Evaluation of the environmental measurements, through a proficiency test, of the environmental laboratories of Nicaragua and Costa Rica

Abstract

A proficiency test was carried out with the participation of 24 environmental laboratories, 12 Nicaraguan and 12 Costa Rican, to give continuity to the MIFIC-PTB cooperation project “Improvement of Services That Ensure Quality for the Water Sector of Nicaragua”. The purpose was to evaluate the analytical competence of participating laboratories and to demonstrate the technical and scientific capacity of CIRA/UNAN by organizing and developing a proficiency test. Two batches of samples were prepared with their respective homogeneity and stability tests according to ISO 13528:2016, one for the measurement of electrical conductivity and the other for determining total hardness, calcium hardness, calcium, and magnesium in aqueous solution. From these results, each magnitude was set an “assigned value”, the statistic used for the evaluation was the “z-score”, which measures the performance relative to bias. Measurements of total hardness and calcium performed excellently, instead of electrical conductivity, calcium hardness, and magnesium showed a good performance. CIRAUNAN-Managua demonstrated its technical and scientific competence when developing the present proficiency testing, positioning it in advantage to become a proficiency testing provider laboratory in Nicaragua in a short time.