Determination Of Ash Content In Coal Using In-House Reference Materials

The quality assurance of ash content in coal analysis was conducted using in-house reference material as a daily standard. This analysis was based on ASTM D 3302-12 using Thermogravimetric Analysis (TGA). The quality assurance of can be seen from the control charts, homogeneity test, and stability test. In the creating of the control chart, performed several selection tests such as Dixon test, Grubbs test, and Precision test. The in-house reference material measurement obtained from Dixon test and Grubbs test resulted the value was in-layer and for precision test obtained CV analysis<CV Horwitz so that the analysis result was stated precision. Homogeneity test obtained F-analysis<F-table meaning in-house reference material on the measurement of ash content was homogeneous and for stability test obtained that the sample is stable for a long time, according to equation <0.3 x nIQR was 0.0051 <0.0108.