LAUSR

Novel organophilic nanohybrid materials (K-TDD) were obtained by the grafting of 1,2-tetradecanediol (TDD) onto the surface of kaolinite (K). XRD, IR, TGA-DTG, and SEM characterization showed that TDD grafting results in a partial exfoliation of kaolinite layers. This material was used to modify a glassy carbon electrode (GCE/K-TDD) and applied for the trace analysis of methyl parathion (MP). The signal of MP recorded on GCE/K-TDD was found more intense compared to the unmodified GCE, or to one modified with a film of natural kaolinite. Several parameters that can affect the stripping response were systematically investigated to optimize the sensitivity of the organokaolinite-modified electrode. A linear calibration curve for MP was obtained in the concentration range from 2×10−6 to 14×10−6 mol L−1 in acetate buffer (pH 6), giving a detection limit of 9×10−8 mol L−1. The sensitivity of the method was found to be 2.42 μA/μM for the range of concentrations that gives a linear calibration curve. The electrode was shown to be very stable, with the electrochemical response of MP decreasing by only 1.5 % after a series of nine measurements. The interference of various inorganic ions and organic compounds likely to influence the stripping determination of the MP were also examined. The results showed that the GCE/K-TDD electrode was effective in solutions containing interfering species and could be applied for the quantification of MP pesticides in natural water.