News
The last of the great standards Scientists at the National Institute of Standards and Technology (NIST) are exploring ways to replace Le Gran K, the platinum-iridium cylinder that has served for 106 years as the standard for the kilogram. Using an artifact as a standard has caused several problems: Its mass changes over time, it is one of a kind, and in this case, the standard is available only at the International Bureau of Weights and Measures in Sèvres, France. According to NIST researchers, a better way of defining standards is to base the definition on a natural constant. They are considering two ways to redefine the kilogram, both based on Avogadro's number, which is defined as the number of atoms in 12 g (1 mole) ofpure12C. One method uses X-ray techniques to measure the lattice spacing of silicon crystals. The lattice spacing, density, and the mean molar mass of silicon (obtained from the mass ratios of the various silicon isotopes to 12C and their relative abundances in a particular sample) are then used to determine Avogadro's number. The other method of determining Avogadro's number is based on the measurements
vision of Tektronix in 1986 and became part of Sony in 1993. CAChe will bring to Oxford Molecular a popular intuitive user interface, desktop accessibility through Macintosh and Windows platforms, and a transparent client-server architecture. Oxford Molecular will bring to CAChe new algorithms to address a wider range of industrial problems and applications of interest to the analytical chemist.
EPA to establish lab accreditation program The Environmental Protection Agency (EPA) is establishing the National Environmental Laboratory Accreditation Program (NELAP) in an effort to provide a level playing field for environmental laboratories and facilitate reciprocity among the states. Under this program, the states K-20, maintained by NIST, is one of the will serve as the primary accrediting auprototype standards calibrated against thority, although they have the option of Le Gran K. It is resting on the mass engaging a third party to fulfill some or all comparator's balance pan on the right. of the accrediting functions. EPA will oversee and evaluate the accrediting authorities and administer those aspects of NELAP requiring standardization among in a watt-balance experiment where, in the various authorities. essence, a coil in a magneticfieldis NELAP will rely on the NELA Confermoved at a certain velocity and the ence (NELAC), a volunteer advisory group power generated electrically is comof environmental accrediting authorities pared with the power generated meand other interested parties, to establish chanically. The researchers expect that the standards on which accreditation will the new definition will be in place in be based. These standards will include 15-25 years. quality control, performance evaluation, and audit programs. Membership in NELAC is open to state and federal officials involved in the accredmolecular modeling software... [and] is Oxford to buy CAChe in line with our strategy to offer software iting programs as well as to laboratory Oxford Molecular Group PLC (Oxford, personnel, industry and environmental U.K.), developer of computer-aided molec- supporting the entire drug design process." CAChe president Ajit Rode says that group representatives, and the general ular design software and database syspublic. Broad participation in the confertems, has announced that it will purchase "Oxford Molecular has computer-aided ence is expected to result in standards for molecular design as its core business and CAChe Scientific (Beaverton, OR), dereliable and uniform data that are acceptwill contribute state-of-the-art science to veloper of computer-aided molecular deable to state and federal environmental our product range. This makes it an ideal sign software, from Sony/Tektronix (Tokyo, Japan) for approximately $9 million in partner to build CAChe's business yet fur- programs. ther, as well as offering us better distribustock. According to A F. Marchington, CEO tion in Europe." Rheometrics acquires rights of Oxford Molecular, the purchase of Oxford Molecular was formed in 1989 to Mettler instruments CAChe "increases our presence and visito commercially develop algorithms origi- Rheometric Scientific has acquired the bility in the U.S. market, and gives us addi- nally conceived at the University of Oxrights to the RM180 and RM260 Theologitional penetration in Japan, where the ford and other academic institutions. cal test instruments manufactured by group will be the largest single supplier of CAChe was formed within the research di- Mettler-Toledo AG and used for QA/QC 232 A
Analytical Chemistry, Vol. 67, No. 7, April 1, 1995
