New approach of classification for the competence of spectrochemical analysis laboratories based on obtained results in a Round Robin scheme

The paper addresses mainly an advanced way of statistical data processing applied to a Round Robin spectrochemical laboratory scheme. This may be applied with adequate modification to the proficiency testing scheme or to other interlaboratories comparisons. BIOMAT and ICEM organized a six laboratories Round Robin scheme designed to demonstrate the competence of the three laboratories that candidate to RENAR accreditation to perform OES-SDAR analysis. The other accredited ones are interested in this scheme to demonstrate that their spectrochemical analysis proficiency is improved or are at the level they were accredited. There were analyzed two MRCs (medium alloyed steel and Al-Cu-Zn alloy) and were dozed simultaneously 10 and 8 elements, respectively. Because of the different Z scores obtained by the laboratories for the same sample it is quite impossible to classify the laboratories competence. In this regard, the authors introduced a new way of classification of the laboratorypsilas analytical competence based on the mean Z score and its associated dispersion.