Ultraviolet-visible spectrophotometer

I. Product Overview

The instrument can perform qualitative and quantitative analysis of sample substances in the ultraviolet and visible spectral regions. It meets the requirements of the standard GB/T 26813-2011 for visible spectrophotometers and the standard JJD 1002-1991 for ultraviolet-visible spectrophotometers. This instrument is widely used in medical and health, clinical testing, biochemistry, petrochemicals, environmental protection, and quality control departments, and is one of the commonly used analytical instruments in physical and chemical laboratories. The LCD display and keyboard make the operation more user-friendly.

II. Working Principle

The basic principle of this instrument is that substances in solution, under the excitation of light irradiation, produce an absorption effect on light. The absorption of light by substances is selective. Different substances have their own absorption spectra. Therefore, when monochromatic light passes through a solution, its energy will be absorbed and weakened. ， The degree of light energy weakening is proportionally related to the concentration of the substance, that is, it conforms to the principle of colorimetry - Beer-Lambert Law.

                     T=I/I ₀

                  log I/I ₀ =KCL

                      A=KCL

Where: T —— Transmittance               I ₀  —— Incident light intensity

        I —— Transmitted light intensity           A —— Absorbance

        K —— Absorption coefficient             L —— Path length of the solution

        C —— Concentration of the solution

From the above formula, we can see that when incident light, absorption coefficient, and path length of the solution remain unchanged, the transmitted light changes according to the concentration of the solution. The basic principle of this instrument is designed based on the above physical and optical phenomena.

III. Optical Principle

This instrument uses a grating CT dispersion system and a single-beam structure path The continuous radiation light emitted by the lamp is projected onto the monochromator entrance slit by a reflector. This slit is exactly on the focal plane of the condenser and the collimator in the monochromator. Therefore, the composite light entering the monochromator is reflected by the reflector and collimated by the collimator into parallel light, which is then directed to the grating, the dispersive element. The grating diffracts the incident composite light to form a continuous monochromatic spectrum uniformly arranged in a certain order. This monochromatic spectrum is reflected on the collimator. Because the instrument's exit slit is set on the focal plane of the collimator, the spectrum dispersed by the grating is imaged on the exit slit after passing through the collimator using the principle of light focusing. The exit slit selects a monochromatic light of a specified bandwidth, which passes through the condenser and falls on the center of the sample being measured in the sample chamber. After the sample absorbs the light, the transmitted light passes through the light gate and is received by the photocell.

IV. Functions and Features

1. Large-capacity sample chamber, can use 5mm-100mm cuvettes.

       2. CT-type monochromator optical path with symmetrical optical performance, better photometric accuracy.

       3. Large-screen LCD display (4-digit LCD).

       4. The instrument automatically zeros and automatically adjusts the full scale, making operation simple and convenient.

       5. Novel design of engineering plastic shell, suitable for any laboratory.

V. Instrument Installation

5.1 Inspection of Accessories

Host                            One

Power cord                          One

Accessory box                          One box (including a box of cuvettes)

Fuse                          One ( 2A)

Blackbody                            One (for zeroing)

Instrument operation and use instruction manual            One

Packing list                      One

Product qualification certificate                      One

Note: If there are any changes to the product accessories, please refer to the product packing list of the instrument.

5.2 Instrument Operating Environment

In order to ensure the normal use of the instrument and to extend its service life, it is necessary to make the instrument in Suitable working environment Working inside Try to avoid operating the instrument at the extreme limits of its environmental conditions.

The instrument should be placed in a dry room with an operating temperature of 5 ℃～ 35 ℃ and a relative humidity not exceeding 85%。

When in use, place it on a firm and stable workbench, and avoid strong or continuous vibrations.

Indoor lighting should not be too strong, and direct sunlight should be avoided.

Fans should not be directed at the instrument to avoid affecting its normal use.

Keep away from strong magnetic fields, electric fields, and high-frequency electrical equipment.

The power supply voltage for the instrument is AC220V ± 22V The frequency is 50Hz ± 1Hz and must have a good ground wire. A regulated AC power supply is recommended to improve the instrument's anti-interference capability Using a power of 500W or more electronic AC voltage regulator or AC constant voltage regulator.

   Avoid using in places with corrosive gases such as hydrogen sulfide and sulfurous acid.

5.3 Installation

5.3.1 Before installation and use, the safety of the instrument should be checked, whether the power voltage is normal, and whether the ground wire is firm and reliable. Only after confirmation can the power be turned on and used.

5.3.2 Due to transportation and handling, the wavelength accuracy may be affected. The instrument should be calibrated before use.

VI, Troubleshooting