Hydrogen compounds formation of calcium in an ICP-DRC-MS

Abstract

Isobaric ions overlap an isotope of interest in mass spectrometry, and an inductively coupled plasmadynamic reaction cell-mass spectrometry (ICP-DRC-MS) analysis also bears the same problem. In this research, processes of 40 CaH + formation and decreasing methods were studied. Plasma power was swept from 1300 W to 600 W to investigate 40 CaH + formation in the plasma. 1.90 Â 10 À4 of 40 CaH + / 40 Ca + with 1300 W decreased to 1.27 Â 10 À4 when 750 W of plasma power was applied. Deionized water of samples was replaced with heavy water to verify if 40 CaH + is formed in the interface part of the equipment. Normally NH 3 gas is injected into the DRC to remove argide ions for a measurement of calcium samples in an ICP-DRC-MS, but we found NH 3 contributes to form hydrogen compounds in the DRC by introducing a strontium sample, which is the same alkaline earth metal as calcium. 1.59 Â 10 À4 of 40 CaH + / 40 Ca + at 0.8 ml min À1 of NH 3 cell gas decreased to 1.72 Â 10 À5 with 0.85 ml min À1 of additional O 2 cell gas injection. Results verify that hydrogen compounds made from NH 3 in an ICP-DRC-MS could affect ultra trace isotope ratio analysis.

Trapping and laser cooling of trace Ca+ isotopes injected from an inductively coupled plasma mass spectrometer

“…The RF power is 1100 W, the Nebulizer gas ow rate is 0.99 L min À1 , and the plasma gas ow rate is 15 L min À1 . 15 Ar for plasma gas, NH 3 , O 2 , N 2 , Ar, He for DRC (Dynamic Reaction Cell) gas, and He for buffer gas are used. The purity of Ar is 99.995% and those of other gasses are all higher than 99.99%.…”

Dynamics of ion loading into a linear Paul trap using an inductively coupled plasma mass spectrometer

“…6 However, AMS requires a large facility. 9 The ratio of 40 CaH/ 40 Ca is evaluated to be 10 À5 , thus 41 Ca + cannot be iden-tied only with ICP-MS. 8 Meanwhile, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a convenient tool which enables continuous sample feeding from the outside of a vacuum chamber with high ionization efficiency and wide applicability over many elements of the Periodic Table. In contrast, for accurate measurement isobaric ions must be separated from target ions.…”

“…In the case of 41 Ca + (isotopic abundance: 10 À14 to 10 À15 ), for instance, 40 CaH + is inevitably produced in an ICP or a reaction cell. 9 The ratio of 40 CaH/ 40 Ca is evaluated to be 10 À5 , thus 41 Ca + cannot be iden-tied only with ICP-MS.…”