Ash Analysis

Question 1

Definition of Ash

Answer 1

Inorganic residue remaining after either ignition or complete oxidation of organic matter

(Total of all inorganic elements)

Question 2

Combustion is done between what range of temperature

Answer 2

500 - 700 degrees C

Question 3

Types of Ashing

Answer 3

Dry - % ash determination

Wet - samples with high fat (mineral determination)

Low Temperature/Plasma
- used to prevent loss of trace and volatile minerals

Question 4

Dry Ashing

Answer 4

High temp (525C or greater)
Leaves inorganic material to be quantified gravimetrically

Question 5

Calculations of Ash Content

Answer 5

%Ash (fwb) = wt. of ash/weight of sample *100

%ash (dwb) = wt. of ash/wt. of dry sample *100

Question 6

Sources of Error (Ashing)

Answer 6

1. Sample not representative
2. Microelement contamination
3. Loss of sample in drying before ashing
4. Volatilization of elements
5. Incomplete combustion

Question 7

Microwave Ashing

Answer 7

Wet & Dry Ashing