Spectrophotometer, multichannel

Advantages This assay in conjunction with the use of Multiwell plates, multichannel pipettes, microplate washer and shaker, together with a plate reading spectrophotometer, enables a large number of samples to be processed quickly. Interfacing the plate reader with a computer would provide an obvious additional advantage. 

These solid state detectors are multichannel devices. They have large number of photon-detecting registers. The registers are semiconductor capacitors that have been formed on a silicon chip. These detectors, which can detect very low levels of light, are primarily used in probe-type, near-infrared, and visible spectrophotometers and in fluorometers. 

Apparatus. Ultraviolet, visible and near infrared spectra were recorded with a Cary 17 spectrophotometer, y spectroscopy was carried out with a Ge-Li detector and a Zoomax (Sein) multichannel analyzer. pH measurements were taken with an Aries 10000 (Tacussel) potentiometer, a spectroscopy was carried with a solid state a detector and a (Intertechnique) multichannel analyzer. 

The spectrophotometer shown in Figure 25-21 can be controlled by most personal computers. The instrument (without the computer) can be purchased for about 10,000. Several instrument companies are combining aixay detector systems with fiber-optic probes that transport the light to and from the sample. These instruments allow measurements in convenient locations that are remote to the spectrometer. We are beginning to see more CCD and CID detectors used in multichannel systems, particularly when advantage can be taken of the two-dimensional nature of these detectors for imaging purposes (see color plate 14). 

The single crystal of gas hydrate prepared from H2 + CO2 and H2 + CO2 + THF mixtures was analyzed by in situ Raman spectroscopy using a laser Raman microprobe spectrophotometer with multichannel CCD detector. In the present study, the single crystal was defined as the gas hydrate crystal for which the Raman peak of the intermolecular 0-0 vibration mode can be detected. The argon ion laser beam (wavelength 514.5 nm, power 100 mW) or He-Ne laser beam (wavelength 632.8 nm, power 35 mW) condensed to 2 pm in spot diameter was irradiated to the sample through the upper sapphire (or quartz) window. The backscatter of the opposite direction was taken in with the same lens. The spectral resolution was about 1 cm ... 

Modern spectrophotometers are equipped with multichannel detecting devices that contain a large number of photodiodes (a photodiode array) and enable simultaneous detection over the whole range of the spectrum. Details of the design and the advantages of using such detectors in spectrophotometric measurements have been presented [17-20]. 

A molecular absorption spectrophotometer based on diode array detection has been available for many years. Although some commercial molecular fluorescence spectrometers have provision for attaching a multichannel detector, it is... 

Figure 2.4 Schematic diagram of a UV-Vis-NIR spectrophotometer with a multichannel detector.

With single-beam designs, the array dark current is measured and stored in conipulcr memory. Next, the specirum of the source is obtained and stored in memory after dark-current subtraction. Finally, the raw spectrum of the sample is obtained and. after dark-current subtraction, the sample values are divided by the source values at each wavelength to give absorbances. Multichannel instruments can also be configured as double-beam-in-time spectrophotometers. 

Multichannel Instrumenis. Array detectors began appearing in L V-visible spectrophotometers in the... 

Figure 13-25 a multichannel diode-array spectrophotometer, the Agilent Technologies 8453, (Courtesy of Agilent Technologies, Palo Alto, CA,)... 

Read implies using a multichannel spectrophotometer to assess the optical density (OD) values of plates and is in all cases in this chapter read at 492 nm. Plates should also be inspected by eye before reading to determine whether there are gross errors and whether the results are feasible. 

Learning to observe tests by eye and by using multichannel spectrophotometers. 

Read the plate by eye and with a multichannel spectrophotometer after titration of antigen (guinea pig IgG) and antibody (anti-guinea pig serum) as described above. 

Read the plate in a multichannel spectrophotometer. Remember to watch the plate as the color develops and make relevant notes. 

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