Influence of Ambient Pressure and Temperature on Laser-induced Breakdown Spectra of MarSCoDe on the Zhurong Mars Rover

The geochemical behavior of silver (Ag) and other trace elements (e.g., Cu) is frequently utilized to investigate magmatic differentiation and hydrothermal ore-forming processes.However, accurate determination of Ag by ICP-MS is hindered by polyatomic interferences (e.g., 91 Zr 16 O on 107 Ag and 93 Nb 16 O on 109 Ag).Traditional separation techniques such as ion-exchange resin column separation have been successfully applied to remove interferences on Ag measurement by ICP-MS.However, it is difficult to simultaneously determine concentrations of major and trace elements in the same sample solution after separation processes.In this study, a new method for the simultaneous determination of Ag and 47 major/trace elements by ICP-MS/MS was proposed.The accurate measurement of Ag in geological materials by ICP-MS/MS was achieved by effectively eliminating polyatomic interferences from Zr and Nb through the addition of 7 mL min -1 NH3 into the collision/reaction cell.When Zr/Ag ratio was < 7000, the mass fraction of Ag was accurately obtained by measuring Ag + (m/z = 107 or 109) and Ag(NH3)2 + (m/z 141 or 143) signals; however, when Zr/Ag ratio was > 7000, the accurate analytical result could be only obtained by measuring Ag(NH3)2 + signal, because the Ag + signal at m/z =107 was still interfered by ZrO + signals.To ensure accuracy of the measurement results of Ag, it suggested to monitor Ag(NH3)2 + (m/z 141 or 143) signals when using NH3 as reaction gas.The limit of quantitation (LOQ) for Ag was 0.92 ng g -1 .After the measurement of Ag was finished, 47 major and trace elements were accurately determined after ICP MS/MS was switched to single quadrupole mode.The relative standard deviation (RSD) for the most of major and trace elements were < 10%.The LOQ of major and trace elements were 0.086-82.6 g g -1 and 0.001-0.21g g -1 .The proposed efficient analytical method achieved simultaneous determination of silver and major/trace elements in rock standard reference materials, which enable comprehensive investigation of geochemistry behavior of Ag with other elements in geological processes.