Optimization of Tribenuron-methyl determination by differential pulse polarography using experimental design

Abstract

Differential pulse polarography (DPP) was applied for the determination of the herbicide Tribenuron-methyl (TBM). This is a first study for various parameters affecting the reduction peak current were simultaneously optimized using experimental design and these results are different from other reports. The effect of factors such as voltage step, voltage step time, pulse amplitude, pulse time, sample pH, concentration of the supporting electrolyte and the mercury drop size were assessed by means of a (2^7-2) fractional factorial design. It was found that the effects and interactions of four out of seven factors were significant. Consequently, a central composite design (CCD) with four factors, i.e., voltage step time, pulse amplitude, pulse time and sample pH was performed and an optimum response surface equation was derived. The statistical parameters of the derived model were R² = 0.95 and F = 20.38. The limit of detection (LOD), limit of quantification (LOQ), linear range and relative standard deviation (RSD) were 36 μg L⁻¹, 119 μg L⁻¹, 0.07–20 mg L⁻¹ and 0.03, respectively. The promising results for the determination of TBM in a trace level show the efficiency of factorial design and response surface methodologies in optimizing the parameters of a DPP method.