Shanghai Visible Spectrophotometer must pay attention to these three matters when using it
Shanghai Visible Spectrophotometer is a commonly used physical and chemical analysis instrument in the laboratory. This article discusses several common problems in the use of Visible Spectrophotometer, such as instrument preheating, wavelength accuracy inspection and correction, absorption The method of using the cell, the repeatability of absorbance measurement, etc. are analyzed, and the appropriate method to solve these problems is proposed.
Shanghai Visible Spectrophotometer is a common analytical instrument in analysis and testing laboratories. It is used to measure the absorbance of a substance to be tested under irradiation of a certain wavelength, so as to achieve qualitative or quantitative analysis of the substance. In the usual daily teaching and research in enterprises, it is found that users have some doubts or irregularities in the use of spectrophotometers. The following is a discussion of some common problems.
Precautions for the use of Shanghai visible spectrophotometer:
1. Temperature and humidity are important factors affecting the performance of the instrument:
They can cause corrosion of mechanical parts, reduce the finish of the metal mirror surface, cause errors or performance degradation of the mechanical parts of the instrument; cause the aluminum film of optical parts such as gratings, mirrors, focusing mirrors, etc. to corrode, resulting in insufficient light energy, stray light, Noise, etc., or even the instrument stops working, thus affecting the life of the instrument. It should be calibrated regularly during maintenance. The use of UV spectrophotometer should have a four-season constant humidity instrument room, equipped with constant temperature equipment, especially the laboratory located in the southern region.
2. Dust and corrosive gases in the environment can also affect the flexibility of the mechanical system, reduce the reliability of various limit switches, buttons, and photoelectric couplers, and are also one of the reasons for the corrosion of the aluminum film of the necessary parts:
Therefore, the use of UV spectrophotometer must be cleaned regularly to ensure the sanitary conditions of the environment and the instrument room, and to prevent dust.
3. After the visible spectrophotometer is used for a certain period, a certain amount of dust will accumulate inside. It is best for the maintenance engineer or under the guidance of the engineer to regularly open the instrument cover to remove dust inside:
At the same time, re-tighten the radiator of each heating element, clean the sealing window of the optical box with the visible spectrophotometer, calibrate the optical path if necessary, and clean and lubricate the mechanical parts as necessary. After Z, return to the original state, and then carry out some necessary inspections, adjustments and records. Analytical instrument workers should understand the daily maintenance of the instrument and the simple test method for the main technical indicators, and frequently maintain and test the instrument to ensure that the instrument works in the best state.
During the measurement process of the Shanghai Visible Spectrophotometer, it was found that the measurement results of the same solution were different at different times, that is, the repeatability was not good.
1. The preheating time of the visible spectrophotometer is not enough or the preheating method is incorrect. The preheating time should be extended or the correct preheating method should be adopted.
2. The photoelectric conversion efficiency of the photoelectric converter has changed due to long-term use. At this time, the absorbance of the standard solution and the solution to be tested are also lower, which has little effect on the results in relative quantification. However, for this type of instrument, it is generally recommended that the continuous use time should not exceed 3 hours. If it needs to be used for a long time, the best interval is 30 minutes.