Some investigations on stability and precision of an HR-ICP-MS

Over a period of 4 months long- and short time stability (precision) of a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) was investigated using an ELEMENT (Finnigan MAT, Germany) instrument. By using a special torch design, significant improvements could be achieved. Without changing any electrical parameters of the mass spectrometer, the long time stability over a time period of 4 months was measured as about ± 15% for ¹¹⁵In for all three steps of resolution (300, 3000, 7500). The short time stability over a period of 2–8 h was measured as about ± 10% (at maximum), also nearly independent of the resolution. The main result was the near independence of the stability from the mass-spectrometer itself, but a strong dependence on the sample introduction system, the ICP-torch and the cones. Received: 18 February 1997 / Revised: 16 June 1997 / Accepted: 19 June 1997