Determination of glyphosate in water samples by IC

Agricultural development and its associated impacts on the environment are resulting in increasingly restrictive guidelines and legislation concerning the use of chemicals in agro-ecosystems. The herbicide glyphosate is widely used for weed control in both cultivated and uncultivated areas and is considered to show low toxicity to mammals. It is highly water-soluble, and its monitoring in surface, underground, and potable waters is recommended by the United States Environmental Protection Agency. This work presents a method for the inclusion of glyphosate determination within routine anion analysis using ion chromatography in water sampler without any kind of extraction, clean-up, or preconcentration step. The equipment used was a Dionex Model ICS-3000 ion chromatograph fitted with a 25-microL loop, Ion Pac AG19 guard and AS19 analytical columns, ASRS-300 (2 mm) suppressor, and conductivity detector. The method showed a linear response to glyphosate between 0.05-0.75 mg/L with a correlation coefficient of 0.999, and a detection limit below the maximum levels permitted by Brazilian legislation. Recoveries in the range 90-105% were achieved in tests using surface, well, potable, and ultrapure water samples.