Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame ato...Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame atomic absorption spectrometry (FAAS) using Triton X-114 as surfactant. The main factors affecting the CPE, such as concentration of Triton X-114 and DPTH, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimum conditions i.e., pH 5.4, [DPTH] = 6x10-3%, [Triton X-114] = 0.25% (v/v), an enhancement factor of 10.5 fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.95 μg L?1. The precision for 8 replicate deter- minations at 20 and 100 μgL?1 Cd were 2.4 % and 2 % relative standard deviation (R.S.D.). The calibration graph using the preconcentration method was linear with a correlation coefficient of 0,998 at levels close to the detection limit up to at least 200 μgL?1. The method was successfully applied to the determination of cadmium in water, environmental and food samples and in a BCR-176 standard reference material.展开更多
建立了一种简单高效的超声辅助离子液体分散液液微萃取(UA-IL-DLLME)结合石墨炉原子吸收光谱法(GFAAS)测定食品中超痕量铅镉。以二乙基二硫代磷酸铵(DDTP)为配位剂,离子液体1-丁基-3-甲基咪唑六氟磷酸盐[C_4Mim][PF_6]为萃取剂,超声用...建立了一种简单高效的超声辅助离子液体分散液液微萃取(UA-IL-DLLME)结合石墨炉原子吸收光谱法(GFAAS)测定食品中超痕量铅镉。以二乙基二硫代磷酸铵(DDTP)为配位剂,离子液体1-丁基-3-甲基咪唑六氟磷酸盐[C_4Mim][PF_6]为萃取剂,超声用于辅助分散离子液体和加速传质。考察优化了影响萃取效率的主要参数如离子液体的种类和体积、样品液p H、螯合剂的用量、超声时间、离心转速与时间等。在最优的萃取条件下,镉铅的校准曲线分别在0.05~20μg/L和0.5~40μg/L范围呈良好的线性,相关系数分别为0.9983 and 0.9969,检出限(S/N=3)分别为0.032和0.32μg/kg,相对标准偏差(RSD,n=11)分别为1.3%和1.8%。大米和白兰地中镉铅3个水平1.60、16.00、32.00μg/kg的平均加标回收率在95.2~102%范围。方法已成功用于检测不同食品中镉铅含量。展开更多
文摘Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame atomic absorption spectrometry (FAAS) using Triton X-114 as surfactant. The main factors affecting the CPE, such as concentration of Triton X-114 and DPTH, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimum conditions i.e., pH 5.4, [DPTH] = 6x10-3%, [Triton X-114] = 0.25% (v/v), an enhancement factor of 10.5 fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.95 μg L?1. The precision for 8 replicate deter- minations at 20 and 100 μgL?1 Cd were 2.4 % and 2 % relative standard deviation (R.S.D.). The calibration graph using the preconcentration method was linear with a correlation coefficient of 0,998 at levels close to the detection limit up to at least 200 μgL?1. The method was successfully applied to the determination of cadmium in water, environmental and food samples and in a BCR-176 standard reference material.
文摘建立了一种简单高效的超声辅助离子液体分散液液微萃取(UA-IL-DLLME)结合石墨炉原子吸收光谱法(GFAAS)测定食品中超痕量铅镉。以二乙基二硫代磷酸铵(DDTP)为配位剂,离子液体1-丁基-3-甲基咪唑六氟磷酸盐[C_4Mim][PF_6]为萃取剂,超声用于辅助分散离子液体和加速传质。考察优化了影响萃取效率的主要参数如离子液体的种类和体积、样品液p H、螯合剂的用量、超声时间、离心转速与时间等。在最优的萃取条件下,镉铅的校准曲线分别在0.05~20μg/L和0.5~40μg/L范围呈良好的线性,相关系数分别为0.9983 and 0.9969,检出限(S/N=3)分别为0.032和0.32μg/kg,相对标准偏差(RSD,n=11)分别为1.3%和1.8%。大米和白兰地中镉铅3个水平1.60、16.00、32.00μg/kg的平均加标回收率在95.2~102%范围。方法已成功用于检测不同食品中镉铅含量。