Azam Mousavi Motlagh - Chemistry Teacher, university of applied science and technology of alifard-sunich, Hashtgerd, Karaj, Iran
Raheleh Khanjani Golvarzi - Student, Department of food science and technology, Faculty of agricultural, Varamin-Pishva branch, Islamic Azad University, Varamin, Tehran, Iran
Sara Pourmand - Chemistry Teacher, university of applied science and technology of alifard-sunich, Hashtgerd, Karaj, Iran

Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential of multi-walled carbon nanotubes (MWNTs) as solid-phase extraction (SPE) adsorbents for the preconcentration of environmental pollutants has been investigated in recent years. The goal of this work was to investigate the feasibility of MWNTs used as SPE adsorbents to enrich difenoconazole at trace level. Parameters that maybe influence the extraction efficiency such as the amount of the adsorbent, the type and volume of eluent, sample flow rate, sample pH and the sample volume were optimized in detail. The experimental results showed the excellent linear relationship between peak area and the concentration of difenoconazole over the range of 0.1-100 μg L-1, and the precisions (RSD) was 3.2% under the optimal conditions. The detection limits of proposed method could reach 15 ng L-1 at signal-to-noise ratios of 3:1. Finally, the method was applied to tap water, well water and river water. Satisfied results were achieved when the proposed method was applied to determine the difenoconazole in realworld water samples with spiked recoveries over the range of 88–105%. All these facts indicated that MWCNTs as SPE packing materials coupled to HPLC was an excellent alternative for the routine analysis of difenoconazole at trace level in environment.

Multi-walled carbon nanotubes, Solid-phase extraction, High- performance liquid chromatography, Difenoconazole