[Uncertainty of measurement as an integral part of the result and a tool of quality of work improvement for the chemical-toxicology laboratory].

An uncertainty in measurements is a numerical defined range that is supposed to find a true value with a given level of probability. The purpose of this study was to estimate a type A and B of uncertainty in the analysis of ethanol using the ADH method and prove it to be useful in lab practice. A large percentage of uncertainty was shown for pipetting of the ADH and perchloric acid solutions. This result formed the basis to make an effort in order to improve the procedure. The results of uncertainty of measurements given by method B are similar to the empiric method A results. The reduction of expenses and time saving of the analysis is an important advantage of the described way of uncertainty.