浊点萃取-石墨炉原子吸收光谱法对不锈钢餐具溶出铬的形态分析

采用浊点萃取一石墨炉原子吸收光谱法分离和测定不锈钢餐具中的溶出铬.利用六价铬和吡咯烷二 硫代氨基甲酸铵(APDC)间发生选择性络合被萃取到表面活性剂相中,而三价态的铬离子留在水相中,探讨了影响浊点萃取的主要凶素:如pH值、APDC试剂的浓度、Triton X-114的浓度、反应温度和时间.在优化的实验条件下,检出限为0.012μg/L,富集倍数为20倍.     

浊点萃取电热原子吸收光谱法测定水中痕量铊

采用吡咯烷基二硫代氨基甲酸铵(APDC)为螯合剂,Triton X-114作为表面活性剂,建立了浊点萃取预富集电热原子吸收光谱法测定水中痕量铊的方法。在优化的实验条件下,方法的检出限可达0.07μg/L,相对标准偏差为3.6%(4μg/L,n=7),加标回收率为93%~106%,富集倍率为31。该方法成功应用于自来水和河水中痕量铊的测定。     

浊点萃取-石英双缝管捕集火焰原子吸收光谱法分析铬价态

在不同pH值的缓冲溶液中,亚硝基苯胲铵盐(铜铁试剂)可与Cr(Ⅵ)及Cr(Ⅲ)络合生成中性疏水络合物,以Triton X-114为萃取剂,浊点萃取分离富集Cr(Ⅵ)及总铬,石英双缝管原子捕集-火焰原子吸收光谱法(STAT-FAAS)测定铬价态.实验对浊点萃取时溶液的pH值、铜铁试剂和Triton X-114的用量、离心分离时间、平衡温度和时间等影响因素进行了研究.结果表明,分别在pH=3.0和6.0的溶液中,40 ℃恒温加热15 min后,离心5 min,Triton X-114浊点萃取Cr(Ⅵ)及总铬的富集倍数达到50倍(100 mL起初样品溶液/2 mL最终测定液).和普通火焰原子吸收光谱法(FAAS)相比,利用石英双缝管原子捕集技术,STAT-FAAS法测定铬的灵敏度提高了近5倍.本方法测定Cr(Ⅵ)及总铬的线性范围分别为0.005～0.5 mg/L和0.01～1.2 mg/L;检出限分别为0.66 μg/L和0.81μg/L.     

浊点萃取-石墨炉原子吸收光谱法测定痕量钯

建立了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量金属钯的新方法,利用表面活性剂Triton X-114和络合剂2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)对钯进行浊点萃取。研究了溶液pH、试剂浓度、平衡温度和加热时间等因素对浊点萃取及测定灵敏度的影响。优化条件为:pH 5.50 HAc-NaAc缓冲,0.08 mL 5×10-4 mol/L 5-Br-PADMA,0.70 mL10g/L Triton X-114。在最佳条件下,方法的线性范围为0.1～10 ng/mL,钯的检出限为0.068 ng/mL,富集倍率为45倍。该方法可用于环境样品中痕量钯的富集和测定,结果令人满意。     

非螯合物浊点萃取-石墨炉原子吸收法测定水中痕量铊(Ⅲ)

建立不需形成螯合物的浊点萃取-石墨炉原子吸收法测定水中铊Ⅲ的新方法。用浊点萃取技术富集水中铊Ⅲ,石墨炉原子吸收法测定。经考察,浊点萃取环境水体中铊Ⅲ的最优条件为pH12,90℃水浴2h,Triton X-114浓度2.0g/L;在优化后实验条件下,方法测定铊Ⅲ的检出限为0.018μg/L;相对标准偏差为8.89%~13.7%(C=0.1μg/L及1.0μg/L,n=7);加标回收率为98.0%~101%。本法适于水中痕量铊Ⅲ的测定。     

浊点萃取-高效液相色谱法测定铜、钴

讨论了以5-Br-PADAP为衍生试剂,用Triton X-114非离子表面活性剂浊点萃取富集铜（Ⅱ）、钴（Ⅱ）的条件,并于ODS柱上,用内含2．0mmol·L^-1十六烷基三甲基溴化铵（CTMAB）和5mmol·L^-1 pH5．0 HAc—NaAc缓冲溶液的V（甲醇）＋V（乙腈）＋V（水）=67＋8＋25混合液作流动相．检测波长为568nm,流量为0．8mL·min^-1。,发展了浊点萃取-高效液相色谱法测定铜、钴的新方法。在选定条件下,大多数离子不干扰测定,方法灵敏度高,经浊点萃取后可提高测定响应值7—8倍,对铜、钴的检测限分别为0．5μg·L^-1,0．8μg·L^-1。方法可用于水样中钴（Ⅱ）、铜（Ⅱ）的测定,结果令人满意。     

浊点萃取-火焰原子吸收光谱法测定食品和饮料中的痕量铜

研究了基于非离子表面活性剂TritonX-114和螯合剂二乙基氨基二硫代甲酸钠(DDTC)的浊点萃取-火焰原子吸收光谱法测定痕量铜的分析方法.考察了影响浊点萃取效率的参数,包括pH值、DDTC浓度、TritonX-114用量、平衡温度及时间等.在优化条件下,本法的检出限(3σ)为1.55μg/L,相对标准偏差RSD为3.4%(n=7,c=100μg/L),线性范围为0～250μg/L.将该法应用于茶叶标准样品(GBW07605)、奶粉和矿泉水等样品中痕量铜的测定,其回收率在96.7%～113.5%之间.     

浊点萃取-原子荧光光谱法测定水产品中砷形态

建立了浊点萃取-原子荧光光谱法测定水产品中砷形态的新方法。在p H 4.6,As(III)可与吡咯啶二硫代氨基甲酸铵(APDC)生成疏水性络合物,通过水浴加热,络合物被萃取到Triton X-114表面活性剂相。测定前,表面活性剂相加入0.4 m L Antifoam 204溶液,并用5%(V/V)HCl溶液定容至3 m L。在优化的实验条件下,As(III)在0.2~4.0μg/L范围内与荧光强度有良好的线性关系,方法检出限为0.009μg/L,RSD为3.4%,对于50 m L样品溶液的富集倍数为9.3。方法成功应用于水产品中砷形态分析,加标回收率为95.8%~104.3%。     

人血白蛋白制品中超痕量铝的测定

建立了浊点萃取石墨炉原子吸收光谱法测定人血白蛋白样品中超痕量铝的新方法。探讨了溶液酸度、络合剂的种类及浓度、非离子表面活性剂的浓度、平衡时间及温度等因素对浊点萃取过程的影响。以1-(2-吡啶偶氮)-2-萘酚为络合剂,Triton X-114为非离子表面活性剂,浊点萃取分离富集10mL样品溶液,Al(Ⅲ)的富集倍数为34.8,在最佳工作条件下,铝的检出限为0.06μg/L;样品测定的相对标准偏差(n=7)为3.6%,加标回收率95.6%~98.4%。方法适合人血白蛋白样品中超痕量铝的分析测定。     

双浊点萃取-毛细管电泳法测定天然水中酚类化合物的研究

建立了双浊点萃取(dCPE)-毛细管电泳(CE)法测定天然水中酚类化合物的新方法。以Triton X-114为萃取剂,NaOH为反萃取剂,对苯酚、2,4,6-三氯苯酚和邻硝基苯酚进行双浊点萃取。考察了pH值、萃取剂浓度、平衡温度及时间和离子强度等因素对萃取率的影响。dCPE方法的优化条件为:pH=2.0、Triton X-114的浓度为0.14%(m/V)、平衡温度为40℃、平衡时间为10min、NaCl浓度为4.0%(m/V);电泳条件为:10mmol/L硼砂-磷酸钠缓冲溶液(pH=9.8)、电压18kV、检测波长210nm。在最优的条件下,苯酚、2,4,6-三氯苯酚、邻硝基苯酚的检出限(S/N=3)分别为0.10、0.15和0.18μg/mL;富集因子分别为24.0、19.3和20.1;相对标准偏差(RSD)分别为3.9%、2.6%和3.3%(c=2.0μg/mL,n=3)。     

Cloud point extraction–thermospray flame quartz furnace atomic absorption spectrometry for determination of ultratrace cadmium in water and urine

A simple, low cost and highly sensitive method based on cloud point extraction (CPE) for separation/preconcentration and thermospray flame quartz furnace atomic absorption spectrometry was proposed for the determination of ultratrace cadmium in water and urine samples. The analytical procedure involved the formation of analyte-entrapped surfactant micelles by mixing the analyte solution with an ammonium pyrrolidinedithiocarbamate (APDC) solution and a Triton X-114 solution. When the temperature of the system was higher than the cloud point of Triton X-114, the complex of cadmium-PDC entered the surfactant-rich phase and thus separation of the analyte from the matrix was achieved. Under optimal chemical and instrumental conditions, the limit of detection was 0.04 μg/L for cadmium with a sample volume of 10 mL. The analytical results of cadmium in water and urine samples agreed well with those by ICP-MS.     

Determination of arsenic in scalp hair samples from exposed subjects using microwave-assisted digestion with and without enrichment based on cloud point extraction by electrothermal atomic absorption spectrometry

A simple and rapid cloud point extraction (CPE) procedure was applied for preconcentration of trace quantities of arsenic (As) in scalp hair samples. The samples were subjected to microwave-assisted digestion in a mixture of nitric acid and hydrogen peroxide (2 + 1, v/v) prior to preconcentration by CPE. The As in digested samples was complexed with ammonium pyrrolidine dithiocarbamate (APDC), and the resultant As-PDC complex was extracted by a nonionic surfactant, octylphenoxypolyethoxyethanol (Triton X-114). After centrifugation, the surfactant-rich phase was diluted with 0.1 M HNO3 in methanol and analyzed by electrothermal atomic absorption spectrometry. The experimental parameters, i.e., amount of APDC, concentration of Triton X-114, equilibrium temperature and time, were optimized. For validation of the proposed method, a certified reference material (CRM) of human hair (BCR 397) was used. No significant difference (P > 0.05) was observed between the experimental results and certified values of the CRM (paired t-test). The LOD and LOQ obtained under the optimal conditions were 0.025 and 0.083 microg/kg, respectively. The developed method was applied for the determination of As in scalp hair samples from male and female subjects of two villages of Khairpur Mir's, Pakistan.     

Cloud point extraction of trace metals from seawater and determination by electrothermal atomic absorption spectrometry with iridium permanent modifier.

A simple method is described for preconcentration and separation of trace metals such as Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb simultaneously from seawater using a cloud point extraction (CPE) procedure. Triton X-114 nonionic surfactant and ammonium pyrrolidine dithiocarbamate (APDC) have been used as an extraction medium and a chelating extractant, respectively. The amounts of Triton X-114 and APDC and the pH value necessary for extraction were carefully optimized. The preconcentration factor of about 200 is achieved for all the studied metals. Electrothermal atomic absorption spectrometry (ETAAS) with an Ir coated graphite tube as permanent chemical modifier has been used for determination. The limits of detection of Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb were 0.003, 0.008, 0.003, 0.006, 0.015, 0.002, 0.009 and 0.01 ng ml-1, respectively. Certified reference materials such as CASS-4 and NASS-5 (seawater) and NIST-1640 (natural water) have been used for validation of the new method. The relative standard deviation (%) obtained for all the metals are in the range 0.8 - 3.6% for natural water and 11-25% for seawater materials, except for Co in NASS-5 for which it was 50%.     

Flame atomic absorption spectrometric determination of trace amounts of palladium,gold and nickel after cloud point extraction

In this article, a sensitive cloud point extraction procedure for the preconcentration of trace amounts of palladium, gold and nickel prior to their determination by flame atomic absorption spectrometry has been developed. The cloud point extraction method is based on the complexation of Pd(II), Au(II), and Ni(II) ions with 1-(2-pyridylazo)-2-naphthol and entrapping in non-ionic surfactant Triton X-114. The main factors affecting cloud point extraction efficiency, such as pH of sample solution, concentration of 1-(2-pyridylazo)-2-naphthol and Triton X-114, equilibration temperature and time, were investigated in detail. Under the optimized conditions, calibration curves were constructed for the determination of palladium, gold and nickel according to the general procedure. Linearity was maintained from 0.01 to 1.0 μg/mL for palladium, 10.0 μg/mL to 1.5 μg/mL for gold, and 10.0 μg/mL to 0.5 μg/mL for nickel. Detection limits based on three times the standard deviation of the blank divided by the slope of analytical curve (3Sb/m) for Pd(II), Au(III), and Ni(11) ions were 3.4, 3.9, and 2.4 μg/mL, respectively. Seven replicate determination of a mixture of 0.5 μg/mL palladium and gold and 0.2 μg/mL nickel gave a mean absorbance of 0.174, 0.150, and 0.201 with relative standard deviation ±1.5, ±1.3, and ±1.8%, respectively. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method has been applied for determination of trace amount of palladium, gold and nickel in certified reference material and water samples with satisfactory results.     

Design of rapidly synergistic cloud point extraction of ultra-trace lead combined with flame atomic absorption spectrometry determination

In this work, traditional cloud point extraction (CPE) pattern was changed and improved by the proposed rapidly synergistic CPE. Using octanol as cloud point revulsant and synergic reagent, non-ionic surfactant Triton X-114 (TX-114) accomplished room temperature extraction rapidly without heating in water bath. The improved extraction was named as rapidly synergistic cloud point extraction (RS-CPE). Compared with traditional CPE, RS-CPE was accomplished in 1 min with considerably high extraction efficiency. The improved CPE pattern was coupled with flame atomic absorption spectrometry (FAAS) for the extraction and detection of trace lead in real and certified water samples with satisfactory analytical results. The proposed method greatly improved the sensitivity of FAAS for the determination of lead. Under the optimal conditions, the limit of detection (LOD) for lead was 4.3 μg/L, with enhancement factor (EF) of 39. Factors influencing RS-CPE efficiency, such as concentrations of surfactant TX-114 and octanol, concentration of chelating agent, pH, conditions of phase separation, environmental temperature, salt effect and instrumental conditions, were studied systematically.     

Speciation Determination of Chromium(VI) and Chromium(III) in Soil Samples after Cloud Point Extraction

Abstract

To measure the different activity of chromium(VI) and chromium(III) in soil samples, chromium(VI) and total chromium (CrVI + CrIII) was extracted by KCl extracting agent and alkali fusion, respectively. Cloud point extraction (CPE) for speciation determination of chromium with double-slotted quartz tube atom trap–flame atomic absorption spectrometry (STAT-FAAS) was developed. Preconcentration of chromium(VI) and total chromium in different pH solutions was achieved by CPE, with ammonium pyrrolidine dithiocarbamate (APDC) as the chelating agent and Triton X-114 as the cloud point extractant. The conditions of CPE and determination were studied. Under the optimal conditions, the enrichment factor was 50 for chromium from the initial 100-mL sample solution to the final 2-mL determined solution. Compared to the FAAS method, the sensitivity was improved seven-fold for chromium by the STAT-FAAS method. The limit of detection was 0.082 µg/L for chromium.     

浊点萃取-紫外可见分光光度法测定痕量钴

浊点萃取(Cloud-Point Extraction,简称CPE)是近年来出现的一种新兴的液-液萃取技术,该法以表面活性剂胶束水溶液的溶解性和浊点现象为基础,通过改变实验参数如溶液pH值、离子强度、温度等引发相分离,将疏水性物质与亲水性物质分离,同时起到富集的作用.     

Synthesis and application of a new thiazolylazo reagent for cloud point extraction and determination of cobalt in pharmaceutical preparations

The synthesis and characterization of the reagent 2-(5-bromothiazolylazo)-4-chlorophenol and its application in the development of a preconcentration procedure for cobalt determination using flame atomic absorption spectrometry after cloud point extraction is presented. This procedure is based on cobalt complexing and entrapment of the metal chelates into micelles of a surfactant-rich phase of Triton X-114. The preconcentration procedure was optimized by using a response surface methodology through the application of the Box-Behnken matrix. Under optimum conditions, the procedure determined the presence of cobalt with an LOD of 2.8 microg/L and LOQ of 9.3 microg/L. The enrichment factor obtained was 25. The precision was evaluated as the RSD, which was 5.5% for 10 microg/L cobalt and 6.9% for 30 microg/L. The accuracy of the procedure was assessed by comparing the results with those found using inductively coupled plasma-optical emission spectrometry. After validation, the procedure was applied to the determination of cobalt in pharmaceutical preparation samples containing cobalamin (vitamin B12).