本文選題：分散液液微萃取　切入點：汞　出處：《天津科技大學(xué)》2012年碩士論文

【摘要】：分散液液微萃取(DLLME)是一種簡便、快速的樣品前處理方法。本研究將分散液液微萃取技術(shù)與分光光度法相結(jié)合,分別建立了食品中汞、鎳的富集測定方法。 分別以三氯甲烷、乙醇、雙硫腙作為DLLME萃取汞的萃取溶劑、分散溶劑和絡(luò)合劑。汞離子與雙硫腙反應(yīng)后形成汞-雙硫腙絡(luò)合物,通過DLLME對該絡(luò)合物進行富集。優(yōu)化了影響富集測定的各種因素。汞離子DLLME的最佳條件為：三氯甲烷體積75μL、乙醇體積1.8mL,體系pH2.0、雙硫腙濃度4.5氯化鈉濃度6％(w/v)、離心速率3500r-min-1。以丙酮作為DLLME沉積相的稀釋溶劑,在波長495nm處對稀釋后的沉積相進行測定。在最佳條件下,汞離子測定的線性范圍為10～200μg·L-1,檢出限為3μg·L-1,7次平行測定的相對標準偏差為4.3%。可使用EDTA-Na2消除Cd2+、 Cu2+、Ni2+、Pb2+的干擾。該方法應(yīng)用于魚、茶葉中汞含量的測定,加標回收試驗的回收率在96.2%-103.0%之間。 分別以四氯甲烷、乙醇、2-(5-溴-2-吡啶偶氮)-5-(二乙氨基)苯酚(Br-PADAP)作為DLLME萃取鎳的萃取溶劑、分散溶劑和絡(luò)合劑。鎳離子與Br-PADAP反應(yīng)后形成鎳-Br-PADAP絡(luò)合物,通過DLLME對該絡(luò)合物進行富集。優(yōu)化了影響富集測定的各種因素。鎳離子DLLME的最佳條件為：四氯甲烷體積100μL、乙醇體積1.2mL、體系pH5.5、Br-PADAP濃度3.0μmol·L-1離心速率3500r·min-1。以乙醇作為DLLME沉積相的稀釋溶劑,在波長565nm處對稀釋后的沉積相進行測定。在最佳條件下,鎳離子測定的線性范圍為1～30μg·L-1,檢出限0.3μg·L-1,7次平行測定的相對標準偏差為3.2%。使用乙酰丙酮和硫脲可以分別消除Fe3+和Cu2+的干擾。該方法應(yīng)用于水、魚、咖啡中鎳含量的測定,加標回收試驗的回收率在96.0%-103.0%之間。
[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%.
【學(xué)位授予單位】：天津科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R155.5

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