The distillation method of sulfur dioxide in food is a commonly used detection method, and here are the steps:
Place the weighed sample in a round-bottom distillation flask, add 250ml of water, install a condensing device, and the lower end of the condenser tube should be inserted into 25ml of lead acetate (20g l) absorption solution in an iodine measuring flask.
Add 10ml (1+1) of hydrochloric acid solution to the distillation flask, immediately cover the plug and heat the distillation, when the distillate is about 200ml, leave the lower end of the condenser tube from the liquid surface, and distill for 1min.
Rinse the part of the device inserted into the lead acetate solution with a small amount of distilled water, and do a blank test while testing the test sample.
Add 10ml of concentrated hydrochloric acid and 1ml (10g l) of starch indicator to the iodine measuring flask and shake well (0.).010mol l) iodine standard dissolves until blue, and does not fade within 30s.
With this method, the amount of sulphur dioxide in food can be detected.
The food sulfur dioxide distillation instrument adopts intelligent integrated design, adopts far-infrared ceramic heating device instead of high-power electric heater, and adopts external cooling water automatic cooling and reflux device and professional design of condenser pipe and other technical means, which realizes the purpose of simple operation, automatic distillation, beautiful and practical, energy saving and consumption reduction, and can be widely used in the distillation operation of sulfur dioxide residue and formaldehyde and alcohol in the field of food testing.
Key features: 1. Integrated design, easy installation and maintenance; 6 groups of samples can be made at a time, and the temperature can be controlled in a single well; The heating power can be adjusted in a single hole;
2. The control module adopts PLC control, with strong and stable performance, 7-inch LCD touch screen;
3. Optional external cooling water circulation device, closed cooling water automatic cooling and circulation return device, energy saving and consumption reduction;
4. The far-infrared ceramic heating device is adopted, which has high heating efficiency, more energy saving, good waterproof effect and acid and alkali corrosion resistance;
5. The heating power is adjustable from 0-500W, and each heating device is independently controlled, with built-in micro-boiling mode;
6. Heating countdown function, the single-channel time can be set arbitrarily, and the heating will be automatically stopped at the point;
7. The independent rotameter controls the nitrogen flow rate, and the nitrogen blowing flow rate can be adjusted independently in a single hole (20-2000ml min);
8. The bottom of the receiving bottle has a built-in magnetic stirrer, and the stirring speed can be monotonic in a single group, and the speed can be adjusted steplessly;
9. It comes with a butterfly clip and a titration holder, and the experiment is completed and titrated directly.