Confirmation criteria

For the confirmatory procedure, it is recommended that the sponsor develop spectral data based on at least three structurally specific ions that completely define the marker residue molecule. These ions may or may not include the molecular ion. The use of water loss and isotopic ions is usually unacceptable and CVM concurrence should be sought when water loss ions or isotopic ions are selected for the confirmatory analysis. The proposed fragment ion structures should be consistent with the fragmentation pattern, and justification for specificity of selected ions or scan range should be included. All confirmation criteria should be specified in the standard operating procedure. 

At least one negative control and one positive control should be run each day. The positive control should meet recovery or confirmation criteria. The negative control should have no interferences greater than those specified in the determinative... 

Kaufmann A, Butcher P, Maden K, Widmer M, Giles K, Uria D (2009) Are liquid chromatog-raphy/electrospray tandem quadrupole fragmentation ratios unequivocal confirmation criteria Rapid Commun Mass Spectrom 23 985-998... 

As regards identification purposes, the use of exhaustive libraries in GC/MS became a routine operation in most laboratories. In contrast, these libraries are still scarce in LC-MS applications, mainly because ESI-MS and APCI-MS spectra are strongly influenced by the instrument settings, the EC conditions, and the sample type. Therefore, much more effort should be paid to define identification and confirmation criteria for herbicide analysis by these ionization techniques. In this way, a confirmation criterion was successfully evaluated on triazines by Flow Injection Analysis... 

Selectivity—degree of specificity for toxin and freedom from interferences confirmation criteria—assurance of the identity of the toxin... 

ESI, triazines) [537]. Recoveries observed were > 80% except for carbendazim, bu-tocarboxim, aldicarb and molinate, all better than 67% [500]. An aoTOF-MS interfaced by ESI was used to screen and identify unknown compounds and pesticides in water samples by MS and MS/MS. Structures for compounds observed besides pesticides were proposed [538]. Traces of the phenylurea pesticides Hnuron and monolinuron in water were determined quantitatively. Calibration graphs obtained after Supelclean ENVI-18 SEE were Hnear with detection limits < 25 pg [511]. Large numbers of phenylurea herbicide analyses led to the elaboration of on-line preconcentration techniques coupled to ESI-LC-MS. The procedure was demonstrated and validated with several pesticides using 10 ml of sample, resulting in detection Hmits of about 10 ng [539]. ESI-LC-MS and MS/MS were applied to quantify and to confirm 16 different herbicides of sulfonylurea [527] type in surface water samples. Surface water samples were extracted by SPE (Spe-ed RP-102). As confirmation criteria RT, molecular ion and two fragment ions besides ion abundance ratios were defined. Quantitation at 0.1 and 1.0 ppb level was demonstrated [540]. 

Confirmation criteria should correspond to a specified uncertainty tolerance... 

Show that validation data support claim for diagnostic power of method identification criteria, rates of false outcomes Harmonize with core confirmation criteria Compare diagnostic spectrum with relevant library of spectra Estimate selectivity index of total method Report identification confidence in numeric or prose terms... 

III. Confirmation criteria. The importance of confirming the identity of the compound whose quantitative concentration is being compared to the regulatory limit is emphasized by the amount of detail in this section of the Guide (FDA 2003). The specifications in the Guide are entirely consistent with the extended discussion of this topic in Section 9.4.3b which in turn is a summary of an earher publication (Bethem 2003). Confirmation of identity is ultimately based on comparisons with the analytical standard... 

Nielen, M. W. F., M. C. van Engelen, R. Zuiderent, and R. Ramaker. 2007. Screening and confirmation criteria for hormone residue analysis using liquid chromatography accurate mass time-of-fiight, Fourier transform ion cyclotron resonance and orbitrap mass spectrometry techniques. Anal Chim. Acta 586 122—129. 

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