DETERMINATION OF IODINE CONTENT IN DIFFERENT BRANDED TABLE SALTS IN INDIA

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1 WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES Ajmal et al. SJIF Impact Factor Volume 7, Issue 6, Research Article ISSN DETERMINATION OF IODINE CONTENT IN DIFFERENT BRANDED TABLE SALTS IN INDIA 1* Ajmal H., 2 Sana K. S., 3 Shereefabi K. and 4 Silpaunni A. P. 1 Assistant Professor, DM WIMS College of Pharmacy, Naseera Nagar, Meppadi P. O., Wayanad, ,3,4 Karuna College of Pharmacy, Thirumittakode P.O., Palakkad. Article Received on 31 March 2018, Revised on 21 April 2018, Accepted on 11 May 2018, DOI: /wjpps *Corresponding Author Ajmal H. Assistant Professor, DM WIMS College of Pharmacy, Naseera Nagar, Meppadi P. O., Wayanad, ABSTRACT IDD (Iodine deficiency disorders) are recognised as a major global public health problem; it is possible to root out this problem by universal salt iodisation. The study was designed to determine iodine concentration in different branded salt from different areas of India. All samples were from various states of India. Concentration of iodine in salt was determined by both titrimetrically and spectrophotometrically. The branded salts doesn t contain adequate amount of iodine as per the indication mentioned in the sample. Additional iodine supplements should taken along with the diet to prevent iodine deficiency disorder. In our country, despite improvements in salt production and marketing technology, the quality of available salt is poor, or salt is incorrectly iodised, or may deteriorate due to excessive or long term exposure to moisture, light, heat and contaminants. So that the process of iodisation is essential for salts. The qualitative and quantitative analysis of iodine present in various brands of table salt helps to correct this problem for an extend. Since iodine plays an important role in the production of thyroid hormones in our body as well as it is the major factor that reduce the iodine deficiency disorders too.various brands of table salt were collected and the quantitative estimation of iodine was done by both titrimetic analysis and uv spectroscopy. Iodometry is an important redox titration method where the iodine reacts directly, and quantitatively with the salts. Due to high sensitivity and less time consuming UV spectroscopy is also used for the iodine determination in table salt. Hence this study aims the determination of iodine content in different branded table salts in India. It also aims to Vol 7, Issue 6,

2 compare quality of various branded salts and thus aware the people about iodine deficiency disorders. KEYWORDS: Iodine, Titrimetry, UV spectrophotometry. INTRODUCTION Iodine is a chemical element with symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black metallic solid at a standard conditions that sublimes readily to form a violet gas. The elemental form was discovered by the French chemist Bernard Courtois in Iodine occurs in many oxidation states, including iodide (I ), iodate (IO 3), and the various periodate anions. It is the least abundant of the stable halogens, being the sixty-first most abundant element. It mainly occurs in nature as stable iodine -127.a small amount of radioactive iodine 129 is produced naturally in the upper atmosphere by the interaction of high energy particles with xenon. Iodine volatilises at ambient temperature into a pretty blue violet gas with an irritating odour. Iodine exhibits some metal like properties and is only slightly soluble in water. It occurs in nature as iodide ions and it is in this form that is taken into our bodies. MATERIALS AND METHODS Collection of Samples The samples for this study are five branded salt collected from different shop in India. Sample 1-Tata, Sample 2- Sprinkle, Sample 3-Pure lay premium, Sample 4- Surya gold Sample 5- Nirma shudh. METHODS QUALITATIVE ANALYSIS QUANTITIVE ANALYSIS 1. Titrimeric method of analysis 2. UVspectrophotometric determination Materials used in qualitativeanalysis Salt, Potassium iodide, Starch and Sulphuric Acid. [1] Vol 7, Issue 6,

3 Materials used in quantitative analysis Chemicals and reagents used in titrimetric analysis are Sodium Thiosulphate, Conc.Sulphuric acid, Potassium Iodide, Potassium iodate, Distilled water and Starch. [2] Chemicals and reagents used in UV spectrophotometric analysis are Sodium chloride, Iodine, Potassium iodate, Sodium hydroxide, Sodium thiosulphate, Phosphoric acid, Sulphuric acid and Starch. [3] Glass apparatus/accessories are Volumetric Flask, Conical Flasks, Watch Glass, Measuring Cylinder, Burette and Stand, Pipette, Beaker, Dropper, Pipette, Pump and Spatula. [4] Equipments/ Machineries, Electronic Balance, Distillation Equipment and UV spectrophotometer. [5] QUALITATIVE METHOD Iodine is slightly soluble in water, when potassium iodide is added to solubilise iodine properly tri-iodide anion (I3-) is formed. [6] Salts are treated with potassium iodide and for hydrolysis sulphuric acid is added to the solution, iodine is evolved. By treating the solution with starch indicator gives a bluish black product. Hence presence of iodine is detected. [7] QUANTITATIVE METHODS Method of titrimetric analysis Preparation of Standard Solutions and Reagents Preparation of 0.005M Sodium thiosulfate - Dissolve 1.24 g of sodium thiosulfate in 1 litre hot distilled water. Preparation of 2N Sulphuric acid- Add 5.56 ml conc.sulphuric acid drop wise into a 90 ml of chilled distilled water and make the final volume upto 100 ml. Preparation of potassium iodide - Dissolve 10 g of potassium iodide in 100 ml of distilled water. Preparation of saturated salt solution- Take 100 ml of distilled water in a conical flask and add sodium chloride until the salt is insoluble. Heat the solution till the sodium chloride crystals are formed on the sides of the vessel.after cooling down the saturated salt solution at room temperature, transfer the supernatant to a clean bottle. Vol 7, Issue 6,

4 Preparation of 1 % Starch solution- Take 1 g of starch and prepare a slurry in 50 ml of water. Add the slurry slowly to 50 ml of boiling water. Standardisation of sodium thiosulfate solution - The sodium thiosulfate solution is to be standardized with standard potassium iodate solution to determine its exact normality. Take 0.005N thiosulfate solution in a burette. Pipette out 25 ml of 0.005N std.kio3 solution in a conical flask. Add 2 ml of 2N sulfuric acid and 5 ml of 10 % potassium iodide solution. Titrate the solution against sodium thiosulfate till the solution becomes pale yellowish in color. To this 1 ml of starch solution is added and the solution turns deep purple. Add thiosulfate solution drop by drop from the burette till the purple color completely disappears. [8] Normality of sodium thiosulfate, N2=(V1*N1)/V2 Where, V1- volume of potassium iodate, N1-normality of potassium iodate, V2-volume of sodium thiosulfate [9] Titration procedure Dissolve 10 g of salt in 50 ml of distilled water.then add 1-2 ml of 2N sulfuric acid and 5 ml of 10% KI to it. On shaking, the solution turns to a yellow color. Close the flask with stopper and keep the flask in the dark for about 10 minutes. Remove the sample from the dark and titrate against sodium thiosulfate solution until it turns into a pale yellowish color. Subsequently, add a few drops of 1% of starch solution. The solution will turns into a deep purple color. Add thiosulfate drop by drop from the burette until the solution become colorless and note the final reading. [10] Iodine content(ppm)=r*100*1000*0.127*n 6 Where, R- volume of thiosulfate used 100-for converting burette reading for 1000 g of salt 1000-for converting grams of iodine to milligram weight of iodine equivalent to sodium thiosulfate solution N-normality of sodium thiosulfate solution 6-to arrive at the value of 1 atom of iodine liberated [11] Vol 7, Issue 6,

5 Hence, 1 ppm= 1mg/kg [12] Before addition of starch METHOD OF UV SPECTROMETRY Potassium iodate in table salt can be spectrophotometrically determined at two well defined UV absorption maxima (288 iodide in the presence of phosphoric acid. Typical results of KIO3 per kg of salt were obtained with samples, comparable with results from a standard. The method has been found adequate for checking homogeneity of iodine distribution in table salt, as small weighed samples are normally required. [13] Methods and Dilutions The following solutions were used in the spectrophotometric procedures. Solution 1: g of the primary standard potassium iodate (dried in an oven to 110 C) were made up to 100 ml in a volumetric flask in order to obtain a mol L-1 solution. This solution was diluted in order to obtain a final standard iodate solution of x 10-5mol L-1, Solution 2: 5.00 g of sodium chloride were made up to a volume of 50 ml. Solution 3: 3.32 g of potassium iodide (iodate free as checked by acidification) were made up to a volume of 100 ml, including 1 ml of 0.1 mol L-1 sodium hydroxide. Solution 4: 11.5 g of phosphoric acid (85%) were made up to a volume of 100 ml to obtain a 1.0 mol L-1 solution. Solution 5: (Blank 1 solution) 2.0 ml of solution 2 plus 1.0 ml of solution 4 were made up to a volume of 10 ml in a volumetric flask. Solution 6A: (Sample solution) About 1 g of the salt was made up to a volume of 25 ml, for checking homogeneity of the product. Solution 6B: (Sample solution) About 100 g of the salt were made up to 500 ml for analysing the average iodate content, and comparing of methods. Solution 7: (Blank 2 solution) 4-7 ml of solution 6A or 6B plus 1.0 ml of solution 4 were made to a volume of 10 ml in a volumetric flask. Procedure 1. Calibration curve. 1-6 ml of the standard iodate solution (1.000 x 10-5 mol L- 1) were pipetted into 10 ml volumetric flasks with 1 ml of solution 3, 2.0 ml of solution 2 and finally 1 ml of phosphoric acid. The volumes were made up and the absorbances at the desired wavelength (288 and/or 352 nm) vs. the blank, solution 5, were measured. 1 cm light Vol 7, Issue 6,

6 path cuvettes were used. The parameters of the linear plot of A vs. [IO3-] or [I] were determined. Procedure 2. Sample analysis. 4-7 ml of solution 6A or 6B, or 0.2 g of the salt, plus 1 ml solution 3 and 1 ml solution 4 were made up to 10 ml.absorbances at 288 or 352 nm vs. blank 2 (solution 7), containing the same salt solution were measured. C is the concentration of potassium iodate or iodine in mg kg-1 of salt and was calculated by the following formula. C= 1000*A*W*V1*V3 b*e*v2*m Where A - absorbance at desired wavelength e- molar absorptivity of iodate at 352 nm, ie =7.320x104 W - mol of potassium iodate, g or the mol of iodine, g b- light path, 1 cm m- the sample of salt weighed out(in g) V1- volume taken in volumetric flask (see solutions 6A and 6B) V2- volume of 4-7 ml pipetted into the V3 volumetric flask, usually 10 ml, in order to prepare the working solution. [14] RESULTS AND DISCUSSION Qualitative test of iodine OBSERVATION EXPERIMENT Before adding H 2 SO 4 After adding H 2 SO 4 TATA+KI+starch solution No colour change Blue colour SPRINKLE+KI+starch solution No colour change Blue colour PURE LAY+KI+starch solution No colour change Blue colour SURYA GOLD+KI+starch solution No colour change Blue colour NIRMASHUDH+KI+starch solution No colour change Blue colour STD+KI+starch Solution No colour change Blue colour Titremetric analysis Standardisation of Na 2 S 2 O 3 Content of flask Burette reading Volume Initial Final consumed Indicator KIO3+KI+ conc H2SO4+ starch Starch Normality of sodium thiosulfate, N2=(V1*N1)/V2 Endpoint Disappearance of purple color Vol 7, Issue 6,

7 =(25x0.005)/24.9 = N Titrimetric determination Iodine content(ppm)=r*100*1000*0.127*n 6 For eg: Iodine content of standard =1.5x100x1000x0.127x =15.87 ppm 6 Sl.No. Sample code Titre value (ml) Concentration(ppm) Concentration(mg/kg) 1 Sample no mg/kg 2 Sample no mg/kg 3 Sample no mg/kg 4 Sample no mg/kg 5 Sample no mg/kg UV spectrophotometric determination Since, C= 1000*A*W*V1*V3 b*e*v2*m Sl.No. Sample code Wavelength (nm) Absorbance Concentration(mg/kg) 1 Standard mg/kg 2 Sample no mg/kg 3 Sample no mg/kg 4 Sample no mg/kg 5 Sample no mg/kg 6 Sample no mg/kg DISCUSSION Iodine deficiency disorders (IDD) are recognised as a major global public health problem. According to the recent estimates, about 2.5 billion people worldwide (38% of the world s population) have insufficient iodine intake, of which 313 million are in the South-eastern Asian region that includes India (WHO, 2005) Iodine deficiency is the single most preventable cause of neurological and intellectual impairment (cretinism) in the world. According to the various laws all salt for human consumption must contain parts per million (ppm) of iodine at the time of production and not less than 20 ppm iodine at the time of retail, to ensure a minimum of 15 ppm iodine at the household level. Accordingly, a plan was undertaken to institute a Universal Salt Iodization (USI) in the country. [15] Vol 7, Issue 6,

8 Most of the salts collected show iodine levels to be in the acceptable range (iodine content = 15 ppm and above (some even around 30). Out of the 5 samples, only one has shown to have poor content of iodine, but that may also be due to long exposure times to moisture or heat while working in the laboratory. Inaccuracies and oversights due to faulty equipments or while working, should also be taken into consideration.we can predict that most of the people of our country were not deprived of the required amount of iodine in salts.. Overall the study portrays that the effort made by various organisations and the government, for decades, is aiding to wipe out IDD from the nation. Since the situation has been taken seriously by the authorities, it has been possible to supply iodised salt to the all levels of people. CONCLUSION The following conclusions are made from the determination study which we conducted The importance of iodine in the production of thyroid hormones in our body. The causes and prevention of IDD and iodine related disorder as well. The amount of iodine content in various branded salts were determined by both titrimetry and spectrophotometry. The branded salt does not contain the adequate amount of iodine as per the indication mentioned in the sample. Hence other iodine supplement should added along with the diet to prevent IDD. ACKNOWLEDGEMENT I am extremely thankful to Mrs. Manjusha K N, Assistant professor, karuna college of pharmacy for her untiring efforts & cooperation. I also thank her for deep insight into subject, discussion & overall help. I convey my thanks to management, karuna college of pharmacy for their co-operation. REFERENCES 1. "Titration". Science & Technology Encyclopedia. McGraw-Hill. Retrieved 30 September Remington: the science and practice of pharmacy. 1 (21 ed.). Lippincott Williams & Wilkins, 2005; ISO : Graphic technology Process control for the production of halftone colour separations, proof and production prints Part 2: Offset lithographic processes. Geneva: International Organization for Standardization, 2013; Vol 7, Issue 6,

9 4. Allen, D., Cooksey, C., & Tsai, B. (2010, October 5). Spectrophotometry. Retrieved from pml/div/grp03/ spectro photometry. 5. Ninfa, Alexander J.; Ballou, David P.; Benore, Marilee (2010). Fundamental Laboratory Approaches for Biochemistry and Biotechnology. 6. Schwedt, Georg. (1997). The Essential Guide to Analytical Chemistry.(Brooks Haderlie, trans.). Chichester, NY: Wiley. (Original Work Published 1943), Khopkar, S.M.(1998). Basic Concepts of Analytical Chemistry (2 ed.). New Age International, Reger, D.L.; S.R. Goode; D.W. Ball (2009). Chemistry: Principles and Practice (3 ed.). Cengage Learning, Bewick, S.; J. Edge; T. Forsythe; R. Parsons (2009). CK12 Chemistry.-12 Foundation, "ph measurements with indicators". Retrieved 29 September "Titrating Soluble RM, R2NM and ROM Reagents"(PDF). Retrieved "Methods for Standardizing Alkyllithium Reagents (literature through) "(PDF). Retrieved, Quantitative Chemical Analysis, 7Ed. by Daniel C. Harris. Freeman and Company, Skoog, D.A.; West, D.M.; Holler, F.J. (2000). Analytical Chemistry: An Introduction, seventh edition. Emily Barrosse, Universal Salt Iodization(USI) in central and eastern europe and the commonwealth of independent states, Vol 7, Issue 6,