Synthesis and Application of a New Polymer with Imprinted Ions for the Preconcentration of Uranium in Natural Water Samples and Determination by Digital Imaging

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 mu g 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 mu g 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 Caetite, Bahia, Brazil. The concentrations obtained ranged from 35 to 75.4 mu g L-1. The accuracy was evaluated by the addition/recovery test, and the values found ranged between 91 and 109%.

Automated summary

This work presents the synthesis and characterization of a new polymer with imprinted ions (IIP) for pre-concentration of uranium in natural waters. The polymer was synthesized using specific reagents and optimized experimental conditions were determined. The proposed method was successfully applied to determine uranium concentrations in water samples collected in Caetite, Bahia, Brazil, with high accuracy and precision.