| Autor: |
Felix CSA; Instituto de Química, Programa de Pós-Graduação em Química, Campus Ondina, Universidade Federal da Bahia, Salvador 40170-115, Brazil.; Centro Interdiciplinar de Energia e Ambiente-CIEnAm, Universidade Federal da Bahia, Salvador 40170-110, Brazil., Chagas AVB; Instituto de Química, Programa de Pós-Graduação em Química, Campus Ondina, Universidade Federal da Bahia, Salvador 40170-115, Brazil., de Jesus RF; Instituto de Química, Programa de Pós-Graduação em Química, Campus Ondina, Universidade Federal da Bahia, Salvador 40170-115, Brazil., Barbosa WT; SENAI CIMATEC University Center, Programa de Pós-Graduação em Gestão e Tecnologia Industrial, Salvador 41650-010, Brazil., Barbosa JDV; SENAI CIMATEC University Center, Programa de Pós-Graduação em Gestão e Tecnologia Industrial, Salvador 41650-010, Brazil., Ferreira SLC; Instituto de Química, Programa de Pós-Graduação em Química, Campus Ondina, Universidade Federal da Bahia, Salvador 40170-115, Brazil., Cerdà V; Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca, Spain. |
| Abstrakt: |
This work proposes the synthesis of a new polymer with imprinted ions (IIP) for the pre-concentration of uranium in natural waters using digital imaging as a detection technique. The polymer was synthesized using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) for complex formation, ethylene glycol dimethacrylate (EGDMA) as a crosslinking reagent, methacrylic acid (AMA) as functional monomer, and 2,2'-azobisisobutyronitrile as a radical initiator. The IIP was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy (FTIR). Uranium determination was performed using digital imaging (ID), and some experimental conditions (sample pH, eluent concentration, and sampling flow rate) were optimized using a two-level full factorial design and Doelhert response surface methodology. Thus, using the optimized conditions, the system allowed the determination of uranium with detection and quantification limits of 2.55 and 8.51 µg L -1 , respectively, and a pre-concentration factor of 8.2. All parameters were determined using a 25 mL sample volume. The precision expressed as relative deviation (RSD%) was 3.5% for a solution with a concentration of 50 µg L -1 . Given this, the proposed method was used for the determination of uranium in four samples of natural waters collected in the city of Caetité, Bahia, Brazil. The concentrations obtained ranged from 35 to 75.4 μg L -1 . The accuracy was evaluated by the addition/recovery test, and the values found ranged between 91 and 109%. |
