Introduction to Quality Assurance

The analyst provides scientific evidence on which important decisions are made. The work of an analyst is devalued if it is merely considered to be making measurements and reporting results. There has to be some added value. This is provided when it can be demonstrated that the results produced have been obtained in an organization that operates a quality management system. It is because of the importance of the work that the quality has to be assured. This means that all of the necessary actions have been taken to make sure that any factor which has an influence on the final result has been considered, understood and reported in a permanent record - that the appropriate measurements have been made and these have been carried out correctly using a validated method. 

No one deliberately produces incorrect results. You may have noticed how often people remind you of the mistakes you have made but rarely of the good work. If your results prove to be wrong, it is not just your reputation that will 

Quality Assurance in Analytical Chemistry E. Prichard and V. Barwick 2007 LGC Limited 

It is important that a measurement made in one laboratory by a particular analyst can be repeated by other analysts in the same laboratory or in another laboratory, even where the other laboratory may be in a different country. We aim to ensure that measurements made in different laboratories are comparable. We are all confident that if we measure the length of a piece of wire, mass of a chemical or the time in any laboratory, we will get, very nearly, the same answer, no matter where we are. The reason for this is that there are international standards of length, mass and time. In order to obtain comparable results, the measuring devices need to be calibrated. For instance, balances are calibrated by using a standard mass, which can be traced to the primary mass standard (see also Chapter 5). The primary standard in chemistry is the amount of substance, i.e. the mole. It is not usually possible to trace all of our measurements back to the mole. We generally trace measurements to other SI units, e.g. mass as in 40 mg kg-1 or trace back to reference materials which are themselves traceable to SI units. 

In analytical chemistry, we do not have a standard mole. Therefore, solutions made up to a well-defined concentration using very pure chemicals are used as a basis from which we can compare other solutions or an instrument scale. This process is calibration . For some analyses, the chemical used may be a Certified Reference Material which has a well documented specification, e.g. in terms of the concentration of a particular species and the uncertainty of the specified value. However, it is not sufficient just to calibrate the apparatus/equipment used, it is important that the complete method of analysis is validated from extraction of the analyte from the sample to the final measurement. 

---

The text especially covers testing requirements and an introduction to quality assurance systems and application of ISO 9001. 

Donobedian A (2003) An introduction to quality assurance in health care. Oxford University Press, New York... 

Donabedian, A. (2003) An Introduction to Quality Assurance in Health Care, Oxford University Press, Oxford. 

A useful introduction to quality assurance issues (even though written with chemical analysis in mind) is given in ... 

This chapter has considered two key aspects related to quality assurance - the use of control charts and the evaluation of measurement uncertainty. These activities, along with method validation, require some knowledge of basic statistics. The chapter therefore started with an introduction to the most important statistical terms. 

With the introduction of quality assurance in the diagnostic laboratory 56 years ago [6], a kind of educational and benchmarking process started forcing laboratories, national and international organizations, and the IVD industry to improve the methods applied in clinical laboratories. Comparison of the measurements of enzyme activity demonstrate that the analytical performance of the methods applied 30 years ago were far beyond the biological variation and most probably insufficient for medical needs. Interlaboratory comparisons show that with the new routine methods based on recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) (Table 5) comparable results can be obtained irrespective of time and space and thus small individual variations can now be detected. Similar improvements in the analytical process in clinical laboratories can be reported generally for homogenous measurands. 

In this period up to the TMI accident, three other facts influenced nuclear safety technology defence against non-natural external events the preparation of the Rasmussen report, WASH 1400 and the introduction of Quality Assurance (QA) in design, construction and operation of plants. 

Introduction Review and audit processes are used in the chemical process industry to evaluate, examine, and verify the design of process equipment, operating procedures, and management systems. These processes assure compliance with company standards and guidelines as well as government regulations. Reviews and audits can encompass the areas of process and personnel safety, environmental and industrial hygiene protection, quality assurance, maintenance procedures, and so on. 

Apart from innovative work, RMs are essential during exerdses such as the introduction to a laboratory of a method from elsewhere or the transfer of an established method onto new instrumentation. Even where the conditions for the analysis have been standardized by the manufacturer of a reagent kit, some validation work should still be undertaken so as to have documented data for quality assurance purposes, e.g. accreditation, as a basis for IQC, for later reference when problems which may be related to equipment, reagents or staff etc. need to be investigated. 

The introduction of GCP has accelerated the need for quality control and quality assurance, particularly in the field of clinical research. Quality control is carried out by the staff who are responsible for the particular activity, working to SOPs that cover all the tasks under scrutiny. SOPs not only need to be written but must also be updated regularly. Quality assurance is the process which seeks to confirm that SOPs have been observed this is accomplished by the process of auditing. Internal audit departments should be under a separate management from the medical department. Regular audits can not only assure external bodies, such as regulatory authorities, that proper procedures have been followed, but also serve to deter those rare attempts at fraud on the part of clinical investigators, which occasionally become evident. ... 

This work is intended to be, as the title implies, a brief introduction to the principles of quality that are important for workers in a modem industrial analytical chemistry laboratory. It is intended to be a textbook for students preparing to become technicians or chemists in the chemical process industry. It is intended to be a quick reference for new employees in an industrial laboratory as they begin to learn the intricacies of regulations and company policies relating to quality and quality assurance. It is also intended for experienced laboratory analysts who need a readable and digestible introductory guide to issues of quality, statistics, quality assurance, and regulations. 

The PAT guidance facilitates introduction of new measurement and control tools in conjunction with well-established statistical methods such as design of experiments and statistical process control. It, therefore, can provide more effective means for product and process design and control, alternate efficient approaches for quality assurance, and a means for moving away from the corrective action to a continuous improvement paradigm. 

Fluorescent tracer techniques hold the promise of improved accuracy in assessing dermal exposures, as they require no assumptions regarding the distribution of exposure across skin surfaces. However, this approach also has several limitations. First, it requires introduction of the tracer compound into the agricultural spray mix. Secondly, there must be demonstration of a correspondence between pesticide deposition and deposition of the fluorescent compound for the production, such that the fluorescence can indeed be considered a tracer of chemical deposition. Thirdly, range-finding and quality assurance studies may be needed to ensure the accuracy of tracer measurements. Fourthly, when protective clothing is worn by workers, the relative penetration of the pesticide and tracer needs to be characterized. All of these limitations make fluorescent tracer methods technically challenging. 

---