On the electroreduction mechanism of 2-pyridinecarboxylic (picolinic) acid on mercury electrodes

Electrochemical Reduction of Pyridinic Herbicides Picloram and Clopyralid on a Mercury Pool Electrode

“…So, a decrease of the signals was found above pH 5 -6 and no signals were obtained above pH 7. This decrease must be attributed, as in the cases of the parent compounds, to a recombination reaction between the "picolinate" ions and the H þ ion [1,2]. Moreover, the limiting and peak currents (in DC polarography and linear-sweep voltammetry) varied with the medium pH, being this dependence attributable to the general acid-base catalysis of the dehydration of the corresponding aldehydes, which must be formed as in the cases of the PIC and 6ClP [1,2].…”

“…In previous papers [1,2] the polarographic (direct current, DC, and differential pulse, DP) and voltammetric (linearsweep cyclic voltammetry) studies on the electroreduction of picolinic acid (2-pyridinecarboxylic acid, PIC) and 6-chloropicolinic acid (6ClP) on mercury electrodes were reported. Above pH 11 (PIC) or 8 (6ClP) no signals were obtained.…”

Complete Elucidation of Electrode Reaction Mechanisms by Using Differential Pulse Polarography

“…From the deconvolution, a bxi p plot is obtained and the two peaks must be complementary, i.e., as the first decreases, the second increases, the shape of the graph resembling an acid-base dissociation curve, with the middle point at pH ¼ pK. This has been tested experimentally in the electroreductions of isonicotinamide [9], thionicotinamide [11], 2,4-diamino-1,3,5-triazine [12], picolinic acid [13], some triazine and pyridine herbicides [14] and imazamethabenz methyl [15]. Figure 2 illustrate these comments in the case of the imazamethabenz methyl reduction.…”

Sensitive voltammetric method for rapid determination of pyridine herbicide triclopyr on bare boron-doped diamond electrode

“…On the basis of the literature survey, any described electrochemical method was not found for detection of TCP but electrochemical reduction of structurally related compounds to TCP like picolinic acid [14], 6-chloropicolinic acid [15], clopyralid [16,17], 3,5,6-trichloro-4-methyl-pyridine-2-carboxylic acid [18], and picloram, e.g. in [17,19,20], has been widely investigated using working electrodes made of liquid mercury in various construction [14][15][16][17]19,20] or glassy carbon electrode [18].…”