Test Systems Based on Nanofibers Produced by Electrospinning for the Determination of Nickel Ions

Test systems based on polymer nanofibers obtained by electrospinning are developed for the determination of nickel ions in natural and waste waters. The detection of the analytical signal of test systems can be carried out both visually and by colorimetry. Polyacrylonitrile and fluoroplastic are used as a polymer matrix, and rubeanic acid, pyridylazonaphthol, dimethylglyoxime, and α-furyldioxime are used as reagents. The immobilization of the reagents into the matrix is carried out by adding them to the polymer spinning solution before the start of the fiber manufacturing process. The optimal conditions for obtaining test systems (composition of the spinning solution, electrospinning parameters, the nature of the polymer and the reagent) and for recording the analytical signal (pH, color parameter, and signal recording time) are chosen. The parameters of calibration dependences for the determination of nickel ions using various test systems are determined, and their selectivity with respect to ions of other heavy metals is studied. It is shown that a test system based on polyacrylonitrile (mass fraction of polymer in the spinning solution 12%) and rubeanic acid (reagent concentration in the spinning solution 0.05 M) ensures the determination of nickel ions in the concentration range 1 × 10 –6 M–0.01 M. The developed test systems are used to determine nickel ions in natural, tap and waste waters. An advantage of the proposed test systems is the simplicity of test fabrication, the absence of sample preparation, and the possibility of conducting analysis in the field.