Statistical evaluation of uncertainty for rapid tests with discrete readings – examination of wastes and soils

 In the course of the colorimetric determination of analytes using a procedure with discrete readings the measurement uncertainly cannot be calculated in the normally practiced manner. The basic principle of the analytical method used is a stepwise and non-equidistant reading. Based on the fact that half a step can be estimated, a calculation of the measurement uncertainty for the 95% confidence level is possible; this is needed to allow a reliable decision of whether a critical value is exceeded or not. Received: 24 February 2000 / Accepted: 28 April 2000