Preparation and certification of reference materials, brown forest soil (JSAC 0401) and volcanic ash soil (JSAC 0411) for the analysis of trace metals.

The Japan Society for Analytical Chemistry has prepared two new reference materials, JSAC 0401 brown forest soil (metal-spiked) and JSAC 0411 volcanic ash soil (non-spiked), for the analysis of trace metals. The materials were certified for the concentrations of 11 metals (Cd, Pb, Cr, Se, Be, Cu, Zn, Ni, Mn and V) in soil and those of several metals (Cd, Be, Cu, Zn, Ni and Mn for the brown forest soil and Mn for the volcanic ash soil) in water leachate as well. For certifying analytical data, an interlaboratory comparison exercise, in which 27 laboratories had participated, was carried out. The participants were requested to digest samples using alkali-fusion or acid digestion to determine the metal composition, and to leach the soil following the protocol issued by the Ministry of Environment, Japan. Various detection methods were employed to determine the metals. In a statistical analysis, the robust method using z-score was applied.