Development of a novel strategy for the determination of Ag(I), Cu(II) and Ni(II) in urine after the extraction mediated by a semipermeable membrane.

The determination of metals in urine using spectrometric techniques presents challenges due to the complex matrix of substances in the samples. This work introduces a novel method for determining Ag(I), Cu(II), and Ni(II) in urine using a semipermeable membrane device (SPMD) filled with chloroform (CHCl₃). The analytes were separated after complexation with ammonium pyrrolidinedithiocarbamate (APDC), forming a substance capable of migrating through the membrane and being absorbed by the internal phase. After extraction, the internal phase (solvent) was transferred to a volumetric flask, diluted with ethanol, and analyzed by graphite furnace atomic absorption spectrometry (GF AAS). Optimization of the extraction process included the acceptor phase, sample pH, APDC concentration, extraction time, and GF AAS temperature program. The limits of detection were 0.19, 0.23, and 0.15 µg L⁻¹ for Ag(I), Cu(II), and Ni(II), respectively, while the limits of quantification were 0.64, 0.77, and 0.51 µg L⁻¹ . Analysis of five urine samples and recovery tests, involving spiking with 5 and 10 µg L⁻¹ of each analyte, resulted in recovery percentages between 85 % and 106 %, confirming the suitability of the method for quantifying metals in complex samples like urine.