Why ammonia is used in limit test for Iron? Explained in English скачать в хорошем качестве

Why ammonia is used in limit test for Iron? Explained in English

#PICEnglish, #1stSmesterBPharm #MedicoPharmaLectures, #BPharm Hello Everyone, Greetings for the day...!!! @MedicoPharma Lectures Download Notes in PDF using Facebook Group:   / files   Instagram-https://www.instagram.com/medicopharm... Welcome back to MedicoPharma Lectures once again. This Lecture is about Iron Limit Test. Introduction: Iron is a cumulative impurity that may not cause an immediate adverse effect but when taken for a prolonged time even in small quantity, will accumulate in the body and causes toxicity. Iron is commonly present in pharmaceutical solvents like water. Its presence in large quantity may lead to the decreased therapeutic value of pharmaceutical preparations and also create technical problems during drug formulation. That's why a limit test for iron is carried out. Principal: The principal behind the limit test for iron is based upon reaction between ferrous ion and thioglycolic acid in the presence of citric acid to produce pink/purple colour in alkaline media(ammonia). Thus produced sample colour is compared with that of Standard colour which is produced by a specific amount of standard ferrous ammonium sulphate under the same reaction condition. Reactions involved in limit test for iron, procedures, observation and results are explained in videos. Why citric acid is added in the limit test for iron? -Citric acid is used to prevent the precipitation of iron as its hydroxide when ammonia is added to the solution. When ammonia is added, it will react with water to form ammonium hydroxide which in turn react with iron to produce ferrous hydroxide or ferric hydroxide ppt and hence the total quantity of iron impurity will not be available to react with thioglycolic acid. So, citric acid is added to solubilize these precipitate of iron as its hydroxide and hence all iron will be available for thioglycolic acid. See the video for the reaction. -Why ammonia is used in the limit test for Iron? Ammonia is added to make the solution alkaline because the ferrous thioglycolate complex produces pink/purple colour in alkaline media but remains colourless in acidic or neutral media. For reaction, kindly watch the video. Pharmaceutical Inorganic Chemistry: Playlist:    • Lecture_01_PIC_ Impurity, Types of Impurit...   Limit Test    • Lecture_02_PIC_Introduction to Limit Test_...   Pharmacology Videos:    • Lecture 01: Introduction to General Pharma...   Facebook Page-   / medicopharmalecture   Thanks & regards, MedicoPharma Lectures