A novel electrochemical sensor modified with the [Cu(SCN)(PPh₃)(dpa)] complex for the simultaneous detection of resorcinol and hydroquinone

This work reports, for the first time, the application of a copper(I) complex, namely [Cu(SCN)(PPh₃)(dpa)] (SCN = thiocyanate, PPh 3 = triphenylphosphine, dpa = 2,2′-dipyridylamine), in the construction of a modified electrochemical screen printed carbon electrode.This sensor represents the first electrochemical device utilizing this copper(I) complex for the simultaneous detection of hydroquinone (HQ) and resorcinol (RS) in natural water. The influence of the solvent used to disperse the Cu(I) complex was investigated, and the results showed that the use of acetonitrile (MeCN) favored the development of a more efficient sensor with a larger active surface area (0.120 cm 2 ), compared to the case when dimethylformamide (DMF) was employed, as was also confirmed by the different coverages of the sensors surface through scanning electron microscopy (SEM) analysis. The newly developed modified sensor demonstrated significant electrocatalytic activity, thus confirming its usefulness for the detection of phenolic compounds. Selectivity studies performed in the presence of structurally related phenolic interferents revealed only minor effects on the electrochemical response, confirming the robustness of the sensor. Using differential pulse voltammetry (DPV), the [Cu(SCN)(PPh 3 )(dpa)]/MeCN/C-SPE sensor exhibited excellent performance over a linear range of 0 μM to 0.045 μM, with limits of detection (LOD) of 16.81 nM for HQ and 2.01 nM for RS, and limits of quantification (LOQ) of 56.04 nM and 4.03 nM, respectively. The sensor also showed high reproducibility and accuracy in real water samples, with recoveries ranging from 88.45% to 114.12%, validating its potential for practical applications in environmental monitoring. • First report of an electrochemical sensor based on the [Cu(SCN)(PPh₃)(dpa)] complex. • Acetonitrile enhances electrocatalytic efficiency and sensor active surface area. • Nanomolar detection limits validated in real environmental water samples. • Simultaneous detection of hydroquinone (HQ) and resorcinol (RS) achieved.