Diazotized reagent for spectrophotometric determination of glyphosate pesticide in environmental and agricultural samples

A new sensitive spectrophotometric method for the determination of glyphosate herbicide in environmental and agricultural samples is developed. The reaction is based on diazotization followed by coupling of glyphosate with p-dimethyl amino benzaldehyde. The resulted complex absorption spectra was observed at lambda(max) = 420 nm. The effects of other metal ions and pesticides were also tested for selective determination of glyphosate. The analytical parameters were optimized and have been successfully applied for determination of glyphosate in various environmental samples such as soil, water and vegetables. This method has a lower limit detection of 6 mu g of glyphosate. Beer's law is obeyed over the concentration range of 6.0 mu g-24.0 mu g glyphosate in 25 mL of the final solution at 420 nm. The standard deviation and relative standard deviation calculated are 0.0055 and 1.023, respectively. The molar absorptivity of the colored system is 1.91 x 10(10) L mol(-1)cm(-1) and Sandell's sensitivity is found 0.408 x 10(-5) mu g cm(-2). The proposed method is simple, sensitive, highly reproducible and time saving as compare to those complicated time consuming methods.