Nitrofurans confirmation

Draisci, R., Giannetti, L., Lucentini, L., Palleschi, L., Brambilla, G., Serpe, L. and Gallo P. (1997). Determination of nitrofuran residues in avian eggs by liquid chromatography - UV photodiode array detection and confirmation by liquid... 

Confirmatory analysis of suspected liquid chromatographic peaks is usually accomplished by a photodiode array detector that continuously collects spectral data during the chromatographic separation and further compares the spectrum (200-550 nm) of the eluted suspected compound with that of a standard (37, 38, 66, 161, 163, 166-168, 178, 180, 181). Online absorbance ratio techniques combined witlr off-line thin-layer chromatography have been also reported (171). Although tliese confirmation techniques are relatively simple, their sensitivity is not generally adequate to identify trace levels of residual nitrofurans in edible animal products. 

Coupling of liquid chromatography with mass spectrometry allows unequivocal online spectrometric identification of all nitrofurans at the very low residue concentrations required by regulatory agencies for confirmatory analysis in animal-derived foods. Typical examples of mass spectrometry applications in confirming nitrofuran residues in edible animal products employ thermospray (174, 176), ionspray (166), or atmospheric pressure chemical ionization (157) interfaces. 

Lopez Ml, Feldlaufer MF, Williams AD, Chu PS, Determination and confirmation of nitrofuran residues in honey using LC-MS/MS, J. Agric. Food Chem. 2007 55(4) 1103-1108. 

Confirmation of quantity may also require the use of the method of standard addition or the inclusion of isotopi-cally labeled standards, although there are currently few such materials available for antimicrobial drugs, as noted in a review in 2009. Some examples of the application of isotopically labeled internal standards to methods for antimicrobial residues include the determination of chloramphenicol in meat, fish, and other biological matrices nitrofuran residues in milk and nitroimidazole residues in eggs and animal plasma. ... 

Particularly, in a residue analysis, identification of detected analytes is required to confirm a result. For nitrofurans analysis, there are a few confirmatory methods reported, including the use of the photodiode-array system and MS detection. The use of a photodiode array detector coupled to HPLC (HPLC-DAD) offers advantages that the target peak can be identified by its retention time and absorption spectrum. In this case, the continuous spectral data generated during the analysis are collected to check for interfering substances by comparing the spectra of samples with those of the standards. However, the specificity and the limit of detection are not sufficient to determine or identify... 

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