No abstract

Critical temperatures and pressures of some organic compounds were measured. There is good agreement between the observed critical pressures and values obtained by extrapolation of equations representing the variation of vapour pressure with temperature in the region of the normal boilingpoint. An incremental scheme relating critical temperatures to normal boiling points is described and is used for the correlation of the critical temperatures, obtained in this and other investigations, of more than 150 compounds.

The Euroanalysis VII conference in Vienna included a two-day session: Quality Assurance in Analytical Chemistry. The contributions comprised 15 lectures devoted to: intra-laboratory quality measures, inter-laboratory control, formal aspects and accreditation and implementation. The paper presents an overview of the main items developed by the contributors.

Critical temperatures and pressures of some organic compounds were measured. There is good agreement between the observed critical pressures and values obtained by extrapolation of equations representing the variation of vapour pressure with temperature in the region of the normal boiling point. An incremental scheme relating critical temperatures to normal boiling points is described and is used for the correlation of the critical temperatures, obtained in this and other investigations, of more than 150 compounds.

NAMAS, the National Measurement Accreditation Service, was formed in 1985 and has currently accredited some 1050 testing and calibration laboratories in the United Kingdom. NAMAS is managed by an Executive of 60 staff which is based at the National Physical Laboratory, one the UK's largest Government Research Establishments. Laboratories seeking accreditation are assessed by fully trained technical experts contracted by NAMAS, against the criteria set out in the NAMAS Accreditation Standard M10; the criteria contained in this document are fully consistent with the international standards for laboratory accreditation EN 45001 and ISO Guide 25. NAMAS has recently published a document which provides guidance on the interpretation of the NAMAS Accreditation Standard for analytical laboratories. Assessment involves a consultative preassessment visit which is followe, d by a thorough on-site assessment of a laboratory's quality system and testing activities by a team of expert assessors. Following the correction of any noncompliances found at the assessment, the laboratory receives a certificate of accreditation and a schedule which defines those tests and analyses for which the laboratory is accredited. NAMAS has negotiated a number of mutual recognition agreements with similar accreditation bodies in other countries and negotiations with other schemes are underway. The imminent approach of the European Single Market has highlighted the need for independent third party assurance of testing and calibration and this should ensure the continued growth of NAMAS and similar schemes elsewhere in Europe.