XRF is the preferred technique for determination of the major element oxides as well as some trace elements, particularly those with solubility issues. Two principal sample pretreatment techniques are used; pressed powder and fused disc. Pressed powders are generally used for determining trace elements but these analyses may be subject to particle size and matrix effects which increase analytical uncertainty, particularly in the light elements. Fusion techniques reduce the matrix effects and eliminate particle size effects; providing more precise major element data, however dilution makes this generally less suitable for trace elements.
Thermo Gravimetric Analaysis (TGA)
Thermo gravimetric analysis or loss on ignition (LOI) is performed using programmable furnaces with an integral balance, at a range of different temperatures; applicable for gravimetric determinations from moisture through to ashing of samples and various intermediate stages. Single point LOI determinations will be measured at 1000°C, unless otherwise specified.