Republication or reproduction of this report or its storage and/or dissemination by electronic means is Selectivity in analytical chemistry (IUPAC Recommendations 2001)Abstract: The correct use of the term "selectivity" and its clear distinction from the term "specificity" are discussed. A definition of selectivity is given, and it is recommended that the use of this term be promoted and that the use of the term "specificity" be discouraged.

Rationale NBS19 carbonate, a primary reference material (RM) for the Vienna Pee Dee Belemnite (VPDB) scale realisation introduced in 1987, was exhausted in 2009, and no primary RM was available for several years. This study describes the preparation and characterisation of a new RM, IAEA‐603 (Ca‐carbonate, calcite of marble origin), which shall serve as a new primary RM (replacement for NBS19) or primary calibrator aimed at the highest realisation of the VPDB scale for δ13C and δ18O values, including the VPDB‐CO2 δ18O scale. Methods IAEA‐603 preparation and characterisation (value transfer) against NBS19 were performed by addressing the major modern technical requirements for the production and characterisation of RMs (ISO Guide 35). IAEA‐603 was produced in a large quantity, and the first batch was sealed into ampoules (0.5 g) to ensure RM integrity during storage; four other batches were sealed for long‐term storage. The most accurate method of CO2 preparation for isotope mass spectrometry was used, namely carbonate–H3PO4 reaction under controlled conditions. Results The assigned values of δ13C = +2.460 ± 0.010‰ and δ18O = −2.370 ± 0.040‰ (k = 1) are based on a large number of analyses (~10 mg aliquots) performed at IAEA and address all the known uncertainty components. For aliquots down to 120 μg, the δ18O uncertainty remains unchanged but shall be doubled for δ13C. The uncertainty components considered are as follows: (a) material homogeneity (within and between the 5200 ampoules produced), (b) value assignment against NBS19, (c) storage effects and (d) effect of the 17O correction. Conclusions The new primary RM IAEA‐603 replaces NBS19 in its use as the highest calibrator for the VPDB δ13C and δ18O scale, including the VPDB‐CO2 δ18O scale. The use of IAEA‐603 will allow laboratories worldwide to establish consistent realisation of the scales for δ13C and δ18O values and metrological comparability of measurement results for decades. The VPDB scale definition based on NBS19 stays valid.

This IUPAC study aims at formulating recommendations concerning the metrological traceability of a measurement result in chemistry. It is intended to provide the chemical measurement community with a consistent view of the creation, meaning, and role of metrological traceability and its underpinning concepts. No distinction is made between measurement results obtained in "high metrology" and in the "field". A description is given of the calibration hierarchies needed in different circumstances to arrive at metrological traceability along a metrological traceability chain. Flow charts of generic calibration hierarchies are presented as well as a variety of examples. The establishment, assessment, and reporting of metrological traceability are discussed, including the provision of metrological references by a metrological institutional framework and the role of interlaboratory comparisons.

Synopsis: ISO, IUPAC and AOAC INTERNATIONAL have co-operated to produce agreed protocols or guidelines on the "Design, Conduct and Interpretation of Method Performance Studies" [1] on the "Proficiency Testing of (Chemical) Analytical Laboratories" [2] and on "Internal Quality Control in Analytical Chemistry Laboratories" [3]. The Working Group that produced these protocols/guidelines was asked to prepare guidelines on the use of recovery information in analytical measurement. Such guidelines would have to outline minimum recommendations to laboratories producing analytical data on the internal quality control procedures to be employed.A draft of the guidelines was discussed at the Seventh International Symposium on the Harmonization of Quality Assurance Systems in Chemical Laboratory, sponsored by IUPAC/ISO/AOAC INTERNATIONAL, held in Orlando, USA, 4-5 September 1996. Proceedings from that Symposium are available [4].The purpose of these guidelines is to outline the conceptual framework needed for considering those types of analysis where loss of analyte during the analytical procedure is inevitable. Certain questions cannot be satisfactorily addressed, and hence remain irreducibly complex, unless such a conceptual framework is established. The questions at issue involve (a) the validity of methods for estimating the recovery of the analyte from the matrix of the test material, and (b) whether the recovery estimate should be used to correct the raw data to produce the test result. The types of chemical analysis most affected by these considerations are those where an organic analyte is present at very low concentrations in a complex matrix."Protocol for the Design, Conduct and Interpretation of Method Performance Studies", W. Horwitz, Pure Appl. Chem. 60, 855- 864 (1988), revised, 67, 331-343 (1995)."The International Harmonized Protocol for the Proficiency Testing of (Chemical) Analytical Laboratories", M. Thompson and R. Wood, Pure Appl. Chem. 65, 2123-2144 (1993). (Also published in J. AOAC International 76, 926-940 (1993). "Harmonized Guidelines for Internal Quality Control in Analytical Chemistry Laboratories", M. Thompson and R. Wood, Pure Appl. Chem. 67, 49-56 (1995)."Quality Assurance for Analytical Laboratories", edited M. Parkany, Royal Society of Chemistry, London, UK, 1996.

Rationale LSVEC, the second anchor Reference Material (RM) for the VPDB δ13C scale realisation, was introduced in 2006. In 2015, its δ13C value was found to be drifting and, in 2017, its use as an RM for δ13C was officially discontinued by IUPAC. New RMs of low uncertainty are needed. This paper describes the preparation and characterisation of IAEA‐610, IAEA‐611 and IAEA‐612 (calcium carbonate, of chemical origin) which shall serve as a set of RMs aimed at anchoring the VPDB scale at negative δ13C values. Methods The preparation and characterisation of IAEA‐610, IAEA‐611 and IAEA‐612 were performed by addressing the contemporary technical requirements for RM production and characterisation (ISO Guide 35:2017). The three RMs were produced in large quantities, and the first batch was sealed into ampoules (0.5 g) to ensure the integrity of the RM during storage; additional batches were sealed for long‐term storage. The most accurate method of CO2 preparation and stable isotope measurements was used, namely carbonate‐H3PO4 reaction under well‐controlled conditions combined with well‐tested stable isotope ratio mass spectrometry. Results The assigned values of δ13C and associated uncertainties are based on a large number of analyses (~10 mg aliquots) performed at IAEA and address all the known uncertainty components. For aliquots down to ~100 μg, the δ13C uncertainty is increased. The uncertainty components considered are as follows: (i) material homogeneity, (ii) value assignment against IAEA‐603, (iii) potential storage effects, (iv) effect of the 17O correction, and (v) mass spectrometer linearity and cross‐contamination memory in the ion source. Conclusions The new RMs IAEA‐610, IAEA‐611 and IAEA‐612 have been characterised on the VPDB δ13C scale in a mutually consistent way. The use of three RMs will allow a consistent realisation of the VPDB δ13C scale with small uncertainty to be established, and to reach metrological compatibility of measurement results over several decades.

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The present paper is a review of the main theoretical and technical aspects of human error treatment (error modelling, reduction and quantification) as applied\ud in aviation, engineering, medicine and other fields. The aim of the review is to attract the attention of analysts and specialists in metrology and quality in chemistry to the human error problem and its influence on the reliability of test results of chemical composition and associated measurement uncertainty. Therefore, the subject of human error is interpreted in the review in application to the conditions of a chemical analytical laboratory