Page 1 of 8 Molecular Formula : C 7 H 5 NaO 3 CAS Registry No. : [54 21 7] Molecular weight : 160.10 Reference : In-house Other names : Benzoic acid, 2 hydroxy, mono sodium salt, Mono sodium salicylate. Description : Slight pinkish to off - white crystalline powder. Solubility : Freely soluble in water and in ethanol (95%); Practically insoluble in ether. TESTS SPECIFICATIONS 1. Identification : A: A 10 % w/v solution in carbon dioxide free water prepared from distilled water (solution S) gives the reactions of salicylates. B: Gives reaction of sodium salts. 2. Clarity & colour of solution : Solution is clear and colourless to pale yellow. (10% w/w solution in water) 3. Acidity : 20 ml of 10% w/w solution in water required not more than 4.00 ml of 0.01 M sodium hydroxide solution. 4. Chlorides (ppm) : Not more than 200 5. Sulphates (ppm) : Not more than 800 6. Heavy metals (ppm) : Not more than 20 7. Loss on drying (%w/w) : Not more than 0.5 (Determined on 1 g at 105 C, 1 hour) 8. Assay (% w/w, on dried basis) : 99.00 to 101.0
Page 2 of 8 1. IDENTIFICATION (A) 1.1 APPARATUS & REAGENTS 1.1.1 Analytical Balance 1.1.2 Volumetric flask, 100 ml 1.1.3 Pipette, 1ml. 1.1.4 Dilute Acetic acid 1.1.5 Dilute Ferric chloride test solution, 1.2 PROCEDURE 1.2.1 Take 1 g of the sample in volumetric flask 100ml, dissolved in distilled water and make up to the mark 1.2.2 Take 1.0 ml of the above solution and add 0.5 ml of Ferric chloride test solution. 1.2.3 A violet color should be produced. 1.2.4 Add 0.1ml of dilute acetic acid to the above solution; the violet color should not be discharged. IDENTIFICATION (B) 1.1 APPARATUS & REAGENTS 1.1.1 Analytical Balance, 1.1.2 Pipettes, 2ml, 5 ml 1.1.3 15% w/v Potassium Carbonate solution 1.1.4 Potassium antimonate solution 1.2 PROCEDURE 1.2.1 Dissolve 0.1g of the sample being examined in 2 ml of water. 1.2.2 Add 2 ml of a 15% w/v solution of potassium Carbonate and heat to boiling, 1.2.3 No precipitate is formed. 1.2.4 Add 4 ml of potassium antimonate solution and heat to boiling. 1.2.5 Allow to cool in ice. 1.2.6 A dense white precipitate is formed.
Page 3 of 8 2. CLARITY AND COLOUR OF SOLUTION 2.1 APPARATUS AND REAGENTS 2.1.1 Nessler Cylinders, 50 ml 2.1.2 Pipette, 20 ml. 2.2 PROCEDURE 2.2.1 Take 1 g of the sample in volumetric flask 100ml, dissolved in distilled water and make up to the mark. 2.2.2 Take 20 ml of solution in one nessler cylinder. In another nessler cylinder take 20 ml of water 2.2.3 Compare the contents of nessler cylinders by viewing down the vertical axis of the cylinders. 2.2.4 The solution is considered clear if its clarity is same as that of the water. 2.2.5 Observe colour of the test solution in nessler cylinder by viewing down the vertical axis of the nessler cylinder. 2.2.6 The solution is considered passes, provided the colour of the solution is colourless to pale yellow coloured. 3. ACIDITY 3.1 APPARATUS AND REAGENTS 3.1.1 Pipettes, 5 ml, 20 ml, 3.1.2 Conical flask, 150 ml 3.1.3 Phenol red indicator, 3.1.4 Sodium hydroxide 0.01 M. 3.2 PROCEDURE 3.2.1 Take 20 ml of the 10 % solution in water into a conical flask and add 3 drops of phenol red indicator. 3.2.2 Titrate with 0.01 M sodium hydroxide solution to a reddish violet colour end point and note the volume V. 3.2.3 Titre volume should not be more than 4.00 ml.
Page 4 of 8 4. CHLORIDES 4.1 APPARATUS AND REAGENTS 4.1.1 Nessler Cylinders, 50 ml, 4.1.2 Glass beaker, 250ml 4.1.3 Glass Funnel, 4.1.4 Measuring Cylinder 25 ml, 4.1.5 Pipettes, 2 ml, 5 ml, 10 ml, 4.1.6 Nitric acid, 2 M, 4.1.7 Silver Nitrate, 0.1M, 4.1.8 Chloride standard solution (5 ppm Cl). 4.2 PROCEDURE 4.2.1 Take 25 ml of 10 % w/v solution in glass beaker and add 15 ml of water. 4.2.2 Add 10 ml of Nitric acid 2M and filter. 4.2.3 Take 25 ml of the filtrate in one nessler cylinder; add 1 ml of 0.1 M Silver nitrate and make upto 50 ml with water. 4.2.4 Stir with a glass rod and allow to stand for 5 minutes. 4.2.5 In another cylinder place 10 ml of Chloride standard solution (25 ppm) and add 10 ml of Nitric acid 2M. Dilute to 50 ml with water and add 1 ml of 0.1 M Silver nitrate. Stir with a glass rod and allow to stand for 5 minutes 4.2.6 The opalescence formed with the test sample should not be more intense than that of the Chloride standard solution (25 ppm). 5. SULPHATES 5.1 APPARATUS AND REAGENTS 5.1.1 Nessler Cylinders, 50 ml, 5.1.2 Pipettes, 1 ml, 5 ml, 10 ml. 5.1.3 Barium chloride, 25%, 5.1.4 Acetic acid,5m 5.1.5 Ethanolic Sulphate standard solution, 10 ppm 5.1.6 Sulphate standard solution, 10 ppm SO 4 )
Page 5 of 8 5.2 PROCEDURE 5.2.1 Take 2.5 ml of the 10 % solution and add 15 ml of water in one nessler cylinder. 5.2.2 Add 1 ml of a 25 % w/v solution of Barium chloride. 5.2.3 Add 0.15 ml of 5 M acetic acid and add sufficient distilled water to produce 50 ml. 5.2.4 Add 1.5 ml of ethanolic Sulphate standard solution (10 ppm SO 4 ), mix and allow to stand for 1 minute. 5.2.5 In another cylinder transfer 1 ml of a 25% w/v solution of Barium chloride and add 1.5 ml of ethanolic Sulphate standard solution, and add sufficient distilled water to produce 50 ml. Stir with a glass rod and allow to stand for 5 minutes. 5.2.6 The opalescence formed is compared against a black background with the test sample should not be more than that of the standard solution. 6. HEAVY METALS 6.1 APPARATUS AND REAGENTS 6.1.1 Analytical Balance, 6.1.2 Glass beaker, 250ml 6.1.3 Nessler Cylinders,, 50 ml 6.1.4 Measuring Cylinders, 25 ml 6.1.5 Glass funnel, 6.1.6 P H Meter, 6.1.7 Pipettes, 1 ml, 2 ml 6.1.8 Standard Lead solution, 20 ppm Pb 6.1.9 Acetic acid, 1N, 6.1.10 Dil. Ammonia solution, 6.1.11 Saturated Hydrogen sulphide solution, 6.1.12 Dilute hydrochloric acid.
Page 6 of 8 6.2 PROCEDURE 6.2.1. Take 2.0 g of sample in a glass beaker, dissolve in 46 ml of water and add 4 ml of dilute hydrochloric acid and filter. 6.2.2. Take 25 ml of the filtrate and adjust the ph between 3.00 and 4.00 with acetic acid or dilute ammonia solution. Transfer the solution into a nessler cylinder. 6.2.3. Mix the contents with a glass rod. 6.2.4. In another nessler cylinder take 25 ml of the water and 1 ml of standard lead solution and adjust the ph between 3.00 and 4.00 with acetic acid or dilute ammonia solution. 6.2.5. Mix the contents with a glass rod. 6.2.6. Add 10 ml of hydrogen sulphide solution to both the nessler cylinder and allow to for 5 minutes. 6.2.7. Any colour produced in the test solution is not more intense than the standard solution. 7. LOSS ON DRYING 7.1 APPARATUS AND REAGENTS 7.1.1. Analytical Balance, 7.1.2. Glass weighing bottle 7.1.3. Electric oven, 7.2 PROCEDURE 7.2.1 Take the empty weight of the glass weighing bottle, which is previously dried at 105 ºC in an oven. Note the weight W 1. 7.2.2 Take 1 gm of test sample into the glass weighing bottle and weigh accurately the bottle and contents. Note the gross weight W 2. 7.2.3 Distribute the sample sidewise, and place the loaded bottle in a electric oven, remove the stopper and leave it also in the oven.
Page 7 of 8 7.2.4 Dry the sample for 1 hour at 105 C. 7.2.5 After drying is completed, open the oven, close the bottle promptly and allow to cool to room temperature. 7.2.6 W eigh the weighing bottle and the contents W 3. 7.2.7 Note the difference in loss in weight of the substance and calculate the percentage. 7.3 CALCULATIONS 7.3.1 The Loss on drying of the substance is expressed by the following formula 8. ASSAY ( W 2 W 3 ) X 100 ( W 2 W 1 ) 8.1 APPARATUS AND REAGENTS 8.1.1 Analytical Balance, 8.1.2 Measuring Cylinder, 50 ml 8.1.3 Conical Flasks, 250 ml. 8.1.4 Perchloric acid 0.1M 8.1.5 Anhydrous glacial acetic acid, 8.1.6 Crystal violet indicator 8.2 PROCEDURE 8.2.1 Transfer 0.15 g of the sample accurately weighed in a 250 ml conical flask contains 30 ml of anhydrous glacial acetic acid previously neutralized with 0.1M Perchloric acid using Crystal violet indicator to blue green end point. 8.2.2 Add 3 drops of crystal violet indicator and mix. 8.2.3 Titrate against 0.1M Perchloric acid to blue-green end point and note the volume TV.
Page 8 of 8 8.3 CALCULATIONS 1 ml of 0.1M Perchloric acid = 0.01601 gm of sodium salicylate TV N F 100 100 Sample Wt. 0.1 (100 LOD) Where TV = Titre volume of 0.1 M Perchloric acid VS, N = Normality of 0.1 M Perchloric acid VS, F = Factor (0.01601) LOD = Loss on drying %.