Ultraviolet-visible spectrophotometer is an analytical instrument based on the principle of ultraviolet-visible spectrophotometry, which uses material molecules to analyze the radiation absorption in the ultraviolet-visible spectrum region.

There are many ways to classify spectrophotometers: according to the optical path system can be divided into single beam and double beam spectrophotometers; According to the measurement method can be divided into single wavelength and double wavelength spectrophotometer; It can be divided into spectral scanning detection and diode array full spectrum detection.

Structure and function

It is composed of light source, monochromator, absorption cell, detector and signal display system.

Light source: It is a device that provides incident light that meets the requirements, including thermal radiation light source and gas discharge light source. The thermal radiation source is used in the visible region, usually tungsten lamp and halogen tungsten lamp, the wavelength range is 350~1000nm; Gas discharge source is used in ultraviolet region, usually hydrogen lamp and deuterium lamp, continuous wavelength range is 180~360nm.

Monochromator: Function is to decompose the composite light produced by the light source into monochromatic light and separate out the required monochromatic light beam, it is the heart of the spectrophotometer.

Absorption tank: also known as a colorimetric dish, it is used for holding test liquid for absorbance measurement. Its bottom and two sides are ground glass, and the other two sides are optical transmittance surfaces. In order to reduce the reflection loss of light, the optical surface of the absorption tank must be completely perpendicular to the direction of the beam. According to the material can be divided into glass pool and quartz pool two kinds, the former is used for visible light area measurement, the latter is used for UV area.

Detector: It is a device that converts optical signals into electrical signals. When measuring absorbance, it does not directly measure the light intensity passing through the absorption pool, but converts the light intensity into current signals for testing. This photoelectric conversion device is called the detector.

Signal display system: is the detector output signal amplification, and display device.

Product application

Application in water and wastewater monitoring, monitoring analysis and comprehensive evaluation of a water system, generally including water phase (solution itself), solid phase (suspended matter, substrate), biological phase (aquatic organisms). In the routine monitoring of water quality, UV - visible spectrophotometry occupies a large proportion. As the composition of water and waste water is complex and changeable, the concentration of the substance to be measured and the concentration of the interference are very different, so the analytical method must be selected in the specific analysis.

In agricultural products and food analysis can be used to detect the components or components of protein, lysine, glucose, vitamin C, nitrate, nitrite, arsenic, mercury, etc.

It can be used to detect chlorophyll, total nitrogen and enzyme activity in plant biochemical analysis.

It can be used to detect niacin, gossypol, phosphine and methyl ester in feed analysis.

Source: Baidu Baike