Potassium Sorbate is white to pale yellow scaly crystal, crystalline powder or granular. Odorless or slightly odorous. Long-term storage in the air is easy to absorb moisture and oxidative decomposition and color. Relative density (d2025) 1.363. Melting point 270 ℃ (decomposition). Easily soluble in water (67.6g/100ml, 20℃) 5% saline (47.5g/100ml, Chemicalbook room temperature), 25% sugar water (5lg/100ml, room temperature). Soluble in propylene glycol (5.8g/100m1) and ethanol (0.3g/100m1). The Ph value of 1% aqueous solution is 7-8. It has a strong inhibitory effect on spoilage bacteria and mold, and has become the most important preservative in the world because its toxicity is far lower than other preservatives. In the food industry, it is used as a preservative and an antifungal agent. Content analysis: take 0.25g (accurate to 0.1mg) of the sample pre-dried at 105°C for 3h. Put it into a 250ml flask with a glass stopper, add 36ml of glacial acetic acid and 4ml of acetic anhydride, and warm to make a solution. Cool to room temperature, add 2 drops of crystal violet test solution (TS-74), and titrate with 0.1mol/L glacial acetic acid solution of perchloric acid to the blue-green end point, and keep it for 30s without disappearing. At the same time, carry out a blank test and make necessary corrections. Each M10.1mol/L perchloric acid is equivalent to 15.02mg potassium sorbate (C6H7KO2).