Recent research put in evidence that indole-3-acetic acid plays a major part as carriers for the indolderivates within biological fluids. In this study we present experimental data on the use of membranes in liquid bulk concentration processes of aqueous solutions of indole 3-acetic acid analytical purposes. Thus it was
studied the influence of the operating parameters on the indole-3-acetic acid permeation through a membrane of chloroform containing as a carrier tributyl phosphate. There were studied operational parameters such as: the influence of the concentration of indole-3-acetic acid on feed phase, the concentration of reactive from stripping phase, the time transport and the presence of carrier tributyl phosphate in membrane phase. The assessment of the process of transport was done by determining the average flux and the concentration factor. It was obtained a recovery efficiency of the indole-3-acetic acid higher than 90% after a time of transport of 3-4 hours.