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Flow injection spectrophotometric determination of glyphosate herbicide in wheat grains via condensation reaction with p-dimethylaminobenzaldehyde
Abstract
A fast and sensitive method was developed for determination of glyphosate, using flow injection analysis. The analyte was converted to a photoactive product that shows maximum absorbance at 405 nm. Beer’s law was obeyed over a range of 0.7–20 μgmL–1. The limit of detection and quantification were found to be 0.20±0.01 and 0.70±0.02 μgmL–1 with a high sample throughput of 60 samples h–1. The investigation of interference effect shows that among the compounds studied, only aminomethyl phosphonic acid exhibits a signal enhancing effect when present in higher concentration ratio with the analyte and this can be assumed to be a limitation of the present method. The percentage recoveries and residue of glyphosate in wheat grains samples, were found in the range of 90.0 ± 0.6 % to 93.0 ± 0.6 % and 1.13 ± 0.009 μg g–1, respectively.
Keywords: Glyphosate, photoactive, absorbance, flow injection analysis, residue