In inductively coupled plasma/mass spectrometry analyte, M may be distributed among several species forms including doubly charged ions (M2+), singly charged ions (M+), mono-oxide ions (MO+), and hydroxide ions (MOH+). Detailed data are presented for Ba to illustrate the dependence of the ion count of these species and their ratios (M2+/M+, MO+/M+, and MOH+/M+) on nebulizer flow rate, plasma power, and sampling depth. Although these data are representative of most elements, many form oxides to a much greater degree than Ba; data are presented for Ti, W, and Ce to illustrate this fact. These various analyte species are important in that serious interelement interferences can occur because of spectral overlap. An extensive pair of tables indicating potential spectral interferences caused by element oxide, hydroxide, and doubly charged ions is presented.
M. A. Vaughan and G. Horlick, "Oxide, Hydroxide, and Doubly Charged Analyte Species in Inductively Coupled Plasma/Mass Spectrometry," Appl. Spectrosc. 40, 434-445 (1986)