H+-selective microelectrodes with optimized measuring range for corrosion studies

Abstract Two newly synthesized H + -selective ionophores: 2,3,4- tris (dodecyloxy)benzyldihexylamine and benzyldioctadecylamine, and six nitro-group containing solvents (2-nitrophenyl octyl ether, 2-nitrophenyl pentyl ether, 2-nitrophenyl phenyl ether, 1,2-dimethyl-3-nitrobenzene, 2-fluorophenyl 2-nitrophenyl ether, benzyl 2-nitrophenyl ether) were investigated to develop a membrane for glass-capillary H + -selective microelectrode with optimized measuring range for corrosion studies. It was shown that the microelectrode based on benzyldioctadecylamine and potassium tetrakis (4-chlorophenyl) borate as anionic site dissolved in 2-nitrophenyl octyl ether possessed the best working pH range (2.6–12.3), Nernstian slope (55.0 mV decade −1 ) and good time-related characteristics (potential drift 0.06 mV h −1 , potential reproducibility ±0.1 mV and response time). It was successfully applied for pH measurements over corroding cut-edge samples of metallic coated steel using scanning ion-selective electrode technique.