Development of Coal Ash Certified Reference Materials JSAC 0521 and 0522 for Determination of Inorganic Constituents

The Japan Society for Analytical Chemistry has developed coal ash certified reference materials (CRMs), JSAC 0521 and 0522, whose concentrations of principal constituents (Si, Al, Ca, Mg, Fe, K, Na, P, Sr, Ti, C and S), trace constituents (As, B, Be, Cd, Co, Cr, Cu, F, Hg, Mn, Ni, Ph, Se, V and Zn) and ignition loss were certified. JSAC 0521 and JSAC 0522 were prepared from Japanese coal ash and foreign coal ash, respectively. CRMs were checked according to the method of,JSAC CRM QM002, and the homogeneities were shown to be excellent. Certified values were obtained from statistical analyses of the results of interlaboratory comparisons for coal ashes. Twenty one laboratories participated in this study, but the results for Cd and F were obtained from 11 and 6 laboratories, respectively. Precise results for Cd (11 laboratories) were obtained only by inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrophotometry and inductively Coupled plasma-atomic emission spectrometry (ICP-AES) at a wavelength of 228.798 nm, because the line is not interfered in the presence of Fe and/or Pt. The results for F proved that, statistically, there is a difference in their extraction efficiency between distillation and pyrohydrolysis. Higher results were obtained by pyrohydrolysis than those by distillation; a recovery of F was incomplete by one-time distillation. Only the results by pyrohydrolysis (6 laboratories) were employed in this study.