Multi-Element Standard 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.
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 Part-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. I'd be happy to answer any other questions you may have.
Serving you in chemistry,
Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist
DISCLAIMER: Advice offered by the chemists at Inorganic Ventures is intended for the individual posing the question. Feel free to contact us to verify whether these suggestions apply to your unique circumstances.