fluorometer

fluo·rom·e·ter

F0207700 (flo͝o-rŏm′ĭ-tər, flô-, flō-)n. An instrument for detecting and measuring fluorescence.

fluo·rom′e·try n.

fluorometer

(ˌflʊəˈrɒmɪtə) or

fluorimeter

n1. (General Physics) an instrument for inducing fluorescence by irradiation and for examination of the emission spectrum of the resulting fluorescent light2. (General Physics) a device for detecting and measuring ultraviolet radiation by determining the amount of fluorescence that it produces from a phosphor fluorometric, fluorimetric adj ˌfluoˈrometry, ˌfluoˈrimetry n

fluo•rom•e•ter

(flʊˈrɒm ɪ tər, flɔ-, floʊ-)

n. an instrument for measuring fluorescence, often as a means of determining the nature of the substance emitting the fluorescence. [1895–1900] fluor•o•met•ric (ˌflʊər əˈmɛ trɪk, ˌflɔr ə-, ˌfloʊr ə-) adj. fluo•rom′e•try, n.

fluorometer

an instrument for measuring the emission of radiation in the form of visible light and identifying the substance that is its source. — fluorometric, adj.See also: Instruments

an instrument for measuring the emission of radiation in the form of visible light and identifying the substance that is its source. — fluorometric, adj.See also: Radiation

Fluorometer

fluorometer

[flu̇′räm·əd·ər] (engineering) 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.

Fluorometer

(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 . 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.

fluorometer

[floo͡-rom´ĕ-ter] the instrument used in fluorometry, consisting of an energy source (e.g., a mercury arc lamp or xenon lamp) to induce fluorescence, filters or monochromators for selection of the wavelength, and a detector.

fluor·om·e·ter

(flōr-om'ĕ-tĕr), A device employing an ultraviolet source, monochromators for selection of wavelength, and a detector of visible light; used in fluorometry.

fluorometer

(1) An instrument used to measure the intensity and wavelength distribution of fluorescent emissions after excitation by a certain spectrum of light.
(2) A now-retired device formerly used to measure the amount of ionising radiation emanating from an X-ray tube.

fluor·om·e·ter

(flōr-om'ĕ-tĕr) A device employing an ultraviolet source, monochromators for selection of wavelength, and a detector of visible light; used in fluorometry.

单词	fluorometer
释义	fluorometer fluo·rom·e·ter F0207700 (flo͝o-rŏm′ĭ-tər, flô-, flō-)n. An instrument for detecting and measuring fluorescence. fluo·rom′e·try n. fluorometer (ˌflʊəˈrɒmɪtə) or fluorimeter n1. (General Physics) an instrument for inducing fluorescence by irradiation and for examination of the emission spectrum of the resulting fluorescent light2. (General Physics) a device for detecting and measuring ultraviolet radiation by determining the amount of fluorescence that it produces from a phosphor fluorometric, fluorimetric adj ˌfluoˈrometry, ˌfluoˈrimetry n fluo•rom•e•ter (flʊˈrɒm ɪ tər, flɔ-, floʊ-) n. an instrument for measuring fluorescence, often as a means of determining the nature of the substance emitting the fluorescence. [1895–1900] fluor•o•met•ric (ˌflʊər əˈmɛ trɪk, ˌflɔr ə-, ˌfloʊr ə-) adj. fluo•rom′e•try, n. fluorometer an instrument for measuring the emission of radiation in the form of visible light and identifying the substance that is its source. — fluorometric, adj.See also: Instruments an instrument for measuring the emission of radiation in the form of visible light and identifying the substance that is its source. — fluorometric, adj.See also: Radiation Fluorometer fluorometer [flu̇′räm·əd·ər] (engineering) 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. Fluorometer (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 . 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. fluorometer fluorometer [floo͡-rom´ĕ-ter] the instrument used in fluorometry, consisting of an energy source (e.g., a mercury arc lamp or xenon lamp) to induce fluorescence, filters or monochromators for selection of the wavelength, and a detector. fluor·om·e·ter (flōr-om'ĕ-tĕr), A device employing an ultraviolet source, monochromators for selection of wavelength, and a detector of visible light; used in fluorometry. fluorometer (1) An instrument used to measure the intensity and wavelength distribution of fluorescent emissions after excitation by a certain spectrum of light. (2) A now-retired device formerly used to measure the amount of ionising radiation emanating from an X-ray tube. fluor·om·e·ter (flōr-om'ĕ-tĕr) A device employing an ultraviolet source, monochromators for selection of wavelength, and a detector of visible light; used in fluorometry.
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