Cloud Point Extraction Preconcentration of Trace Cadmium as 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone Complex and Determination by Flame Atomic Absorption Spectrometry

A new method for the determination of trace cadmium in water samples by flame atomic absorption spectrometry (FAAS) after cloud point extraction (CPE) is proposed. The method is based on the complexation of Cd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) in the presence of non-ionic micelles of Triton X-100. The effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction was studied. Under the optimum conditions, the detection limits are 0.64 ng mL^±1 with relative standard deviations (RSDs) of 2.1% (n = 10). The proposed method was applied to the determination of trace cadmium in water samples with satisfactory results.     

浊点萃取-高效液相色谱法测定草莓汁中的多种农药残留

建立了浊点萃取(CPE)对草莓汁中的7种农药(克百威、异丙威、甲霜灵、杀扑磷、敌草隆、烯酰吗啉和苯噻酰草胺)进行萃取富集,然后用高效液相色谱-紫外检测器进行检测分析的方法。所用的表面活性剂为非离子表面活性剂聚氧乙烯山梨糖醇酐单月桂酸酯(Tween-20),该表面活性剂在一定条件下能够对分析物进行提取与富集。实验确定了CPE方法的优化条件:Tween-20的浓度为3%(V/V)、硫酸钠和正丁醇的浓度分别为12%(W/V)和5%(V/V)、平衡温度为50℃以及平衡时间为40min;色谱条件:流动相为V(甲醇)∶V(水)=70∶30,流速为0.6mL/min,检测波长为215nm。在上述实验条件下,在草莓汁样品的平均加标回收率为80.5%～92.8%,检出限是0.9～2.1μg/kg。     

浊点萃取-石墨炉原子吸收光谱法测定膨化食品中铅

以8-羟基喹啉(8-HQ)为螯合剂,在pH 9缓冲溶液中,痕量铅(Ⅱ)与8-HQ生成螯合物,加入表面活性剂Triton X-100用浊点萃取分离富集样品中痕量铅。分取部分表面活性剂相用0.1mol·L-1硝酸溶液定容至2mL,所得溶液直接用石墨炉原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰等进行了试验并予以优化。方法的检出限(3σ)为0.85pg。应用所提出的方法测定了膨化食品样品中铅的含量,在5种样品中用标准加入法进行方法的回收试验,测得回收率在91.7%～101.7%之间。     

Fluorescence Quenching Method for Determination of Trace Tungsten in Soil after Cloud Point Extraction

A new procedure for trace tungsten W(VI) in soil by fluorescence quenching method coupled with cloud point extraction (CPE) as the separation-preconcentration method was described. The Triton X-100 CPE behavior of W(VI)-salicylfluorone (SAF)was investigated. Under the optimized conditions, the fluorescence quenched intensity (ΔF) was linearly with W(VI). The range of linear was 0.8 ～ 20.0 μg · L^?1, the detection limit (DL) was 0.14 ng · mL^?1 (3σ), the relative standard deviation 3.3% (c = 10.0 μg · L^?1, n = 5) and the recovery was 101.0–102.2%. The proposed method applied to the analysis of W(VI) in certified reference materials and real samples.     

Preconcentration and Determination of Tin in Water Samples by Using Cloud Point Extraction and Graphite Furnace Atomic Absorption Spectrometry

A method based on cloud point extraction and graphite furnace atomic absorption spectrometry (GFAAS) was developed for the analysis of trace tin in water samples. After cloud point extraction, the tin in the water samples was preconcentrated and successfully separated from most interferents. During the procedure, 8-hydroxyquinoline (8-HQ) was used as chelating reagent, and Triton X-114 was added as surfactant. The parameters affecting the sensitivity and the extraction efficiency, such as solution pH, concentration of 8-HQ and Triton X-114, equilibration temperature and centrifuge time, were evaluated and optimized. Under the optimum conditions, a preconcentration factor of 96.2 was obtained for a 20 mL water sample. The detection limit (LOD) was as low as 0.012 ng mL⁻¹, and the analytical curve was linear in the range of 0.05–2.0 ng mL⁻¹ with satisfactory precision (RSD <4.1%). The proposed method was successfully applied to the determination of trace tin in water samples with recoveries in the range of 85.0–112.0%.     

A Pre-Concentration Procedure Using Cloud Point Extraction for the Determination of Manganese in Saline Effluents of a Petroleum Refinery by Flame Atomic Absorption Spectrometry

This paper describes the development of a cloud point extraction procedure for the determination of manganese in saline effluents by flame atomic absorption spectrometry (FAAS). The optimization step was performed using the Doehlert matrix involving the following variables: buffer concentration, pH and centrifugation time. The validation process was assessed as: parameters of the analytical curve, precision, effect of other ions in the proposed procedure, robustness test and accuracy. The proposed procedure allows the determination of manganese with a detection limit (3δ/S) of 0.60 μg L⁻¹, and a precision expressed as relative standard deviation (RSD) of 2.2 (n = 8) and 1.5% (n = 8) for a manganese concentration of 1 and 5 μg L⁻¹, respectively. The pre-concentration factor obtained was 84. The recovery achieved for the determination of manganese in the presence of several other metal ions demonstrated that this procedure could be satisfactorily applied to the analysis of environmental samples. The accuracy was confirmed by the analysis of CRM trace elements in water (NIST 1643d). This procedure was applied to the determination of manganese in saline effluents of a petroleum refinery. For three analyzed samples the manganese content varied between 44.9 and 67.9 μg L⁻¹.     

Determination of Vitamins A and E Exploiting Cloud Point Extraction and Micellar Liquid Chromatography

Cloud point extraction and micellar chromatographic methods were developed for determination of vitamins A and E. The stationary phase was C18 and the mobile phase was 3.00% (w/v) SDS, 15.0% (v/v) butyl alcohol and 0.02 mol L^?1 phosphate buffer solution at pH 7.0. The retention times for vitamins A and E were 9.6 and 13.0, respectively. The extraction solution was 100 mmol L^?1 Triton X-100, 650 mg NaCl and 1.0% ascorbic acid at 70°C for 30 min. The method is precise (r.s.d. < 7%), the linear range was from 5.0 up to 360.0 mg L^?1 for both vitamins. Recovery test showed recuperation between 90.2 and 99.2%, and LOD and LOQ of 0.234 and 0.108 mg L^?1, 0.780 and 0.360 mg L^?1 to vitamins A and E were found.     

浊点萃取-异辛烷反萃取-气相色谱测定茶叶中拟除虫菊酯农药残留

建立了浊点萃取-异辛烷反萃取-气相色谱(ECD)检测茶叶中联苯菊酯(Bifenthrin)、甲氰菊酯(Fenpropathrin)、功夫菊酯(Cyhalothrin)、氯菊酯(Permethrin)、氰戊菊酯(Fenvalerate)、溴氰菊酯(Deltamethrin)6种拟除虫菊酯农药残留的方法.对含1.2%(m/V)聚乙二醇6000(PEG6000)表面活性剂和40%(m/V)(NH4)2SO4的6种拟除虫菊酯溶液进行加热萃取,所获得的富集相用异辛烷超声反萃取,并经离心对上层异辛烷溶液进行进一步净化处理,即可获得富集倍数达75倍的6种农药.本方法的检出限(LOD)为:联苯菊酯、甲氰菊酯和功夫菊酯0.4 μg/kg;氰戊菊酯2.1 μg/kg;氯菊酯和溴氰菊酯3.0 μg/kg;用本方法测定了新鲜茶叶中6种拟除虫菊酯农药,含量分别为4.17, 4.15, 4.09, 4.01, 3.93和3.51 μg/kg.在上述茶叶样品中添加20 μg/kg 的6种农药后测定,添加回收率为72.3%～85.6%; 相对标准偏差为2.2%～5.6%.     

浊点萃取与光度法联用测定防晒霜中的2-羟基-4-甲氧基二苯甲酮-5-磺酸

本文提出了浊点萃取-光度法测定防晒剂的新方法,实验优化了影响浊点萃取分离防晒剂(2-羟基-4-甲氧基二苯甲酮-5-磺酸,BP-4)的诸因素,如:溶液pH、表面活性剂浓度、平衡温度和时间等。所建立的方法用于防晒霜中BP-4的测定,结果满意。     

浊点萃取预富集火焰原子吸收光谱法测定水样中痕量钴

本文提出了浊点萃取预富集火焰原子吸收光谱法测定痕量钴的新方法。详细研究了溶液pH值、络合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。在优化的实验条件下,本法对钴的富集倍数为20倍,检出限为3．28ng／mL,相对标准偏差(RSD)为4．1％(n=10)。所建立的方法用于自来水、湖水中痕量钴的测定,分析结果满意。     

阳离子表面活性剂Aliquat 336对水中双酚A的浊点萃取及作用机制

研究了阳离子表面活性剂Aliquat 336(三辛基甲基氯化铵)浊点萃取水中双酚A(BPA)后以高效液相色谱测定的方法.探讨了Aliquat 336与Na_2SO_4/NaCl用量、pH值、萃取时间等因素对萃取效果的影响,经条件实验选定各因素水平如下:0.8 g/L Aliquat 336,4.0 g/L Na_2SO_4,超声萃取15 min,pH和对萃取影响不大,故不予调节.结果表明: 在此选定条件下,本方法富集效率高(BPA在胶束相-水相分配系数达10~4),萃取效率稳定(相对标准偏差均小于10%),其对BPA在不同水质、不同加标浓度下的回收率均大于90%,去离子水中检出限为0.34 μg/L.本方法操作简单、方便、成本低,易于推广.同时以胶束粒径与Zeta电位分析等确证盐含量对阳离子表面活性剂胶束形成的决定性作用,并结合影响因子分析,推测Aliquat 336浊点萃取过程中BPA可能存在静电作用、阳离子-π键等疏水分配以外的作用机制.     

浊点萃取技术及其在有机化合物分离分析中的应用

浊点萃取是基于表面活性剂水溶液中相分离现象的萃取浓缩技术,已成功实现了与HPLC、CE和FI等分析仪器的联用,用于各种金属离子、生物分子和不同极性有机化合物浓缩分离处理,是一种替代有机溶剂萃取的良好形式。本文简要介绍了浊点萃取技术的原理和流程,详细总结了在有机化合物分离分析中的应用以及与不同分析仪器联用时遇到的问题和处理方法。     

浊点萃取预富集胶束增稳室温燐光法测定吲哚-3-丁酸

提出了以非离子表面活性剂Triton X-100为萃取剂的浊点萃取预富集吲哚-3-丁酸,进而用胶束增稳室温燐光法对其进行测定的新方法。通过加入氯化钠降低表面活性剂溶液的浊点,使浊点萃取得以在15℃的环境温度下顺利完成。在基于浊点萃取而进行的相分离之后,富表面活性剂相以水适当稀释,然后用胶束增稳室温燐光法测定其中被富集的吲哚-3-丁酸。在最佳条件下,工作曲线的线性范围为1.0×10-8~2.4×10-7mol/L,检出限(信噪比为3)为7.4×10-9mol/L。方法用于自来水、江水、池塘水和土壤等强化样品中吲哚-3-丁酸的测定,回收率95%~105%,相对标准偏差2.5%~4.8%。     

浊点萃取-火焰原子吸收光谱法测定菠菜中镁、锌和铜

在pH 8.0缓冲溶液中,以8-羟基喹啉为螯合剂,镁、锌和铜均与8-羟基喹啉生成螯合物,加入Triton X-100表面活性剂用浊点萃取分离富集菠菜样品中镁、锌和铜。分取部分表面活性剂相用乙醇定容至25mL,所得溶液直接用火焰原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰等进行了试验并予以优化。镁、锌和铜的检出限(3s/k)依次为0.057,0.064,0.032mg.L-1。应用此法测定了大叶菠菜和小叶菠菜中3种元素的含量,在两种样品中用标准加入法进行方法的回收试验,测得镁的回收率在93.3%～100.5%之间;锌的回收率在91.7%～97.9%之间;铜的回收率在94.0%～107.1%之间。     

Determination of Ultratrace Amounts of Copper(Ⅱ) in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

A novel approach was developed for the determination of ultratrace amounts of copper in water samples by using electrothermal atomic absorption spectrometry (ETAAS) after cloud point extraction (CPE). 1-( 2-Pyridylazo)-2-naphthol was used as the chelating reagent and Triton X-114 as the micellar-forming surfactant. CPE was conducted in a pH 8.0 medium at 40 ℃ for 10 min. After the separation of the phases by centrifugation, the surfactant-rich phase was diluted with 1 mL of a methanol solution of 0. 1 mol/L HNO3. Then 20 μL of the diluted surfactant-rich phase was injected into the graphite furnace for atomization in the absence of any matrix modifier. Various experimental conditions that affect the extraction and atomization processes were optimized. A detection limit of 5 ng/L was obtained after preconcentration. The linear dynamic range of the copper mass concentration was found to be 0-2.0ng/mL, and the relative standard deviation was found to be less than 3.1% for a sample containing 1.0 ng/mL Cu(Ⅱ). This developed method was successfully applied to the determination of ultratrace amounts of Cu in drinking water, tap water, and seawater samples.     

浊点萃取-火焰原子吸收光谱法测定矿渣中痕量金

研究了以双硫腙为络合剂,以非离子型表面活性剂Triton X-100为萃取剂的浊点萃取-火焰原子吸收光谱法(CPE-FAAS)测定痕量金(Ⅲ)的新方法。详细考察了溶液的pH值、络合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。该方法的线性范围为0.05~0.8μg/mL,检出限为7.9 ng/mL,相对标准偏差为4.12%(n=11),回收率在98.0%~102.0%之间,用于矿渣中金的测定,结果满意。     

浊点萃取-石墨炉原子吸收光谱法测定食品包装材料中锑

以吡咯烷二硫代氨基甲酸铵(APDC)为络合剂,在pH5.0乙酸-乙酸钠缓冲溶液中,痕量锑(Ⅲ)与APDC生成络合物,加入表面活性剂TritonX-114用浊点萃取分离富集样品中痕量锑。分取部分表面活性剂相用0.1mol·L-1硝酸甲醇溶液溶解,所得溶液直接用石墨炉原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰等进行了试验并予以优化。方法的检出限(3σ/k)为0.37μg.L-1。应用所提出的方法测定了食品包装材料陶瓷样品中锑的含量,并用标准加入法进行方法的回收试验,测得回收率为99.3%。     

浊点萃取-氢化物发生-原子荧光光谱法测定水样中痕量铅

提出了氢化物发生-原子荧光光谱法测定水中痕量铅的方法。以双硫腙为络合剂,在pH 8.0的硼砂溶液中,用非离子表面活性剂Triton X-114浊点萃取样品溶液中痕量铅。选用15.0 g·L~(-1)硼氢化钾溶液作为产生氢化铅的还原剂,氢化物发生反应在盐酸(1+99)介质中进行,铅的质量浓度在0.05～3.2μg·L~(-1)范围内与其相应的荧光强度呈线性关系。方法的检出限(3S/N)为0.016μg·L~(-1)。应用此方法测定了水中铅的含量,测得回收率在96.5%～104.6%之间,相对标准偏差(n=6)均小于5%。     

Selective Determination of Copper in Water Samples by Atomic Absorption Spectrometry after Cloud Point Extraction

A preconcentration methodology utilizing the cloud point phenomenon is described for the determination of copper by flame atomic absorption spectrometry. The reagent Sulfathiazolylazo resorsin was used as a complexing agent. The preconcentration factor of 25-fold was obtained. The calibration curve is linear in the range of 4–400 µ g L^?1 with a limit of detection of 0.64 µ g L^?1. The relative standard deviation (n = 5, 12 µ g L^?1) was 3.5%. The cloud point is formed in the presence of phenol at room temperature. The method was successfully applied to the determination of copper in water samples and a standard reference material.     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的镉

建立了浊点萃取分离富集石墨炉原子吸收光谱法测定环境样品中痕量镉的方法.浊点萃取选择8-羟基喹啉为螯合剂,Triton X-100为表面活性剂.在pH 8～9、0.01%8-羟基喹啉和0.2%-Triton X-100、80 ℃水浴20 min的优化条件下,所建立方法的检出限为2.5 ng/L; 加标回收率为94.6%～106.2%; 对样品溶液进行富集的富集因子为17.利用该方法分别测定了2个实际水样和2个国家标准参考物质中的总镉含量,结果令人满意.