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

Isobaric ions overlap an isotope of interest in mass spectrometry, and an inductively coupled plasma-dynamic 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 10 4 of 40 CaH + / 40 Ca + with 1300 W decreased to 1.27 10 4 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 10 4 of 40 CaH + / 40 Ca + at 0.8 ml min 1 of NH 3 cell gas decreased to 1.72 10 5 with 0.85 ml min 1 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. Investigation of 40 CaH + formation in the ICP-DRC-MS with liquid calcium and strontium samples.