Multi-Element Compatibility and Preparation

Mark was looking for a 22-element blend composed of Zn, As, Se, Mo, Co, Ni, Cu, Ba, Cs, V, Sb, Cd, Pb, Cr, Mn, Th, Tl, Pt, W, Be, Pd, and U. He planned to create calibration standards diluted from this blend for low-level ICP-MS analysis. Mark wanted further information about the compatibility and preparation of such a blend.

	RE: Multi-Element Compatibility and Preparation Dear Mark,      All of the elements listed can go together except Mo and Sb. Therefore, you'll want to have two blends prepared; the first will consist of Zn, As, Se, Co, Ni, Cu, Ba, Cs, V, Cd, Pb, Cr, Mn, Th, Tl, Pt, W, Be, Pd, and U, while the second will include Mo and Sb by themselves.      The matrix of the first blend will be nitric acid at about the 3.5% (abs) concentration level (5% v/v). We will avoid the use of HCl so as to eliminate the ArCl 75 interference upon As. Since yours is an ICP-MS application, I like to use 10 µg/mL stock solutions. The second blend will consist exclusively of Mo and Sb in 3.5% nitric acid with a trace of HF. The two blends will mix well and you will achieve good stability. For more information about elemental stability, refer to our Parts-Per-Billion Stability Study. This study shows the stability of all of the elements mixed together for a period of 1 year in 1% v/v nitric acid. LDPE acid-cleaned at 60 °C for ~ 5 days was used for the basis of the study. Thank you for your question.     Paul R. Gaines, Ph.D. Serving you in chemistry