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. Author manuscript; available in PMC: 2009 Nov 1.
Published in final edited form as: Anal Chem. 2008 Oct 10;80(21):7921–7929. doi: 10.1021/ac801712s

Figure 2.

Figure 2

(a) A graph of the transmission dependence on sample N2 pressure introduced at the Q0 inlet. As pressure increases, collisional focusing facilitates transmission of the secondary ions through the Q0 quadrupole rods. A maximum efficiency is reached at ~8 millitorr, and further increases in pressure reduces the secondary ion counts, presumably due to primary ion collisions with the gas. (b) An In spectrum acquired with a typical operating sample pressure of 8 millitorr N2. The spectrum consists almost entirely of In and various In-oxide peaks.