Quality control, analytical methods

When developing or routinely using an analytical method, quality control (QC) fortifications can be added to each sample at critical points in the procedure to ensure that sensitive steps in the method were conducted properly and to pinpoint where problems occurred if results are less than satisfactory. For example, if the QC fortification samples for detection and cleanup were to show acceptable results in a batch of samples, but the extraction QC spike gave low recovery and/or high variability, then the analyst could modify instrument conditions or altering cleanup parameters immediately. Likewise, if the QC spike added just before analysis gives poor results, then instrument maintenance could be done and the samples merely re-analyzed rather than re-extracted. 

Bandemer considered the role of fuzzy set theory in analytical chemistry. The applications they described focused on pattern recognition problems, the calibration of analytical methods,quality control, and component identification and mixture evaluation. Gordon and Somorjai applied a fuzzy clustering technique to the detection of similarities among protein substructures. A molecular dynamics trajectory of a protein fragment was analyzed. In the following subsections, some applications based on the hierarchical fuzzy clustering techniques presented in this chapter are reviewed. 

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