Adsorption Properties of Sediments for Pesticides: Investigation with Supercritical Fluid Extraction and Gas Chromatograph Mass Spectrometry

Abstract

Use of pesticides is necessary in the recent agricultural production for removal of weeds and pests which interfere growth of crops. Though use amount and use methods are determined by standards for the each pesticide, residual pesticides in environments and foods are paid attentions much from the view point of food safety. Therefore, analytical methods to evaluate pesticide residue contained in foods are investigated well (Okihashi et al. 2005). On the other hand, pesticides spread in agricultural fields and golf links are not only taken by plants but also drawn to environment as waste water with rain water and supplied waters, and it is issued that the pesticides pass through sediments to reach to ground waters (Sudo et al., 2002). Japanese Ministry of Environment determined pesticide control law and standard indexes for golf link pesticides to monitor and control the pesticides emitted to environment (Ministry of Environment, Government of Japan, 2001). Determination methods for the pesticides contained in several kinds of samples are usually complicated and difficult to determine accurately without sophisticated skill (Ormad et al., 1996; Zhou et al., 2009). In addition, the determination methods are different with different target analyte and samples, and it takes long time to determine several kinds of pesticides. In 2005, the positive list for residual pesticides was presented and multiple analysis methods were shown such as gas chromatography (GC) analysis after supercritical fluid extraction (SFE) (Okihashi et al., 2005; Tobino et al., 2007). For each pesticide, on the other hand, liquid-liquid extraction (LLE) (Ormad et al., 1996) and solid phase extraction (SPE) (Zhou et al., 2009) are popular for the determination. However, they are time consuming and require good experimental skill and also consume much organic solvent not to be good for environmental charging. Accordingly, we tried to apply SFE method to environmental analysis which is already used for food analysis as Tobino et al. presented before (2007). The SFE is effective extraction utilizing supercritical fluid characteristics such as high permeability of the fluid and high solubility of organic solutes to the fluid. Such SFE has been applied to determination of dioxines contained in sediments (Miyawaki et al., 2003). Glazkov et al.