Refractometers are common laboratory instruments that can be used to understand the optical properties, purity, concentration, and dispersion of substances. It has extremely wide applications in scientific research and industries such as petroleum, fats, pharmaceuticals, paint making, food, sugar making, and daily chemical industry. The Abbe refractometer can measure the refractive index formed when the light shines into the material, so as to judge some conditions of the material. As long as the measuring instrument is inevitably affected by various factors, resulting in certain errors in the measurement results. Therefore, we cannot ignore these errors when using the measuring instrument, but should take them into account to ensure the accuracy of the measurement. The factors affecting the Abbe refractometer include light wavelength, temperature, air pressure, etc. The errors caused by different factors are different. When measuring, we should consider carefully in advance and have solutions! In this article, I will discuss the two major factors that affect the measurement error of Abbe refractometer -- light wavelength and temperature.

First, the influence of light wavelength on the refractive index measured by Abbe refractometer. Light wave refers to the electromagnetic wave whose wavelength ranges from {{0}}.1mm to about 0.1wm. And the wavelength of this electromagnetic wave varies, and different lengths of wavelengths have an impact on the refractive index. If the wavelength is longer, the refractive index is smaller, while if the wavelength is shorter, the refractive index is larger. The light source we use for measuring refractive index is generally white light. White light, on the other hand, produces dispersion, which means that when white light refracts through a prism and sample solution, the degree of refraction varies at different wavelengths, and after refraction, it decomposes into various colored light. And these multiple colors of light can hinder the line of sight from distinguishing between light and dark, resulting in measurement errors. In order to eliminate this obstacle, the Abbe refractometer has a special design, that is, a dispersion compensator is installed at the lower end of the observation lens tube, which can solve this problem well.

Secondly, the influence of temperature on the refractive index of Abbe refractometer. The measured refractive index varies depending on the temperature of the solution. The specific relationship between temperature and refractive index is as follows: generally, the refractive index decreases as the temperature increases, and increases as the temperature decreases. Therefore, it is necessary to ensure that the temperature during measurement is 20 degree . For this, the temperature marking of Abbe refractometer is also 20 degree . If the temperature cannot be guaranteed to be at 20 degree , this can be done: when it exceeds 20 degree , add the correction number, and vice versa, subtract the correction number. In this case, it is also possible to subtract the error value to ensure the accuracy of the measurement! To reduce the measurement error of the Abbe refractometer, in addition to avoiding the interference of the above two factors, it is also necessary to correctly operate the instrument and zero it before use.