Space charge effects and internal standardization in a four ion lenses interface: What is changing in quadrupole inductively coupled plasma mass spectrometry?

摘要

Space charge effects and internal standardization were evaluated in quadrupole inductively coupled plasma mass spectrometry (ICP-MS). Changes in analyte ion sensitivities as a function of analyte ion mass (B-11(+), Mg-24(+), Sc-45(+), Ni-60(+), Ga-71(+), As-75(+), Cd-111(+), Ba-138(+) and Yb-172(+)) due to the presence of seven different matrix elements (Na-23(+), Cu-63(+), Y-89(+), In-115(+), Tb-159(+), Lu-175(+) and Tl-205(+)) were measured by a current ICP-MS instrument arrangement. Elements with different masses (light, middle and high mass range) were evaluated as internal standard (IS): Li-7(+), Sr-88(+) and Bi-209(+). Space charge effects generally becomes more severe for matrices containing elements with middle mass (In-115(+)) and high masses (Tb-159(+), Lu-175(+) and Tl-205(+)) but are not dependent on the masses of most analyte ions, differently from which was known about space charge effects when using first generation ICP-MS instruments. Thus, a single IS was effective for minimize the matrix induced changes (range from -20 to +20%) for analytes with different masses in In matrix (except to mass-to-charge ratio lower than 50); Tb matrix (except to Li-7(+)); Lu matrix (except to Yb-175(+)); and Tl matrix (except to Mg-25(+)).