Matters needing attention when testing Abbe refractometer

1) Abbe refractometer should be placed in a place with dryness, air circulation and suitable temperature to prevent the optical parts of the instrument from being damp and mildewed;

2) Before each measurement work and when performing the indication calibration, the matte surface of the light-increasing prism, the polished surface of the refractive prism and the polished surface of the standard sample must be used, and a mixture of anhydrous alcohol and diethyl ether (1:1) is used. The degreased cotton is lightly wiped clean to avoid leaving other substances, affecting the phase clarity and measurement accuracy;

3) The sample to be tested must not have solid impurities. When detecting the solid sample, the working surface layer of the refractive prism should be prevented from being pulled or indented, and it cannot be used to detect samples with high corrosivity;

4) Before starting the measurement, the reading must be corrected with distilled water or with a standard sample. If using a standard sample, add 1-2 drops of bromine to the polished surface of the refractive 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 the dark and dark points in the telescope. Whether the boundary is in the middle of the crosshair, if there is a deviation, use a screwdriver to slightly rotate the screw in the small hole, and take the eccentricity of the animal mirror to shift the boundary line to the center of the crosshair. By repeated observation and correction. Minimize the initial error of the indication (including the operator's aiming error). After the calibration is completed, it is not allowed to move the part at random during the subsequent measurement process (in general, there is no need to calibrate the instrument in daily measurement work. If there is any doubt about the measured refractive index value, it can be tested according to the above method. Whether there is a starting error, if there is an error, it should be corrected);

5) For each measurement, the sample should not be added too much, generally only need to add 2 to 3 drops;

6) Pay attention to keep the instrument clean and protect the dial. After each experiment, add a few drops of acetone to the mirror and dry it with a mirror paper. Finally, two layers of lens paper are sandwiched between the prism faces to avoid mirror damage;

7) When reading, sometimes there is no clear light-dark boundary in the eyepiece, but it is deformed. This is because the prisms are not filled with liquid. If there is a curved aura, it may be because the light is not directly irradiated through the prism. Condenser lens;

8) If the refractive index of the sample to be tested is not in the range of 1.3 to 1.7, the Abbe refractometer cannot be measured, and the boundary between light and dark is not seen.