Spectrophotometer grating

Spectrophotometer grating prism with 10 nm band width xenon lamp [G] [LD ] [L-ns]12 Phototaxigraph. Rate photoaccumulation. Spectrum is of relative efficiency (as a function of incident intensity) to produce constant response Diehn23)... 

For ultraviolet/visible spectrophotometers the gratings employed have between 10000 and 30000 lines cm-1. This very fine ruling means that the value of d in equation (14) is small and produces high dispersion between wavelengths in the first-order spectrum. Only a single grating is required to cover the region between 200 and 900 nm. 

Fig. 19.2 Layout of an infrared spectrophotometer employing a diffraction grating for monochromation. Reproduced by permission from R. C. J. Osland, Principles and Practices of Infrared Spectroscopy, 2nd edn, Philips Ltd, 1985.

In a simple flame (emission) photometer an interference filter (Section 17.7) can be used. In more sophisticated flame emission spectrophotometers which require better isolation of the emitted frequency, a prism or a grating monochromator is employed. 

A modern spectrophotometer (UV/VIS, NIR, mid-IR) consists of a number of essential components source optical bench (mirror, filter, grating, Fourier transform, diode array, IRED, AOTF) sample holder detector (PDA, CCD) amplifier computer control. Important experimental parameters are the optical resolution (the minimum difference in wavelength that can be separated by the spectrometer) and the width of the light beam entering the spectrometer (the fixed entrance slit or fibre core). Modern echelle spectral analysers record simultaneously from UV to NIR. 

Analyses I.r. spectra were measured as smears on sodium chloride plates or as a solution in carbon tetrachloride using a Perkin-Elmer 567 grating spectrophotometer, while u.v. spectra were measured as a solution in hexane (spectroscopic grade) using a Unicam SP 1700 instrument. Fluorescence and phosphorescence spectra were recorded as described elsewhere (5, 6). 

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. 

Flame photometer or spectrophotometer incorporating nebulizer and burner, filters, prism or grating monochromator, photocell or photomultiplier detection system. 

Spectral interferences may arise from the close proximity of other emission lines or bands to the analyte line or by overlap with it. They can often be eliminated or minimized by increasing the resolution of the instrumentation, e.g. changing from a filter photometer to a grating spectrophotometer. Alternatively, another analyte line can be selected for measurements. Correction for background emission is also important and is made by monitoring the emission from a blank solution at the wavelength of the analyte line or by averaging measurements made close to the line and on either side of it. 

Filter-photometer or spectrophotometer incorporating prism or grating monochromator, phototube photomultiplier or diode array, glass, quartz or plastic cells. 

The infrared spectrum of calcitriol is shown in Figure 1 (1). The spectrum was recorded on a Perkin-Elmer Model 283 Grating Infrared Spectrophotometer and was measured in a KBr pellet which contained 1 mg of calcitriol in 300 mg of KBr. 

Figures 6 and 7. Spectra were run on a Perkin-Elmer Model 467 grating spectrophotometer as a KC1 pellet (1 mg/200 mg KCl), and as a Nujol mull (20 mg/3 drops). The spectra are essentially identical. The CTC-HC1 spectrum may also be found in a compilation of IR spectra of Drug Reference Standards by Hayden et al. (26). Major absorption frequencies have been compiled (27) and assignments have been made on many of the bands(28-31). Some of the major frequencies and band assignments are ...

The infrared spectrum of griseofulvln, obtained as a mineral oil mull, was run on a Perkin-Elmer Model 180 grating IR spectrophotometer. Important absorption assignments are given in Table V. The spectrum is given in Figure 6. 

A diode array is a series of several hundred photodiodes arranged in a linear array. Single-beam spectrophotometers have been invented that utilize a diode array as the detector. In this case, the cuvette is positioned between the source and the dispersing element. Then, following the dispersion of the fight, there is no exit slit. The spray of wavelengths created by the grating fall instead across the diode array,... 

A spectrophotometer is an instrument which is capable of isolating monochromatic radiation or that which specifically contains a dispersing element a prism or a grating. 

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