ANALYTICAL METHOD FOR DETERMINATION OF AURAMINE DYES IN ECOTOXICITY TESTS AND IN SURFACE WATERS. Dyes can be considered important environmental contaminants. Auramine dyes, known commercially as Solvent Yellow 34 and Basic Yellow 2, are used in several industrial products, including textile and paper. In this study, an analytical method was developed and validated using Liquid-Liquid Extraction and High-Performance Liquid Chromatography coupled to Diode Array Detector (LLE and HPLC-DAD) to determine the exposure concentrations in the ecotoxicological tests with auramine dyes, increasing the results reliability about the hazard of these compounds. The method was also used to monitor auramine dyes in surface water samples, in a region considered one of the most critical regions for dyes contamination in Brazil. The results showed no risk for the aquatic organisms considering the analyzed samples. The method using simple instrumentation showed the results of selectivity, linearity (R2> 0.99), precision (CV: 5.6-29%) and accuracy (recovery: 82-90%) considered satisfactory for the two purposes with Instrumental LOQ of the 12 µg L-1; and the Method LOQ of the 12 ng L-1;. The results indicated that the proposed method was effective and practical for the auramine determination in environmental levels and will be an important tool to verify the potential risk of auramine dyes in future studies.