Oxychlorine ions in inductively coupled plasma mass spectrometry: effect of chlorine speciation as Cl– and ClO4–

Abstract

Differences in the inductively coupled plasma mass spectra of 0.2 mol l^–1 HCl and 0.2 mol l^–1 HClO₄ are reported. An enhancement was observed of the ion signal in the mass spectra of several oxychlorine species (ClO₂⁺, HClO₂⁺, ClO₃⁺, HClO₃⁺, HClO₄⁺ and H₂ClO₄⁺) in a solution of HClO₄ compared with the spectra of an equimolar solution of HCl. Spectra of Ca in HClO₄ showed enhanced formation of CaClO⁺, CaClO₂⁺, CaClO₃⁺ and CaClO₄⁺ compared with equimolar solutions of Ca in HCl. Similarly, solutions of Mg in HClO₄ showed enhanced formation of MgClO₂⁺, MgClO₃⁺ and MgClO₄⁺ compared with equimolar solutions of Mg in HCl. Other major rock-forming elements (Na, Al, K, Sc, Ti, Mn and Fe) did not produce enhanced signals from oxychlorine polyatomic ions.