170135_inorganicventures_flipping

16.12 ICP-MS Measurement

Space Charge Effects:

• These effects are thought to occur at the MS interface, the region between the skimmer 8p and ion op8cs and in the ion op8cs region. • The net result is a suppression of the signal in high concentra8ons of a matrix element. • The kine8c energy of the ion element matrix affects the degree of suppression with larger masses (higher kine8c energy) causing more depression than lower masses. • Due to differences between instruments in interface and ion op8c designs it is difficult to predict the condi8ons under which the effect is minimal.

16.13 ICP-MS Measurement

Space Charge Effects: (cont.)

• Working at matrix element concentra3ons of 100 - 200 μg/g should cause only a slight reduc3on in the signal. • Under 'cool plasma' condi3ons, this suppression effect will be much more pronounced. • The approach taken in our laboratory is to aHempt to keep the matrix element concentra3on at or below the 100 μg/g concentra3on level and to use only ‘high power’ when analyzing matrices containing > 10 μg/g matrix element(s).