Abstract

GIANELLI, Valeria Rosana; ZELAYA, Manuel José; BEDMAR, Francisco  and  COSTA, José Luis. Determination of imazapir residues of soils from Argentina by means of ultra performance liquid chromatography-mass spectrometry. Rev. Int. Contam. Ambient [online]. 2013, vol.29, n.2, pp.177-187. ISSN 0188-4999.

Extraction and quantification of herbicide residues from soil are important to make monitoring studies and to minimize the pollution risk. The objectives of this research were: to evaluate the efficacy of different solvents for the extraction and quantification of imazapyr residues from Argentine soils and to determine the concentration effect and soil properties influences on herbicide recovery. Extraction solutions including 0.1M pH 7 potassium chloride (KCl), 0.5 M sodium hydroxide (NaOH), 0.1M pH 14 potassium chloride (KCl), 0.1 M potassium hydroxide (KOH), methanol/water (CH₃OH/H₂0 80:20), 0.5 M sodium hydroxide/methanol(NaOH/CH₃OH 80:20), and 0.5 M sodium hydroxide/acetonitrile (NaOH/CH₃CN 80:20) to extract imazapyr from soil were investigated. Percentage recovery with each solution extraction was obtained. Then four argentine soils (Tres Arroyos, Balcarce, Anguil and Cerro Azul) and four imazapyr concentrations (5, 25, 50 and 100 ng/kg) were selected to evaluate the chosen method. Treatments were arranged in a completely randomized factorial design. The herbicide residues were determined and quantified by ultra performance liquid chromatography-mass spectrometry. The recovery obtained showed significant differences between the extraction solutions. The best recovery (95%) was obtained using 0.1 M pH 7 potassium chloride. Interaction effect between soils and concentration was detected. The lowest recovery from soils was found using low imazapyr concentrations. Results have shown that the proposed methodology was suitable to detect and quantify imazapyr residues in different soils and in a wide range of concentrations.

Keywords : imidazolinones; extraction method; recovery percentage.