Certified Reference Material (CRM).

250 mg/L each of Ba, Cr, Cu, Zn, 150 mg/L V, 125 mg/L Ni, 100 mg/L each of Co, Pb, Sb, 50 mg/L each of As, Cd, 25 mg/L each of Ag, Be, Se, Tl in HNO₃ 5%