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Possibilities Of Using A New Graphite-Castor Oil Polyurethane Composite Electrode As An Amperometric Flow Detector

�?�?�?�?�?�?�?�?der Tadeu Gomes Cavalheiro, Priscila Cervini, Luiz Ant�?�?�?�?�?�?�?´nio Ramos

The performance of a new graphite castor oil polyurethane composite electrode is evaluated as an amperometric flow injection detector using hydroquinone (HQ) as a probe. HQ was determined in photographic developers with a minimum detectable net concentration of 100 μmol L-1, and 81 determinations h-1, after optimization of parameters such as the detection potential, sample loop volume, and carrier solution flow rate. Interference of SO3 2- present in the developers has been observed and could be eliminated by appropriate sample preparation. Results obtained at the composite electrode agreed with those from HPLC procedure within 95% confidence level, showing that the new composite can be used as an amperometric detector for flow analysis.