This paper aims at discussing the use of reference materials (RM) by water testing laboratories, on the context of RM purchase, based on the requirements of the standard ABNT NBR ISO/IEC 17025, section "Purchasing services and supplies" (4.6). The role of RM in chemical analysis is to provide metrological reference to assure measurement traceability. This is an essential aspect of quality assurance in order to have analytical results accepted in the international market. In this case study, based on the methodological exploratory and qualitative approach, a questionnaire was sent to testing laboratories which provide analytical services to the National Agency for Waters involved in the accreditation system performed by the General Coordination for Accreditation of Inmetro (Cgcre/Inmetro) by using structured questionnaire and with 50% of return. The results showed that there are few RM certificates with indication of third party recognition, i.e., accreditation bodies, based on standards dealing with metrological traceability. Finally, a policy is proposed to assure the traceability of laboratories measurement results, when certified RMs are unavailable.
Water analysis; traceability; reference material
