Chemists at
the National Institute of Standards and Technology recently demonstrated
that their measurements of lead in wine are among the most accurate
in the world. NIST was one of 14 National Measurement Institutes
participating in an international pilot study of how accurately
the official national standards agencies measure lead in wine.
All participating
measurement institutes performed very well. They agreed very closely
on the exact level of lead in wine samples provided by the Institute
for Reference Materials and Measurements in Geel, Belgium. An
official international "key" comparison of lead in wine
measurements is planned.
NIST chemists
made the exceptionally accurate measurements of trace amounts
of lead in wine in a new Advanced Chemical Sciences Laboratory
clean room facility in Gaithersburg, Md. This chemistry clean
room has specially designed air handling and work space structures
so metal contamination is substantially reduced. The air is continuously
filtered to remove particles. These special features allow scientists
to measure metals, such as lead, in an environment that greatly
diminishes the risk of contaminating a sample.
The results
of these studies will help prevent measurement disagreements from
becoming barriers to U.S. wine producers who wish to export their
products overseas. International measurement comparisons are important
for global trade because any country could potentially require
proof that imports, especially imported foods and beverages, are
sufficiently free of toxic elements and have been measured against
reliable standards.
The wine
study is one of many underway in the NIST Laboratories. To avoid
measurement disputes in global trade, 42 nations have signed an
international
mutual recognition arrangement to establish comparability
of measurement standards and calibrations made in each country's
national metrology institute. Measurement comparisons serve as
the technical basis for the arrangement which outlines a formal
system for carrying out such "key" measurement comparisons
among the participating nations.
The comparisons
establish how closely a particular measurement performed at one
national metrology institute agrees with the results of other
participating nations. They also give merchants and trade officials
confidence in the measurement standards of participating nations.
NIST maintains an international
comparisons database of the results of completed comparisons.
The mutual recognition arrangement, drawn up by the International
Committee of Weights and Measures, was originally signed by 38
nations and two international measurement organizations in October
1999.
