Spectrophotometer single beam

It is impossible to give more detailed information or protocols for using the wide range of single-beam instruments on the market. The advice given here is that which must apply throughout this chapter consult the manufacturer s manual. 

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Procedure. The study can be carried out using either a manually operated single-beam spectrophotometer, or an automatic recording double-beam spectrophotometer. In both cases the wavelengths at which HMR and MR-exhibit absorption maxima are readily obtained from the spectra. 

The decomposition kinetics of the N-Br-amino acids was studied spectro-photometrically by following the fall in absorbance at the wavelength of the absorbance maximum of the N-bromoamino acid, in a Milton Roy Spectronic 3000 Array or a Beckman DU65 single-beam spectrophotometer, both equipped with a cell carrier thermostated to within 0.1 °C by water flow. Kinetic experiments were initiated using a hand-driven HI-TECH SFA-12 Rapid Kinetics Accessory with a 1.00 cm flow cell. 

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,... 

What features of a single-beam spectrophotometer differentiate it from a double-beam spectrophotometer In what situations is it used over a double-beam instrument ... 

What is meant by the precalibration of a single-beam spectrophotometer ... 

For what kind of experiment is the use of a single-beam spectrophotometer a slow, tedious process Why is it slow and tedious ... 

Can a single-beam spectrophotometer be used for rapid scanning Explain. 

Absorption spectra are usually registered by instruments known as spectrophotometers. Figure 1.5(a) shows a schematic diagram with the main elements of the simplest spectrophotometer (a single-beam spectrophotometer). Basically, it consists of the following elements (i) a light source (usually a deuterium lamp for the UV spectral... 

Figure 1.5 Schematic diagrams of (a) a single-beam spectrophotometer and (b) a doublebeam spectrophotometer.

A single-beam spectrophotometer, hke the one shown in Figure 1.5(a), presents a variety of problems, because the spectra are affected by spectral and temporal variations in the illumination intensity. The spectral variations are due to the combined effects of the lamp spectrum and the monochromator response, while the temporal variations occur because of lamp stability. 

Figure 11.12—Schematic ant optica path of a single beam spectrophotometer equipped with electronic regulation (Hitachi U-1000). Measurements in solution are often carried out at a fixed wavelength after a calibration curve has been plotted. The use of higher performance double beam UV/Visible spectrometers is not necessary for these measurements in which the spectrum is not recorded. On the other hand, quantitative measurements from mixtures represent a different type of analysis.

A single-beam spectrophotometer is inconvenient because the sample and reference must be placed alternately in the beam. For measurements at multiple wavelengths, the reference must be run at each wavelength. A single-beam instrument is poorly suited to measuring... 

In order to determine the chlorophyll and carotenoid content of your extract, you must measure the absorbance at several wavelengths, 661.6, 644.8, and 470 nm. If you are using a single-beam spectrophotometer, use a cuvette of acetone to zero the instrument at each wavelength. A double-beam instrument should have a cuvette of acetone in the reference beam and the acetone extract solution in the sample beam. If desired, it is instructive to obtain a complete spectrum of the extract in the range 400-700 nm. This can be compared to the spectrum obtained for each of the individual pigments in part D. 

Figure 10.8 The optical assembly of a Fourier transform apparatus, (a) 90° Michelson interferometer with below, some details of the beam-splitter (b) the optical diagram of a single beam spectrophotometer (picture of Shimadzu model 8300). A low power He/Ne laser is used as an internal standard (632.8 nm) in order to locate with precision the position of the mobile mirror by an interference method (this second sinusoidal interferogram which follows the same optical pathway, is used by the software to determine the optical path difference).

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