Ash via Muffle Furnance Combustion


Background:  Ash refers to any inorganic material, such as minerals, present in food.  It’s called ash because it’s residue that remains after ignition removes water and organic material such as fat and protein.  Ash is composed of the minerals which do not combust during the analysis such as salts, carbonates and silicates.  Ash can include both compounds with essential minerals, such as calcium and potassium, and toxic materials, such as mercury.  Generally, any natural food will be less than 5% ash in content, while some processed foods can have an ash content of 10% or more.


Method

Equipment

Turn Around Time

Sample Required

Type of Test

Reportable Units

Measurement Range

AOAC 923.03 Ash of Flour; 920.153 Ash of Meat; 900.02 Ash of Sugars & Syrups

Muffle Furnace

5 to 10 Business Days

2 to 5 grams is analyzed from a homogenized sample

High temperature combustion

% Ash

Lower detection limit:  0.01 % Ash


Analysis Description:  Samples to be analyzed are homogenized and a representative test portion is weighed into a crucible which has been previously ignited.  Samples are then ignited in a muffle furnace at 550°C until light gray ash results.  Ash is weighed and a percentage of the total ash in the original sample is calculated and reported.

Additional sample preparation steps are taken as required by certain sample matrices.