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Related to Fluorometer: fluorometry, Fluorescence spectroscopy


An instrument that measures the fluorescent radiation emitted by a sample which is exposed to monochromatic radiation, usually radiation from a mercury-arc lamp or a tungsten or molybdenum x-ray source that has passed through a filter; used in chemical analysis, or to determine the intensity of the radiation producing fluorescence. Also spelled fluorimeter.



(also fluorimeter), an instrument used for measuring the decay time τ of fluorescence, which is approximately 10–8–10–9 sec. A fluorometer operates on the following principle. During high-frequency modulated excitation of luminescence, the luminescence is modulated at the same frequency as the excitation; however, because of the finite duration of the luminescence emission, the phase of the luminescence modulation lags behind that of the excitation modulation. In the case of excitation that is sinusoidally modulated at a frequency ω and fluorescence that decays exponentially, the phase angle φ = tan–1 (ωτ). The relation between the amplitude A0 of the excitation modulation and the amplitude A of the luminescence modulation is Fluorometer. Thus, to determine τ either φ or the ratio A0/A must be measured. If the decay is not exponential, the same method may be used to establish the mean lifetime of the excited state and to estimate the extent to which the decay is not exponential.

Figure 1. Schematic diagram of a phase fluorometer

The most widely used fluorometers are phase fluorometers, which measure φ (Figure 1). In an optical-excitation phase fluorometer, a light beam from a source (1) is focused on a modulator (2). A portion of the modulated flux is deflected by a semi-transparent plate (3) and enters a photomultiplier (5). The remainder of the flux is focused on a specimen (4) to excite fluorescence, which is deflected to another photomultiplier (6). The phase difference φ between the photoelectric currents from (5) and (6) is measured by means of a phase meter (7). A cathode-ray tube or phase detector (8) serves as the phase indicator. Fluorometers based on electron-beam and X-ray excitation have also been developed.

In an instrument that is more advanced than a fluorometer, luminescence is excited by short light pulses, and the decay curve is recorded directly.

Instruments that are used for luminescence analysis are also called fluorometers, or fluorimeters. Such instruments measure the intensity of luminescence and contain both a source for exciting the luminescence and a photometer.

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Ballast-Check[TM]2 is a small, lightweight, highly durable handheld fluorometer ideal for quick indicative compliance checks of ballast water.
The PCR samples were quantified using Fluorometer (Promega) and were sent to 1stBASE Laboratory at Malaysia for PCR clean up and sequencing.
When compared to a commercial fluorometer for detecting active Shiga toxin, both instruments detected the same levels of toxin.
The camera method, which can easily be adapted for detecting other foodborne toxins,was compared to a commercial fluorometer for detecting active Shiga toxin, Rasooly adds.
The R&D leading to the FiBIR fluorometer was supported in part by an SBIR Phase I award from the National Institutes of Health.
The latter was done to evaluate the stability of the fluorometer during the experimental period (~2 mo).
This fluorometer provides six colors of pulse-modulated measuring light (400, 440, 480, 540, 590 and 625 nm) and five colors of actinic light (440, 480, 540, 590, 625).
The Bactiquant[R]-water package includes sampling equipment, membrane filter, enzyme substrate and fluorometer.
The commercial availability of reasonably cheap, easy-to-use, and portable modulated fluorometers extended the use of Chi fluorescence analysis to a wide range of photosynthetic organisms, including photosynthetic sea slugs (e.
Three tenders for the supply of (a) fluorometer - real time PCR - Elisa System, (b) computer printers, screens, scanners, fans, air suction fans among other items, also (c) telephone sets, earphone wire, also single and double line telephone sets.
Fluorometer was used to identify quantum yield of photosystem II.
Depending on the application, oxygen presence or pH can be visually determined by colour change with a handheld LED, or a fluorometer can be used to make exact measurements.