963 (2002) 117–123 Journal of Chromatography A, www.elsevier.com / locate / chroma Comparison of solid-phase extraction and solid-phase microextraction for carbofuran in water analyzed by high- performance liquid chromatography–photodiode-array detection * ´ ´ M.C. Lopez-Blanco, B. Cancho-Grande, J. Simal-Gandara Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, 32004 Ourense, Spain Abstract In this study a direct solid-phase microextraction (SPME) procedure has been developed for the determination of carbofuran in water. Experimental parameters such as selection of SPME coating, effect of temperature, effect of salt addition and solvent desorption were studied and optimized. Analytical parameters such as linearity, precision, detection and quantitation limits, and matrix effects for solid-phase extraction (SPE) and SPME methods were evaluated for comparison purposes with the aim of selecting the most appropriate depending on the detection capabilities required. SPE and SPME were followed by high-performance liquid chromatography with diode-array detection, using a 5034.6 mm I.D. guard column and a 15034.6 mm I.D. analytical column, both packed with C silica. Both methods can be applied to real samples 18 and give the same results, but SPE allows the detection of lower carbofuran concentrations (0.06 mg/L) as compared to SPME (8.9 mg / L).  2002 Elsevier Science B.V. All rights reserved. Keywords: Extraction methods; Water analysis; Carbofuran 1. Introduction (EPA) maximum contaminant level (MCL) for carbo- furan in drinking water is 40 mg / L. However, the Carbofuran is used extensively in agriculture as an current California MCL is 18 mg/L and the Office of insecticide to control a broad spectrum of insects on Environmental Health Hazard Protection Agency potatoes, corn, rice, alfalfa, grapes and other food- (OEHHA) of the California Environmental Protec- stuffs. Its implications as a potential endocrine tion Agency proposes a public health goal of 1.7 disrupter have been demonstrated [1]. Carbofuran is mg / L. The European Union has set a maximum highly mobile in soils and appears in waters because admissible concentration of 0.5 mg/L for the sum of of its high solubility [2,3]. It has a high potential for all pesticides and 0.1 mg / L for an individual com- groundwater contamination of aquifers via leaching pound in drinking water [4]. from treated fields, and also from surface waters The aim of this study was to develop methods which enter as a result of runoff from treated fields. based on solid-phase extraction (SPE) and microex- The current US Environmental Protection Agency traction (SPME) followed by HPLC–photodiode- array detection (DAD) for the determination of carbofuran in water. No commercial interface is used *Corresponding author. Tel.: 134-988-387-000; fax: 134-988- for coupling SPME with HPLC equipment and high 387-001. ´ E-mail address: jsimal@uvigo.es (J. Simal-Gandara). reproducibility was achieved. Five commercially 0021-9673 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0021-9673(02)00552-6