The principle of hand-held sugar meter
1. The working principle of the sugar meter
The phenomenon of refraction occurs when light enters another medium from one medium, and the ratio of the sine of the incident angle is constant, and this ratio is called the refractive index. The content of soluble solids in fruit and vegetable juices is proportional to the refractive index under certain conditions (same temperature and pressure), so the concentration (sugar content) of fruit and vegetable juices can be obtained by measuring the refractive index of fruit and vegetable juices. Commonly used instruments are hand-held refractometers, also known as sugar mirrors and hand-held sugar content meters. By measuring the soluble solid content (sugar content) of fruits and vegetables, the quality of fruits and vegetables can be understood, and the maturity of fruits can be roughly estimated.
Hand-held sugar meters are generally cylindrical.
2. Instructions for Handheld Sugar Refractometer
(1) Instrument structure
①. Refractive prism ②. Cover plate ③. Calibration bolt ④. Optical system pipeline ⑤. Eyepiece (diopter adjustment ring)
(2) How to use
Open the cover ②, and carefully wipe the detection prism ① with a soft cloth. Take a few drops of the solution to be tested, place it on the detection prism, and gently close the cover to avoid the generation of air bubbles, so that the solution spreads over the surface of the prism. Aim the light inlet plate of the instrument at the light source or a bright place, observe the field of view through the eyepiece, and turn the eyepiece adjustment handwheel ⑤ to make the blue-white boundary line of the field of view clear. The scale value of the dividing line is the concentration of the solution.
(3), calibration and temperature correction
The instrument needs to be zero-calibrated before measurement. Take a few drops of distilled water, put it on the detection prism, and turn the zero adjustment screw ③ to adjust the dividing line to the 0% position of the scale. Then wipe off the detection prism for detection. Some models of instruments need to configure standard solution instead of distilled water when calibrating.
Another method is (only suitable for the determination of sugar content): use the temperature correction table to add (or subtract) the temperature correction value to the value read at the ambient temperature to obtain an accurate value.
(4) Matters needing attention
The instrument is a precision optical instrument, and the following items should be paid attention to during use and maintenance:
1. You must be careful during use, use it strictly according to the instructions, do not loosen the connecting parts of the instrument arbitrarily, do not drop, collide, and violent vibration is strictly prohibited.
2. After use, it is strictly forbidden to put it in water directly for cleaning. It should be wiped with a clean soft cloth. For the optical surface, it should not be scratched or scratched.
3. The instrument should be kept in a dry place without corrosive gas.
4. Avoid loss of spare parts.
