Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Si, Sr, Ti, V and Zn are determined simultaneously by Inductively Coupled Plasma (ICP) Optical Emission Spectrometry (ICP-OES). Samples should be acidified as soon as possible to 1% HNO3. For “dissolved” elements, samples are filtered with a 0.45m filter before analysis. For “Total” elements the sample is digested with 5% HNO3 for one hour in a digestion block prior to analysis.
(See Method References No. 50 and No. 21)