分散液液微萃取分光光度法测定汞、镍的研究

发布时间：2018-03-30 03:16

本文选题：分散液液微萃取　切入点：汞　出处：《天津科技大学》2012年硕士论文

【摘要】：分散液液微萃取(DLLME)是一种简便、快速的样品前处理方法。本研究将分散液液微萃取技术与分光光度法相结合,分别建立了食品中汞、镍的富集测定方法。分别以三氯甲烷、乙醇、双硫腙作为DLLME萃取汞的萃取溶剂、分散溶剂和络合剂。汞离子与双硫腙反应后形成汞-双硫腙络合物,通过DLLME对该络合物进行富集。优化了影响富集测定的各种因素。汞离子DLLME的最佳条件为：三氯甲烷体积75μL、乙醇体积1.8mL,体系pH2.0、双硫腙浓度4.5氯化钠浓度6％(w/v)、离心速率3500r-min-1。以丙酮作为DLLME沉积相的稀释溶剂,在波长495nm处对稀释后的沉积相进行测定。在最佳条件下,汞离子测定的线性范围为10～200μg·L-1,检出限为3μg·L-1,7次平行测定的相对标准偏差为4.3%。可使用EDTA-Na2消除Cd2+、 Cu2+、Ni2+、Pb2+的干扰。该方法应用于鱼、茶叶中汞含量的测定,加标回收试验的回收率在96.2%-103.0%之间。分别以四氯甲烷、乙醇、2-(5-溴-2-吡啶偶氮)-5-(二乙氨基)苯酚(Br-PADAP)作为DLLME萃取镍的萃取溶剂、分散溶剂和络合剂。镍离子与Br-PADAP反应后形成镍-Br-PADAP络合物,通过DLLME对该络合物进行富集。优化了影响富集测定的各种因素。镍离子DLLME的最佳条件为：四氯甲烷体积100μL、乙醇体积1.2mL、体系pH5.5、Br-PADAP浓度3.0μmol·L-1离心速率3500r·min-1。以乙醇作为DLLME沉积相的稀释溶剂,在波长565nm处对稀释后的沉积相进行测定。在最佳条件下,镍离子测定的线性范围为1～30μg·L-1,检出限0.3μg·L-1,7次平行测定的相对标准偏差为3.2%。使用乙酰丙酮和硫脲可以分别消除Fe3+和Cu2+的干扰。该方法应用于水、鱼、咖啡中镍含量的测定,加标回收试验的回收率在96.0%-103.0%之间。
[Abstract]:Dispersible liquid microextraction (DLLME) is a simple and rapid method for sample pretreatment. In this study, a method for the determination of mercury and nickel in food was established by combining the dispersible liquid microextraction technique with spectrophotometry. Trichloromethane, ethanol and dithizone were used as extractant, dispersion solvent and complexing agent for DLLME extraction of mercury respectively. Mercury ion reacted with dithizone to form mercury-dithizone complex. The optimum conditions of mercury ion DLLME were as follows: volume of trichloromethane 75 渭 L, volume of ethanol 1.8 mL, pH 2.0, dithizone 4.5% sodium chloride concentration 6 W / v ~ (-1), centrifugation rate. 3500r-min-1. Acetone was used as dilution solvent of DLLME deposition phase. The diluted sedimentary facies were determined at wavelength 495nm. The linear range for the determination of mercury ion is 10 ~ 200 渭 g / L ~ (-1) and the detection limit is 3 渭 g / L ~ (-1). The relative standard deviation is 4.3. EDTA-Na2 can be used to eliminate the interference of Cd2, Cu2 Ni2 and Pb _ 2. The method has been applied to the determination of mercury in fish and tea. The recovery rate of the recovery test was between 96.2-103.0%. Tetrachloromethane, 2-bromo-2-bromo-2-pyridylazo (2-bromo-2-pyridylazo) -5-( diethylamino) phenol (Br-PADAP) were used as the extraction solvent for the extraction of nickel by DLLME, dispersion solvent and complexing agent. Nickel ion reacted with Br-PADAP to form nickel-Br-PADAP complex. The complex was enriched by DLLME. The factors affecting the concentration and determination of the complex were optimized. The optimum conditions of nickel ion DLLME were as follows: volume of tetrachloromethane 100 渭 L, volume of ethanol 1.2 mL, concentration of pH5.5% Br-PADAP 3.0 渭 mol L-1 centrifugation rate 3500r min-1. Ethanol was used as dilution solvent of DLLME deposition phase. The diluted sedimentary facies were determined at wavelength 565nm. The linear range for the determination of nickel ion is 1 ~ 30 渭 g / L ~ (-1) and the detection limit is 0.3 渭 g / L ~ (-1). The relative standard deviation is 3.2. The interference of Fe3 and Cu2 can be eliminated by acetylacetone and thiourea, respectively. The method has been applied to the determination of nickel in water, fish and coffee. The recovery rate of the recovery test was between 96.0- 103.0%.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R155.5

【参考文献】