【作者】 武春霞；

【导师】 王志； 王春；

【作者基本信息】 河北农业大学 ， 分析化学， 2011， 硕士

【摘要】 样品前处理是整个分析过程中最为关键的步骤之一,既要从样品中分离和浓缩目标分析物,又要减少或消除样品中的干扰物以便实现目标分析物的低浓度检测。近年来,为了节省时间、实现样品前处理的自动化以及尽量减少有机溶剂的使用,发展了多种微萃取技术。液相微萃取(Liquid phase microextraction,LPME)是上个世纪九十年代发展起来的一种样品前处理技术,它无需昂贵的装置,具有操作简单、省时、仅需微升级有机溶剂、集采样、萃取、浓缩于一体、环境友好等优点。本论文将超声乳化微萃取(Ultrasound-assisted emulsification microextraction,USAEME)、表面活性剂辅助超声乳化微萃取(Ultrasound-assisted surfactant-enhanced emulsification microextraction , UASEME )、悬浮凝固化有机液滴液相微萃取(Dispersive liquid-liquid microextraction based on solidification of ?oating organic droplet,DLLME-SFO)与高效液相色谱(High performance liquid chromatography,HPLC)及原子吸收光谱法(Flame atomic absorption spectrometry,FAAS)技术相结合建立了水样、饮料等样品中三嗪类除草剂、有机磷类农药及金属离子的检测新方法。在系统查阅有关文献资料的基础上,进行了以下研究工作:1.建立了表面活性剂辅助超声乳化微萃取(UASEME)与高效液相色谱联用测定环境水样中7种有机磷类农药(水胺硫磷、亚胺硫磷、对硫磷、甲基对硫磷、杀螟松、地虫硫磷和辛硫磷)残留的快速、灵敏的新方法。表面活性剂作为乳化剂能够促进萃取剂在样品溶液中的分散,加快萃取过程中的传质速率,从而提高萃取效率。对影响UASEME富集效率的诸因素如萃取剂的种类及用量、表面活性剂的种类及浓度、萃取时间及温度、盐浓度等进行了系统的优化。在优化实验条件下,7种有机磷农药的富集倍数可达210~242,线性范围均在1~200 ng/mL之间,线性相关系数为0.9973~0.9998。方法的检出限在0.1~0.3 ng/mL(S/N=3)范围内。该方法已成功用于井水、水库水等实际水样中有机磷类农药残留的测定,平均加标回收率为82.8%~106.0%,相对标准偏差(RSD)为3.3%~5.6%。该方法操作简便、快速,具有较高的灵敏度,适于环境水样中有机磷类农药残留的检测。2.应用超声乳化微萃取(USAEME)与高效液相色谱联用技术建立了测定环境水样中5种三嗪类农药(西玛津、阿特拉津、扑灭通、莠灭净和扑草净)残留的新方法,并对影响萃取富集效率的实验条件进行了系统优化。在优化的实验条件下,该方法对5种三嗪类农药的富集倍数可达148~225,检出限为0.06~0.1 ng/mL(S/N=3)。5种三嗪类农药在0.5~200 ng/mL范围内具有良好的线性关系,线性相关系数(r)在0.9993~0.9998之间。在水样中加标浓度为5 ng/mL和50 ng/mL的平均加标回收率在82.4%~107.0%之间,相对标准偏差在3.0%~4.6%之间,结果令人满意。该方法已成功应用于分析实际水样中的三嗪类除草剂残留。3.应用悬浮凝固化有机液滴液相微萃取(DLLME-SFO)和高效液相色谱联用技术建立了环境水样中三唑磷、对硫磷、二嗪磷、辛硫磷、甲基对硫磷等5种有机磷类农药的分析新方法。为了提高方法的测定回收率和富集效率,依次对影响萃取效率的诸条件进行了系统优化。所使用的萃取剂低毒、低密度且熔点接近室温,在低温下容易凝固,易于收集。在最佳的实验条件下,DLLME-SFO方法测定5种有机磷类农药的富集倍数高达215~557,方法的检出限(LOD)在0.1~0.3 ng/mL(S/N=3)范围内,可以满足实际样品的测定。五种有机磷类农药在1~200.0 ng/mL范围内具有良好的线性关系,线性相关系数(r)为0.9991~0.9998。对含有5.0 ng/mL和50.0 ng/mL的有机磷类农药的混合标准样品平行测定五次,平均加标回收率在82.2%~104.0%之间,相对标准偏差(RSD)为4.4%~6.3%。该方法操作简便、快速、环境友好、具有较高的灵敏度,应用于实际水样中有机磷类农药残留的测定取得了满意的结果。4.应用悬浮凝固化有机液滴液相微萃取-火焰原子吸收光谱联用技术,以8-羟基喹啉为螯合剂,1-十二醇为萃取剂,建立了灵敏、快速分析测定环境水样和饮料中痕量铜的新方法。对影响DLLME-SFO萃取富集效率的诸因素进行了系统的优化。在优化的实验条件下,铜的富集倍数可达122倍,线性范围在0.5~500 ng/mL之间,线性相关系数(r)为0.9996。方法的检出限为0.1 ng/mL(S/N=3)。本方法已成功用于实际样品中铜残留的测定,平均加标回收率为92.4%~98.0%,相对标准偏差(RSD)为4.67%。该方法操作简便、快速,具有较高的灵敏度,可满足于水样和饮料中痕量铜残留的检测。更多还原

【Abstract】 Sample preparation prior to the chromatographic analysis is one of the most important and crucial steps in the whole analytical procedure to obtain accurate and sensitive results. The primary objective of the sample preparation is to clean up and concentrate the analytes of interest, thus reducing or even eliminating the interferences originally present in the samples to determine the target analytes at low levels. Recently, much attention is being paid to the development of miniaturized, more efficient, and environmentally friendly extraction techniques which could greatly reduce the organic solvent consumptions. For this purpose, several different types of liquid-phase microextraction (LPME) techniques have emerged for sample preparations. LPMEs have advantages of simplicity, rapidity, effectiveness, low cost, and minimum use of solvents.In the work, on the basis of ultrasound-assisted emulsification microextraction (USAEME), ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) and dispersive liquid-liquid microextraction based on solidification of ?oating organic droplet (DLLME-SFO) in combination with high performance liquid chromatography (HPLC), several analytical methods were developed for the determination of some pesticides in environmental water, milk and agricultural samples. This thesis is mainly concerned with the following aspects:1. An ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) was developed as a new approach for the extraction of seven organophosphorus pesticides (Ops) in water samples prior to high performance liquid chromatography with diode array detection (HPLC-DAD). The use of a surfactant as an emulsifier in the UASEME method could enhance the dispersion of water-immiscible extraction solvent into aqueous phase and is favorable for the mass-transfer of the analytes from aqueous phase to the organic phase. Several variables that affect the extraction efficiency, including the kind and volume of the extraction solvent, the type and concentration of the surfactant, salt addition, ultrasound emulsification time and temperature, were investigated and optimized. Under the optimum experimental conditions, the calibration curve was linear in the concentration range from 1 to 200 ng/mL for the seven Ops (isocarbophos, phosmet, parathion, parathion-methyl, fenitrothion, fonofos and phoxim), with the correlation coefficients (r) varying from 0.9973 to 0.9998. High enrichment factors were achieved ranging from 210 to 242. The established UASEME-HPLC-DAD method has been successfully applied for the determination of the Ops in real water samples. The limits of detection were in the range between 0.1 and 0.3 ng/mL. The recoveries of the target analytes over the three spiked concentration levels of the compounds (10, 50, and 100 ng/mL, respectively) in rain, reservoir and well water samples were between 83% and 106% with the relative standard deviations varying from 3.3% to 5.6%. The method was shown to be simple, efficient and sensitive, and was suitable for the determination of these compounds in water samples.2. A novel, simple, rapid, efficient, and environmentally friendly method for the determination of five triazine herbicides in water samples was developed by ultrasound-assisted emulsification microextraction (USAEME) coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). Parameters that affect the extraction efficiencies, such as the kind and volume of the extraction solvent, ultrasound emulsification time and salt addition, were investigated and optimized. Under the optimum conditions, the proposed method is sensitive and shows a good linearity within a range of 0.5~200 ng/mL for simazine, atrazine, prometon, ametryn and prometryn, with the correlation coefficients (r) varying from 0.9993 to 0.9998. High enrichment factors were obtained ranging from 148 to 225. The limits of detection (LODs) were in the range between 0.06 and 0.1 ng/mL. The recoveries of the target analytes from water samples at spiking levels of 5.0 and 50.0 ng/mL were ranged from 82.4% to 107.0%. The relative standard deviations (RSD) varied from 3.0% to 4.6%. The results demonstrated that USAEME-HPLC-DAD was an efficient pretreatment and enrichment procedure for the determination of triazine pesticides in real water samples.3. A novel simple, rapid, efficient and environmentally friendly method, dispersive liquid–liquid microextraction based on solidification of ?oating organic droplet (DLLME-SFO) coupled with high performance liquid chromatography-diode array detection (HPLC-DAD), was developed for the determination of five organophosphorus pesticides (Ops) in water samples. In this method, the extraction solvent is of low density, low toxicity and proper melting point around room temperature, and the extractant droplet can be readily solidified in the lower temperature and carried out from the aqueous sample. A series of parameters that affect the extraction efficiencies were investigated and optimized. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 1 to 200 ng/mL for the five Ops, with the correlation coefficients (r) varying from 0.9991 to 0.9998. High enrichment factors were achieved ranging from 215 to 557. The limits of detection (LODs) were in the range between 0.1 and 0.3 ng/mL. The recoveries of the target analytes from water samples were 82.2%~104.0%. The relative standard deviations (RSD) varied from 4.4% to 6.3%. The proposed method has been successfully applied for the determination of organophosphorus pesticides in real water samples.4. A dispersive liquid–liquid microextraction based on solidification of ?oating organic droplet (DLLME-SFO) has been developed as a new approach for the extraction of trace copper in water and beverage samples followed by the determination with flame atomic absorption spectrometry. In the DLLME-SFO, 8-hydroxy quinoline, 1-dodecanol, and methanol were used as chelating agent, extraction solvent and dispersive solvent, respectively. The experimental parameters related to the DLLME-SFO such as the type and volume of the extraction and dispersive solvent, extraction time, sample volume, the concentration of chelating agent and salt addition were investigated and optimized. Under the optimum conditions, the enrichment factor for copper was 122. The method was linear in the range from 0.5 to 300 ng/mL of copper in the samples with a correlation coefficient (r) of 0.9996 and a limit of detection of 0.1 ng/mL. The method was applied to the determination of copper in water and beverage samples. The recoveries for the spiked water and beverage samples at the copper concentration levels of 5.0 and 10.0 ng/mL were in the range between 92.0% and 108.0%. The relative standard deviations (RSD) varied from 3.0% to 5.6%.更多还原