The Chemistry of Dyes - Southern Ontario Pub Night – Burlington

On April 27, 2011, Laurentian SETAC held another successful pub night at Emma’s Back Porch in Burlington. Vimal Balakrishnan, Research Scientist with Environment Canada's Aquatic Ecosystem Protection Research Division, entertained us with a dynamic presentation on "Priority Organic Substances: From method development to environmental fate and behaviour ". Dr. Balakrishnan first walked us through the long, arduous and iterative steps involved with the development of analytical methods for the analysis of azo and anthracenedione dyes and pigments in aqueous matrices, soils, sediments and biota. This would include, amongst others, separation of the various analytes by liquid chromatography and selection of the optimal extraction technique (e.g., solid phase extraction, solid-phase microextraction, Soxhlet extraction and microwave-assisted extraction) and specific conditions (e.g., solvent, pH, temperature, time). Dr. Balakrishnan then presented the results of recent studies in his laboratory, investigating the fate of selected compounds in environmental matrices, notably the sorption/desorption of Sudan 3, Sudan Red G and Disperse Yellow 7 in sediments, and the persistence of Acid Blue 129 and Disperse Yellow 7 in aqueous solutions. His studies indicate that dyes can degrade to form potentially carcinogenic aromatic amines; further studies will be extended to azo and benzidine compounds, as well as studies into their toxicity. Submitted by Ève Gilroy