Ash content determination.pptx- materials- procedure- formula

Ash content determination.pptx

1. Ash content determination By: Kristel A. Honrado-Peralta, RPh

2. Objective To determine the total ash and acid- insoluble ash content of plant material.

3. Discussion The ash content of a crude drug is generally taken to be the residue remaining after incineration. Incineration is  a waste treatment process that involves the combustion of substances contained in waste materials . It usually represents the inorganic salts naturally accuring in the drug adhering to it, but it may also include inorganic matter added for the purpose of adulteration.

4. Discussion Ash standards have been established for a number of the official drugs; usually these standards set a maximum limit on the total ash or on the acid-insoluble ash permitted. The total ash is the residue remaining after incineration; the acid insoluble ash is the part of the total ash which is insoluble in diluted hydrochloric acid. In making ash determination, an electric furnace is used for ignitions.

5. Discussion The following temperatures equivalents, which are only approximate, will be found of value: Color Temperature Very dull red heat 500- 550 °C Dull red heat 550- 700 °C Bright red heat 800- 1000 °C Yellow red heat 1000-1200 °C White heat 1200- 1600 °C

6. Discussion Note: the crucible in which the drug is to be ignited should be heated to dull redness until constant weight, cooled in a dessicator and weighed. This procedure drives off the moisture and the absorbed gases present in the surface of the crucible. The drug is incinerated at a temperature not toexceed a dull redness.

7. Materials Ethyl alcohol Dilute hydrochloric acid Tared plain crucible Ashless filter paper Bunsen burner Mettler balance Dried plant material (any) Crucible tong Dessicator Funnel Glass rod Clay triangle Oven

8. Procedure Determination of the total ash content. 1. Accurately weigh a quantity of the ground drug representing 2-4g of the dried plant material in a tared plain crucible. The crucible is covered and heated gently until all the carbon is driven off. The cover is then removed and the crucible placed in an inclined position on the clay triangle. Incinerate at a low temperature for it to become very dull red and until it turns to a white ash. Cool and determine the weight of the ash. 2. If a carbon-free ash cannot be obtained in this manner, exhaust the charred mass with hot water, collect the insoluble residue on an ashless filter paper, incinerate the residue and filter paper until the ash is white. 3. If again, carbon-free ash cannot be obtained in this manner, cool the crucible. Add 15mL of alcohol to break up the ash with a glass rod. Burn off the alcohol, and again, heat the whole to dull redness. 4. Cool and weigh the ash. Compute the percentage of the total ash from the weight of the plant sample taken.

9. Procedure Determination of Acid- Insoluble Ash content. Boil the ash obtained in procedure A with 25mL of dilute HCl for 5 minutes. Collect the insoluble matter on an ashless filter paper. Wash with hot water. Ignite, cool, and weigh. Determine the percentage of acid-insoluble ash from the weight of the plant sample taken.

10. Formula Formula: % Total Ash = (Weight of Ash) / Weight of Plant Sample x 100 % Acid-insoluble Ash = (Weight of the acid-insoluble ash) / (Weight of the plant sample) x 100

11. Thank you!