COF-42 as sensory material for voltammetric determination of Cu(II) ion: optimizing experimental condition via central composite design.

Two-dimensional (2D) COF-42 has been prepared and the COF-42/carbon paste electrode (COF-42/CPE) has been applied as a voltammetric sensor for determining copper(II). Different characterization procedures (FTIR, XRD, SEM/EDX, BET, cyclic voltammetry, and electrochemical impedance) have been implemented on the prepared COF-42 and the constructed COF-42/CPE. The central composite design has been applied for optimizing the production and function circumstances of this sensor. The existence of various functional groups in the structure of the COF-42 makes this COF greatly efficient in recognizing Cu(II) and creating stable complexes with it. The COF-42 possesses high porosity and contains various binding sites for strong interaction with copper(II), so the existence of the COF-42 in the sensor assembly decreases the mass transfer resistance in the electrode matrix and also eventuates to the precipitation of a large amount of copper analyte. The precise selection of COF and optimization of sensor preparation and operating conditions has resulted in high sensitivity and selectivity for the constructed sensor. A proper mechanism for sensor performance has been presented and confirmed by SEM/EDX and electrochemical procedures. The linear response range of the fabricated sensor is from 0.001 to 10.0 μM. The detection limit is 2.5 × 10⁻¹⁰ M. The analytical performance features of the proposed sensor have been explored by performing different statistical tests. Sensor performance is not affected by the presence of most potentially interfering species. The interference of silver(I) and mercury(II) was also removed by using a masking agent. Based on the experimental results and statistical tests, it was found that when using the masking agent, the precision and accuracy of the method remains at its previous appropriate value. The ability of the sensor has been confirmed in the analysis of real samples. [ABSTRACT FROM AUTHOR]