limit test for chloride

LIMIT TEST FOR CHLORIDE

1. LIMIT TEST FOR CHLORIDE BY PROF. TAUFIK MULLA ASSISTANT PROFESSOR DEPARTMENT OF PHARMACEUTICS SPBC COLLEGE OF PHARMACY.

2. WHAT IS LIMIT TEST ? Every product must be clinically safe for the use of human or animal. Before formulation need to be verify that every compound/drug/solvent all are must be pure/free from impurity. As we know, if impurity present in product or drug leads to change physical, chemical property, also change color, odour, taste also change therapeutic effect of drug and produce toxic effect. So purchasing of pure chemical or making free from impurity is expensive and difficult process. Indian Pharmacopoeia has provide certain limit of impurity if present in substance so we can used for manufacturing process. The limit of impurity expressed in term of PPM = 1 micro gm = 10 -6 gm

3. Limit = amount present in substance Test = investigation or examination Impurity = foreign substance present in compound Limit test = "Limit test is defined as quantitative or semi-quantitative test designed to identify and control small amount of impurity which is likely to be present in the substance. Limit test is generally carried out to determine the inorganic impurities present in the compound. Importance of Limit test To find out amount of harmful impurity To find out permissible amount of impurity

4. Apparatus used for performing limit test Nessler cylinder

5. Limit test for chloride The Chloride Limit Test is designed to determine the allowable limit of chloride contained in a sample. Principle: Limit test for chloride is based on the reaction between sodium chloride or chloride ion with silver nitrate in the presence of dilute nitric acid to form silver chloride, which appears as opalescence in the solution. NaCl AgN03 dil. HN03 AgCI NaN03 sodium chloride silver nitrate silver chloride sodium nitrate

6. Reagent Preparations: Dil. Nitric Acid: 106 ml HN03 is diluted to 1000 ml with water. Silver Nitrate Solution: 5 9 of AgN03 is dissolved in 100 ml of water. Standard Sodium Chloride solution: Dissolve 0.05845 gm of NaCl in 100 ml in distilled water.

7. PROCEDURE TEST SAMPLE STANDARD SAMPLE REASON Dissolve given sample in 10 ml of distilled water and transfer the solution in Nessler cylinder and marked it as ‘T’ Take 1 ml 0.05845% w/v solution of Sodium chloride in Nessler cylinder and marked it as ‘S’ The aqueous solution will leach out all the chloride ions present in the sample and make them ready to react with silver nitrate. Add 10 ml of nitric acid Add 10 ml of Oil. nitric acid Dil. Nitric acid is added in limit test of chloride to make solution acidic and help silver chloride precipitate to make solution turbid at the end of process. Dilute to 50 ml in Nessler’s cylinder Dilute to 50 ml in Nessler’s cylinder Equal volume of the solutions is taken to compare the opalescence. Add 1 ml AgNO3 solution. Stir properly and keep aside for 3 minute. Add 1 ml AgNO3 solution. Stir properly and keep aside for 3 minute. The Ag+ ions will react with CI- ions to form opalescence of silver chloride. Ag + Cl = AgCI Observe the opalescence/turbidity Observe the opalescence/turbidity Compare after 5 min.

8. conclusion The opalescence produced in the sample solution should not be greater than standard solution. If opalescence produced in the sample solution is less than the standard solution, the sample will pass the limit test of chloride and vice versa. Opalescent means colorless or white / milky color Turbidity means the quality of being cloudy