Validation and Quality Control

Validation describes in general the assurance that an analytical procedure provides reproducible and secure results that are required for the application intended. 

The first step in developing a relative analytical method is calibration. It is based on the use of standard solutions or of a solid standard. The calibration function (Eq. (4.1)) is constructed by means of linear regression analysis as discussed in Section 6.1. 

The precision of the procedure can be characterized by the standard deviation of the procedure. As additional performance characteristics, the limit of detection (Eq. (4.3)) and working range are reported. 

To test for systematic deviations, explained by influences due to different steps of an analytical procedure or by the sample matrix, the recovery rate is calculated (c Eq. (4.6)). To investigate an analytical procedure for systematic deviations, the recovery function is applied. 

The limit of determination is the lowest analyte concentration that can be determined with an acceptable accuracy. 

---

Particularly for direct microanalytical techniques using <10 mg of sample for analysis, it is highly desirable to obtain quantitative information on element- and compound-specific homogeneity in the certificates for validation and quality control of measurements. As the mean concentration in a CRM is clearly material-related, the standard deviation of this mean value should represent the element s distribution in this matrix rather than differences in the analytical procedures used. 

Untreated (control) soil is collected to determine the presence of substances that may interfere with the measurement of target analytes. Control soil is also necessary for analytical recovery determinations made using laboratory-fortified samples. Thus, basic field study design divides the test area into one or more treated plots and an untreated control plot. Unlike the treated plots, the untreated control is typically not replicated but must be sufficiently large to provide soil for characterization, analytical method validation, and quality control. To prevent spray drift on to the control area and other potential forms of contamination, the control area is positioned > 15 m away and upwind of the treated plot, relative to prevailing wind patterns. 

Single-site IVD "Home brew" or "in-house" IVD made with an analyte specific reagent FDA requires labeling disclosing the "in-house" nature of the test but has no premarket review requirement CLIA requires analytical validation and quality control systems... 

European Commission (2007) Method validation and quality control procedures for pesticide residues analysis in food and feed. SANCO/2007/3131, available from ec.emopa.eu... 

A procedure for standard curve, validation, and quality control sample... 

There should be a reasonable balance between validation and quality control. 

Data coding—Adverse events (AE), medications Incorporation of local laboratory data into database Investigation and resolution of data discrepancies Data validation and quality control audit Data transfers (test and final)... 

The assumption of 100% efficient digestion with negligible uncertainty is valid for the total uncertainty estimation of the presented example. This uncertainty estimation proved to be a valuable criterion for method validation and quality control, which can be tested by a... 

The methods used for laboratory testing of held samples should have validated performance and be conducted within a rigorous quality management system. To avoid reliance on poor data, great care is needed to ensure that the test results reported are derived from methods of known performance that have been applied exactly. This can be confirmed by ensuring that full validation and quality control information is available to support test data.14... 

Experiment 39 provides practice in method validation and quality control, and Experiment 40 is an exercise in proficiency testing. These are class team experiments. Read these, even if they are not part of your assigned laboratory exercises. 

New. A new microscale titration experiment is included, provided by Professor John Richardson from Shippensburg State University, for the analysis of hard-water samples (Experiment 18). The tools an4 techniques used for that experiment could be used to design similar experiments for other titrations if desired. (If your in-stractor tries this with you, I may include your experiment in the next edition ) Two team experiments are added (Experiments 39 and 40) to illustrate the principles presented in Chapter 4 on statistical validation. One is on method validation and quality control, in which different members of teams perform different parts of the validation for a chosen experiment. The other is on proficiency testing, in which you calculate the z-values for all the student results of one or more class experiments and you compare your z-value to see how well you have performed. 

Shuttlbe IL (1995) Validation and quality control with atomic absorption spectrometry for environmental monitoring. In Subramanian G, ed. Quality assurance in environmental monitoring, instmmental methods, pp. 55-93. VCH Ver-lagsgesellschaft mbH, Weinheim. 

There are samples or crude extracts containing the analyte of interest but whose concentration has not been accurately established. For marine biotoxins, such materials may be frozen homogenates of naturally contaminated seafood, crude or partially purified extracts of such seafood, or of harmful algae. Digestive glands of contaminated shellfish are a source of concentrated toxins and their metabolites. Such materials cannot be used to calibrate methods of analysis but can serve very useful functions in method validation and quality control, especially when they contain rare toxins not readily available elsewhere (i) Retention times and spectral properties can be established on a routine basis for LC-UV, LC-FL, or LC-MS methods (ii) Partially purified extracts can be used for fortification experiments during method validation and thus establish recovery and precision data (iii) If concentrations of toxins can be established by reference to CRMs, then the materials can be used as in-house or interlaboratory reference materials for quality control. Issues such as toxin stability and homogeneity then become more important. ... 

Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed, SANCO/10684/2009, Directorate General for Health and Consumers (SANCO), European Commission, Brussels, 2009 (available at http //ec.europa.eu/food/plant/ protection/resources/qualcontrol en.pdf accessed 10/23/10). 

Method Validation and Quality Control Procedures for Pesticide Residue Analysis in Food and Feed (Document SANCO/10684/2009)... 

As an analytical approach to residue analysis, immunoassay methods are not well characterized, and no validation protocols have been established. The Association of Official Analytical Chemists, whose primary purpose is validation of analytical methods, established a Task Force on Test Kits and Proprietary Methods (2), which has addressed some of the issues relating to immunoassay methods. The International Union of Pure and Applied Chemistry s Commission on Food Chemistry has established a Working Group on Immunochemical Methods, whose first project is to develop draft guidelines on criteria for evaluation, validation, and quality control for r o-immunoassay methods (10). Similar guidelines for EIAs will also be developed. These documents will assist in development and standardization of requirements for precision for both between-laboratories and within-laboratory andyses, accuracy, and ruggedness, and— for qualitative methods— false positive and false negative rates. 

Pure reference standards of B complex vitamins can be obtained from USP. Once a LC-MS method for pantothenic acid analysis from multivitamin dietary supplements is developed, the multi-element multivitamin dietary supplement Standard Reference Material 3280 (SRM 3280) from the National Institute of Standards and Technology (NIST, Gaithersburg, MD, USA) can be used for validation and quality control. 

---