Fabrication of a cost-effective and highly selective GA-CPE membrane sensor for the potentiometric detection of Cu2+ in environmental and biological samples

The presence of Cu2+ in water resources and the human body can be extremely harmful to health. The detection of Cu2+ in environmental liquid sources is very important in preventing copper-related diseases and environmental pollution. In this study, for the first time, a gallic acid- carbon paste electrode (GA-CPE) membrane potentiometric sensor was developed using GA acid by a simple method for detecting Cu2+ in various liquid samples. The structure of the GA-CPE membrane electrode of the sensor was elucidated by analyses of SEM-EDS. Using the GA-CPE sensor, potentiometric measurements of 14 different ions, including the Cu2+, were carried out in solutions (10(-2) M), and their results were compared. The experimental results showed that the GA-CPE sensor exhibits selective potentiometric behavior toward Cu2+. The experimental results in 1.0 x 10(-2)-1.0 x 10(-6) M Cu2+ solutions revealed that the GA-CPE sensor has a 25.8 +/- 1.12 mV/decade Nernstian behavior and a linear curvilinear result (E = - 25.8 [- log(Cu2+)] + 1368.8 R-2 = 0.9996). The obtained GA-CPE membrane structured sensor was determined to be selective, stable, and highly sensitive in the detection of Cu+2. The limit of detection of GA-CPE in the experiments performed with different concentrations of Cu2+ was found to be 1.92 x 10(-7) M. DFT studies of the GA-CPE structure were performed to determine possible interactions and theoretical calculations. DFT studies of HOMO, LOMO, and band gap energy gaps were found to be - 6.4834 eV, - 1.7015 eV, and 4.7819 eV, respectively. The experimental results were found to be in line with the theoretical studies. The experimental parameters using the GA-CPE sensor for detecting Cu2+, such as repeatability at a large number of concentrations, pH (5-11), and response time (7 s), were successfully performed. As a result, our findings showed that the GA-CPE sensor is sensitive, low-cost, stable, and selective towards Cu2+.