Design Of Quadrupole Collision/reaction Cell And Study Of Its Working Conditions

Inductively coupled plasma mass spectrometry?ICP-MS? is not only widely used in the analysis of trace and ultra-trace element, but also plays an important role in the analysis of isotope ratios and morphology. ICP-MS detection is seriously interfered by polyatomic ion, and collision/reaction cell technology can efficiently remove this kind of interference, improving the detection capability of ICP-MS and decreasing detection limit of it.This paper is based on and supported by the project ?development and application of ICP trace analytical instruments?, designing a quadrupole collision/ reaction cell and studying its working conditions. Based on studying of multipole theory and theory of collision/reaction cell, this paper designs a quadrupole collision/ reaction cell, and carrys out the experimental evaluation of it, and improves the design based on results of experimental evaluation.This paper studies the mechanism of remove of polyatomic ion interferencere of quadrupole collision/reaction cell, and evaluates the ability of collision gas, reaction gas and mixed gas to remove interference in quadrupole collision/reaction cell through experiments. Mixed gases are first used in quadrupole collision/reaction cell. Results show that mixed gas is the most efficient gas, and collision gas is the least efficient.The effects of RPq, cell rod offset?CRO? and quadrupole rod offset?QRO? on quadrupole collision reaction are studied through experiments under different gas conditions. Results show that RPq affects the quadrupole collision reaction cell in the same way under different gas conditions, and that effects of CRO and QRO on quadrupole collision reaction cell are different between collision mode and reacton mode. This paper gives out optimal values of RPq, CRO and QRO under different gas conditions.This paper studies conditions of quadrupole collision reaction cell to improve detection limits of trace Fe. Effects of He?H₂?N₂O?CH₄?NH₃?He+H₂? He+NH₃ on ICP-MS detection of trace Fe are studied, and the best result is obtained when using a mixture of He and NH₃.