Electrochemical monitoring of the biointeraction between glyphosate, glufosinate and their formulants with DNA samples.

Glyphosate (GLY) and glufosinate (GLU), which is similar to GLY, are affordable and non-selective herbicides which are used globally. They are natural resources pollutants whose genotoxic effects have been investigated. For the first time in literature, this study monitored the biointeraction between glyphosate (GLY), glufosinate (GLU), their commercial formulants (GLY-T and GLU-T), and various DNA samples. This was achieved using a pencil graphite electrode (PGE) with cyclic voltammetry (CV). Fish sperm DNA (fsDNA), calf thymus double-stranded (ctdsDNA) and single-stranded DNA (ctssDNA) and single-stranded 25-base-length purine or pyrimidine oligonucleotides were immobilized on the surface of PGE, and the biointeraction was investigated. The decreases in the average cathodic peak (Ic) measured by CV were evaluated. GLU, GLU-T and their formulants showed their effects on fsDNA and ctssDNA more than ctdsDNA. Voltammetric results indicated that GLU, GLU-T, and their formulants exhibited effects on pyrimidine bases, with the most effect observed on cytosine. The decreases % in the average Ic were calculated as 23.19%, 15.91%, 18.53% and 28.34% after the biointeraction between 750 nM polyC and 50 μg/mL GLU, 10 μg/mL GLU-T, 5 μg/mL GLY or 0.25 μg/mL GLY-T, respectively. The biointeraction between the herbicides and their formulants with polyC was also investigated in simulated water and tap water samples with slight changes in the biosensor response. Molecular docking studies enlightened binding mechanisms of GLY and GLU on the polyoligonucleotides, and confirmed the electrochemical results. The greenness level of the study was calculated as 0.77 using Analytical GREEnness Metric Approach and Software (AGREE).