as it emerges from the chromatography column. 

Ultraviolet absorption spectra of etodolac at concentrations of 20 pg/mL were obtained using a Varian DMS-200 spectrophotometer, scanning over the wavelength range 200-400 nm. The spectrum of the protonated form of etodolac was obtained in neat ethanol, and the spectrum of the deprotonated form was obtained in 0.5 N NaOH. The spectra shown in Figures 5 and 6, respectively. 

A dispersive IR spectrophotometer scans the compound by means of a monochromator, and gives the absorption for each wavenumber, which is called a spectrum. A machine based upon Fourier transformation determines the absorption for each wavenumber at the same time, using a Michelson interfero-... 

The primary components of automobiles are steel or aluminum, so one of the fastest methods for analysis with the least amount of preparation of the sample is the emissions spectrometer. From Table 2.1, we can see that a carbon sulfur analyzer, such as a Leco, or atomic absorption spectrophotometer scanning electron microscopy (SEM) x-ray and GC-MS are also used for this type of analysis. However, an emissions spectrophotometer is most often used because of its lack of sample preparation. Again, it is not our attempt here to go into great detail on each method. Within an automotive analytical laboratory, however, speed is a priority so that a material is identified and classified rapidly. An emissions spectrophotometer is such an instrument. 

In this study, we reported the preparation of mesoporous Ti02 materials via the sol-gel method involving a co-assembly of titanium (IV) isopropoxide and mainly neutral soluble starch CTMACl is used only for comparative reason. Ethanol and cyclohexane were used as solvents. The effect of key parameters, including surfactant removal process either by washing and/or by calcination and the solvent nature are discussed. Ti02 samples were characterized by means of N2 adsorption-desorption experiments, X-ray Diffraction analysis, UV-vis spectrophotometer. Scanning Electron Microscopy and Atomic Force Microscopy. 

Physical Measurements of Colored Spots. Transmission or reflectance measurements on a strip or plate are made using a spectrophotometer. Scanning photodensitometers are devices that measure spot intensity by reflectance and display the result on a recorder. Visual methods are accurate to 5-10% scanning methods, to... 

Therefore, UV-visible spectra can be used to indicate the presence of the proper form of PANIS. UV-visible spectra were recorded on a Hitachi Model U-2000 spectrophotometer scanning between 320 nm and 1100 nm which clearly show the absorption peaks of the material. 

Diffuse reflectance measurements were made using a Foss NIRSystems Model 6500 spectrophotometer scanning from 400 to 2500 nm with a 2 nm resolution. The SmartProbe attachment was linked via a 1.5-m fiber-optic cable and mounted a fixed 1 mm above the surface. Using this configuration, light was normally directed onto the surface of the lane where it penetrated the sample... 

Fig.2. Spectrophotometer scan at 671 nm of normal size electophoretic gels of control(a) and 40 min. hydrogenated thylakoids (b), and contrasting minigels of the same control (c) and 40 min. hydrogenated (d) preparations.

Fourier transform infrared spectroscopy (FTIR) was recorded using Thermo Scientific Nicolet iSlO FTIR Spectrophotometer. Scanning electron microscopy (SEM) imaging was carried out using Gemini FE-SEM from Zeiss to study the morphological nature of the film. 

Block diagram for a double-beam in-time scanning spectrophotometer with photo of a typical instrument. 

In the case of 2- and 6-hydroxypteridine and their derivatives, the anhydrous species in neutral solutions (produced by rapid addition of equilibrated alkaline solutions to neutral buffers) change sufficiently slowly into the hydrated species that serial scans on a recording spectrophotometer can be used to demonstrate the process. The results shown in Fig. 1 for 6-hydroxy-2-methylpteridine are typical. 

Double-beam spectrophotometers. Most modern general-purpose ultraviolet/ visible spectrophotometers are double-beam instruments which cover the range between about 200 and 800 nm by a continuous automatic scanning process producing the spectrum as a pen trace on calibrated chart paper. 

Colorimeter Also called color comparator or photoelectric color comparator. An instrument for matching colors with results about the same as those of visual inspection, but more consistent. Basically the sample is illuminated by light from the three primary color filters and scanned by an electronic detecting system. It is sometimes used in conjunction with a spectrophotometer, which is used for close control of color in production. 

Stability of 2,3,7,8-Tetrachlorodibenzo- >-dioxin Towards Air Oxidation Under Simulated Conditions. Air was bubbled through two borosilicate glass gas absorption bottles equipped with fritted glass bubblers. The first bottle contained 1-octanol for presaturation of the air, and the second bottle contained 1-octanol solutions of the dioxin treated as follows (1) octanol only, (2) octanol mixed with 74-105ju, glass beads to increase the surface area, and (3) octanol mixed with magnesium oxide to simulate a basic soil. The original solution and the sample solutions were scanned with a UV spectrophotometer at various time intervals for 4 days to determine the stability of 2,3,7,8-tetrachlorodibenzo-p-dioxin. 

FT-IR spectra were recorded at RT on a Perkin-Elmer 1760-X spectrophotometer equipped with a cryodetector, at a resolution of 2 cm-" (number of scans -100). In the 1070-960 cm- region, band integration and curve fitting were carried out by Curve fit, in Spectra Calc. (Galactic Industries Co.). Powdered materials were pelleted in self-supporting discs of 25-50 mg cm-2 and 0.1-0.2 mm thick, placed in an IR cell allowing thermal treatments in vacuo or in a controlled atmosphere. 

Retzik, M. and Froehlich, P., Extending the capability of luminescence spectroscopy with a rapid-scanning fluorescence spectrophotometer, Am. Lab., March, 68, 1992. 

Generally, measurement of absorption spectra of the colored form of spirobenzopyran is very difficult using normal spectrophotometry, as the colored form is thermally unstable. The absorption spectra of the colored form of 6,8-dinitro-BIPS 7, which is exceptionally stable in DMSO even at 23°C, are shown in Figure 1.4. Generally, it is possible to obtain a reasonable absorption spectrum of the colored form by the use of a rapid scanning spectrophotometer. 

Parallel methods using scanning 96/384-well plate UV spectrophotometers are inherently faster [292]. They will become 50-fold faster with the imminent introduction of diode-array plate readers. 

The IR spectra were obtained with a Perkin-Elmer PE-467 grating spectrophotometer from about 4000-500 cm . Normal slit position and medium scan mode were used. Films of polymer samples were cast from CS2 solutions on NaCl windows. 

A Cary 500 Scan UV-visible spectrophotometer was used to evaluate the amount of ibuprofen adsorbed and released by the MCM-41-IBU. 

The infrared spectrum of hydralazine hydrochloride (Figure 1) was obtained with a Beckman IR-12 spectrophotometer. A mineral oil dispersion between potassium bromide plates was scanned from 420 to 4000 cm-1, and a thicker layer of the dispersion, supported on polyethylene film,... 

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