Chemical measurements, quality

Taylor, J. K. Quality Assurance of Chemical Measurements. Lewis Publishers Ghelsea, MI, 1987. 

Since the early 1970 s there has been a growing belief that chemical measurements must not only be done correctly, but that data, the product of the measurement process, must be seen to be accurate, precise, and reliable. Analytical data have become another manufactured product and like all manufactured products, the customers demand that Quality Assurance (QA) must be built in. 

Taylor JK (1985) Principles of Quality Assurance of Chemical Measurements. NBS (now NIST)... 

EURACHEM is a network of organizations in Europe, having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices. It provides a forum for the discussion of common problems and for developing an informed and considered approach to both technical and policy issues. 

Within Europe there are thousands of organizations concerned with analytical measurement. However, within the broad field of testing, chemical measurement has generally been poorly represented. EURACHEM was established to address this concern by enabling analytical laboratories to work together, across international boundaries, on analytical measurement issues. EURACHEM s uniqueness as an organization comes from its primary concern, which is the analytical quality of chemical measurement. 

Taylor JK (1987) Quality assurance of chemical measurements. Lewis Publishers, Chelsea, MI... 

Analysts like to make chemical measurements to the highest quality they can, and this is possible with modem instrumentation and good analytical practice. Chemical parameters are generally measured more accurately and reproducibly than parameters measured in biological systems, and the results are more reliable than values calculated by software from structure alone (e.g., calculated log P, pKa). Of all the information available to medicinal chemists, measured chemical parameters are probably the most reliable. With these thoughts in mind, it makes sense not to... 

Analysis result, n - the numerical or qualitative estimate of a physical, chemical, or quality parameter produced by applying the calibration model to the spectral data collected by an instmment according to specified measurement conditions. 

Informed debate and decisions on such important matters as the depletion of the ozone layer, acid rain and the quality of waterways all depend on the data provided by analytical chemists. Forensic evidence also often depends on chemical measurements. National and international trade are critically dependent on analytical results. Chemical composition is often the basis for the definition of the nature of goods and tariff classification. In all of these areas not only is it important to get the right answer but it is essential that the user of the results is confident and assured that the data are truly representative of the sample and that the results are defendable, traceable and mutually acceptable by all laboratories. 

Primary methods have the highest metrological qualities, whose operation can be completely described and understood, and for which a complete uncertainty statement can be written down in terms of SI units. Such methods are used by national laboratories participating in the development of a national or international chemical measurement system. 

It is clear then that some indicator of quality is required if chemical measurements are to be used with confidence. Such an indicator must ... 

As stated above, SCADA systems can be designed to measure a variety of equipment operating conditions and parameters, or volumes and flow rates, or chemical and chemical mixture quality parameters, and to respond to changes in those parameters... 

Many facilities already measure the above parameters (and many others) on a regular basis to control plant operations and confirm chemical mixture quality more closely monitoring these parameters may create operational benefits for facilities that extend far beyond security, such as reducing operating costs and chemical usage. Chemical industrial facilities also should thoughtfully monitor customer complaints and improve connections with local public health networks to detect public health anomalies. Customer complaints and public health anomalies are important ways to detect potential contamination problems and other environmental quality concerns. 

The use of appropriate reference materials should be a key feature of the quality assurance/quality control structure in any future ocean science project involving chemical measurement. Reference materials use should be explicitly addressed in the project planning stages, proposals, and publications. 

Taylor J.K. 1987, Quality Assurance of Chemical Measurements Lewis PubUshers Boca Ratan, EL. 

Chemical measurements are widely used for different pnrposes, e.g. as a basis for decision. Qnite often the consequences of wrong decisions wonld be very costly. So the quality of chemical measurements is very important. Since cnstomers of chemical laboratories are normally not able to jndge the qnality of a laboratory, an independent check of a laboratory by a third party is of ntmost importance. 

When talking about quality of chemical measurements trueness, precision, accuracy and error are some of the more important keywords. Therefore a clear definition is necessary (see also chapter 11, slides 36 and 44). 

Neidhart B, Wegscheider W (2001) Quality in Chemical Measurements, Springer, Berlin... 

The importance of quality assurance of chemical measurements not only for global trade but also for a global society has been characterized in a statement by Paul de Bi re, one of the foremimers concerned about analytical results and their use in widespread applications ... 

The intention is to give an overview of all topics relevant for quality assurance in chemical measurement. For details on single topics we refer the reader to the relevant specialized literature. We have added some recent references for further studies and information at the end of each chapter. 

The Valid Analytical Measurement (VAM LGC 2005) program of the LGC (the U.K. National Measurement Institute for chemical measurements) typifies a modern approach to quality in chemical measurements. The program s six principles are a clear exposition of the important aspects of making reliable analytical measurements ... 

---