Retrospective detection analytical methods

Black RM, Noort D. Methods for the retrospective detection of exposure to toxic scheduled chemicals. Part A analysis of free metabohtes. In Mesilaakso M, ed. Chemical Weapons Convention Chemicals Analysis Sample Collection, Preparation, and Analytical Methods. Chichester, West Sussex, England John Wiley Sons 2(K)5 4()3 431. 

Once the cause(s) of the problem is (are) identified, it is important to determine also whether samples analyzed previous to detection that the method was out of control are still valid and whether or not the entire study could have been negatively impacted or is suspect. Retrospective investigations of this kind are even more difficult and it is here that the maintenance of QC control charts, for various types of QCs (e.g. blanks, analyte-only and SIS-only QCs), shows up as an essential feature of assurance of the validity of the final results reported to the user(s). 

Modem human sports drug testing laboratories are commonly equipped with a wide variety of mass spectrometry-based analyzers to cope with the demand to determine a constantly increasing number of prohibited compounds and methods of doping. The diverse physicochemical properties of target analytes necessitates the exploration of all possible features of state-of-the-art mass spectrometry to ensure the best possible detection methods and retrospective analyses. Until now, no analytical technique has provided unequivocal results as reliable as those generated by mass spectrometry however, immunochemical methods have shown superior sensitivities for selected substances and are, thus, also valuable complementary assays in doping controls. 

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