Electrochemical Reduction as a Powerful Tool to Highlight the Possible Formation of By-Products More Toxic Than Sudan III Dye

The present work describes the electrochemical reduction of the azo dye Sudan III in methanol/0.01 mol l(-1) Bu4NBF4 at applied potential of -1.2V, which promotes 98% discoloration of the commercial sample. The reduction products were analyzed by high performance liquid chromatography, after optimized conditions for 20 aromatic amines with carcinogenic potentiality. The harmful compounds such as: aniline, benzidine, o-toluidine, 2,6-dimethylaniline, 4,4'-oxydianiline, 4,4'-metileno-bis-2-methylaniline and 4-aminobiphenyl are formed after azo bond cleavage. The electrochemical reduction is compared with chemical reduction by using sodium thiosulfate. Our findings illustrates that commercial Sudan III under reductive condition can forms a number of products, which some are known active genotoxins. The technique could be used to mimic important redox reactions in human metabolism or environment, highlighting the possible formation of by-products more toxic than the original dyes.

A New Genus and Species of a Minute Suckermouth Armored Catfish (Siluriformes: Loricariidae) from the Rio Tocantins Drainage, Central Brazil: The Smallest Known Loricariid Catfish

Nannoplecostomus eleonorae, a new genus and species of a miniature suckermouth armored catfish, is described based on specimens collected from the karst region of Sao Domingos, upper Rio Tocantins basin, Goias State, central Brazil. The new genus and species can be diagnosed among loricariids by presenting a unique reductive pattern of lateral dermal plates, with most of the body covered by only three series of plates (viz., dorsal, mid-ventral, and ventral). Based on the available published phylogenetic studies for the family, we provisionally consider Nannoplecostomus eleonorae as being an incertae sedis taxon within Loricariidae. Achieving a maximum standard length of 22.2 mm SL, Nannoplecostomus eleonorae is the smallest known loricariid catfish, and a list of the remaining smallest loricariids is provided.