| Summary: | 碩士 === 國立高雄師範大學 === 化學系 === 99 === Paraquat (PQ) and diquat (DQ) are commonly used herbicides, which are used in agriculture for weed control and crop desciccation. On the basis of their toxicity, the World Health Organization (WHO) has classified these two compounds as moderately hazardous. Many countries have also included PQ and DQ in a priority list of hazardous chemicals and have established maximum contamination levels (MCLs) for drinking waters and agricultural products. Therefore, it is required to develop a simple and sensitive analytical method for determination of residual herbicides in drinking waters and food samples.
In this research, we combined silica nanoparticles(SiNPs) extraction with CE-UV detection to analyze the herbicides. The surface of silica forms SiO- under neutral or basic condition, which could attract positively charged hebicids through electrostatic attraction. Under optimum extraction and separation conditions, the limits of detection (LODs) of PQ and DQ at signal-to-noise(S/N) ratio of 3 in aqueous solution were 0.03 μM and 0.05 μM, respectively. In comparison with the CE-UV detection without the extraction procedure, approximately 33- and 26-fold improvements in the sensitivity were observed for PQ and DQ, respectively. In addition, the developed method was successfully applied to the determination of residual PQ in mung bean. A calibration curve for PQ in mung bean ranging from 0.06 ～ 6.43 μg/g was linear, and the correlation coefficient (r) was 0.9994. The limit of detection and recovery of PQ in mung bean were 0.01 μg/g and 25.1 ％, respectively.
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