Determination of Potassium Sorbate by UV-1100 Spectrophotometry - Master's thesis - Dissertation

Spectrophotometric determination of potassium sorbate

Determination of the content of potassium sorbate by spectrophotometry. Key words: spectrophotometry; potassium sorbate; analysis instrument ; UV-1300 pure potassium sorbate has the maximum absorption peak at 254 nm. After the sample is extracted with chloroform, it is extracted with sodium hydrogencarbonate to dissolve sodium sorbate into aqueous solution, and the absorbance is measured.
1. The main instrument UV spectrophotometer UV-1300.
2. Main reagent 1 chloroform: extracted twice with sodium bicarbonate (o.5 m01.L-1) in half by volume of chloroform, then dried over anhydrous sodium sulfate and filtered for use.
20.5 mol·L-1 sodium bicarbonate: 21 g of sodium hydrogencarbonate was dissolved in 500 mL of water.
30.3 mol·L-1 sodium bicarbonate. 3. Operation step 1 Standard curve drawing: a standard solution of 0, 1, 2, 3, 4, 5 g·mL-1 was prepared with 0.3 mol·L-1 sodium bicarbonate solution and sorbic acid at a wavelength of 254 nm. The absorbance was measured separately. By plotting the concentration as the abscissa and the absorbance as the ordinate, the standard curve of sorbic acid can be obtained.
2 Preparation of sample solution: Weigh 50.00 g of sample and add 350 mL of water to the tissue mincer, pulverize for 5 min, homogenize, dilute to 500 mL with water, and shake well. Accurately weigh 10 g of this homogenate, quantitatively transfer it to a 50 mL volumetric flask, dilute to volume with water, and mix. Accurately transfer 10 mL of this solution into a 250 mL separatory funnel and extract with 1.0 mL for 1 min. The layer was transferred to a 125 mL Erlenmeyer flask with 5 g of anhydrous sodium sulfate built in, shaken and allowed to stand.
3 Determination of sorbic acid in the sample: Transfer 50 mL of the above solution into a 125 mL separatory funnel and extract with 25 mL of 0.3 mol·L-1 sodium bicarbonate for 1 min. After standing and layering, carefully remove the layers. A layer of sodium bicarbonate solution was taken and the absorbance was measured at 254 nm. The content of sorbic acid in the sample can be calculated by finding the content of sorbic acid from the standard curve. 4. Calculation (imported reference material: http://)
Sorbic acid content (μg·g-1) = (from the standard curve, the content of potassium sorbate × dilution factor) / sample weight (g) Keywords: spectrophotometry; potassium sorbate; analysis instrument .com;UV-1300