• Title, Summary, Keyword: hydride generation method

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Ultra-trace Arsenic Determination in Urine and Whole Blood Samples by Flow Injection-Hydride Generation Atomic Absorption Spectrometry after Preconcentration and Speciation Based on Dispersive Liquid-Liquid Microextraction

  • Shirkhanloo, Hamid;Rouhollahi, Ahmad;Mousavi, Hassan Zavvar
    • Bulletin of the Korean Chemical Society
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    • v.32 no.11
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    • pp.3923-3927
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    • 2011
  • A noble method for pre-concentration and speciation of ultra trace As (III) and As (V) in urine and whole blood samples based on dispersive liquid-liquid microextraction (DLLME) has been developed. In this method, As (III) was complexed with ammonium pyrrolidine dithiocarbamate at pH = 4 and Then, As (III) was extracted into the ionic liquid (IL). Finally, As (III) was back-extracted from the IL with hydrochloric acid (HCl) and its concentration was determined by flow injection coupled with hydride generation atomic absorption spectrometry (FI-HGAAS). Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution and then, As (V) was calculated by the subtracting the total arsenic and As (III) content. Under the optimum conditions, for 5-15 mL of blood and urine samples, the detection limit ($3{\sigma}$) and linear range were achieved 5 ng $L^{-1}$ and 0.02-10 ${\mu}g\;L^{-1}$, respectively. The method was applied successfully to the speciation and determination of As (III) and As (V) in biological samples of multiple sclerosis patients with suitable precision results (RSD < 5%). Validation of the methodology was performed by the standard reference material (CRM).

Determination of Selenium in Milk by ICP-OES (ICP-OES를 이용한 우유의 Selenium 분석)

  • 김효중;박종길;신정걸;백영진
    • Food Science of Animal Resources
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    • v.23 no.4
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    • pp.356-360
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    • 2003
  • The purpose of this paper was to determine the quantity of selenium in milk by inductively coupled plasma optical emission spectrometry. The sample was digested in teflon vessel containing nitric-hydrogen peroxide acid mixture. After digestion, the sample is treated with additional hydrochloric acid. Total selenium was reduced with sodium borohydride and concentrated hydrochloric acid in a simplified hydride generation(HG) manifold. The optimum conditions of HG are 2 M for HCl, 1.5% for NaBH$_4$, 1.2 mL/mim for sample flow. Recovery rates by the standard addition method were 88.0% at 10 ppb and 92.2% at 10 ppm. The relative standard deviations were 4.8 and 3.2%, respectively. This method showed a good accuracy and precision. And so it was highly suitable for determination of small quantity of selenium in milk.

Determination of Selenium in Foods by HG-AAS (HG-AAS에 의한 식품 중의 셀렌의 정량에 대한 연구)

  • Ki-Won Cha;Sang-Ho Park;Jae-Sung Choi
    • Journal of the Korean Chemical Society
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    • v.38 no.12
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    • pp.891-897
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    • 1994
  • A method has been investigated for the determination of Selenium in Ginseng radix, Ganoderma Lucidum and Garlic using hydride generation atomic absorption spectrometry (HG-AAS). The effects of several acids and sodium tetrahydroborate concentration and their flow rate on the determination of Selenium for the hydride generation were investigated. The method of sample decomposition was also investigated using various mineral acids, such as nitric, perchloric and sulfuric acid in the closed system and foreign ion effects were studied. In the optimum conditions, we obtained calibration curve in the range 0-40 ppb. The analytical data of Garlic, Ganoderma Lucidum and Ginseng radix are 289, 296, 198 ppb, respectively.

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Separation and Sensitive Determination of Sb Species using Yeast Bonded Bio-column with Continuous Hydride Generation (이이스트 고정 bio칼럼을 이용한 Sb의 화학종분리 및 연속적 수소화물발생법에 의한 감도개선)

  • Lee, Jeong-Ok;Kwon, Hyo-Shik;Pak, Yong-Nam
    • Journal of the Korean Chemical Society
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    • v.54 no.6
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    • pp.696-700
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    • 2010
  • Yeast is immobilized upon $100{\mu}m$ CPG(controlled pore glass bead) to separate $Sb^{3+}$ and $Sb^{5+}$. Continuous hydride generation is performed after the bio-column. The optimum conditions are 0.8 M nitric acid as an eluent with the flow rate of 1.0 mL $min^{-1}$ and the optimum conditions for the generation of hydride are 2 M HCl, 3% (w/v) $NaBH_4$ with the flow rate of 0.83 mL $min^{-1}$, Ar carrier gas flow rate of 50 mL $min^{-1}$. Two species are separated at 112 and 354 seconds each. The sensitivity is enhanced by 10 times for $200{\mu}L$ of sample and the detection limits are 3.0 ppb and 7.0 ppb for $Sb^{3+}$ and $Sb^{5+}$, respectively. When compared with the standard samples, this method showed accurate results.

Comparisons of Urinary Arsenic Analysis by Pre-reductant for Preconditioning via the FI-HG-AAS Method (FI-HG-AAS를 이용한 전처리 과정에서 사용되는 예비환원제의 종류에 따른 요중 비소 분석결과 비교)

  • Choi, Seung-Hyun;Choi, Jae Wook;Cho, YongMin;Bae, Munjoo
    • Journal of Environmental Health Sciences
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    • v.41 no.5
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    • pp.289-298
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    • 2015
  • Objectives: The method of analyzing urinary arsenic by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) is generally used because it shows relatively greater sensitivity, low detection limits, low blocking action, and is simple to operate. In this study, the results of analysis according to three pre-reductants commonly used in the FI-HG-AAS method were compared with each other. Methods: To analyze urinary arsenic, nineteen urine samples were collected from adults aged 43-79 years old without occupational arsenic exposure. Analysis equipment was FI-HG-AAS (AAnalyst 800/FIAS 400, Perkin- Elmer Inc., USA). The three pre-reductants were potassium iodide (KI/AA), C3H7NO2S (L-cysteine), and a mixture of KI/AA and L-cysteine (KI/AA&L-cysteine). Results: In the results of the analysis, the recovery rate of the method using KI/AA was 82.3%, 95.7% for Lcysteine, and 123.5% for KI/AA and L-cysteine combined. When compared with the results by use of high performance liquid chromatography inductively-coupled plasma mass spectrometry (HPLC-ICP-MS), the method using L-cysteine was the closest to those using HPLC-ICP-MS ($98.57{\mu}g/L$ for HPLC-ICP-MS; $74.96{\mu}g/L$ for L-cysteine; $69.23{\mu}g/L$ for KI/AA and L-cysteine; $13.06{\mu}g/L$ for KI/AA) and were significantly correlated (R2=0.882). In addition, they showed the lowest coefficient of variation in the results between two laboratories that applied the same method. Conclusion: The efficiency of hydride generation is considered highly important to the analysis of urinary arsenic via FI-HG-AAS. This study suggests that using L-cysteine as a pre-reductant may be suitable and the most rational among the FI-Hg-AAS methods using pre-reductants.

Semi-Automatic Hydride Generation and Atomic Absorption Determination of Bismuth with in situ Concentration in a Graphite Furnace

  • Yong-Keun Lee;Dong Soo Lee;Byung Mok Yoon;Hoon Hwang
    • Bulletin of the Korean Chemical Society
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    • v.12 no.3
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    • pp.290-295
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    • 1991
  • A semi-automatic method for the determination of dissolved bismuth at parts per trillion levels is described. The method involves bismuthine generation, in situ collection of bismuthine in a graphite furnace, and atomic absorption detection. In order to facilitate semi-automation of bismuthine generation and separation from aqueous solution, Gore-tex microporous PTEE membrane is used. The absolute detection limit, taken as three times the standard deviation of the instrument noise is 2 pg. The precisions are 3.1% for 100 pg and 1.9% for 1 ng of bismuth, respectively. As many as 90 measurements can be made in an hour.

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Determination of trace arsenic in seawater by flow injection-hydride generation inductively coupled plasma mass spectrometry (연속흐름주입-수소화물생성-유도결합플라스마 질량분석장치를 이용한 바닷물표준시료중의 극미량 비소분석방법의 확립)

  • Suh, Jung-Ki
    • Analytical Science and Technology
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    • v.21 no.4
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    • pp.316-325
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    • 2008
  • An inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with flow injection-hydride generation system was used for the determination of trace arsenic in seawater sample. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of seawater (CASS-4, NASS-5). The analytical results agreed with certified value within the range of uncertainty. The expanded uncertainties for CASS-4 and NASS-5 in this experiment were ranged from 6.2% to 6.8% obtained from repeated analyses of the CRMs (n=5). The detection limit of $As^+$ (m/z=74.9216) in this method was confirmed about 0.01 ug/kg. Linearity obtained from calibration curve of arsenic was excellent ($R^2=1$). The detection at $As^+$ (m/z=74.9216) and $AsO^+$ (m/z=90.9165) by using oxygen reaction gas in DRC mode was compared. Sensitivity at $AsO^+$ (m/z=90.9165) was decreased about 25-fold, but the analytical results are the same that at $As^+$ (m/z=74.9216).

Thermal Management of a Nickel/Metal Hydride Battery (Nickel/Metal Hydride 전지의 열관리기술 개발)

  • Kim, Junbom
    • Applied Chemistry for Engineering
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    • v.8 no.4
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    • pp.667-672
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    • 1997
  • Thermal behavior of high capacity Nickel/Metal hybride battery in analyzed using the NISA software which is based on the three dimensional finite element method. Differential energy balance equation is used for the conduction heat transfer of the battery, while convective heat transfer equation is used for the interface between the battery and air. Heat generation rate and convective heat transfer coefficient are tested as variables to investigate thermal behavior, and the generalized equation for maximum temperature inside the battery is developed. The abrupt rise of the battery temperature due to the quick charge or discharge can be prevented from the use of metallic cooling fin. In addition, temperature augmentation of the battery is negligible when the low thermal conductive and thin insulating material is used outside of the battery case.

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Direct Determination of Tellurium in Simulated Nuclear Spent Fuels by Hydride Generation-Inductively Coupled Plasma Atomic Emission Spectrometry (수소화물 생성-유도결합플라스마 원자방출분광법을 이용한 모의사용후 핵연료 중의 텔루르 분석)

  • Choi, Kwang Soon;Lee, Chang Heon;Han, Sun Ho;Joe, Kih Soo;Kim, Won Ho
    • Analytical Science and Technology
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    • v.13 no.6
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    • pp.781-788
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    • 2000
  • Tellurium in simulated nuclear spent fuels (SIMFUEL) has been determined by hydride generation-inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). Parameters such as concentrations of HCl and $NaBH_4$, flow rate of HCl and $NaBH_4$ were optimized and then the effects of U, Mo, Pd, Rh and Ru on the Te intensity were investigated. A thiourea as a masking agent was used to eliminate or minimize such interferences specially caused by palladium. Tellurium was measured by HG-ICP-AES and ICP-MS after separation of tellurium from SIMFUEL with cation exchange chromatography. The relative deviation between direct measurement and separation method was less than 6% based on the data by ICP-MS.

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Studies on Determination of trace amount of Se in Volcanic Rocks by Atomic Absorption Spectrophotometry (원자 흡수 분광광도법에 의한 화산암중 극미량의 Se정량에 관한 연구)

  • Kim, Chan-Kook;Sung, Hak-Je;Chung, Kang-Sup;Yamaya, Kazuhisa
    • Analytical Science and Technology
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    • v.12 no.6
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    • pp.484-489
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    • 1999
  • The extraction of trace amounts of Se in volcanic rock was investigated using the hydride generation method and atomic absorption spectrophotometry. The powdered rock, 1.0 g, was decomposed with the mixture of $HClO_4$, $HNO_3$ and HF in an acid digestion bomb at $140^{\circ}C$ for 2 hours. For the reduction of Se(VI) to Se(IV) in the solution, 10 mL of 6 M HCl and 0.2 mL of 1 M KBr were added to the solution and the mixture was heated for 30~45 minutes. $H_2Se$ was produced by adding 3% $NaBH_4$ as a strong reducing agent, extracted by nitrogen gas, and was absorbed twice into $KMnO_4$solution. The contents of Se in the solution were determined by generation/AAS. According to the proposed method, 1.0 ng or more of Se was quantitatively extracted and Se levels of 2.5 ng/g or more in rock samples could be determined. For example, Se in a rhyolite was determined with the precision of $19.5{\pm}1.3ng/g$(95% confidence, n=6).

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