Objective: To Determine Total Ash Value of Crude Drug
Ash value are helpful in determining the quality & purity of crude drugs especially in powdered form. The objective of ash-ing vegetable drug is to remove all traces of organic matter which may interferes in analytical determination.
Principle: On incineration, the crude drugs normally produce ash which is usually consisting of carbonates, phosphates and silicates of sodium, potassium, calcium and magnesium.
The total ash of a crude drug reveals the care taken during its preparation. A higher limit of acid- insoluble ash is incorporated especially in cases where silica may be present or when the calcium oxalate content of the drug is very high.
Hear Resistant Gloves, Muffle/furnace, Silica crucible, Desiccator, Ash less filter paper, Spatula & Dil. HCl, Sample of crude drugs.
- Take a clean, empty silica crucible and keep it in the muffle furnace for 10-15 minutes for ignition.
- Then, Take out the Silica crucible and keep it in desiccator for cooling for 15-20 minutes.
- Weigh the empty silica crucible and note the reading.
- Take 2 gm of crude drug sample in the silica crucible and spread with the help of spatula.
- Now, keep the silica crucible in muffle furnace at temperature of 450°C – 600°C for incineration of crude drug.
- Turn the temperature knob to 0°C after some time.
- Take our the silica crucible and keep it in desiccator for cooling.
- Weigh the silica crucible again and note the readings.
- Calculate the percentage of the total as in contrast to the air dried sample of the crude drug.
Determination of acid-insoluble ash
- Boil the total obtained ash for 5 minutes and mix 25 ml of dilute hydrochloric acid.
- Filter and collect the insoluble matter on a ash-less filter paper, after that wash the filter paper with hot water, ignite in tared crucible, cool and keep in desiccator.
- Weigh the obtained residue and calculate acid-insoluble ash of the crude drug with reference to the air dried drug.
- For Example: The unpeeled variety of liquorice root must contain not more than 10% of total ash and 2.5% of acid-insoluble ash.
Ash Value of given sample of crude drug is _____