Miniaturized determination of ash content in kraft lignin samples using oxidative thermogravimetric analysis

Thermogravimetric analysis (TGA) in oxidative conditions is a promising alternative to ignition in oven for the determination of inorganic residue, commonly referred to as ash, in kraft lignin samples. It is here shown that TGA can be used with temperature programs resembling the temperature profiles in standardized methods for oven ignition, and obtain equivalent results even though the sample amount is several orders of magnitude lower. The precision and limit of quantification of TGA are also discussed.