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Yong-Hyun Kim Ki-Hyun Kim Jan E. Szulejko Min-Suk Bae Richard J.C. Brown 《Analytica chimica acta》2014
For the quantitative analysis of ‘compounds lacking authentic standards or surrogates’ (CLASS) in environmental media, we previously introduced an effective carbon number (ECN) approach to develop an empirical equation for the prediction of their response factor (RF). In this research, a series of laboratory experiments were carried out to benchmark the reliability of an ECN approach for sorbent tube/thermal desorption/gas chromatography (GC)/mass spectrometry (MS) applications. First, the ECN values were determined using external calibration data from 25 reference volatile organic compounds (VOCs) using two MS dectectors (quadrupole (Q) and time-of-flight (TOF)). Then, a certified standard mixture of 54 VOCs was analyzed by each system as a simulated unknown sample. The analytical bias, assessed in terms of percentage difference (PD) between the certified and ECN-predicted mass values, averaged 19.2 ± 16.1% (TOF-MS) and 28.2 ± 27.6% (Q-MS). The bias using a more simplified carbon number (CN)-based prediction increased considerably, yielding 53.4 ± 53.3% (TOF-MS) and 61.7 ± 81.3% (Q-MS). However, the bias obtained using the ECN-based prediction decreased significantly to yield average PD values of 9.84 ± 7.28% (TOF-MS) and 16.8 ± 8.35% (Q-MS), if the comparison was limited to 26 (out of 54) VOCs with CN ≥ 4 (i.e., 25 aromatics and hexachlorobutadiene). 相似文献
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合成方法对MCM-22分子筛的结构、性质及催化性能的影响 总被引:5,自引:0,他引:5
在水热条件下分别以动态法和静态法合成了高纯度和高结晶度的MCM-22分子筛.采用N2吸附、XRD、TEM和FTIR等方法研究了制备方法对分子筛的结构及性质的影响.结果表明,动态法合成的MCM-22比静态法合成的分子筛的晶粒小,酸量低.在丙酮一步法合成甲基异丁基酮反应中,静态条件下合成的MCM-22为载体的催化剂的丙酮转化率较高,这是由于该分子筛的酸量较高所致.而MIBK的选择性则呈相反趋势,这可能与动态条件下合成的分子筛粒径小、孔道短有关. 相似文献
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萃取分离ICP-AES法测定高纯金中的杂质元素 总被引:11,自引:0,他引:11
通过用有机溶剂甲基异丁基酮(MIBK)在10%的盐酸溶液中萃取高纯金(99.99%)中的基体元素,使得大量的金得以分离,消除了基体的存在对杂质元素测定的干扰,使微量的杂质元素的测定成为可能,进而用等离子体发射光谱仪测定了高纯金中Cd,Cr,Cu,Fe,Mn,Ni,Pb,Pt等元素的含量。 相似文献
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为了给以甲基异丁基酮为溶剂含环己酮废水萃取过程的设计和流程模拟计算提供数据支撑,本文测定了常压下,水+环己酮+甲基异丁基酮(MIBK)三元体系在303.15、313.15及323.15 K的液液相平衡数据。据相平衡数据计算了分配系数和分离因子,所有的分离因子均远大于1,表明MIBK从水中萃取环己酮是可行的;Hand方程和Bachman方程的相关系数在0.99以上,表明实验数据具有较好的一致可靠性。同时,采用NRTL和UNIQUAC活度状态方程对实验数据进行了关联,回归得到了该三元物系的二元交互参数,结果表明两种模型均能很好关联实验数据,实验值和模拟值的相对均方根差(RMSD)低于0.5%。 相似文献
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Combining Ammonium Pyrrolidine Dithiocarbamate/methyl Isobutyl Ketone Microextraction in an Inexpensive Disposable Pipette with Laser Ablation Inductively Coupled Plasma Mass Spectrometry for the Determination of Cd and Pd 下载免费PDF全文
This paper describes a new analytical method, using a combination of ammonium pyrrolidine dithiocarbamate/methyl isobutyl ketone (APDC‐MIBK) microextraction and laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS), for the determination of the concentrations of Cd and Pb in aqueous samples. Only 200 μL of organic solvent was used throughout the entire analysis process, with enhancement factors as high as 25. Recoveries from replicate analyses of natural water [NIST 1640(a)] containing mean concentrations of 3.1 μg Cd L?1 and 9.3 μg Pb L?1 were 95 ± 3 and 104 ± 4%, respectively. The corresponding detection limits were 0.6 μg L ?1 for Cd and 0.9 μg L ?1 for Pb. The main advantage of this approach is its simplicity in terms of sample preparation, as demonstrated by quantifying the levels of Cd and Pd in real samples, including tap water, groundwater, and seawater, using a standard addition method. 相似文献
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《Analytical letters》2012,45(11):2157-2163
Abstract Inductively coupled plasma/mass spectrometer (ICP/MS) has been used for the determination of lead and nickel in different Saudi Arabian crude oils. MIBK-nitric acid extraction system is used for sample pretreatment and compared to previously investigated sampling techniques. 相似文献
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A long path atomic absorption cell has been modified to achieve high sensitvity in the determination of lead after MIBK extraction. This was achieved by using thermal insulation of the absorption cell and positioning the burner at an optimum angle. Insertion of rings inside the cell and oxygen supply line reduced the background noise to a low level while producing high sensitivities. This resulted in a marked improvement in detection limits for some metals in aqueous solution. 相似文献
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S. A. Popova L. Bezur L. Pólos E. Pungor 《Fresenius' Journal of Analytical Chemistry》1974,270(3):180-183
Summary Gallium can satisfactorily be determined by atomic absorption in organic solvents using air-acetylene or nitrous oxide-acetylene flame. It is recommandable to extract it as chloride complex. By employing MIBK and nitrous oxide-acetylene flame a considerable increase of absorption signal and sensitivity and elimination of the interference effect of a large number of metal ions was achieved.
Bestimmung von Gallium durch Extraktion und Atomabsorptionsmessung
Zusammenfassung Mit Hilfe der Luft/Acetylen- oder N2O/Acetylen-Flamme kann Ga aus organischen Lösungsmitteln mit guten Ergebnissen bestimmt werden. Zu bevorzugen ist die Extraktion als Chloridkomplex, Extraktion mit MIBK und Verwendung der N2O-Acetylen-Flamme. So kann eine wesentliche Zunahme des Absorptionssignals, eine Verbesserung der Empfindlichkeit und Ausschaltung des störenden Einflusses zahlreicher Fremdionen bewirkt werden.相似文献
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Mohapatra PK Ansari SA Sarkar A Bhattacharyya A Manchanda VK 《Analytica chimica acta》2006,571(2):308-314
Extraction of Cs-137 from nitric acid was carried out using nitrobenzene solutions of calix-crowns such as calix[4]arene-bis(crown-6) (CC-A), calix[4]arene-bis(benzo crown-6) (CC-B) and calix[4]arene-bis(napthocrown-6) (CC-C). CC-C was found to be superior extractant for Cs(I) as compared to the other two calix-crown ligands used in the present study. The effect of diluent on the extraction of Cs(I) indicated the trend: nitrobenzene>dichloroethane>chloroform>decanol>carbon tetrachloride approximately n-hexane approximately toluene. Subsequently, the studies were carried out with nitrobenzene solutions of the calix-crown ligands (mainly CC-C) on the effects of (a) aqueous phase acidity, (b) ligand concentration, and (c) cesium concentration on Cs extraction from nitric acid media. Conditions for quantitative extraction and stripping were optimized and the extracted species conformed to {[CsL]+.[NO3]-.nH2O}. Selectivity studies were carried out using an irradiated natural U target involving tracer amount of fission products activities. Extraction of Cs(I) from a synthetic high level waste solution was also carried out. The promising results obtained in the present studies indicate possible use of the calix-crown ligand for Cs(I) recovery from the acidic high level waste. 相似文献