by Assay
Carry out the following assays on the well-mixed contents of an individual sachet or on a suitable sample from the well-mixed contents of a bulk container. Where the amount in an individual sachet is insufficient to carry out all the assays, thoroughly mix the contents of sufficient sachets to provide enough material for all of the assays.
For the Assays for potassium, for sodium and for chloride dissolve about 8 g of the test sample in sufficient water to produce 500 ml (solution A).
For potassium:
Dilute a suitable volume of solution A with a solution of strontium chloride such that there is a 1500- to 2000-fold excess of strontium ions in the final solution and determine by Method I for atomic emission spectrophotometry, measuring at 767 nm. Use potassium standard solution (600 ppm K), suitably diluted with the strontium chloride solution, for the standard solutions.
Each mg of Potassium Chloride is equivalent to 0.5245 mg of K.
For sodium:
Dilute a suitable volume of solution A with a solution of strontium chloride such that there is a 1500- to 2000-fold excess of strontium ions in the final solution and determine by Method I for atomic emission spectrophotometry, measuring at 589 nm. Use sodium standard solution (200 ppm Na), suitably diluted with the strontium chloride solution, for the standard solutions.
Each mg of Sodium Chloride, of Sodium Bicarbonate and of Sodium Citrate is equivalent to 0.3934, 0.2737 and 0.2345 mg of Na respectively.
Total Sodium (Na+) and Potassium content by Flame Photometry.
Standard solution of sodium and potassium: Weigh accurately of potassium chloride and sodium chloride equivalent to about 197 mg of potassium and about 427 mg of sodium in 500 ml of volumetric flask. Add 100 ml of water dissolve and make up volume with water, filter. Take 5 ml of the filtrate in 250 ml volumetric flask and make up volume with water. Make the dilution about 8.0 mcg/ml of potassium and about 17.0 mcg/ml of sodium.
Test preparation: Weigh accurately powder equivalent to about 786.75 mg of potassium and about 1702.06 mg of sodium (1 sachet) in 1000 ml volumetric flask, dissolve and make up volume with water, filter. Take 2 ml of the filtrate in 200 ml volumetric flask, make up the volume with water. Make the dilution about 8.0 mcg/ml of potassium and about 17.0 mcg/ml of sodium.
Procedure:
For total sodium: Set the filter of sodium and set sensitivity 100 by sodium standard solution, than set zero sensitivity by water. Again set 100 sensitivity by sodium standard solution and than set zero sensitivity by water. Repeat this process for 3 times, than take the reading of test solution.
Calculation:
For total sodium:
Test reading Weight of Std. 5 23 1000 200
—————-x ——————–x ——-x ———-x ————————-x ———x Average fill weight
100 500 250 58.5 Weight of sample 2
For potassium: Set the filter of potassium and set sensitivity 100 by potassium standard solution, than set zero sensitivity by water. Again set 100 sensitivity by potassium standard solution and than set zero sensitivity by water. Repeat this process for 3 times, than take the reading of test solution.
Calculation:
For potassium:
Test reading Weight of Std. 5 39 1000 200
—————-x ———————x ——-x ——–x ————————–x ——–x average fill weight
100 500 250 74.5 Weight of sample 2
For total chloride
Titrate a suitable volume (50 ml for the formula stated above) of solution A with 0.1M silver nitrate VS using a 5% w/v solution of potassium chromate as indicator. Each ml of 0.1M Silver nitrate VS is equivalent to 3.545 mg of Cl.
For citrate
Disperse about 2.8 g of the test sample in 80 ml of anhydrous acetic acid, heat to about 50ºC, cool, dilute to 100 ml with anhydrous acetic acid, allow to stand for 10 minutes and carry out Method I for non-aqueous titration, using 20 ml of the supernatant liquid and 1-naphtholbenzein solution as indicator. Each ml of 0.1M perchloric acid VS is equivalent to 6.303 mg of C6H5O7.
Each mg of Sodium Citrate is equivalent to 0.6430 mg of C6H5O7.
For glucose
Dissolve about 7.5 g of the test sample in 40 ml of water, add 0.5 ml of 1M ammonia, dilute to 50 ml with water, mix well and allow to stand for not less than 5 hours. If necessary use a suitable method of filtration to obtain a clear solution. Determine the optical rotation of the solution. The observed rotation in degrees multiplied by 0.9477 represents the weight, in g, of C6H12O6 in the weight taken for the Assay.
