Nitrofurazone analysis

Nitrofurazone (A) is first reduced to the hydroxylamine B) which is further reduced to the amine (C). These chemical structures are verified by elemental and infra-red analysis. Austin described the chemical properties of 4-cyano-2-oxobutyraldehyde semicarbazone (Z)) which is produced by the opening of the furan ring. On the other hand nitrofurazone yields 5-nitrofurfuraldehyde ( ) and semicarbazide (F) by the acidic hydrolysis of the —CH=N— linkage. This aldehyde gives 5-nitrofiiroic acid (G) by oxidation in animal tissues. 

Nitrofurans are banned substances within the EU and in some other countries because of their mutagenic and geno-toxic characteristics. Nitrofuran metabolites are still found, primarily in aquaculture products originating from Southeast Asia, with SEM (the metabolite of nitrofurazone) having the highest incidence. Methods for detecting residues of nitrofurans aim for protein-bound metabolites that may persist in tissues for considerable periods after treatment. Methods are reported for the detection and identification of nitrofuran metabolites in many different food products. The main difficulty in nitrofuran metabolite analysis is the low selectivity of SEM as a marker metabolite of nitrofurazone. Several other possible sources of SEM have been identified and investigated, the most important of which is the use of... 

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