Using high resolution and dynamic reaction cell for the improvement of the sensitivity of direct silicon determination in uranium materials by inductively coupled plasma mass spectrometry

The paper describes solving the problem of direct silicon determination at low levels in uranium materials, caused by the spectral interferences of polyatomic ions and the high value of blank levels, using inductively coupled plasma mass spectrometry ( ICP MS ). To overcome the interference problem, two primary techniques have been applied: double focusing high-resolution ICP MS and dynamic reaction cell ( DRC ) filled with highly reactive ammonia gas. All measurements were performed at high resolution ( m /Δ m = 4000) on an Element-2 mass spectrometer and pressurized mode of a dynamic reaction cell on an Elan DRC II mass spectrometer. The ways to reducing background levels are investigated. The effects of operating conditions, such as plasma parameters, DRC system original parameters, and uranium matrix influence on the analytical signals of silicon at m / z = 28 have been observed for different mass spectrometer types. The detection limits and the random error characteristics (relative standard deviation) of silicon determination in uranium materials were estimated.