http://www.citac.cc/

Co-Operation on International Traceability in Anaytical Chemistry

CITAC arose out of an international workshop held in association with the
Pittsburgh Conference in Atlanta in March 1993. The aim of this workshop was
to discuss how analytical activities could be developed to meet the needs of
the 21st century, and it identified a wide variety of issues to be addressed
to ensure that analytical measurements made in different countries or at
different times are comparable.