How to operate a polarimeter

Automatic polarimeter is an instrument　　for measuring the optical rotation of a substance . By measuring the optical rotation of a sample, the concentration, content and purity of the substance can be analyzed and determined. Automatic polarimeter uses a photoelectric detector and an electronic automatic reading device, which has the characteristics of small size, high sensitivity, no human error, and easy reading. It is suitable for low optical rotation samples that are difficult to analyze with a visual polarimeter.

　　Therefore, it is widely used in various fields such as medicine, food, organic chemical industry, etc.

　　Agriculture: Analysis of agricultural antibiotics, agricultural hormones, microbial pesticides and agricultural product ingredients.

　　Medicine: Analysis of antibiotics, vitamins, glucose and other drugs, and pharmacological research on Chinese herbal medicines.

　　Food: Control of production process and inspection of finished products of sugar, monosodium glutamate, soy sauce, etc., and determination of sugar content in food.

　　Petroleum: Analysis of mineral oil and monitoring of petroleum fermentation process.

　　Fragrance: Analysis of essential oils.

　　Health Careers: Analysis of Clinical Diabetes in Hospitals.

　　1. Operation method

　　1. Insert the power plug of the instrument into a 220V AC power supply [requires the use of an AC electronic voltage stabilizer (1KVA)] and ground the ground pin securely.

　　2. Turn on the power switch and preheat the sodium lamp for 5 minutes to make the light stable.

　　3. Turn on the DC switch. (If the sodium lamp goes out after the DC switch is turned on, turn the DC switch up and down 1 to 2 times to make the sodium lamp light up under DC, which is normal.)

　　4. Turn on the indication switch and adjust the zero position handwheel so that the optical rotation indication is zero.

　　5. Place the test tube filled with distilled water or other blank solvent into the sample chamber and close the lid. If there are bubbles in the test tube, let them float on the convex neck first; the mist-like water droplets at both ends of the light-transmitting surface should be wiped dry with a soft cloth. The test tube nut should not be screwed too tight to avoid stress and affect the reading. Pay attention to the position and direction of the mark when placing the test tube.

　　6. Take out the test tube. Pour the sample to be tested into the test tube, put it into the sample chamber in the same position and direction, and cover the box. The dial will turn to show the optical rotation of the sample. The red value on the dial indicates left-hand rotation (-) and the black value indicates right-hand rotation (+).

　　7. Press the retest button repeatedly, read the numbers several times, and take the average value as the measurement result of the sample.

　　8. If the sample exceeds the measuring range, the instrument will automatically stop at ±45. At this time, take out the test tube and press the reset button, and the instrument will automatically return to zero.

　　9. After using the instrument, turn off the display, DC and power switches in sequence.

　　10. When the DC power supply system of the sodium lamp fails and cannot be used, the instrument can also be tested when the sodium lamp is powered by AC, but the performance of the instrument may be slightly reduced.

　　2. Determination of concentration or content

　　First, the standard or reference sample of known purity is divided into several samples of different concentrations according to a certain ratio, and their optical rotations are measured respectively. Then, the optical rotation curve is drawn with the concentration on the horizontal axis and the optical rotation on the vertical axis. Generally, the optical rotation curve is made into a lookup table by arithmetic interpolation. When measuring, first measure the optical rotation of the sample, and then find out the concentration or content of the sample from the optical rotation curve according to the optical rotation. The optical rotation curve should be made with the same instrument and the same test tube, and attention should be paid when measuring.