Calibration method of refractometer
The zero point of the scale of the refractometer dial sometimes moves and needs to be corrected. Generally, a standard liquid with a known refractive index is used, and pure water is commonly used. The specific correction method is as follows:
Before starting the measurement, the reading must be checked with a standard sample. Add 1~2 drops of bromonaphthalene to the polished surface of the refracting prism, and then paste the polished surface of the standard sample. When the reading field of view indicates the value on the standard sample, observe whether the dividing line between light and dark in the telescope is in the middle of the cross line. If there is a deviation, use a screwdriver to slightly rotate the screw in the small hole to drive the objective lens to deflect, so that the image of the dividing line is displaced to the center of the cross line. Through repeated observation and correction, the initial error of the indication value is minimized (including operation aiming error). After the calibration is completed, it is not allowed to move this part arbitrarily in the subsequent measurement process.
In daily work, if you have any doubts about the measured refractive index, you can use the standard sample to check whether there is an initial error according to the above method, and correct it, so as to ensure the accuracy of the measurement results.
