Uncertainty of dead time estimation in ICP-MS

Abstract

The dead time of the detection system of a quadrupole ICP-MS is estimated and the different calculation methods are rated for transparency and ease of use. They are optimised to yield minimum uncertainty of measurement and minimum bias. The dead time is calculated only from the count rates of the two isotopes and the precision of the count rates is governed by Poisson statistics. None of the investigated methods are biased, but differences between the methods concerning the uncertainty of the estimated dead times are visible. Nevertheless it is possible to rank one method as the best. This method allows us to estimate the uncertainty of the estimated dead time via error propagation following the CITAC-Eurachem-Guide.