The difference between UV Vis spectrophotometry and fluorescence spectrophotometry
The principle of ultraviolet visible spectrophotometry is to calculate the concentration (content) of the light absorbed by the object at a particular wavelength;The method of measuring certain substances in the environment by means of fluorescence photometry is called fluorescence photometryThe concept of fluorescence spectrophotometer is big
A functional curve describing the extent to which radiation absorption of a molecule of matter varies with wavelength is known as an absorption spectrum or an absorption curve. The ultraviolet visible absorption spectrum is usually composed of one or several broad absorption bands. The maximum absorption wavelength (lambda max) represents the characteristic absorption or selective absorption of a substance by radiation. It is related to the structure of the outer electrons or valence electrons in the molecule (or bonding, non bonding, and counter bonding electrons). Lambert Bill law is the basis of spectrophotometry and colorimetry. The law states that when a monochromatic radiation with a I0 intensity is irradiated to a light absorbing material of a thickness of B and a concentration of C, the absorption of radiant energy depends on the concentration of the substance and the thickness of the absorption layer. The mathematical expression: the type of A called I0 absorbance; incident radiation intensity; I radiation intensity through the absorption layer; (I / I0) called for Wisteria transmittance of T; E is a constant, called the molar absorption coefficient values is bigger, the sensitivity of spectrophotometry is higher.
UV Vis spectrophotometry, UV visible spectrophotometry is a qualitative and quantitative analysis methods and structure according to the material properties of the molecular absorption wavelength of 200-760nm the range of the electromagnetic wave is established. The operation is simple, the accuracy is high and the reproducibility is good. Long wave (small frequency) light, small energy, short wavelength (large frequency) of light energy. Spectrophotometry is the measurement of the degree of radiation absorption of matter molecules at different wavelengths and at specific wavelengths.
UV VIS spectrophotometer consists of 5 components: 1. Radiation source. The continuous spectrum must have a stable and sufficient output power, the use of equipment such as band, tungsten lamp, halogen lamp (wavelength range from 350 to 2500 nm), hydrogen deuterium lamp or lamp (180 ~ 460 nm), or tunable dye laser light source etc.. The monochromator [1]. It consists of the incident, the exit slit and lens system and a dispersive element (prism or grating), is a device used to produce high purity monochromatic beam, its functions include composite light generated from the light source into monochromatic light beams of monochromatic light and separation required. Sample container, also called absorption tank. For a solution of absorbance measurement for quartz glass tank is divided into pools and two, the former is applicable to the ultraviolet to the visible region, the latter is only applicable to the visible region. The vessel's optical path is usually 0.5 to 10 cm. Detector, also known as photoelectric converter. Commonly used are photoelectric tubes or photomultiplier tubes, the latter is more sensitive than the former, especially suitable for detecting weak radiation. In recent years, vidicon or photodiode array is used as detector, which has the characteristics of fast scanning. Display device. This part of the device is developing faster. The higher photometer has a microprocessor, a screen display and a recorder, etc., and displays the atlas, data, and operating conditions.
