1, Propósito y principio
2, Medicines and equipment: Tomatoes, oranges, pineapples, distilled water, beakers, droppers, rolls of paper, and handheld refractometers. 3. Operating steps: Open the cover plate of the handheld refractometer (a), and carefully dry the prism glass surface with clean gauze or rolls of paper. Drop 2 drops of distilled water on the prism glass surface and cover it with a cover. In a horizontal state, observe from the eye (b) and check whether the boundary between light and dark in the field of view is at the zero line of the scale. If it does not coincide with the zero line, rotate the scale adjustment screw so that the boundary plane falls exactly on the zero line. Open the cover, dry the water with gauze or roll paper, and then drop 2 drops of fruit and vegetable juice on the prism glass surface as described above. Observe and read the scale on the light dark intersection line in the field of view, which is the soluble solid content ( percent ) (approximate sugar content) in the fruit and vegetable juice. Repeat three times.
