Response on “Regulations in the field of residue and doping analysis should ensure a well-defined risk of a false positive declaration” by N. M. Faber

Abstract

Dr. Faber provided support for a valuable methodology for the comparison of mass spectra. However, since many other factors are involved in the evaluation process before declaring a sample “positive”, i.e. reporting an adverse analytical finding, his conclusions on this subject are incorrect. In this paper a number of arguments are listed showing that Dr. Faber did not take all factors under consideration when making his claims. These factors involve parameters directly related to mass spectrometric criteria, but also to other equally important factors including sample preparation specificity, retention time (since in doping control mass spectrometry is used as part of a hyphenated technique), etc. These arguments clearly illustrate that the risks for a false positive declaration can not be calculated according to Dr. Faber’s proposed methodology.