170135_inorganicventures_flipping

16.10 ICP-MS Measurement

Doubly Charged Ion Interferences:

• Doubly charged ion interference is due to doubly charged element isotopes with twice the mass of the analyte isotope. For example, interference from 206Pb++ (m/e = 103) upon 103Rh+ . • ReducGon in the sample Ar will minimize this interference. • Care should be exercised in matrices containing high levels of mid to heavy mass element isotopes. • The Alkaline and Rare Earth elements form doubly charged ions to an extent that is greater, relaGve to the other elements. (For example, Ce is a good tuning soluGon element using mass 140. Not only can mass 70 be monitored for doulbe ions but the Rare Earths have a greater tendency to form the molecular oxides making mass 156 another mass to monitor.)

16.11 ICP-MS Measurement

Matrix Effects encountered include:

• Viscosity and surface tension which influence sample uptake rates and nebuliza9on efficiency iden9cal to those encountered for ICP- OES.

• Space charge effects • Salt buildup on the orifice of the interface sampler cone.