Agar: Physical and chemical tests / Analysis of crude drugs
To identify the chemical characteristics of a given sample.
|1.||Boil 1gm of agar with 10ml of water until the solution is affected, cool to room temperature||A slip jet is formed. (Jelly-like mass is formed)||Agar|
|2.||0.2% solution of agar, + aqueous solution of tannic acid||No Precipitate is formed||Distinction from gelatin|
|3.||Warm little sample in an alcoholic solution of Pot. Hydroxide||Canary yellow colour is produced||Agar present|
|4.||Mount a small quantity of powder in the solution of ruthenium red and examine microscopically||Particles acquire red or pink colour||Presence of mucilage in agar.|
|5.||Add 1 drop of N/10 solution of iodine to 10ml of decoction of agar. Rapidly cool under tap water to room temperature.||Crimson or Pale yellow colour is produced||Agar is present|
|6.||Add 0.5ml of conc. HCl to 4ml of 0.5% solution of agar. Heat it in a water bath for 30minutes, cool at room temperature and divide it into two portions. Add 3ml of 10% NaOH solution and Fehling’s solution A and B in equal quantities and warm over a water bath. Add 10% of barium chloride solution.||Red ppt of cuprous oxide is obtained Slight white ppt of barium sulphate is obtained||Reducing sugars are present|
|7.||Incinerate agar to ash, and add a drop of con.HCl observe under the microscope||Fragments of diatoms||Agar is present|
The above morphological characteristics and chemical tests indicate that the crude drug is Agar.
Kokate CK. Practical Pharmacognosy, 4 edition, VallabhPrakashan. Delhi; 1994: 98.
F Y D Pharm & S Y D Pharm Notes, Books, Syllabus, PDF, Videos
Second Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise