Important indicators of colorimeter
For the colorimeter, there are several most important indicators which are wavelength repeatability, photometric accuracy and photometric repeatability. In the process of judging whether the instrument is normal or not, the above indicators will also be analyzed.
● Wavelength accuracy. In the process of analyzing the colorimeter, a very critical factor is the wavelength accuracy. The wavelength accuracy mainly refers to the measurement of a wavelength of matter spectral lines through the star measurement tool in the process of star measurement. There is a certain gap between the theoretical value of the wavelength and the Han Qu value. This gap is expressed in terms of wavelength accuracy. To a certain extent, the wavelength accuracy can have an effective impact on the correct results. In the process of manufacturing and preparation, because the device is not in the standby state, there is a phenomenon that there is a gap between the actual parameters and the required parameters. This is the wavelength system error, which can also be called the mechanism error.
● In the process of measuring the photometric accuracy of the instrument, it is necessary to further ensure the accuracy and correctness of the stain amount by selecting the accuracy of the transmittance of the liquid or solid standard transmissivity testing instrument, and the correct reflectance ratio is accurate. Degree mainly refers to the difference between the measured star value and the theoretical value obtained by the instrument in the process of measuring the standard transmittance value sample. It can accurately break and respond to the comprehensive performance of the instrument in all aspects, but the selection Transmittance accuracy does not include random errors including wavelength repeatability, but only refers to the systematic error of the instrument’s luminosity value. The most concerned issue of transmittance accuracy users during use is whether it is accurate.
● The photometric repeatability of the caliber 8mm portable colorimeter mainly refers to maintaining the consistency of the environment on the basis of ignoring the systematic error, taking samples without aging changes in a relatively short period of time, and continuously placing them in the sample cell. The results obtained after several stellar surveys have remained consistent.
The application skills
● Amplify or give a small multiples method. This method is mainly by selecting the appropriate absorbance method to measure the star range. And reading in different absorbance ranges will cause different degrees of error. In order to further improve the accuracy of the measurement, the absorbance range can be determined to a certain extent. After a certain introduction, the most suitable absorbance range is between 0.2 and 0.8, and a thinner cuvette should be used as much as possible in the process of colorimetry.
● The standard pheasant sample is used as a reference. In the process of measuring with visible light and external light colorimeters, the standard curve developed under the same conditions is usually selected. The anti-quasi-curve method itself has very great advantages. Not only can it be used to measure stars quickly, but it is also very convenient in operation, and its stability is relatively high.
● Colorimetric cell correction. In the process of quantitative analysis, it is necessary to select the thickness of a set of absorption cells to keep the photometric absorption and scattering properties consistently. After that, there will be a color difference in the colorimetric cell itself, and the colorimetric cell that cannot be used will be updated. After replacement, there will be a certain color difference between the old and new colorimetric cells.
● Pay more attention to the voltage of the instrument. Instruments and equipment have internal or external stabilization devices. Many people usually ignore the working voltage, but in fact, the working voltage will have a very large impact on the measurement results. Especially when using a digital colorimeter and when the impurity content is low, the instability of the instrument voltage will have a great influence on the stability of the measurement results.

In conclusion
The application skills that need to be mastered for the application of colorimeter in industrial analysis, in addition to the above points of attention, it is also necessary to pay attention to the relationship between the sensitivity of instrument equipment and the accuracy of instrument star measurement, and it is also necessary to control temperature and humidity, guarantee Sanitary conditions, attention to the maintenance of instruments and equipment, and regular calibration of instruments, etc., do the corresponding daily cleaning work to further ensure the accuracy of the measurement.
