Detection Method Of Iodine And Polysaccharide Content In Kelp

[Content Determination] Take about 10g from this product, cut it into small pieces, weigh it accurately, place it in a porcelain dish and slowly heat it up. Keep it for 10 minutes every time the temperature rises by 100°C, and keep it for 40 minutes when the temperature rises to 400 ~ 500°C, then take it out and let it cool. Put the residue on ignition in a beaker, add 100ml of water, boil for about 5 minutes, filter, and treat the residue with water for 2 times, 100ml each time. filter, combine the filtrate, then wash the residue with hot water for 3 times.  Combine the washing solution and the filtrate, heat and concentrate to about 80ml, let cool, transfer the concentrated solution to a 100ml measuring flask, add water to the mark, shake well, accurately measure 5ml, place in a stoppered Erlenmeyer flask, add 50ml of water and 2 drops of methyl orange indicator solution, drop Add dilute sulfuric acid until red, add 5ml of newly prepared bromine test solution, and heat it to boiling. Add 5ml of 20% sodium formate solution along the bottle wall, and then heat for 10-15 minutes. Wash the wall of the bottle with hot water, let it cool, add 5mL of dilute sulfuric acid and 5ml of 15% potassium iodide solution.  Immediately titrate with sodium thiosulfate titration solution (0.01mol/L) to light yellow, add 1ml starch indicator solution , and continue to titrate until the blue color disappeared.  Each 1ML of sodium thiosulfate titration solution (0.01mol /L) is equivalent to 0.2115mg of iodine (I).

This product is calculated as a dry product. The iodine (I) in kelp shall be not less than 0. 35%;  the iodine (I) in Kombu shall not be less than 0.20%.

Polysaccharose Preparation of Reference Substance Solution: Take an appropriate amount of fucose reference substance, accurately weigh it, and add water to make a solution containing 0.12 mg per 1 ml.

Preparation of The Standard Curve: Precisely absorb the reference solution 0.2ml, 0.4ml, 0.6ml, 0.8ml, 1.0ml, 1.2ml, put them into 15ml graduated test tube with stopper, and add water to each to 2.0ml , quickly add 6ml of 0.1% anthrone sulfuric acid solution in precision, shake it immediately, and leave it for 15 minutes, immediately place it in an ice bath to cool for 15 minutes, take it out. With the corresponding reagent as a blank, according to the UV-Visible spectrophotometry. Measure the absorbance at a wavelength of 580nm, and draw a standard curve with absorbance as the ordinate and concentration as the abscissa.

Detection Method: Take about 1g of this product powder (through No. 3 sieve), accurately weigh it, put it in a round bottom flask, add 200ml of water, let it for 1 hour, heat and reflux for 4 hours, cool and transfer it to a 250ml centrifuge cup for centrifugation ( at a speed of 9000 revolutions per minute) for 30 minutes. Aspirate the supernatant, transfer it to a 250ml measuring flask, wash the precipitate with a small amount of water, transfer it to a 50ml centrifuge tube, and centrifuge (at speed of 9000 revolutions per minute) for 30 minutes. Aspirate the supernatant, put it in the same measuring flask, add water to the mark, and shake well. Accurately measure 5ml of the supernatant, place it in a 100ml centrifuge tube, slowly add 75ml of ethanol while stirring, shake well, and left it at 4°C for 12 hours, take it out, centrifuge (rotating at speed of 9000 rpm) for 30 minutes. Discard the supernatant, dissolve the precipitate with boiling water, let it cool, transfer it to a 20ml measuring flask, add water to the mark, shake well and centrifuge.  2ml of supernatant was accurately measured and put into a 15ml graduated test tube with stopper. According to the method under the preparation of the standard curve, from the "rapid and precise addition of 6ml of 0.1% anthrone sulfuric acid solution", the absorbance was measured in accordance with the law, and the weight of fucose contained in the test solution was read from the standard curve ( mg ), calculated and obtained.

This product is calculated as a dry product, and  the polysaccharide contained in the form of fucose (C6H12O5) shall not be less than 2.0%.