Vocabulary of terms in protometrology

Protometrology is a new term recently proposed to designate the science of observation. As any field of knowledge needs a terminological system, in this article a system of terms and definitions on protometrology, with examples belonging to clinical laboratory sciences, is presented. This terminological system starts with the definitions of the two primitive concepts “object” and “property”.

Replicated observations in metrology and testing: modelling repeated and non-repeated measurements

In order to choose the right statistical tool, a basic issue for an accurate analysis of each specific problem is to understand whether the set of replicated measurement results under examination is to be considered as pertaining to repeated measurements or not. This issue is particularly important, since most of the traditional tools are valid only for repeated measurements, but, in many cases, such as laboratory comparisons (in metrology and in testing), the measurements necessary to assess correctly the measurand value and the associated uncertainty do not represent repeated measurements. The analysis performed in this paper aims to shine some light on these issues, starting with a review of the basic concepts, such as repeatability, reproducibility, accuracy, systematic error and bias, as defined in international documents and as used in the literature. The paper shows that, currently, a full consensus on a common language and understanding has not yet been achieved, and then shows how this fact reflects on the basic data models, especially those concerning inter-comparison data.

Recovery revisited

During the last decade, various IUPAC documents have presented concepts related to the important ability of a measurement procedure to provide correct quantity values for amount, concentration, or content of a component in a system. The measurement procedure often, but not necessarily, includes one or more separation steps prior to the final instrumental reading. The vocabularies present concepts with some definitions and terms that disagree or are ambiguous, mostly revolving around the term recovery and its derivatives. The present proposal consists in defining three concepts with the terms actual quantity, initially estimated quantity, and recovered quantity ratio, where quantity is used in the metrological sense of the international vocabulary of basic and general terms in metrology (BIPM, IEC, IFCC, ILAC, ISO, IUPAC, IUPAP, OIML International vocabulary of basic and general terms in metrology, draft, 3rd edn. BIPM, Sèvres, 2005), not as a synonym of amount.

The meaning of ‘concentration’

Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings of “concentration” are explored to present a systematic nomenclature, including a concept diagram.

ISO 5725 and GUM: comparison and comments

We compare the approach to measure uncertainties proposed in ISO 5725 and GUM from a statistician point of view. In particular we give some warnings to the application of the expanded uncertainty introduced in GUM when the input variables are few and we report some considerations on the relevant role of the interactions among the input variables in the measurement equation as well as the role of statistical design of experiments to measure uncertainties.

Can auditing save us from a quality disaster?

Auditing of clinical laboratories is a recognized component of quality assurance practice. National regulatory standards, such as the U.S. Clinical Laboratory Improvement Amendments (CLIA), and international voluntary standards, such as those promulgated by the International Organization for Standardization (ISO), are used in the auditing. Professional organizations have long recognized the benefit of on-site, peer review. However, recent events in the U.S. question the validity of current auditing practices. To be effective, auditing must be part of a continuous quality improvement system and a key component of laboratory leadership.

Correlation between repeated measurements: bane and boon of the GUM approach to the uncertainty of measurement

With measurement uncertainty estimation accounting for all relevant uncertainty contributions, the results of measurements using the same procedure on different objects or samples may no longer be considered as being independent, and correlations have to be taken into account. For this purpose, a simple approximation for the estimation of covariances is derived and applied to the estimation of uncertainty for some basic combinations of two measurement results. This covariance estimate is also applied to the estimation of uncertainty for the mean value of the results of replicate measurements on the same object or sample.

Assessing publically financed metrology expenditure against economic parameters

The objective of this paper is to provide an economic perspective to those involved in public financing of the national metrology infrastructure. Whereas justifications for subsidising the national metrological activities are often historically biased, we raise the importance of economic considerations, which could be used during prioritisation. The expenditure in measurement and metrology infrastructure of European countries are compared to economic indicators for quality of life. Various proxies are used, such as measuring instruments sale (for measurement infrastructure) and data from the BIPM’s KCDB (as a proxy for national standards). As the EU Internal Market also holds for the provision of metrological services, the paper exposes possible trends regarding public financing to the sector.

Chemical supervenience

This paper surveys some ways in which the chemical realm can be described and outlined in terms of the concept of supervenience. The particular contours of general chemical theory provide a ready basis for interpretation of determination, covariance, and nonreduction—the characteristic metaphysical facets of the supervenience relation—in mutual terms. Building on this, the extent to which chemically characterized properties and entities can be described in terms of a supervenience-scaffolded structure represents a particularly vivid application that philosophers in general interested in supervenience would do well to attend to. In addition, the model of chemical supervenience given here can be used as a rubric on which to decide on issues already raised by philosophers of chemistry.

The increasing demands of quality assurance in chemical testing

The chemical and microbiological testing community is going through a rather difficult period of change. Publication of ISO/IEC 17025 (General requirements for the competence of Calibration and Testing Laboratories, 1999) [1] is placing additional demands on testing laboratories to ensure traceability and estimate uncertainty in their measurements. At the same time, laboratories must remain mindful of the need to provide relevant, timely and economic services to their clients. International Accreditation New Zealand (IANZ) and its accredited laboratories are currently focussing on establishing realistic methods for ensuring traceability to national and international standards and estimating measurement uncertainty. To this end, IANZ recognizes that it has an important role in providing as much advice and assistance as possible, not only to its accredited chemical laboratories but also to all those contemplating accreditation in New Zealand.

Metrological traceability: I make it 42; you make it 42; but is it the same 42?

The paper reproduces a talk given at a 2-day symposium on quality assurance in chemistry held in Brisbane, Australia in 2005. Intended for an audience of analysts in the field, the theme of the symposium drew inspiration from the series of books by Douglas Adams “The Hitchhiker's Guide to the Galaxy”. An introduction to basic concepts of metrological traceability is followed by a discussion of practical steps to ensure metrological traceability of field measurement results. The relationship between metrological traceability and comparability of measurement results is discussed. To achieve metrological traceability in the field, the use of appropriate certified reference materials for calibration is recommended. Examples of atmospheric carbon dioxide and roadside breathalyzer measurements are given.

Uncertainty from sampling,in the context of fitness for purpose

Sampling is an integral part of nearly all chemical measurement and often makes a substantial or even a dominant contribution to the uncertainty of the measurement result. In contrast with analysis, however, the uncertainty contribution from sampling has usually been ignored. Indeed, far less is known about sampling uncertainty, although in some application sectors it is known to exceed the analytical uncertainty, especially when raw materials (natural or industrial) are under test. In 1995 the authors of this paper proposed a framework of concepts and procedures for studying, quantifying, and controlling the uncertainty arising from the sampling that normally precedes analysis. Many of the ideas were based on analogy with well-established procedures and considerations relating to quality of analytical measurement, ideas such as validation of the sampling protocol, sampling quality control and fitness for purpose. Since that time many of these ideas have been explored experimentally and found to be effective. This paper is a summary of progress to date. Presented at the AOAC Europe Workshop, November 2006, Limassol, Cyprus.

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Paneth, Kant, and the philosophy of chemistry

Immanuel Kant has built up a dualistic epistemology that seems to fit to the peculiarities of chemistry quite well. Friedrich Paneth used Kant’s concept and characterised simple and basic substances which refer to the empirical and to the transcendental world, respectively. This paper takes account of the Kantian influences in Paneth’s philosophy of chemistry, and discusses pertinent topics, like observables, atomism and realism.

The Australian perspective

This presentation deals with issues of comparability and traceability in food analysis in Australia from several perspectives. This includes the current national (Australian) and increasingly international (Codex) performance-based approach to food analysis. The Australian food regulatory process will be described, particularly those aspects that impact on the analysis of food in a regulatory sense. This section will also describe two areas where specific methods have been mandated in legislation and discuss two case studies where the analytical method has impacted on the elaboration of standards. Other areas to be covered include regulation/requirements relating to supply/availability of reference materials, the use of proficiency testing as a means of ensuring comparability, and, finally, some thoughts on what role BIPM/CCQM may play in the analysis of food.Electronic Supplementary Material  Supplementary material is available for this article at

Kinetics of substitution at [tris(3,5-dimethylpyrazolyl)-hydroborato]molybdenum nitrosyl dihalides by alcohols and by aniline

The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure are reported and interpreted in terms of an associative mechanism.

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Measurement uncertainty and the use of reference materials

The use of (certified) reference materials and quality control materials can form a suitable basis for evaluating measurement uncertainty of routine measurements. In particular when these materials are used for quality control purposes, it is not always evident how the quality control data can be used in the uncertainty budget of a routine measurement. Current guidance documents on the evaluation of measurement uncertainty and the use of reference materials treat this subject only in part, or in very generic terms. ISO/REMCO has established a new working group that will provide practical guidance and examples on how to use quality control data in the evaluation of measurement uncertainty. A short introduction to the subject is given.

Do we need to rethink collaborative trials?

The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would be more informative.

Operating ‘cost’ characteristics in sampling by variable and attribute

A discussion in economic terms of common rules in conformity assessment based on measurement is given. The present work extends tools of sampling when using inspection by variable and attribute, such as the setting of acceptance quality limits (AQL) and limiting quality limits (LQL), by including an economic decision theory approach, leading, amongst other things, to a new ‘cost’ curve as a complement to the traditional operating characteristic curves of statistical significance testing. The methodology is of general applicability but is illustrated in the present work in the simple case of homogeneously pre-packaged goods priced linearly with the amount of content. The relation to the optimised uncertainty methodology is explained. Optimum strategies for the supplier are illustrated in terms of minimising production and testing costs, while at the same time maintaining satisfactory levels of customer satisfaction.

A note on Michael Weisberg’s: challenges to the structural conception of chemical bonding

Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is in trouble. This note casts doubts on that claim.