WorldWideScience

Sample records for automated potentiometric titrations

  1. Semi-automated potentiometric titration method for uranium characterization.

    Science.gov (United States)

    Cristiano, B F G; Delgado, J U; da Silva, J W S; de Barros, P D; de Araújo, R M S; Lopes, R T

    2012-07-01

    The manual version of the potentiometric titration method has been used for certification and characterization of uranium compounds. In order to reduce the analysis time and the influence of the analyst, a semi-automatic version of the method was developed in the Brazilian Nuclear Energy Commission. The method was applied with traceability assured by using a potassium dichromate primary standard. The combined standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization. PMID:22154105

  2. Semi-automated potentiometric titration method for uranium characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, B.F.G., E-mail: barbara@ird.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Instituto de Radioprotecao e Dosimetria (IRD), Avenida Salvador Allende s/n Recreio dos Bandeirantes, PO Box 37750, Rio de Janeiro, 22780-160 RJ (Brazil); Delgado, J.U.; Silva, J.W.S. da; Barros, P.D. de; Araujo, R.M.S. de [Comissao Nacional de Energia Nuclear (CNEN), Instituto de Radioprotecao e Dosimetria (IRD), Avenida Salvador Allende s/n Recreio dos Bandeirantes, PO Box 37750, Rio de Janeiro, 22780-160 RJ (Brazil); Lopes, R.T. [Programa de Engenharia Nuclear (PEN/COPPE), Universidade Federal do Rio de Janeiro (UFRJ), Ilha do Fundao, PO Box 68509, Rio de Janeiro, 21945-970 RJ (Brazil)

    2012-07-15

    The manual version of the potentiometric titration method has been used for certification and characterization of uranium compounds. In order to reduce the analysis time and the influence of the analyst, a semi-automatic version of the method was developed in the Brazilian Nuclear Energy Commission. The method was applied with traceability assured by using a potassium dichromate primary standard. The combined standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization. - Highlights: Black-Right-Pointing-Pointer We developed a semi-automatic version of potentiometric titration method. Black-Right-Pointing-Pointer The method is used for certification and characterization of uranium compounds. Black-Right-Pointing-Pointer The traceability of the method was assured by a K{sub 2}Cr{sub 2}O{sub 7} primary standard. Black-Right-Pointing-Pointer The results of U{sub 3}O{sub 8} reference material analyzed was consistent with certified value. Black-Right-Pointing-Pointer The uncertainty obtained, near 0.01%, is useful for characterization purposes.

  3. A generalized approach for the calculation and automation of potentiometric titrations Part 1. Acid-Base Titrations

    NARCIS (Netherlands)

    Stur, J.; Bos, M.; Linden, van der W.E.

    1984-01-01

    Fast and accurate calculation procedures for pH and redox potentials are required for optimum control of automatic titrations. The procedure suggested is based on a three-dimensional titration curve V = f(pH, redox potential). All possible interactions between species in the solution, e.g., changes

  4. Titulador potenciométrico automatizado baseado em sistema de fluxo monossegmentado Automated potentiometric titrator based in monosegmented flow system

    Directory of Open Access Journals (Sweden)

    Edgard Moreira Ganzarolli

    1999-02-01

    Full Text Available A new automated system for acid-base flow titrations is proposed. In the operation mode, several sample to titrant volumetric ratios are injected in an air segmented plug. Five three way solenoid valves and three acrilic junctions, assembled in a hidrodynamic injection system, were accountable for the monosegmented reagents plug formation. A turbulent flow reactor was used for a perfect mix of reagents in the plug. The detector system employed a glass combined electrode fitted in an acrilic holder. Titrations of hydrochloric, nitric and acetic acids, in several concentrations, were performed with standard sodium hidroxide, for evaluation of the efficiency of the system. The relative standard deviation of the determinations was about ±0,5% and each titration was carried out in 3-4 minutes. A Quick BASIC 4.5® program was developed for the titrator control.

  5. Determination of total acidity index in bioethanol by automated potentiometric titration; Determinacao do indice de acidez total em bioetanol por titulacao potenciometrica automatizada

    Energy Technology Data Exchange (ETDEWEB)

    Sobral, Sidney Pereira; Ribeiro, Carla de Matos; Fraga, Isabel Cristina Serta; Goncalves, Mary Ane [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (DIMCI/INMETRO), Duque de Caxias, RJ (Brazil). Diretoria de Metrologia Cientifica e Industrial], E-mail: spsobral@inmetro.gov.br

    2009-07-01

    This paper determines the total acidity index of bioethanol by volumetric titration with potentiometric detection. Also, viewing the optimization of the method, studies are exhibited related to the repeatable, besides the comparison with the colorimetric method with the objective to contribute to the certification of bioethanol reference materials.

  6. Implementation and assessment of a computerized potentiometric titration

    International Nuclear Information System (INIS)

    Potentiometric titrations still have a great importance in the work of chemical analysis laboratories of different nature, as well as in the Chemistry programs or related to this discipline. At the same time, such titrations have been frequently criticized as tedious and arduous. At our laboratories, potentiometric titrations are important to determine the performance of several radiochemical separations and as a complement to the nuclear techniques in some analysis. Due to the automatic potentiometric titrations high-cost, some authors have proposed some relatively low-cost alternatives that may be built or implemented in research, services or instruction analytical laboratories. This work describes a controlled system by computer, developed and used at the Chemical Department laboratories of the General Direction of Promotion and Technological Development of IPEN

  7. Natural Monocrystalline Pyrite as Sensor for Potentiometric Redox Titrations. Part I. Titrations with Permanganate

    OpenAIRE

    Vukanovic, B. V.; Mihajlovic, R. P.; Antonijevic, M. M.

    2002-01-01

    Results obtained in potentiometric titrations of Fe(II), Mn(II), Fe(CN)64-, C2O42- and As(III) with standard potassium permanganate solution, are presented. The titration end point (TEP) was detected with a universal electrode whose sensor is natural crystalline pyrite. The titrations of As(III) were carried out in HCl (1.2 M) and H2SO4 solutions (0.1- 4.5 M), whereas oxalate was determined in H2SO4 (0.1-4.5 M). Iron(II) and hexacyanoferrate(II) were titrated in H2SO4 and also in H3PO4 soluti...

  8. Potentiometric titration and equivalent weight of humic acid

    Science.gov (United States)

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    The "acid nature" of humic acid has been controversial for many years. Some investigators claim that humic acid is a true weak acid, while others feel that its behaviour during potentiometric titration can be accounted for by colloidal adsorption of hydrogen ions. The acid character of humic acid has been reinvestigated using newly-derived relationships for the titration of weak acids with strong base. Re-interpreting the potentiometric titration data published by Thiele and Kettner in 1953, it was found that Merck humic acid behaves as a weak polyelectrolytic acid having an equivalent weight of 150, a pKa of 6.8 to 7.0, and a titration exponent of about 4.8. Interdretation of similar data pertaining to the titration of phenol-formaldehyde and pyrogallol-formaldehyde resins, considered to be analogs for humic acid by Thiele and Kettner, leads to the conclusion that it is not possible to differentiate between adsorption and acid-base reaction for these substances. ?? 1960.

  9. Characterization of Native and Modified Starches by Potentiometric Titration

    OpenAIRE

    Diana Soto; Jose Urdaneta; Kelly Pernia

    2014-01-01

    The use of potentiometric titration for the analysis and characterization of native and modified starches is highlighted. The polyelectrolytic behavior of oxidized starches (thermal and thermal-chemical oxidation), a graft copolymer of itaconic acid (IA) onto starch, and starch esters (mono- and diester itaconate) was compared with the behavior of native starch, the homopolymer, and the acid employed as a graft monomer and substituent. Starch esters showed higher percentages of acidity, follo...

  10. Characterization of Native and Modified Starches by Potentiometric Titration

    Directory of Open Access Journals (Sweden)

    Diana Soto

    2014-01-01

    Full Text Available The use of potentiometric titration for the analysis and characterization of native and modified starches is highlighted. The polyelectrolytic behavior of oxidized starches (thermal and thermal-chemical oxidation, a graft copolymer of itaconic acid (IA onto starch, and starch esters (mono- and diester itaconate was compared with the behavior of native starch, the homopolymer, and the acid employed as a graft monomer and substituent. Starch esters showed higher percentages of acidity, followed by graft copolymer of itaconic acid and finally oxidized starches. Analytical techniques and synthesis of modified starches were also described.

  11. Implementation of the automated potentiometric titration method for total U at the CNEN Safeguard Laboratory, Brazil; Implementacao do metodo de titulacao potenciometrica automatizado para U total no Laboratorio de Salvaguardas da CNEN, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, Barbara F.G.; Delgado, Jose U.; Araujo, Radier M.S. de; Silva, Jose W.S. da; Barros, Pedro D. de, E-mail: barbara@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Brazilian nuclear facilities, in accordance with the regulation CNEN-NN-2.02, must have available measurement systems which allow to determine their nuclear material inventories. For the evaluation and the follow up the performance of the involved laboratories in those measurement systems, the accomplishment of interlaboratory comparison programmes becomes fundamental. Therefore, the implementation of the potentiometric titration viewing the characterization of uranium samples, represents an reference element for the Brazilian programs

  12. Natural Monocrystalline Pyrite as Sensor for Potentiometric Redox Titrations. Part I. Titrations with Permanganate

    Directory of Open Access Journals (Sweden)

    B. V. Vukanovic

    2002-04-01

    Full Text Available Results obtained in potentiometric titrations of Fe(II, Mn(II, Fe(CN64-, C2O42- and As(III with standard potassium permanganate solution, are presented. The titration end point (TEP was detected with a universal electrode whose sensor is natural crystalline pyrite. The titrations of As(III were carried out in HCl (1.2 M and H2SO4 solutions (0.1- 4.5 M, whereas oxalate was determined in H2SO4 (0.1-4.5 M. Iron(II and hexacyanoferrate(II were titrated in H2SO4 and also in H3PO4 solutions (0.1-4.5 M. The titrations of Mn(II were performed in H2P2O72- media at pH 4.0, 5.0, 6.0 and 7.0. The results obtained by using the pyrite electrode were compared with those obtained by the application of a Pt-electrode, and good agreement, reproducibility and accuracy were obtained. The potentials in the course of the titration and at the end-point (TEP are rapidly established. The potential changes at the TEP ranged from 90 to 330 mV/0.1 mL, depending on the titrated system. The highest changes were observed in titrations of Fe(II in H3PO4 (240-330 mV/0.1 mL. Reversed titrations were also performed and accurate and reproducible results were obtained.

  13. Comparative Study of the Total Acidity Determination in Wine by Potentiometric and Volumetric Titration

    OpenAIRE

    Budić-Leto, Irena; Mešin, Nela; Gajdoš Kljusurić, Jasenka; Pezo, Ivan; Bralić, Marija

    2009-01-01

    Total acidity was determined in thirty-seven samples of Croatian red, white and rosé wines by potentiometric titration. In order to find the effect of the corresponding rate of the automatic titrant added, several procedures were employed. For different rates of titration, the aberrances were found from 0.1 to 0.4 g L–1 for some wines. The value of the total acid content in wine determined by the automatic potentiometric titration method was compared to that obtained by the conventional volum...

  14. Determination of Sulfides in FCC Gasoline by Using the Potentiometric Titration of Lead Tetraacetate

    Institute of Scientific and Technical Information of China (English)

    罗立文; 夏道宏

    2004-01-01

    Compared with conventional method of violet spectrum, determination of the content of sulfides in fluid catalytic cracking (FCC) gasoline by using the potentiometric titration of lead tetraacetate has some advantages such as clear potentiometric abrupt change at the stoichiometric point, stable potentiometric value, exact and credible results, and simple operation. The content of sulfides in FCC gasoline of Shenghua refinery is 0.136% by this method. The standard deviation about this method is less than 0.01% and the relative standard deviation is less than 2.42%.

  15. Simple home-made sensors for potentiometric titrations. [Nitroform CH(NO/sub 2/)/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Selig, W.

    1982-04-01

    A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctyphthalate in tetrahydrofuran. The reference electrode was an Ag/AgCl single-junction electrode. The sensor was used in precipitation, acid-base, compleximetric, and redox titrations. Preparation of the coated-graphite sensor is simple and rapid. Moreover, it is quite inexpensive. A limitation is its applicability in aqueous media only, because organic solvents will dissolve the membrane. Various uncoated types of graphite have also been investigated as sensors, particularly in two applications of interest in the analysis of propellants: the titration of nitroform and perchlorate. Obviously, these sensors can be used also in nonaqueous, or partially nonaqueous media. These sensors may also find use in the potentiometric titration of fluoride vs La(III) or Th(IV).

  16. Comparative Study of the Total Acidity Determination in Wine by Potentiometric and Volumetric Titration

    Directory of Open Access Journals (Sweden)

    Irena Budić-leto

    2009-03-01

    Full Text Available Total acidity was determined in thirty-seven samples of Croatian red, white and rosé wines by potentiometric titration. In order to find the effect of the corresponding rate of the automatic titrant added, several procedures were employed. For different rates of titration, the aberrances were found from 0.1 to 0.4 g L–1 for some wines. The value of the total acid content in wine determined by the automatic potentiometric titration method was compared to that obtained by the conventional volumetric titration method. The ANOVA and cluster analysis (CA were applied to detect possible resemblance. The results of total acidity depended on the methods used. However, a good correlation between the results by these methods was found.

  17. A novel approach for high precision rapid potentiometric titrations: Application to hydrazine assay

    Science.gov (United States)

    Sahoo, P.; Malathi, N.; Ananthanarayanan, R.; Praveen, K.; Murali, N.

    2011-11-01

    We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50-100 μl) in a total volume of ˜2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions--hydrazine against KIO3 in HCl medium, Fe(II) against Ce(IV) and uranium using Davies-Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors.

  18. Concentration-related response potentiometric titrations to study the interaction of small molecules with large biomolecules.

    Science.gov (United States)

    Hamidi-Asl, Ezat; Daems, Devin; De Wael, Karolien; Van Camp, Guy; Nagels, Luc J

    2014-12-16

    In the present paper, the utility of a special potentiometric titration approach for recognition and calculation of biomolecule/small-molecule interactions is reported. This approach is fast, sensitive, reproducible, and inexpensive in comparison to the other methods for the determination of the association constant values (Ka) and the interaction energies (ΔG). The potentiometric titration measurement is based on the use of a classical polymeric membrane indicator electrode in a solution of the small-molecule ligand. The biomolecule is used as a titrant. The potential is measured versus a reference electrode and transformed into a concentration-related signal over the entire concentration interval, also at low concentrations, where the millivolt (y-axis) versus log canalyte (x-axis) potentiometric calibration curve is not linear. In the procedure, Ka is calculated for the interaction of cocaine with a cocaine binding aptamer and with an anticocaine antibody. To study the selectivity and cross-reactivity, other oligonucleotides and aptamers are tested, as well as other small ligand molecules such as tetrakis(4-chlorophenyl)borate, metergoline, lidocaine, and bromhexine. The calculated Ka compared favorably to the value reported in the literature using surface plasmon resonance. The potentiometric titration approach called "concentration-related response potentiometry" is used to study molecular interaction for seven macromolecular target molecules and four small-molecule ligands.

  19. Semi-automatic version of the potentiometric titration method for characterization of uranium compounds.

    Science.gov (United States)

    Cristiano, Bárbara F G; Delgado, José Ubiratan; da Silva, José Wanderley S; de Barros, Pedro D; de Araújo, Radier M S; Dias, Fábio C; Lopes, Ricardo T

    2012-09-01

    The potentiometric titration method was used for characterization of uranium compounds to be applied in intercomparison programs. The method is applied with traceability assured using a potassium dichromate primary standard. A semi-automatic version was developed to reduce the analysis time and the operator variation. The standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization and compatible with those obtained by manual techniques. PMID:22406220

  20. Comparing characterization of functionalized multi-walled carbon nanotubes by potentiometric proton titration, NEXAFS, and XPS

    Institute of Scientific and Technical Information of China (English)

    Zhiteng Zhang; Lisa Pfefferle; Gary L. Haller

    2014-01-01

    Since the discovery of carbon nanotubes (CNT), this material has been recognized as an attractive catalyst support. CNT must be functionalized before use as a catalyst support and typically this involves oxidation. However, the functional group distribution on the CNT is very complex mixture of groups and varies with oxidation agent used. Here a simple acid-base titration is introduced to characterize the oxygen functionalized CNT. By comparing characterization with near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) for both at the C and O K-edges, it can be demonstrated that potentiometric proton titration can be a fast and quan-titative analysis for Brönsted acid functional groups on CNT.

  1. Determination of vanadium(V) by direct automatic potentiometric titration with EDTA using a chemically modified electrode as a potentiometric sensor.

    Science.gov (United States)

    Quintar, S E; Santagata, J P; Cortinez, V A

    2005-10-15

    A chemically modified electrode (CME) was prepared and studied as a potentiometric sensor for the end-point detection in the automatic titration of vanadium(V) with EDTA. The CME was constructed with a paste prepared by mixing spectral-grade graphite powder, Nujol oil and N-2-naphthoyl-N-p-tolylhydroxamic acid (NTHA). Buffer systems, pH effects and the concentration range were studied. Interference ions were separated by applying a liquid-liquid extraction procedure. The CME did not require any special conditioning before using. The electrode was constructed with very inexpensive materials and was easily made. It could be continuously used, at least two months without removing the paste. Automatic potentiometric titration curves were obtained for V(V) within 5 x 10(-5) to 2 x 10(-3)M with acceptable accuracy and precision. The developed method was applied to V(V) determination in alloys for hip prosthesis. PMID:18970248

  2. Potentiometric determination of plutonium by argentic oxidation, ferrous reduction and dichromate titration.

    Science.gov (United States)

    Drummond, J L; Grant, R A

    1966-03-01

    A simple and rapid method is described for the routine determination of plutonium with a coefficient of variation of better than 0.2%. It is directly applicable to nitrate solutions containing a large amount of uranium; moderate amounts of iron, molybdenum, fluoride and phosphate do not interfere. Chromium, cerium and manganese interfere quantitatively, and the procedure may also prove convenient for the determination of these elements. The plutonium is oxidised to the sexivalent state with argentic oxide in nitric acid solution, and the excess of oxidant is destroyed by reaction with sulphamic acid. A weighed small excess of iron(II) solution is then added, and the excess is titrated potentiometrically with standard potassium dichromate solution using polarised gold indicator electrodes. The whole determination is performed in one vessel at room temperature, and takes about 20 min. PMID:18959901

  3. Determination of quaternary ammonium compounds by potentiometric titration with an ionic surfactant electrode: single-laboratory validation.

    Science.gov (United States)

    Price, Randi; Wan, Ping

    2010-01-01

    A potentiometric titration for determining the quaternary ammonium compounds (QAC) commonly found in antimicrobial products was validated by a single laboratory. Traditionally, QACs were determined by using a biphasic (chloroform and water) manual titration procedure. Because of safety considerations regarding chloroform, as well as the subjectivity of color indicator-based manual titration determinations, an automatic potentiometric titration procedure was tested with quaternary nitrogen product formulations. By using the Metrohm Titrando system coupled with an ionic surfactant electrode and an Ag/AgCl reference electrode, titrations were performed with various QAC-containing formulation products/matrixes; a standard sodium lauryl sulfate solution was used as the titrant. Results for the products tested are sufficiently reproducible and accurate for the purpose of regulatory product enforcement. The robustness of the method was measured by varying pH levels, as well as by comparing buffered versus unbuffered titration systems. A quantitation range of 1-1000 ppm quaternary nitrogen was established. Eight commercially available antimicrobial products covering a variety of matrixes were assayed; the results obtained were comparable to those obtained by the manual titration method. Recoveries of 94 to 104% were obtained for spiked samples. PMID:21140668

  4. Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

    Science.gov (United States)

    Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

    2016-07-01

    Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g-1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=-0.736; α = 0.05) as well as ash content (R=-0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g-1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

  5. Analysis of variance in determinations of equivalence volume and of the ionic product of water in potentiometric titrations.

    Science.gov (United States)

    Braibanti, A; Bruschi, C; Fisicaro, E; Pasquali, M

    1986-06-01

    Homogeneous sets of data from strong acid-strong base potentiometric titrations in aqueous solution at various constant ionic strengths have been analysed by statistical criteria. The aim is to see whether the error distribution matches that for the equilibrium constants determined by competitive potentiometric methods using the glass electrode. The titration curve can be defined when the estimated equivalence volume VEM, with standard deviation (s.d.) sigma (VEM), the standard potential E(0), with s.d. sigma(E(0)), and the operational ionic product of water K(*)(w) (or E(*)(w) in mV), with s.d. sigma(K(*)(w)) [or sigma(E(*)(w))] are known. A special computer program, BEATRIX, has been written which optimizes the values of VEM, E(0) and K(*)(w) by linearization of the titration curve as a Gran plot. Analysis of variance applied to a set of 11 titrations in 1.0M sodium chloride medium at 298 K has demonstrated that the values of VEM belong to a normal population of points corresponding to individual potential/volume data-pairs (E(i); v(i)) of any titration, whereas the values of pK(*)(w) (or of E(*)(w)) belong to a normal population with members corresponding to individual titrations, which is also the case for the equilibrium constants. The intertitration variation is attributable to the electrochemical component of the system and appears as signal noise distributed over the titrations. The correction for junction-potentials, introduced in a further stage of the program by optimization in a Nernst equation, increases the noise, i.e., sigma(pK(*)(w)). This correction should therefore be avoided whenever it causes an increase of sigma(pK(*)(w)). The influence of the ionic medium has been examined by processing data from acid-base titrations in 0.1M potassium chloride and 0.5M potassium nitrate media. The titrations in potassium chloride medium showed the same behaviour as those in sodium chloride medium, but with an s.d. for pK(*)(w) that was smaller and close to the

  6. Automatic potentiometric titration study of the iodine content in salt%食盐中碘含量的自动电位滴定法测定研究

    Institute of Scientific and Technical Information of China (English)

    麦浪; 梁雄宇; 黄义活; 梁水基

    2012-01-01

    Objective Establish a fast, easy, accurate iodine in salt content by automatic potentiometric detection method. Methods Determination of iodine content in salt use the Metrohm809 Titrando automatic potentiometric titrator. Results The recovery rate in the different samples was 97,4% -99.0%, relative standard deviation was 0.81% - 1.37%( n =6). It was shown that there was no significant difference between automatic potentiometric titration and direct titration by applying 10 samples( P > 0. 05). Conclusion Automatic potentiometric titration method was simple, rapid and high degree of automation, the determination of iodine content in salt, high accuracy, good reproducibility, conventionally analytical methods for the determination of salt iodine.%目的 建立快速、简便、准确的食盐中碘含量的自动电位滴定检测方法.方法 用瑞士万通Metrohm809 Titrando自动电位滴定仪测定食盐中的碘含量.结果 不同样品中的加标回收率为97.4% ~ 99.0%,相对标准偏差为0.81%~1.37%(n=6),对10份样品分别用自动电位滴定法和直接滴定法测定,两种方法所得结果无显著性差异(P>0.05).结论 自动电位滴定法操作简单、快速,自动化程度高,测定食盐中碘含量时准确度高,重现性好,适合作为盐碘测定的常规分析方法.

  7. Potentiometric titration of uranium reduced by chromic salts in chloridic solutions

    International Nuclear Information System (INIS)

    The utilization of chromic salts for reducing the uranium (VI) from chloridic solutions, for potentiometric dosage is described. This method is used in the range of 0,002 to 1,0 M of uranium. (C.G.C.)

  8. Programa de ajuste multiparamétrico de curvas de titulação potenciométricas de ácidos húmicos Multiparametric adjustment program of potentiometric titration curves of humic acids

    Directory of Open Access Journals (Sweden)

    Clausius Duque Gonçalves Reis

    2010-04-01

    Full Text Available Tendo em vista a dificuldade de determinação dos pontos de inflexão na curva de titulação potenciométrica de ácidos húmicos, por metodologias tradicionais, foi desenvolvido foi desenvolvido um programa na linguagem Delphi para ajuste multiparamétrico de dados de titulação potenciométrica. Para isso um processo iterativo para estimar as raízes de um polinômio, com base no método de Newton-Raphson, foi utilizado. Os dados das titulações potenciométricas de ácidos húmicos usados nas regressões foram obtidos em um sistema automatizado de titulação potenciométrica. O programa desenvolvido na linguagem Delphi permite maior versatilidade e facilidade de operação, com uma interação mais amigável com o usuário. As curvas de titulação potenciométricas ajustadas sobrepuseram-se quase que totalmente às curvas experimentais. Os valores de pKa e as percentagens de grupos tituláveis dos ácidos húmicos, parâmetros ajustáveis na regressão multiparamétrica, apresentaram valores comparáveis com dados da literatura.Regarding the difficulty of determining the inflection points in the potentiometric titration curve of humic acids by means of traditional methodologies, a Delphi program a Delphi program was developed for the multiparametric data adjustment in potentiometric titration. For this purpose, an iterative process was used, based on the Newton-Raphson method to estimate the roots of a polynomial. The humic acid potentiometric titration data, used in regressions, were obtained in an automated system of potentiometric titration. The program developed in Delphi language features greater versatility, ease of operation and better interaction with the user. The adjusted potentiometric titration curves overlap the experimental curves almost entirely. The pKa values and percentages of titrable groups of humic acids extracted from soil, adjustable parameters in the multiparametric regression, were comparable with those reported

  9. Determination of soil organic matter by automatically potentiometric titration method%自动电位滴定法测定土壤有机质含量

    Institute of Scientific and Technical Information of China (English)

    郝会军; 杨俐苹; 金继运

    2011-01-01

    采用丘林滴定法与自动电位滴定法测定土壤中有机质含量,并对自动电位滴定法做了精密度和加标回收率试验.同时进行了用自动电位滴定法与手工滴定法标定硫酸亚铁标准溶液试验.结果表明,两种方法标定硫酸亚铁标准溶液结果一致,并无显著差别;丘林滴定法和自动电位滴定法均能满足土壤中有机质含量的分析要求,测定结果无显著性差异.自动电位滴定法显示了很好的准确度和重现性,加标回收率在98.43%~101.8%之间,相对标准偏差(RSD)为0.693%~0.936%,可见自动电位滴定法是一种测定土壤有机质含量的好方法.%Soil organic matter (SOM) was determined by Tyurin method with manual titration and automatically potentiometric titration. The precision and recovery rate of automatically potentiometric titration was studied. The concentration of FeSO4 standard solution of was calibrated by both automatically potentiometric titration and manual titration method. The results indicated that there was identical and no remarkable difference for calibration of FeSO4 standard solution by two methods. There was no significance difference for determining SOM by Tyurin method with manual titration and automatically potentiometric titration method which showed two methods could meet analysis requirement. Automatically potentiometric titration method revealed a good accuracy and reproducibility with recovery rate of 98. 43% ~ 101.8% and RSD of 0. 693% ~ 0. 936%. It was obvious automatically potentiometric titration method could be recommended as a good method to determine SOM.

  10. Determination of the biodiesel acidity index by potentiometric titration by using different methods; Determinacao do indice de acidez de biodiesel por titulacao potenciometrica utilizando-se diferentes metodos

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Mary Ane; Sobral, Sidney Pereira; Borges, Paulo Paschoal [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (DIMCI/INMETRO), Duque de Caxias, RJ (Brazil). Diretoria de Metrologia Cientifica e Industrial], E-mail: magoncalves@inmetro.gov.br

    2009-07-01

    This work determined the index of the soybean/fat bio diesel through the potentiometric titration. Four different methods were used with variation of solvent and electrodes. The results were compared by F and t (Student) and it was verified that they were agreed in a 95% confidence interval.

  11. Number of independent parameters in the potentiometric titration of humic substances.

    Science.gov (United States)

    Lenoir, Thomas; Manceau, Alain

    2010-03-16

    With the advent of high-precision automatic titrators operating in pH stat mode, measuring the mass balance of protons in solid-solution mixtures against the pH of natural and synthetic polyelectrolytes is now routine. However, titration curves of complex molecules typically lack obvious inflection points, which complicates their analysis despite the high-precision measurements. The calculation of site densities and median proton affinity constants (pK) from such data can lead to considerable covariance between fit parameters. Knowing the number of independent parameters that can be freely varied during the least-squares minimization of a model fit to titration data is necessary to improve the model's applicability. This number was calculated for natural organic matter by applying principal component analysis (PCA) to a reference data set of 47 independent titration curves from fulvic and humic acids measured at I = 0.1 M. The complete data set was reconstructed statistically from pH 3.5 to 9.8 with only six parameters, compared to seven or eight generally adjusted with common semi-empirical speciation models for organic matter, and explains correlations that occur with the higher number of parameters. Existing proton-binding models are not necessarily overparametrized, but instead titration data lack the sensitivity needed to quantify the full set of binding properties of humic materials. Model-independent conditional pK values can be obtained directly from the derivative of titration data, and this approach is the most conservative. The apparent proton-binding constants of the 23 fulvic acids (FA) and 24 humic acids (HA) derived from a high-quality polynomial parametrization of the data set are pK(H,COOH)(FA) = 4.18 +/- 0.21, pK(H,Ph-OH)(FA) = 9.29 +/- 0.33, pK(H,COOH)(HA) = 4.49 +/- 0.18, and pK(H,Ph-OH)(HA) = 9.29 +/- 0.38. Their values at other ionic strengths are more reliably calculated with the empirical Davies equation than any existing model fit. PMID

  12. 自动电位滴定法测定硫磺总酸度%Automatic Potentiometric Titration Determination of Total Acidity in Sulfur

    Institute of Scientific and Technical Information of China (English)

    潘存艳; 齐云鹏; 宁海龙; 张金龙

    2014-01-01

    Basing on samples of imported industrial sulfur in Alashankou port, the automatic potentiometric titration determination of total acidity was established. The titration mode, main titration parameters and the dissolving time of the samples were studied. Each sample tested 10 times, the relative standard deviation was 1. 6560% ~1. 7857%, and in the recovery experiment, the recovery rate was 98. 56% ~101. 02%, which proved that automatic potentiometric titration method possessed high precision and accuracy.%以阿拉山口口岸进口的工业硫磺为样品,建立了测定硫磺总酸度的自动电位滴定法。对滴定模式、主要滴定参数和样品溶解时间进行了探究。每个样品平行测定10次,计算的相对标准偏差为1.6560%~1.7857%;加标回收实验中,得到回收率为95.39%~107.29%,说明了自动电位滴定法精密度很高,同时具有很高的准确度。

  13. Investigating the early stages of mineral precipitation by potentiometric titration and analytical ultracentrifugation.

    Science.gov (United States)

    Kellermeier, Matthias; Cölfen, Helmut; Gebauer, Denis

    2013-01-01

    Despite the importance of crystallization for various areas of research, our understanding of the early stages of the mineral precipitation from solution and of the actual mechanism of nucleation is still rather limited. Indeed, detailed insights into the processes underlying nucleation may enable a systematic development of novel strategies for controlling mineralization, which is highly relevant for fields ranging from materials chemistry to medicine. In this work, we describe experimental aspects of a quantitative assay, which relies on pH titrations combined with in situ metal ion potentiometry and conductivity measurements. The assay has originally been designed to study the crystallization of calcium carbonate, one of the most abundant biominerals. However, the developed procedures can also be readily applied to any compound containing cations for which ion-selective electrodes are available. Besides the possibility to quantitatively assess ion association prior to nucleation and to directly determine thermodynamic solubility products of precipitated phases, the main advantage of the crystallization assay is the unambiguous identification of the different stages of precipitation (i.e., prenucleation, nucleation, and early postnucleation) and the characterization of the multiple effects of additives. Furthermore, the experiments permit targeted access to distinct precursor species and intermediate stages, which thus can be analyzed by additional methods such as cryo-electron microscopy or analytical ultracentrifugation (AUC). Regarding ion association in solution, AUC detects entities significantly larger than simple ion pairs, so-called prenucleation clusters. Sedimentation coefficient values and distributions obtained for the calcium carbonate system are discussed in light of recent insights into the structural nature of prenucleation clusters.

  14. Determination of Acidity of Triacetin with Automatic Potentiometric Titration%自动电位滴定法测定三乙酸甘油酯的酸度

    Institute of Scientific and Technical Information of China (English)

    周培琛; 刘泽春; 黄华发; 张峰; 张鼎方; 刘江生; 赖伟玲

    2011-01-01

    为了克服常规酸碱滴定法测定三乙酸甘油酯酸度存在的诸如终点不易观察,相对标准偏差( RSD)较大等缺点,考察了自动电位滴定法.结果表明,自动电位滴定法的RSD为0.774%,定量限0.00175%,回收率99.5%~103.3%.该方法可以快速准确地测定三乙酸甘油酯的酸度.%In order to get rid of the disadvantages of conventional acid-base titration in determining the acidity of triacetin, such as inconvenience in endpoint differentiation and high relative standard deviation, automatic potentiometric titration was investigated. The results showed that the recoveries of the method ranged from 99.5% to 103.3% with the relative standard deviation of 0.774% and the limit of quantitation of 0.00175%. It proved that the acidity of triacetin could be rapidly and accurately determined with automatic potentiometric titration.

  15. 自动电位滴定法测定油脂皂化值%Determination of saponification value of oils and fats by automatic potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    曾正策; 苏军; 吴昊

    2011-01-01

    An automatic potentiometric titration method was established for determining saponification value of oils and fats. Automatic potentiometric titration and the method of GB/T 5534-2008 were separately used to determine the three rapeseed oil samples for 6 times. The relative standard deviations of automatic potentiometric titration and GB/T 5534-2008 were 0. 16% -0. 22% and 0. 36% -0. 81% respectively, so the former was superior to the method of GB/T 5534-2008.%采用电位滴定仪测定了油脂的皂化值,利用电位滴定仪能够识别多个滴定终点的特点,采用分步滴定法用盐酸分别滴定皂化液中过量的氢氧化钾和生成的钾皂,根据滴定钾皂消耗的盐酸的量可计算出样品的皂化值.分别采用全自动电位滴定法和国标GB/T 5534-2008规定的方法对3个不同菜籽油样品各平行测定6次,前者测定结果的相对标准偏差为0.16%~0.22%,优于国标方法测定结果的相对标准偏差0.36%~0.81%.

  16. Determination of sulfides in FCC gasoline by using the potentiometric titration of lead tetraacetate%FCC汽油中硫醚硫的测定--四乙酸铅电位滴定法

    Institute of Scientific and Technical Information of China (English)

    罗立文; 夏道宏

    2004-01-01

    Compared with conventional method of violet spectrum,determination of the content of sulfides in fluid catalytic cracking(FCC)gasoline by using the potentiometric titration of lead tetraacetate has some advantages such as clear potentiometric abrupt change at the stoichiometric point,stable potentiometric value,exact and credible results,and simple operation.The content of sulfides in FCC gasoline of Shenghua refinery is 0.136% by this method.The standard deviation about this method is less than 0.01% and the relative standard deviation is less than 2.42%.

  17. On the binding of calcium by micelles composed of carboxy-modified pluronics measured by means of differential potentiometric titration and modelled with a self-consistent-field theory

    NARCIS (Netherlands)

    Lauw, Y.; Leermakers, F.A.M.; Cohen Stuart, M.A.; Pinheiro, J.P.; Custers, J.P.A.; Broeke, van den L.J.P.; Keurentjes, J.T.F.

    2006-01-01

    We perform differential potentiometric titration measurements for the binding of Ca2+ ions to micelles composed of the carboxylic acid end-standing Pluronic P85 block copolymer (i.e., CAE-85 (COOH-(EO)(26)-(PO)(39)-(EO)(26)-COOH)). Two different ion-selective electrodes (ISEs) are used to detect the

  18. Potentiometric titration method for determination of basic nitrogen in petroleum products%电位滴定法测定石油产品中碱性氮

    Institute of Scientific and Technical Information of China (English)

    关旭; 马守涛; 吴显军; 季荣磊; 崔建慧

    2014-01-01

    为了能够准确测定深色油品中的碱性氮含量,对石油产品中碱性氮的测定方法进行了阐述和对比。在此基础上进行了新方法的探究,用电位滴定法测定汽油、柴油、渣油油品中碱性氮含量。通过以手动滴定为基础,用电位滴定法测定了几种深色油品的碱性氮含量,结果显示试验数据准确,重复性良好,满足SH/T0162中的误差范围的要求,可以作为SH/T0162之外的另一种可供选择的分析方法。%In order to accurately determine the basic nitrogen content of dark oils, the determination methods for basic nitrogen in petroleum products were elaborated and compared in this paper. A potentiometric titration method was explored to determinate the basic nitrogen content of gasoline, diesel and residual. Based on the manual titra⁃tion, the basic nitrogen content of dark oils was determined by using potentiometric titration method. The experi⁃mental data is accurate, with good reproducibility. The error is within the range of the SH/T0162. It can be an al⁃ternative method besides the analysis criterion SH/T0162.

  19. Microcalorimetric and potentiometric titration studies on the adsorption of copper by P. putida and B. thuringiensis and their composites with minerals

    Energy Technology Data Exchange (ETDEWEB)

    Fang Linchuan [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Cai Peng; Li Pengxiang; Wu Huayong; Liang Wei; Rong Xingmin [Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Chen Wenli [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Huang Qiaoyun, E-mail: qyhuang@mail.hzau.edu.cn [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China)

    2010-09-15

    In order to have a better understanding of the interactions of heavy metals with bacteria and minerals in soil and associated environments, isothermal titration calorimetry (ITC), potentiometric titration and equilibrium sorption experiments were conducted to investigate the adsorption behavior of Cu(II) by Bacillus thuringiensis, Pseudomonas putida and their composites with minerals. The interaction of montmorillonite with bacteria increased the reactive sites and resulted in greater adsorption for Cu(II) on their composites, while decreased adsorption sites and capacities for Cu(II) were observed on goethite-bacteria composites. A gram-positive bacterium B. thuringiensis played a more important role than a gram-negative bacterium P. putida in determining the properties of the bacteria-minerals interfaces. The enthalpy changes ({Delta}H{sub ads}) from endothermic (6.14 kJ mol{sup -1}) to slightly exothermic (-0.78 kJ mol{sup -1}) suggested that Cu(II) is complexed with the anionic oxygen ligands on the surface of bacteria-mineral composites. Large entropies (32.96-58.89 J mol{sup -1} K{sup -1}) of Cu(II) adsorption onto bacteria-mineral composites demonstrated the formation of inner-sphere complexes in the presence of bacteria. The thermodynamic data implied that Cu(II) mainly bound to the carboxyl and phosphoryl groups as inner-sphere complexes on bacteria and mineral-bacteria composites.

  20. Microcalorimetric and potentiometric titration studies on the adsorption of copper by P. putida and B. thuringiensis and their composites with minerals

    International Nuclear Information System (INIS)

    In order to have a better understanding of the interactions of heavy metals with bacteria and minerals in soil and associated environments, isothermal titration calorimetry (ITC), potentiometric titration and equilibrium sorption experiments were conducted to investigate the adsorption behavior of Cu(II) by Bacillus thuringiensis, Pseudomonas putida and their composites with minerals. The interaction of montmorillonite with bacteria increased the reactive sites and resulted in greater adsorption for Cu(II) on their composites, while decreased adsorption sites and capacities for Cu(II) were observed on goethite-bacteria composites. A gram-positive bacterium B. thuringiensis played a more important role than a gram-negative bacterium P. putida in determining the properties of the bacteria-minerals interfaces. The enthalpy changes (ΔHads) from endothermic (6.14 kJ mol-1) to slightly exothermic (-0.78 kJ mol-1) suggested that Cu(II) is complexed with the anionic oxygen ligands on the surface of bacteria-mineral composites. Large entropies (32.96-58.89 J mol-1 K-1) of Cu(II) adsorption onto bacteria-mineral composites demonstrated the formation of inner-sphere complexes in the presence of bacteria. The thermodynamic data implied that Cu(II) mainly bound to the carboxyl and phosphoryl groups as inner-sphere complexes on bacteria and mineral-bacteria composites.

  1. Automatic Potentiometric Titrator Determinated Chloride Ions in Water%自动电位滴定仪测定水中氯离子的探讨

    Institute of Scientific and Technical Information of China (English)

    李芳; 李文胜

    2014-01-01

    Using automatic potentiometric titrator, standard solution of silver nitrate was calibrated and chloride ions in industrial circulating wate was determined. The matters need attention of the electrode maintenance and the end point of titration to set were summarized. The result showed that the determination of chloride ions in water by using the instrument, its accuracy and precision can be obtained satisfactory results.%通过使用自动电位滴定仪标定硝酸银标准溶液和测定工业循环水中氯离子的实验研究,总结了在使用中应注意的电极的维护保养和滴定终点设定方面的一些规律,结果表明用该仪器测定水中氯离子,其准确性和精密度均可获得满意的结果。

  2. 等电位间隔电位滴定法测定葡萄酒中游离二氧化硫%Determination of free sulfur dioxide in wine by the equal potential interval potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    冯俊贤; 李家栋; 孙晓丽; 苏洪茹; 刘元昀

    2013-01-01

    目的:建立等电位间隔电位滴定法测定葡萄酒中游离SO2的方法.方法:采用间接碘量滴定,以等电位间隔法识别滴定终点.结果:方法RSD≤0.5%,游离二氧化硫回收率在94.50% ~ 103.7%,与自动电位滴定法比较,相对误差小于1.0%.结论:间接碘量法无需碘标准溶液,等电位间隔电位滴定法识别滴定终点准确可靠,重现性好,适合葡萄酒中游离二氧化硫含量的测定.%Objective:To establish a method for determination of free sulfur dioxide in wine by the equal potential interval potentiometric titration. Methods: According to indirect iodimetry, the end - point of titration could be judged with the equal potential interval potentiometric titration. Results: The RSD was 0.3% ~0.5% , the recovery rate for free sulfur dioxide was 94. 50% ~ 103. 7%. Compared with automatic potentiometric titration, the relative deviation for free sulfur dioxide was less than 1.0%. Conclusion: The indirect iodimetry is simple, accurate without iodine standard solution. The equal potential interval potentiometric titration is accurate, reliable with good repeatability. It is suitable for determination of free sulfur dioxid in wine.

  3. Development of a Novel Solid-State Sensor Electrode Based on Titanium Thin Film as an Indicator Electrode in Potentiometric and Conductometric Acid-Base Titration in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Nasser Abu Ghalwa

    2012-01-01

    Full Text Available A modified Ti/(SnO2 + Sb2O3 electrode was prepared by thermal deposition on titanium substrate and its use as indicator electrode to potentiometric and conductometric acid-base titration in aqueous solution at 298 K was developed. The E-pH curve is linear with slope of 0.0512 V/dec at 298 K. The standard potential of this electrode, E0, was determined with respect to the SCE as reference electrode. The recovery percentages for potentiometric and conductometric acid-base titration for acetic acid against NaOH were calculated. The cell constant, specific conductance, and the molar conductance with dilution for some common electrolytes were measured.

  4. 自动电位滴定法测定米糠油酸值的研究%Detection of acid value of rice bran oil by automatic potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    薛斌; 曹文明; 包杰; 陈纯; 金俊

    2014-01-01

    为了克服传统的人工指示剂滴定法在测定米糠油酸值过程中,米糠油本身的颜色和高含量的γ-谷维素对测定结果的严重干扰,采用自动电位滴定法,根据经典的酸碱滴定理论,采用二次作图法,在滴定的同时由联机电脑实时同步绘制酸碱滴定的pH-滴定体积曲线及其相应的一阶微分曲线,以这些曲线上游离脂肪酸发生中和反应引起的“pH突跃”为滴定终点的判定依据,建立米糠油酸值测定的自动电位滴定法。结果发现,自动电位滴定法能够准确区分游离脂肪酸和γ-谷维素各自的滴定终点,从而排除γ-谷维素对米糠油酸值测定的干扰。对比实验发现,除了米糠油外,自动电位滴定法对各类食用植物油酸值的测定结果与传统的人工指示剂滴定法的测定结果十分接近;但对于米糠油,人工指示剂滴定法的酸值(KOH)测定结果一般偏高0.3~1.0 mg/g。表明自动电位滴定法更能准确地测定米糠油的酸值。%In order to overcome the severe interferences of color and high contentγ-oryzanol in the de-tection of acid value of rice bran oil by traditional manual indicator titration method, according to the classical theory of acid base titration, using methods of automatic potentiometric titration and “second graph”, a detection method of the acid value of rice bran oil was established. Using this method, the pH-titration volume curve and corresponding first -order difference curve of acid base titration were drawn by computer real-timely and synchronously, then the “pH jump” in these curves, which was caused by the neutralization of free fatty acids, was taken as the foundation for judgment of titration end point. The results showed that the titration end points of free fatty acids and γ-oryzanol could be distin-guished correctly by automatic potentiometric titration method, therefore the interference of γ-oryzanol in the detection

  5. 全自动电位滴定法测定有色液态食品中的糖含量%Determination of sugar content in colored liquid food by automatic potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    纪丽君; 陈英; 李培; 姚卫蓉

    2013-01-01

    本论文针对国标法测定糖含量所采用的手工滴定法存在不适合深色样品的缺点,研究采用高温氧化还原电极的全自动滴定法进行替代的可能性.首先通过测定3个含酒精饮料,研究样品中的酒精对全自动滴定结果的影响,结果表明有色液态样品中所含酒精对全自动电位滴定法测定结果没有影响;采用全自动电位滴定法测定了9个有色液态食品(包括7个含酒精饮料和2个碳酸饮料)的糖含量,相对标准偏差(RSD)、回收率分别为0.124% ~ 1.637%、96.0% ~104.6%,并将结果与国标方法的结果进行了比对,相关系数r达到0.99997,说明全自动电位滴定法作为糖含量测定的一种新方式,其精密度和准确度均满足要求,可以取代传统手工滴定法.%The traditional manual titration method for determination sugar is not so suitable for the dark samples to overcome this shortcorning.A replace method of automatic potentiometric titrator equipped with high temperature redox electrode was studied,Firstly,the effect of alcohol on the determiantion result was stuidied by detecting 3 kinds of alcoholic beverage, which showed no effect.Then the sugar content of 9 kinds of colored liquid food, including 7 alcoholic beverage and 2 sodas, were measured by automatic potentiometric titration.Their relative standard deviation( RSD) and recoveries were 0.124% ~ 1.637% and 96.0%~104.6% respectively.The correlation between automatic potentiometric titration and manual titration was 0.99997. Our result showed that the automatic potentiometric titration method could meet the demand of detection sugar and could replace of the manual titration method.

  6. Preliminary Discussion on Development of Automatic Potentiometric Titration Technology and Its Application to Routine Detection of Solution%浅谈自动电位滴定技术发展及在常规检测中的应用

    Institute of Scientific and Technical Information of China (English)

    王桂林; 陶淑芸

    2013-01-01

    According to the simple and quick,accurate and efficient advantages,the application of automatic potentiometric titration technology in the detection industry is becoming increasingly popular. This article describes the development of the potentiometer titration method,and analyses the principle,to study the application in routine detection,compared with direct potential. Compared through experiments by automatic potentiometric titrator and the traditional manual titration,the results showed no significant difference.%  自动电位滴定技术因其简便快捷、准确高效的优点在检测行业的应用越来越普及。介绍了电位滴定法的发展,分析其原理,研究其在常规检测中的应用,比较其与直接电位法的区别,并使用自动电位滴定仪与传统人工滴定进行实验对比,得出无显著性差异结果。

  7. Instrumentation and Automated Photometric Titration Procedure for Total Acidity Determination in Red Wine Employing a Multicommuted Flow System

    OpenAIRE

    Boaventura F. Reis; Ausberta Jesus Cabezas Garcia

    2006-01-01

    An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were...

  8. Determination of total manganese in manganese ore by automatic potentiometric titrator%自动电位滴定仪测定锰矿石中全锰量

    Institute of Scientific and Technical Information of China (English)

    马德起; 韩娟; 胡德新; 武素茹; 王永芳

    2012-01-01

    样品经盐酸、磷酸、硝酸、高氯酸加热溶解后,以硫酸亚铁铵为标准溶液为滴定液,采用自动电位滴定仪测定全锰量.经过对5个有证标准样品进行测试,全锰量测定的平均值与认定值的误差在0.015%~0.145%之间,标准差为0.074%,t检验值为0.366.选取主要进口国含量不同的样品进行全锰量的测定,并进行方法对比,其允许差符合标准GB/T 1506-2002规定.本法具有较高灵敏度和准确度,可用于大批量锰矿石的日常检测.%The sample was dissolved in hydrochloric acid, phosphoric acid, nitric acid and perchloric acid by heating. The content of total manganese was determined by automatic potentiometric titrator. Five certified reference materials were tested. The errors between average determination value and certified value of total manganese content were in the range of 0. 015 %-0. 145%. The standard deviation was 0. 074% and the t test value was 0. 366. Various samples with difference total manganese contents from main import countries were selected for the determination of total manganese. The method comparison was conducted, and the admissible error complied with rules in GB/T 1506-2002. This method had high sensitivity and accuracy, and it could be used for the routing inspection of large numbers of manganese ores.

  9. Titulações potenciométricas de cátions metálicos tendo como eletrodo indicador o sistema Cu/Cu(II-EDTA Potentiometric titrations of metal cations with edta using the Cu/Cu(II-EDTA system as indicator electrode

    Directory of Open Access Journals (Sweden)

    Paulo H. Pereira da Silva

    2008-01-01

    Full Text Available In potentiometric titrations of metal cations with EDTA the Hg/HgY2- system is usually used to detect the end point. However, the use of mercury has been discouraged in analytical procedures due to its toxicity. In this work the Cu/CuY2- system was used as indicator electrode for potentiometric titrations of some metal cations with EDTA. The solutions of Cu2+, Cd2+, Mn2+, Co2+ and Zn2+ were titrated with Na2EDTA solution in the presence of a small concentration of the CuY2- complex using a copper wire as indicator electrode. The potentiometric titrations with the Cu/CuY2- system showed good correlation when compared with an Hg/HgY2- system.

  10. Automatic Potentiometric Titration Method to Measure the Different Types of Wine in the Total Acid Ester and Comparison of the Total%自动电位滴定法测不同类酒中的总酸总酯

    Institute of Scientific and Technical Information of China (English)

    杨盛春; 杨明惠; 高云涛

    2013-01-01

    Total acid and total alcohol ester is an important indicator of the two, the quality of the wine production and has a great influence. Conventional methods of determination of total acid titration method directly, pH meter and so on, while the total esters are used saponification were determined by neutralization. As two indicators were measured, and both manual systems and thus easy to operate, big error. In the paper, the analysis by automatic potentiometric titration to determine by potentiometric titration Category 3 of 6 total acid total ester alcohol, obtained satisfactory results.%  总酸与总酯是酒分析中的两个重要指标,对酒的生产及其品质有很大的影响。常规检测总酸的方法有直接滴定法、酸度计法等,而总酯则采用皂化中和法加以测定。由于二项指标分别测定,且均系手工操作,因而操作繁琐,误差较大。文章应用自动电位滴定法进行分析,测定了3类6种酒中总酸与总酯的含量,获得了较为满意的结果。

  11. The measurement of alkalinity in the Raney nickel catalyst activation by Automatic potentiometric titration%自动电位滴定法测定Raney镍催化剂活化中的碱度

    Institute of Scientific and Technical Information of China (English)

    叶乃义

    2011-01-01

    This research studies the method of potentiometric titration to determinate the concentration of NaOH in the lotion off in the activativity process of Raney nickel catalyst.It can meet the testing demand of Raney nickel catalyst to activation and possesses its application values in the actual work.%本文研究采用电位滴定法测定Raney镍催化剂在活化过程中脱洗液中NaOH含量,能够满足Raney镍催化剂活化时的检测需求,具有实际的工作应用价值。

  12. Method of semi-automatic high precision potentiometric titration for characterization of uranium compounds; Metodo de titulacao potenciometrica de alta precisao semi-automatizado para a caracterizacao de compostos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, Barbara Fernandes G.; Dias, Fabio C.; Barros, Pedro D. de; Araujo, Radier Mario S. de; Delgado, Jose Ubiratan; Silva, Jose Wanderley S. da, E-mail: barbara@ird.gov.b, E-mail: fabio@ird.gov.b, E-mail: pedrodio@ird.gov.b, E-mail: radier@ird.gov.b, E-mail: delgado@ird.gov.b, E-mail: wanderley@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (LIN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Lab. de Instrumentacao Nuclear

    2011-10-26

    The method of high precision potentiometric titration is widely used in the certification and characterization of uranium compounds. In order to reduce the analysis and diminish the influence if the annalist, a semi-automatic version of the method was developed at the safeguards laboratory of the CNEN-RJ, Brazil. The method was applied with traceability guaranteed by use of primary standard of potassium dichromate. The standard uncertainty combined in the determination of concentration of total uranium was of the order of 0.01%, which is better related to traditionally methods used by the nuclear installations which is of the order of 0.1%

  13. Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Christopher J.; Martin, Paul F.; Chen, Jeffrey; Benezeth, Pascale; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.

    2014-04-17

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell’s infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct radiation from a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system is demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay’s sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve

  14. Determinação de ácido acéttico em amostra de vinagre adulterada com ácido clorídrico - um experimento integrado de titulação potenciométrica e condutométrica Determination of acetic acid in vinegar adulterated sample with cloridric acid - an experiment integrated of potentiometric and conductometric titrations

    Directory of Open Access Journals (Sweden)

    José Vinicius Martins

    2010-01-01

    Full Text Available The determination of acetic acid in vinegar adulterated sample using simultaneous potentiometric and condutometric titrations was used as an example of integrated experiment in instrumental analysis. An Excel® spreadsheet, which allows the entry of simultaneous data and the construction of the superimposed experimental curves (condutometric, potentiometric, first and second derivative potentiometric curve and, distribution diagrama of the acetic species as function of pH, was used as powerful tool to discuss the fundamental concepts involved in each technique and choose the best of them to quantify, without mutual interference, H3CCOOH and HCl in vinegar adulterated sample.

  15. Potentiometric determination of peroxodisulfuric acid during electrolysis sulfuric acid

    Directory of Open Access Journals (Sweden)

    Fedor Malchik

    2013-09-01

    Full Text Available Was proposed two potentiometric methods for determining peroxodisulfuric acid during electrolysis of sulfuric acid (potentiometric titration method and direct potentiometry, based on its interaction with a known excess of a solution Fe2+.

  16. 自动电位滴定法快速测定铝箔生产液中的氯离子%Automtic potentiometric titration determinated chloride ions in electrolyte

    Institute of Scientific and Technical Information of China (English)

    林庆宇; 张志; 罗杨合; 练洁婷

    2011-01-01

    利用自动电位滴定仪,在体积分数为80%的丙酮介质中,以Ag电极为指示电极,双盐桥甘汞电极为参比电极,对铝箔生产液中Cl-进行非水滴定,方法的电位突跃明显,电极响应速度较快,SO42-、Cu2+、Fe3+及可能存在其他离子均对测定结果无影响,实现了自动电位滴定法快速测定铝箔生产过程液中Cl-的含量,结果表明本法是一种测定Cl-含量的有效方法.%Using automatic potentiometric titration, chlorine ions in aluminum electrolyte was determined at 80% acetone medium, with the silver electrode as indicator electrode, double salt bridge calomel electrode as reference electrode. The end point jumped of method over 500mV, the electrode responsed faster. Sulfate, copper ions, iron ions and other ions were no effect on the determination. The result showed that content of chloride could be achieved quickly by automatic potentiometric titration. It is an effective way to determine of industry chloride ion.

  17. 自动电位滴定法测定马蹄中的总还原糖%Determination of Reducing Sugar in Eleocharis dulcis by Automatic Potentiometric Titration

    Institute of Scientific and Technical Information of China (English)

    林庆宇; 张志; 魏小平; 严瑶

    2011-01-01

    [Objective] To study the new system for determining the reducing sugar in Eleocharis dukis by automatic potentiometric titration. [ Method] According to the principles of Film's indirect iodometric method,the automatic potentiometric titration was adopted to detect the con tent of reducing sugar,and the optimal conditions of the system were determined. [ Result] The standard deviation detected by the method was 2.47% ,RSD was 1. 30% , the added recovery was 99. 2% - 102. 5% ,and the average recovery was 99. 26%. [ Conclusion] The method was easy,rapid and accurate,which provided effective method for determining the sugar content of fruit products.%[目的]研究自动电位滴定法测定马蹄中总还原糖含量的新体系.[方法]根据菲林氏间接碘量法的原理,应用自动电位滴定法测定,确定了体系的最优条件.[结果]方法测定的标准偏差为2.47%,RSD为1.30%,加标回收率为99.2% ~ 102.5%,平均回收率为99.26%.[结论]该法操作简便快速、结果准确,为果品糖分含量提供有效的测定方法.

  18. Instrumentation and automated photometric titration procedure for total acidity determination in red wine employing a multicommuted flow system.

    Science.gov (United States)

    Garcia, Ausberta Jesus Cabezas; Reis, Boaventura F

    2006-01-01

    An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were controlled by a microcomputer through an electronic interface card. The software, written in Quick BASIC 4.5, was designed with abilities to accomplish all steps of the titration procedure including data acquisition and real-time processing to decide about the course of titration in the following step and so forth, until the titration endpoint was reached. The usefulness of the proposed titration system was demonstrated by analyzing red wine samples. When results were compared with those obtained using the AOAC reference method, no significant difference was observed at the 95% confidence level. A relative standard deviation of ca 2% (n=9) was obtained when processing a typical red wine sample containing 7.3 gl-1 total acidity expressed as tartaric acid. PMID:17671625

  19. Determination for acid and peroxide value in nuts by potentiometric titration method%电位滴定法测定坚果食品中的酸价和过氧化值

    Institute of Scientific and Technical Information of China (English)

    王国桢; 苏菊萍; 刘俐君; 李丹; 董琳; 王萍

    2015-01-01

    目的:建立坚果食品中酸价和过氧化值的电位滴定检测方法。方法本试验采用石油醚对坚果食品试样进行浸提,过滤后用旋转蒸发仪对试剂回收利用,并将浸提出的油脂用电位滴定法测定酸价和过氧化值,计算出坚果食品中酸价和过氧化值结果。结果选择瓜子、花生、杏仁、核桃4类坚果,不同实验室重复测定16次,酸价的电位滴定结果:0.29~4.09 mg/g,相对标准偏差:0.64%~3.63%;过氧化值的电位滴定结果:0.011~0.071 g/100 g,相对标准偏差:1.28%~8.77%。电位滴定结果与手动滴定结果相比较,无显著性差异(P>0.05)。结论坚果食品中酸价和过氧化值的电位滴定检测方法操作简单,结果准确度能满足国标要求,且灵敏度高,精密度好。%Objective To establish a testing method for determination of acid and peroxide value in nuts by potentiometric titration. Methods The nuts samples were extracted by the petroleum ether, the reagent after filtration was recycled with the rotary evaporator, the acid and peroxide value of the extraction of oil were tested by potentiometric titration, and then the results of acid and peroxide value in nuts were calculated. Results The melon-seeds, peanuts, almonds and walnuts as samples were used to detect in different labs, the results of acid value were 0.29~4.09 mg/g, the RSD was 0.64~3.63%, the results of peroxide value were 0.011~0.071 g/100 g, and the RSD was 1.28~8.77%. There is no significant difference between potentiometric titration and manual titration (P>0.05). Conclusion The method is simple, accurate, sensitive, and of high precision. It can be used to detect acid and peroxide value in nuts.

  20. Automated high-pressure titration system with in situ infrared spectroscopic detection

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Christopher J., E-mail: chris.thompson@pnnl.gov; Martin, Paul F.; Chen, Jeffrey; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Benezeth, Pascale [Géosciences Environnement Toulouse (GET), CNRS-Université de Toulouse, 31400 Toulouse (France)

    2014-04-15

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO{sub 2} (scCO{sub 2}) to generate an infrared calibration curve and determine the solubility of water in CO{sub 2} at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO{sub 2} at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO{sub 2} hydration, and ATR measurements provided insights into competitive residency of water and CO{sub 2} on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg{sub 2}SiO{sub 4}) in water-bearing scCO{sub 2} at 50 °C and 90 bar. Immediately after water dissolved in the scCO{sub 2}, a thin film of adsorbed water formed on the mineral surface

  1. 自动电位滴定仪测定铁矿石中全铁量的自动化程序设计%Program designing for determination of total iron content in iron ore by automatic potentiometric titrator

    Institute of Scientific and Technical Information of China (English)

    马德起; 武素茹; 臧世阳

    2012-01-01

    本文采用微波消解—自动电位滴定法测定铁矿石全铁量.重点研究自动电位滴定仪编写空白的滴定程序编写的方式对结果的影响、设计滴定程序,以经典的手工滴定法作对比,结果相似,达到滴定过程的自动化.结果表明:本法适用于铁矿石中全铁量的检测,测定范围为40%~70%,相对标准偏差小于2%.%A method based on Time Slice Model (TSM) is proposed for batch processes heat exchanger network synthesis by taking place. Total iron content in iron ore was determined by automatic potentiometric titrator and the sample was digested by microwave. The program designing for blank was discussed which effect on the results, and also the program designing for total titration, and then the results conformed to the manual titration method. The method applies to determination of total iron content in iron ore, the inspection range was 40%~70%, RSD

  2. Determination of the content of sodium acetate anhydrous by aqueous potentiometric titration method%水相电位滴定法测定无水乙酸钠含量

    Institute of Scientific and Technical Information of China (English)

    杨晓丽

    2011-01-01

    将无水NaAc配成水溶液,用自动电位滴定仪,以DETU滴定模式水相滴定法快速准确分析无水NaAc主体含量.结果表明,无水NaAc溶液浓度为0.1000mol· L-1时,滴定结果与国家标准方法分析结果基本一致,允许误差小于0.2%;标准偏差为0.030~0.057,相对标准偏差为0.030%~0.057%.%The anhydrous sodium acetate is prepared into water solution, The main content of anhydrous sodium acetate was determined by DETU aqueous titration method with automatic potentiometric titration.The results show that, anhydrous sodium acetate solution concentration was 0.1000 mol'L-1, GB/T titration and 694-1995 analysis results are basically consistent, allowable error is less than 0.2%; the standard deviation was 0.030-0.057, the relative standard deviation is 0.030%~0.057%.

  3. 自动电位滴定仪在铜元素分析中的应用研究%Analysis of Copper Element Using Automatic Potentiometric Titration Method

    Institute of Scientific and Technical Information of China (English)

    黄乐斯; 徐美娇; 彭娜; 彭锦锋; 吴文进; 范远红

    2011-01-01

    利用自动电位滴定仪,建立了铜合金和铜矿石中铜含量检测的一种新方法。结果表明:用二阶微商法确定滴定终点为245 mV,在预控点设置为310 mV,滴定剂硫代硫酸钠标准溶液浓度为0.01 mol/L滴定,pH在3~4之间时,加入2 mL氟化氢铵,取10 mL消解液的滴定结果较接近,且标准偏差较小,精密度高,测定结果准确。%Using automatic potentiometric titration instrument,a new method to examine the copper alloy and copper copper content palygorskite was established.5 kinds of titration parameters,like precontrol point setting,concentration of titrant,solution of to be tested acidity,addition amount of ammonium bifluoride and amount of testing solution were researched.Using second-order micro business method to judge titration end volume and abrupt jump potential points.At the best possible conditions,the copper alloy and copper ore content was determined by nitric acid digestion method.And make a comprehensive analysis on its precision and recovery percent.The results showed that the two order derivative method to determine the end point of titration for the 245 mV,in control point was set to 310 mV,the titration of sodium thiosulfate standard solution concentration was 0.01 mol/L titration,pH in 3~4,2 mL ammonium hydrogen fluoride,and 10 mL digestion liquid titration results were very close.The measuring result was accurate,with high precision and litter deviation.

  4. 多项目电位滴定系统在工业锅炉水质检测中的应用%The Usage of Automatic Potentiometric Titration in Industrial Boiler Water-treatment

    Institute of Scientific and Technical Information of China (English)

    黄容; 张居光; 邱康勇

    2012-01-01

    在工业锅炉水质检测中采用多项目电位滴定系统实现锅炉水中的pH、碱度、氯离子等多项目的同步检测,检测过程可溯源,检测效率高。该检测方法重复性符合相关标准,与手动测定结果的比对试验的相对平均偏差低于2%,回收率97%~105%。%By means of automatic potentiometric titration,multi-items of industrial boiler water-treatment such as pH,alkalinity,chlorinity can be synchronous detected.This detection method is traceable and efficient.The relative average deviation of comparative test is less than 2 %.The result of recovery test was 97 %~105 %.

  5. Recent Progress of Application of Potentiometric Titration in Drug Analysis%电位滴定法在药物分析中的应用进展

    Institute of Scientific and Technical Information of China (English)

    俞学炜; 丁荣敏

    2014-01-01

    A review of recent progress of application of potentiometric titrimetry to drug analysis covering the years from 1986 to 2012 was presented,relating especially to the topics on research works,on applications of vari-ous methods of potentiometric titrimetry to different kinds of drugs,and on future prospections in this field (48 ref. cited).%综述了从1986-2012年间电位滴定法在药物分析中的应用,主要涉及在此领域中的研究工作,不同电位滴定方法在不同类型药物分析中的应用以及对未来发展的展望(引用文献48篇)。

  6. 自动电位滴定仪测定海洋沉积物中碳酸盐百分含量%THE DETERMINATION OF CARBONATE CONTENT IN MARINE SEDIMENTS BY AUTOMATIC POTENTIOMETRIC TITRATOR

    Institute of Scientific and Technical Information of China (English)

    孙晗杰; 李铁刚; 于心科

    2012-01-01

    Based on the volumetric method, the determination of carbonate content in marine sediment was carried out by automatic potentiometric titrator with related software-tiamo, which can export the results automatically. This method is simple and rapid for batch measurement. The results were consistent with standards defined by the National Standard Reference of Deep-Sea Sediment. Seven independent determinations were measured for the same sample, and the standard deviation of the results was less than 0. 9 %. Several samples of sediment core MD06-3050 were used to measure carbonate content by automatic potentiometric titrator and ICP-OES. The results of two methods were consistent.%基于容量法原理,探讨了海底沉积物中碳酸盐的自动电位滴定法,配合tiamo软件,自动计算并输出测定结果.该法简单快速,且可以批量测试,经深海沉积物等国家标准物质验证,结果与标准值相符.对同一样品进行7次测定,其结果的相对标准偏差小于0.9%.该方法应用于西菲律宾海岩心MD06-3050的部分样品,测试结果与ICP-OES方法得到的结果具有一致性,该方法再现性良好,准确可信.

  7. Uncertainty Evaluation for the Determination of Chromium in Ferrochromium by Automatic Potentiometric Titration%自动电位滴定法测定铬铁中铬含量的不确定度评定

    Institute of Scientific and Technical Information of China (English)

    赵晶晶

    2013-01-01

    建立了自动电位滴定法测定铬铁中铬含量的数学模型,对数学模型中各个参数进行不确定度来源分析,分别对A类不确定度及B类不确定度进行评定,对各不确定度分量进行合成,得到铬质量分数的不确定度。当铬铁中铬含量为68.31%时,扩展不确定度为0.52%(k=2)。结果表明玻璃器具的精度、自动电位滴定仪自带体积管的误差、自动电位滴定仪终点识别的误差是测量不确定度的主要来源。%A mathematics model for evaluating the uncertainty for the determination of chromium in ferrochromium by automatic potentiometric titration was established. The uncertainty sources for each of the parameters in the model were analyzed. The uncertainties of type A or type B were evaluted. According to the method,the component uncertainties were synthesized, which were used to obtain the uncertainty evalution. The expanded uncertainty was 0.52%(k=2) as chromium content in errochromium was 0.52%.The results showed that the accuracy of glassware, inaccuracy from prover of automatic potentiometric titration and error from end identification were the main sources for uncertainties.

  8. Feasibility Study on the Application of Automatic Potentiometric Titrator in the Measurement of Organic Carbon in Marine Sediments%自动电位滴定仪应用于测定海洋沉积物中有机碳的可行性研究

    Institute of Scientific and Technical Information of China (English)

    王兵; 高丰蕾; 杨佩华; 孙承君; 韩彬

    2016-01-01

    The automatic potentiometric titrator has the advantages of being simple to operate and giving fast measurement results,which could reduce artifical influence due to manual operation. In this study, organic carbon content of marine sediments was determined by Automatic Potentiometric Titrator.In order to investigate if the Automatic Potentiometric Titrator could accurately determine the titration end-point,this method was compared with the national standard method (GB 17378.5—2007)in which the titration end-point was visually determined through color change.Results show that the detection limits of the automatic potentiometric titrator and manual methods were 0.029% and 0.086%,respectively.There are no significant differences between the two methods in titration end-point determination.However,the Automatic Potentiometric Titrator has better accuracy and precision than manual operation.Therefore,under certain circumstances,Automatic Potentiometric Titrator can take over the visual method to determine the titration end-point.It is also noteworthy that there are some problems in measuring real samples.For example,the Automatic Potentiometric Titrator might be unable to accurately determine the target titration end-point when there are complex electrical potential changes due to redox reactions and chelating interactions in the reaction system.On this occasion,the titration end-point can be determined visually.%自动电位滴定仪具有操作简便、测定速度快的优势,减少了人为操作的影响,本文使用自动电位滴定仪测定海洋沉积物中有机碳的含量,并与国家标准(GB 17378.5—2007)中根据滴定过程中溶液颜色变化用肉眼判定滴定终点的方法进行了对比分析,确定通过仪器自动判断滴定终点实现准确测定的可行性。结果表明:自动电位滴定的方法检出限为0.029%,人工肉眼判定终点的方法检出限为0.086%,在滴定终点判定方面两种方法

  9. 自动电位滴定仪测定水中氯化物的应用研究%Application Research on the Determination of Chloride in Water by Automatic Potentiometric Ti-tration Instrument

    Institute of Scientific and Technical Information of China (English)

    窦蓓蕾; 杏艳; 王舒婷; 郭晋君; 田渭花

    2014-01-01

    Determination of water by automatic potentiometric titration of chloride,can get high precision and accuracy,the quality control result in confidence.Compared with the traditional manual titration method, with a lower detection limit,is not affected by the turbidity and chroma of the determination of water,more suitable for low concentration of water samples and special water sample,worthy of promotion in environ-mental monitoring system.%采用自动电位滴定仪测定水中的氯化物,可得到较好的精密度及准确度,经质控样测定结果可信。与传统手工滴定法相比较,该方法具有更低的检出限,且不受水体浊度及色度的影响,更适用于低浓度水样和特殊水样的测定,值得在环境监测系统中推广应用。

  10. Determination of Chloride with Automatic Potentiometric Titration%自动电位滴定仪测定氯化物的探讨

    Institute of Scientific and Technical Information of China (English)

    李莉; 郑璇; 赵彬; 肖溶

    2012-01-01

    该实验就自动电位滴定仪测定氯化物的检出限、适用的水样pH范围及对其干扰物质的最大容忍浓度作了实验研究,对分析实际水样有一定的参考作用.%The detection limit, applicable pH and interference tolerance to chloride in the automatic potentiometric titrationwere discussed, which would be beneficial to the analysis of chloride.

  11. Quantitative determination of alkylcarboxylbetaine surfactants by automatic potentiometric titration%自动电位滴定法定量测定烷基羧基甜菜碱类表面活性剂含量

    Institute of Scientific and Technical Information of China (English)

    王海江; 戚晶晶; 许宗会; 郑昌戈; 崔正刚

    2012-01-01

    Quantitative determination of a series of alkylcarboxylbetaines by automatic potentiometric titration was studied with emphases as effect of selection of acidification agents, acidification temperature and time on the titralion result with respect to the content of alkylcarboxylbetaines. The results showed that the determination accuracy is significantly affected by the pH of the acidification system as well as the acidification temperature and time. Key issue is to assure the complete acidification of the alkylcarboxylbetaine molecules. By using acetic acid - sodium acetate buffer solution of pH = 3 as acidification system at 70 ~ 80 ℃ for 2 -3 h,the content of C12 - C18 alkyldimethylcarboxylbetaines and bis - dodecylmethylcarboxylbetaine can be potentiometric titrated by sodium dodecyl sulfate (SDS) with satisfactory result and the recovery achieves 97% - 102%. Good results have also be obtained by acidification in sulfuric acid solution of pH = 2 for 1 h at room temperature. For samples of technical grade betaine product, under the titration conditions, content of tertiary amine in the product will participate the titration reaction,so that the titration result is actually the sum of content of alkylbetaine and corresponding tertiary amine. Since the tertiary amine content can be independently measured using suitable method,the content of alkylbetaine can thus be quantitatively identified.%研究了酸化剂种类、酸化温度及时间等对电位滴定法测定烷基摹羧基甜菜碱含量的影响.结果表明,酸化剂的pH,酸化温度和时间等对测定结果有显著影响,关键是保证甜菜碱分子的完全酸化.以pH =3的醋酸-醋酸钠缓冲溶液作酸化体系,于70 ~80℃下酸化2~3h后用十二烷基硫酸钠(SDS)进行电位滴定,对C12-C18单长链烷基甜菜碱以及双十二烷基甜菜碱都能得到满意的结果,回收牢达到97%一102%.以硫酸作酸化剂,将pH提高到2左右,于室温下酸化lh后滴定,亦

  12. 无汞重铬酸钾-自动电位滴定法准确测定矿石中的全铁含量%Accurate Determination of Total Iron in Ores by Automatic Potentiometric Titration without Potassium Dichromate

    Institute of Scientific and Technical Information of China (English)

    赵怀颖; 温宏利; 夏月莲; 巩爱华; 马生凤

    2012-01-01

    铁矿石样品采用Na2O2碱熔进行前处理,自动电位滴定法准确测定矿石中全铁的含量.对于样品溶液Fe3+的还原方式,考察了SnCl2-HgC12、SnC12、TiC13、SnCl2-TiCl3四种方式,确定选用SnCl2-TiCl3联合还原,不仅避免了有毒试剂的使用,而且滴定终点电位突跃明显.自动电位滴定法的相对误差(RE)为0.13%,精密度(RSD)为0.22%,优于手动滴定法,避免了手动滴定受终点颜色判断误差、分析者水平等因素影响的不足.将建立的SnCl2-TiCl3-K2Cr2O7自动电位滴定法应用于6个铁含量大于30%的矿石标准物质分析,RE<0.2%,RSD<0.3%(n=10).该方法对于钒钛磁铁矿样品GBW07226a、GBW07224无需分离,可直接测定,样品分解方法简单快捷,适用性强,样品不会飞溅且分解完全,适用于需要较高准确度的铁矿石尤其是高含量铁矿石样品的分析工作.%For iron ores, this paper discusses an alkali fusion method of sodium peroxide to resolve the ores without splash and complete decomposition. Four methods of reducing Fe3+ to Fe2+ are also discussed, using stannous chloride and titanium trichloride as this not only avoids the use of toxic reagents, but also has a clearly potential jump at the end of the titration. Finally, the manual titration method is replaced by an automatic potentiometric titration to avoid manual errors, such as the judgement of the end of titration by colour and the level of experience of the analyst. The relative error can be reduced to 0. 13% and the relative standard deviation is 0. 22%. A new SnCl2 - TiCl3 - K2 Cr2 O7 automatic potentiometric titration method has been developed. It has been applied to detect six National Standard Reference iron ore samples where the content of iron is higher than 30% and the relative error is lower than 0. 2% , the relative standard deviation being lower than 0. 3% (n = l0). The magnetite GBW 07226a and GBW 07224 with high vanadium and titanium can be determined

  13. Determination on Content of Chloride in the FGD System Wastewater by Automatic Potentiometric Titration%自动电位滴定法测定湿法脱硫系统脱硫废水中氯化物

    Institute of Scientific and Technical Information of China (English)

    高姗; 郭磊; 宋晓红

    2011-01-01

    By automatic potentiometric titration,at pH=5 sourish water mixtures with total ionic strength buffer,wet de-sulfurization wastewater was determinted with titration teagen of 0.05 mo1·L-1 AgNO 3.The different concentration of chloride desulfurization wastewater samples were experienced and analyzed.Tests for recovery were made by the stan-dard addition method,and the recovery were between 95.21% and 107.46%.Tests for precision were made with different samples,and the relative standard deviation(sRSDs)were between 0.19% and 5.30%.%应用自动电位滴定法,在pH=5的总离子强度缓冲溶液存在的微酸性水溶液中,用0.05 mo1·L-1硝酸银标准溶液作为滴定剂,测定了湿法脱硫废水中氯化物含量。实验对不同浓度氯化物的脱硫废水样品分别进行了实验并加以分析。用标准加入法进行了回收率试验,结果在95.21%~107.46%之间。用不同样品进行了精密度试验,方法的相对标准偏差(n=6)在0.19%~5.30%之间。

  14. 电位滴定法测定白酒总酯的不确定度分析%Evaluation of the Uncertainty in the Determination of Total Esters Content in Liquor by Automatic Potentiometric Titration

    Institute of Scientific and Technical Information of China (English)

    刘妙芬; 邱佩丽; 丁怡; 黄秋婷; 彭程

    2012-01-01

    The uncertainty components in the determination of total esters content in liquor by potentiometric titration were analyzed and quantified according to the evaluation principles of uncertainty.The effects of measurement repeatability,sampling,preparation process of standard solution,burette and molar weight etc on the uncertainty were also investigated to establish the mathematical model of uncertainty.The combined standard measurement uncertainty of total ester content was calculated to be 0.00836 g / L and the expanded uncertainty was 0.0167g / L(k = 2).%根据测量不确定度的评定原理和方法,对电位滴定法测定白酒中总酯含量过程的不确定度分量进行分析和定量,分析了测量重复性、取样、标准滴定液的标定过程、滴定管和摩尔质量等因素对测量不确定度的影响,建立了不确定度的数学模型。计算得到总酯的合成标准不确定度为uc=0.00836 g/L,扩展不确定度为U=0.0167 g/L;k=2。

  15. Determination of Content of Calcium in Desulfurization Slury by Automatic Potentiometric Titration%自动电位滴定法测定脱硫浆液中的钙含量

    Institute of Scientific and Technical Information of China (English)

    张瑞枝

    2011-01-01

    The content of calcium in desulfurization slury was determined by automatic potentiometric titration.The proposed method was applied to the determination of calcium in various contents of 14.8~26.7 mmol/L desulfurization slury,giving values of recovery and RSD's(n =5) in the ranges of 97.60%~100.72% and 0.54%~0.99% respectively.%建立了自动电位滴定法测定脱硫浆液中钙含量的方法,即取适量浆液经适当程序处理后进行滴定。对实际样品和标准溶液的测试结果表明:不同浆液样品中,14.8~26.7 mmoL/L的加标回收率为97.60%~100.72%,相对标准偏差为0.54%~0.99%(n=5),方法操作简单、快速,自动化程度高,准确度和重复性好,适用于钙含量的常规分析。

  16. Determination of chromium content in ferrochromium alloy by automatic potentiometric titration%自动电位滴定法测定铬铁合金中的铬含量

    Institute of Scientific and Technical Information of China (English)

    赵晶晶; 宁海龙; 常健辉

    2011-01-01

    A new method based on automatic potentiometric titration was established for the determination of chromium content in ferrochromium. The precision, recovery and accuracy of the method were investigated. The RSD was 0. 07%~0. 09%, and the recovery was 100. 38%~100. 45%. The method is simple and rapid* and the results are satisfactory.%利用自动电位滴定仪,建立了铬铁合金铬含量检测的一种新方法,对方法的准确度、回收率、精密度进行了全面的分析,该方法相对标准偏差为0.07%~0.09%,回收率为100.38~100.45%,该方法操作简便、测定快速,结果令人满意,是一种简便易行的测定铬铁合金中铬含量的新方法.

  17. 自动电位滴定测定马蹄提取物中多酚类化合物%Determination of Polyphenols in Chinese Water Chestnut Extraction by Automatic Potentiometric Titration

    Institute of Scientific and Technical Information of China (English)

    汤亚芳; 黄广凤

    2016-01-01

    建立电位滴定法测定马蹄中多酚类化合物含量的定量分析方法。以高锰酸钾为氧化剂,在强酸性介质中,以没食子酸为参照,用二阶微分法确定待测样品试液的滴定终点电位,对马蹄提取物中的多酚类化合物进行自动滴定,并与可见分光光度法进行对比。方法的RSD为1.29%(n=5),平均回收率为99.34%。结果表明,本方法体系可以完成对多酚类物质的快速测定。%The automatically potentiometric titration was used to determine polyphenols in Chinese Water chestnut. The sample was tested used potassium permanganate as an oxidant in strong acid medium , gallic acid as reference, and the result was compared with the visible spectrophotometry. The RSD of method was 1.29%(n=5), and the average recovery was 99.34%. The results showed that the methodology can be completed on the rapid determination of polyphenols.

  18. Determination of Chloride in Infant Formula and Adult/Pediatric Nutritional Formula by Potentiometric Titration: Single-Laboratory Validation, First Action 2015.07.

    Science.gov (United States)

    Bolong, Wu; Fengxia, Zhang; Xiaoning, Ma; Fengjuan, Zhou; Brunelle, Sharon L

    2016-01-01

    A potentiometric method for determination of chloride was validated against AOAC Standard Method Performance Requirement (SMPR(®)) 2014.015. Ten AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1849a, were tested in duplicate on 6 independent days. The repeatability (RSDr) ranged from 0.43 to 1.34%, and the intermediate reproducibility (RSDiR) ranged from 0.80 to 3.04%. All results for NIST SRM 1849a were within the range of the certified concentration (701 ± 17 mg/100 g). Recovery was demonstrated with two overspike levels, 50 and 100%, in the 10 SPIFAN matrixes. Samples were tested in duplicate on 3 different days, and all results were within the SMPR requirement of 95 to 105%. The LOQs of the method for powdered products and ready-to-feed or reconstituted products were 20 mg/100 g and 2.2 mg/100 mL, respectively. A wide analytical range from the LOQ to 99.5% chlorine content can be reached with an appropriate dilution factor, but in practice, the upper analytical value observed in routine matrix testing was approximately 1080 mg/100 g in skim milk powder. This is a rapid, simple, and reliable chlorine-testing method applicable to infant formula, adult nutritionals, and ingredients used in these dairy-based products, such as skim milk powder, desalted whey powder, whey protein powder, and whole milk powder. PMID:26822885

  19. An estimated potentiometric surface of the Death Valley region, Nevada and California, developed using geographic information system and automated interpolation techniques

    International Nuclear Information System (INIS)

    An estimated potentiometric surface was constructed for the Death Valley region, Nevada and California, from numerous, disparate data sets. The potentiometric surface was required for conceptualization of the ground-water flow system and for construction of a numerical model to aid in the regional characterization for the Yucca Mountain repository. Because accurate, manual extrapolation of potentiometric levels over large distances is difficult, a geographic-information-system method was developed to incorporate available data and apply hydrogeologic rules during contour construction. Altitudes of lakes, springs, and wetlands, interpreted as areas where the potentiometric surface intercepts the land surface, were combined with water levels from well data. Because interpreted ground-water recharge and discharge areas commonly coincide with groundwater basin boundaries, these areas also were used to constrain a gridding algorithm and to appropriately place local maxima and minima in the potentiometric-surface map. The resulting initial potentiometric surface was examined to define areas where the algorithm incorrectly extrapolated the potentiometric surface above the land surface. A map of low-permeability rocks overlaid on the potentiometric surface also indicated areas that required editing based on hydrogeologic reasoning. An interactive editor was used to adjust generated contours to better represent the natural water table conditions, such as large hydraulic gradients and troughs, or ''vees''. The resulting estimated potentiometric-surface map agreed well with previously constructed maps. Potentiometric-surface characteristics including potentiometric-surface mounds and depressions, surface troughs, and large hydraulic gradients were described

  20. Study on automatic potentiometric titration for the determination of free hydroxide in the straight hair cream (agent)%自动电位滴定仪连续测定直发产品中游离氢氧化物方法的研究

    Institute of Scientific and Technical Information of China (English)

    周长美; 李小娟; 吴健

    2012-01-01

    Objective: To build up a method for fast and accurate determination of free hydroxide in the straight hair products. Methods: Free hydroxide in the straight hair products reacted with the hydrochloric acid, pH combination glass electrode potential may change and automatic potentiometric titrator was used to record the titration of the hydrochloric acid standard solution at pH =9. 2, then free hydroxide content in the samples was calculated. Results : The precision of automatic potentiometric titrator method was better than manual titration, the relative standard deviation was 0. 55% ; the former also has better accuracy, the average recovery of three groups of samples was between 97. 6% and 102. 9%. It has a good effect on removing ammonia from straight hair products by vacuum. Conclusion: Automatic potentiometric titration method for the determination of free hydroxide in the straight hair cream (agent) in the samples is simple, fast and accurate, suitable for batch testing with strong practical utility.%目的:建立一种快速、准确的测定直发产品中游离氢氧化物的方法.方法:直发产品中游离氢氧化物与盐酸发生中和反应,pH复合玻璃电极上电位发生变化,在溶液pH =9.2时自动记录盐酸标准溶液的滴定量,从而计算出样品中游离氢氧化物含量.结果:自动电位滴定仪法的精密度优于人工滴定法,相对标准偏差为0.55%;方法有较好的准确度,三组样品测得的平均加标回收率为97.6% ~ 102.9%,总平均加标回收率为98.9%;方法中抽真空法去除氨效果良好.结论:运用自动电位滴定法测定直发膏(剂)类样品中的游离氢氧化物,方法简便、快速、准确,该方法适合批量检测,实用性强.

  1. Simultaneous and automated monitoring of the multimetal biosorption processes by potentiometric sensor array and artificial neural network.

    Science.gov (United States)

    Wilson, D; del Valle, M; Alegret, S; Valderrama, C; Florido, A

    2013-09-30

    In this communication, a new methodology for the simultaneous and automated monitoring of biosorption processes of multimetal mixtures of polluting heavy metals on vegetable wastes based on flow-injection potentiometry (FIP) and electronic tongue detection (ET) is presented. A fixed-bed column filled with grape stalks from wine industry wastes is used as the biosorption setup to remove the metal mixtures from the influent solution. The monitoring system consists in a computer controlled-FIP prototype with the ET based on an array of 9 flow-through ion-selective electrodes and electrodes with generic response to divalent ions placed in series, plus an artificial neural network response model. The cross-response to Cu(2+), Cd(2+), Zn(2+), Pb(2+) and Ca(2+) (as target ions) is used, and only when dynamic treatment of the kinetic components of the transient signal is incorporated, a correct operation of the system is achieved. For this purpose, the FIA peaks are transformed via use of Fourier treatment, and selected coefficients are used to feed an artificial neural network response model. Real-time monitoring of different binary (Cu(2+)/ Pb(2+)), (Cu(2+)/ Zn(2+)) and ternary mixtures (Cu(2+)/ Pb(2+)/ Zn(2+)), (Cu(2+)/ Zn(2+)/ Cd(2+)), simultaneous to the release of Ca(2+) in the effluent solution, are achieved satisfactorily using the reported system, obtaining the corresponding breakthrough curves, and showing the ion-exchange mechanism among the different metals. Analytical performance is verified against conventional spectroscopic techniques, with good concordance of the obtained breakthrough curves and modeled adsorption parameters. PMID:23953435

  2. The Study on Detection of Chloride Ion in Flue Gas Ammonium Sulfate Slurry by Automatic Potentiometric Titration Method%自动电位滴定法测定烟气氨法脱硫模拟浆液中氯离子的研究

    Institute of Scientific and Technical Information of China (English)

    杭蕾; 吕程; 陈慧慧; 连洲洋; 袁礼锐; 魏无际

    2015-01-01

    Chloride ion content of ammonia desulfurization process is an important monitoring indicators and this paper dis-cusses the detection of chloride ions in ammonium sulfate slurry by automatic potentiometric titration .The results show that :adding ethanol helps to increase the magnitude of the potential jump ;when pH=3-5 ,the result is accurate ;the recovery rate keeps between 90% and 110% ;compared with the Mohr method ,the test result is more accurate and precise and free from ash color;also the tested result is close to ion chromatography detection result ,but the high concentrations of chloride ion potentiometric titration is more advantageous .%氯离子含量是氨法脱硫工艺中的一个重要监控指标,用自动电位滴定法测定氨法脱硫浆液中的氯离子。结果表明,实验加入乙醇有利于增大电位突跃幅度;pH值为3~5时实验结果准确;加标回收率为90%~110%;与莫尔法相比,测定结果准确度、精密度更高,且不受灰分颜色干扰;与离子色谱法测定结果准确度、精密度相近,但测定高浓度氯离子电位滴定法更有优势。

  3. The determination of titratable acidity and total tannins in red wine

    OpenAIRE

    Rajković Miloš B.; Sredović Ivana D.

    2009-01-01

    Titration acidity and content of total tannins in mass-market red wines are analyzed in this paper. The content of total acids in wine, expressed through wine acid, was analyzed by potentiometric titration on 7.00 pH value. According to titratable acidity in analyzed wines, all wines (only) with analyzed parameters according to Regulations about wine quality. The analysis of differential potentiometric curves shows that these curves can give the answer to the question if non organic substance...

  4. 超声溶解-电位滴定法测定硅钢涂层用纳米二氧化钛中氯%Determination of chlorine in nanoscale titanium dioxide used in silicon steel coating by potentiometric titration with ultrasonic dissolution

    Institute of Scientific and Technical Information of China (English)

    闻向东; 谭谦; 邵梅; 张穗忠

    2015-01-01

    采用加酸后超声震荡的方法处理样品,建立了电位滴定法测定了硅钢涂层用纳米二氧化钛中氯离子含量的方法。实验确定了最佳条件:称取0.1 g过300目(50μm)筛孔的样品,加入20 mL硝酸(1+5)后,在90 kHz的条件下室温超声振荡30 min,过滤后稀释,以等体积自动加入0.10 mL 0.01 mol/L硝酸银标准滴定溶液的方式进行滴定,以d2 E/dV2-V滴定曲线中E/V的二阶倒数为零时计算滴定终点。将方法应用于硅钢涂层用纳米二氧化钛实际样品分析,结果与分光光度法一致,相对标准偏差(RSD, n=8)小于5%,加标回收率为99%~102%。%The sample was treated in acid by ultrasonic oscillation. A determination method of chlorine ion content in nanoscale titanium dioxide used in silicon steel coating was established by potentiometric titration. The optimal conditions were obtained by experiments:0. 1 g of sample was screened with 300-mesh (50μm) sieve;the sample was dissolved at room temperature with 20 mL of nitric acid (1+5) by ultrasonic oscillation at 90 kHz for 30 min;after filtration and dilution, the sample solution was titrated with 0. 10 mL of 0. 01 mol/L silver nitrate standard ti-tration solution by isovolumetric automatic addition. The titration endpoint was calculated when the second deriva-tive of E/V in d2 E/dV2-V titration curve was zero. The proposed method was applied to the analysis of actual sam-ple of nanoscale titanium dioxide used in silicon steel coating. The results were consistent with those obtained by spectrophotometry. The relative standard deviation ( RSD, n=8 ) was less than 5%, and the recoveries were be-tween 99% and 102%.

  5. Determination of titratable acidity in white wine

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2007-01-01

    Full Text Available The amount of titration acid in must is in the largest number of cases with in the range 5.0-8.0 g/dm3. Wines, as a rule, contain less acids than must, and according to Regulations, titratable acidity is in the range of 4.0-8.0 g/dm3 expressed in tartaric acid, because a part of tartaric acid is deposited in the form of salts (tartar or argol during alcohol fermentation. For wines that contain less than 4 g/dm3 of titratable acids there arises a suspicion about their origin, that is, that during the preparation some illegal acts were done. Because of that, the aim of this paper is to determine titratable acidity in white wine, using standard methods of determination, which are compared with the results received by potentiometric titration using ion-selective electrode. According to the received results it can be seen that wine titration with indicator gives sufficient reliable values of wine titration acidity. However, as potentiometric titration at pH value 7.00 is more reliable and objective method, the values of titratable acids content in wine, expressed through tartaric acid, are given according to this result. The analysis of differential potentiometric curves shows that these curves can give us an answer to the question of the presence of a larger amount of other nonorganic substances, which have already existed in wine. However, none of the used methods gives absolutely reliable answer what substances are present in analysed samples.

  6. HPLC法和非水电位滴定法测定盐酸艾咪朵尔含量%Determination content of imidol hydrochloride by HPLC and non-aqueous potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    徐丽佳; 陈晓辉; 刘中博; 宫平; 于治国; 毕开顺

    2009-01-01

    目的:分别建立高效液相色谱法和非水电位滴定法测定盐酸艾咪朵尔含量.方法:高效液相色谱法:色谱柱为Kromasil C_(18)(250 mm×4.6 mm,5 μm);流动相为甲醇-水-甲酸(36:64:0.5,v/v/v),流速1.0 mL·min~(-1);检测波长为254 nm;柱温30℃.非水电位滴定法以冰醋酸和醋酐为溶剂,用0.1 mol·L~(-1)高氯酸溶液进行滴定.结果:高效液相色谱法:盐酸艾咪朵尔在2.02~50.4 μg·mL~(-1)范围内线性关系良好,r=0.9999;方法精密度RSD为0.45%(n=5);平均回收率为100.0%(n=9).非水电位滴定法:方法精密度RSD为0.13%(n=5);平均同收率为99.8%,RSD为0.15%(n=5).结论:高效液相色谱法和非水电位滴定法的测定结果在统计学上无显著性筹异.高效液相色谱法分离能力高,专属性强,消耗样占占最少;非水电位滴定法简单、快速,测定结果精密,准确度高.%Objective:To establish an HPLC method and a non-aqueous potentiometry titration method for the content determination of imidol hydrochloride.Methods:An HPLC method was used.The separation was performed on a Kromasil C_(18) column(250 mm×4.6 mm,5 μm).The mobile phase was methanol-water-formic acid(36:64:0.5,v/v/v)at a flow rate of 1.0 mL·min~(-1).The UV detection was set at 254 nm and the column temperature was maintained at 30℃.Acetic acid and acetic anhydride were used as solvent for non-aqueous potentiomerry titration.0.1 mol·L~(-1) perchloric acid was used to titrate the content of imidol hydrochloride.Resuits:HPLC:The linear range for imidol hydrochloride was 2.02-50.4 μg·mL~(-1)(r=0.9999),the precision RSD was 0.45%(n=5),the average recovery was 100.0%(n=9),non-aqueous potentiometry titration:The precision RSD was 0.13%(n=5),the average recovery was 99.8%with an RSD of 0.15%(n=5).Conclusions:The HPLC method and non-aqueous potentimetry titration method are identical statistically.The HPLC method is sensitive,specific and needs small amount of sample.Non-aqueous potentiometry

  7. Application of mensurating alkalinity in PO by automatic potentiometric titration%自动电位滴定仪在测定环氧丙烷中碱度的应用

    Institute of Scientific and Technical Information of China (English)

    庄恒榕

    2015-01-01

    采用电石渣作皂化剂的氯醇法生产环氧丙烷(PO),其碱度会对下游产品产生影响,而目前PO碱度检测无国家标准可参考。为了有效检测PO中的碱度,本文研究建立了一种自动电位滴定仪测定方法。实验结果表明,该方法的精密度和准确度符合要求,且操作简单。%At present,the normal chlorohydrination of carbide slag as saponification agent to produce the propylene oxide (denoted as PO)has a negative effect for the down-stream product,and the alkalinity of PO has not been exactly detected so far. Herein,we develop an efficient automatic potentiometric tritration method to detect the alkalinity of PO sample. In conclusion,a facile method can be employed to mensurate the alkalinity of PO,and the results are much more accurate than normal measurement method.

  8. 电位滴定法测定乙醇/水混合体系中松香酸的离解常数%The Determination of the Dissociation Constants of Abietic Acidin Ethanol/Water Mixed Solvent by Potentiometric Titration

    Institute of Scientific and Technical Information of China (English)

    南丹; 蒋丽丹; 王良贵

    2012-01-01

    采用电位滴定法,在乙醇/水混合溶剂体系(I=0.10mol/L,Kcl)测定了松香酸在不同乙醇含量(Ⅳ%)时的离解常数。结果表明,在试验范围内pK同乙醇含量的体积分数有良好线性关系,通过外推求得在试验条件下松香酸水溶液中的离解常数pK为4·937。%The dissociation constants of abietic acid in water- ethanol mixed solvent (I =0.10 mol/L, KC1) were determinded by potentiometric titration. The results showed that the pKa was a good linear function of the volume fraction of ethanol in the concentration range. The dissociation constants of abietic acid in water were determinded by extrapolation to be 4. 937 under the experimental conditions.

  9. 自动电位滴定法标定硫酸铈溶液和测定硫酸亚铁片中铁含量%Calibration of Ceric Sulfate Solution and Determination of Fe in Ferrous Sulfate Tablets by Automatic Potentiometric Titration Method

    Institute of Scientific and Technical Information of China (English)

    伍建君; 汪严; 杨孝容

    2014-01-01

    Automatic potentiometric titration method (APTM)was applied to the calibration of ceric sulfate solution and ferrum in ferrous sulfate tablets was determined by APTM.The end-point of titration was measured with potential jump by APTM.Value of RSD (n=5)found was 0.070% for calibration of ceric sulfate with sodium oxalate solution at temperatures between 45 ℃ and 50 ℃.A ferrous sulfate tablet was dissolved with 0.01 mol· L-1 sulfuric acid solution (30 mL)and titrated directly with ceric sulfate solution for determination of ferrum.The proposed method was applied in the analysis of samples of ferrous sulfate tablets,giving values of recovery of 100%and RSD′s (n=5)in the range of 1.2%-2.6%.%采用自动电位滴定法标定硫酸铈溶液,并进行硫酸亚铁片中铁含量的测定。自动电位滴定法以电位突跃监测终点,在45℃~50℃之间,以草酸钠溶液标定硫酸铈溶液,测定值的相对标准偏差(n=5)为0.070%。取硫酸亚铁片1片用0.01 mol·L-1硫酸溶液30 mL 溶解,直接用硫酸铈溶液滴定测定铁含量。方法用于硫酸亚铁片样品分析,回收率为100%,测定值的相对标准偏差(n=5)在1.2%~2.6%之间。

  10. Potentiometric determination of ibuprofen, indomethacin and naproxen using an artificial neural network calibration

    Directory of Open Access Journals (Sweden)

    A. HAKAN AKTAŞ

    2008-01-01

    Full Text Available In this study, three anti-inflammatory agents, namely ibuprofen, indomethacin and naproxen, were titrated potentiometrically using tetrabutylammonium hydroxide in acetonitrile solvent under a nitrogen atmosphere at 25 °C. MATLAB 7.0 software was applied for data treatment as a multivariate calibration tool in the potentiometric titration procedure. An artificial neural network (ANN was used as a multivariate calibration tool in the potentiometric titration to model the complex non-linear relationship between ibuprofen, indomethacin and naproxen concentrations and the millivolt (mV of the solutions measured after the addition of different volumes of the titrant. The optimized network predicted the concentrations of agents in synthetic mixtures. The results showed that the employed ANN can precede the titration data with an average relative error of prediction of less than 2.30 %.

  11. 修饰铂电极上Bi(Ⅲ)的示波双电位滴定法%Oscillo-Potentiometric Titration of Bismuth(Ⅲ)Using Modified Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    齐蕾; 齐同喜

    2011-01-01

    Bi ( Ⅲ ) modified Pt-electrode was prepared and the adsorption character of Bi ( Ⅲ ) on the electrode was studied by cyclic voltammetry. The mechanism of electrode response was discussed. A method using oscillo-potentiometry for the titration of Bi( Ⅲ) was described. In 0. 1 mol/L nitric acid solution (pH = 1.0) , Bi( Ⅲ) was titrated with EDTA, and two modified Pt-electrodes were used as bi-indicator electrode system. The end point of titration was determined by an abrupt maximum displacement of the fluorescence spot observed on the screen of the cathodic oscillograph. When Bi( Ⅲ) content was in the range of 1. 19 × 10 -4 ~ 1.44× 10-2 mol/L, the recovery was in the range of 99. 8% ~ 100. 1% and the detection limit was 1. 0 × 10-4 mol/L(S/N = 3). Furthermore, the modified electrode showed excellent stability and reproducibility. In 1.0 × 10-2 mol/L Bi ( Ⅲ ) solution, the values of end point potentials obtained from 7 continuous determinations were all around 100 mV, and the relative standard deviation( RSD) was 0.04%. Moreover, the proposed method has been used in the determination of Bi ( Ⅲ) contained in samples with recoveries of 99. 5%~100. 5% and RSD(n = 7) less than 0. 25% , which are in accordance with the indicator method.%制备了Bi(Ⅲ)修饰铂电极,用循环伏安法表征了Bi(Ⅲ)在电极上的吸附特性,探讨了电极的响应机理.通过优化实验条件,建立了一种测定Bi(Ⅲ)的示波双电位滴定法.在0.1 moL/L的硝酸溶液中(pH=1.0).用制备的修饰铂电极作为双指示电极,以EDTA标准溶液滴定Bi(Ⅲ),利用示波器屏幕上荧光点的显著最大位移指示滴定终点.Bi(Ⅲ)在1.19×10(-1)~1.44×10(-2)moL/L时,回收率为99.8%~100.1%,检出限(S,N=3)为1.0×10(-4)mol/L.该修饰电极具有良好的稳定性和重现性,在含有1.0×10(-2)moL/L Bi(Ⅲ)的溶液中,连续7次测定,所得终点电位值均在100 mV左右,其相对标准偏差(RSD)为0.04%.应用该

  12. Method for the Determination of Chloride Ion Flux with the Automatic Potentiometric Titration%自动电位滴定法测定焊剂中氯离子的方法

    Institute of Scientific and Technical Information of China (English)

    朵云琨; 邓勇; 朵云峰

    2014-01-01

    采用自动电位滴定法测定焊剂中氯离子的质量分数,对试样的处理、酸度的影响、线性范围、标准回收、精密度和准确度等进行探究.结果表明:对样品11次测定值的相对标准偏差(RSD)为2.27%~2.35%,标准回收率为99.00%~100.80%;所用方法的准确度和精密度较好,适合于焊剂中0.02%~1.00%氯离子的测定.%Using Auto-electric titration method measured Cl-in flux of mass fraction,the sample processing,the effects of acidity,linear range,standard recovery,precision and accuracy were studied.The results show that:the relative standard deviation of the measured val-ue of the samples for eleven times (RSD)ranged from 2.27%-2.35%;the standard recovery rate was 99.0%-100.8%;The accuracy and precision of the method are good,and suitable for the determination of 0.02%-1.00%in the flux of chloride ion.

  13. Study on the determination of chIoride ions in the continuous detection by muIti-project automatic potentiometric titration%多项目自动电位滴定连续检测中氯离子测定的研究

    Institute of Scientific and Technical Information of China (English)

    戴恩贤; 周英

    2015-01-01

    采用国际先进的多功能自动电位滴定仪,实现在同一杯水中自动连续检测多项水质指标,是水处理工作中先进高效的新颖检测方法。然而在同一杯水中测定多项指标,是否会彼此产生干扰,需要进行试验研究。作者为配合该方法的国家标准制订,针对多项目连续检测中氯离子测定的影响因素进行系列研究分析,确认多项目自动检测中氯离子的测定是准确可靠的。%Multiple indices of water quality can be detected in the same cup of water automatically and continuously by the international,advanced,multifunctional&automatic potentiometric titration,which is an advanced and effi-cient detection method in water treatment. However ,it needs to be tested and studied whether there will be interfer-ence when multiple indices are detected in the same cup of water. According to the influential factors of chloride ion determination in the continuous detection ,series of study and analyses have been carried out to coordinate with the formulation of national standards. It is confirmed that the determination of chloride ions in the multi-project automatic detection is accurate and reliable.

  14. Caracterização ácido-base da superfície de espécies mistas da alga Spirulina através de titulação potenciométrica e modelo de distribuição de sítios discretos Acid base characterization of the surface of mixed species of algae Spirulin by potentiometric titration and discrete site distribution model

    Directory of Open Access Journals (Sweden)

    Elizabete C. de Lima

    1999-09-01

    Full Text Available Acid base properties of mixed species of the microalgae Spirulina were studied by potentiometric titration in medium of 0.01 and 0.10 mols L-1 NaNO3 at 25.0±0.10 C using modified Gran functions or nonlinear regression techniques for data fitting. The discrete site distribution model was used, permitting the characterization of five classes of ionizable sites in both ionic media. This fact suggests that the chemical heterogeneity of the ionizable sites on the cell surface plays a major role on the acid-base properties of the suspension in comparison to electrostatic effects due to charge-charge interactions. The total of ionizable sites were 1.75±0.10 and 1.86±0.20 mmolsg-1 in ionic media of 0.01 and 0.10 mols L-1 NaNO3, respectively. A major contribution of carboxylic groups was observed with an average 34 and 22% of ionizable sites being titrated with conditional pcKa of 4.0 and 5.4, respectively. The remaining 44% of ionizable sites were divided in three classes with averaged conditional pcKa of 6.9, 8.7 and 10.12, which may be assigned respectively to imidazolic, aminic, and phenolic functionalities.

  15. Dysprosium selective potentiometric membrane sensor

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Faridbod, Farnoush; Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

    2013-03-01

    A novel Dy(III) ion-selective PVC membrane sensor was made using a new synthesized organic compound, 3,4-diamino-N Prime -((pyridin-2-yl)methylene)benzohydrazide (L) as an excellent sensing element. The electrode showed a Nernstian slope of 19.8 {+-} 0.6 mV per decade in a wide concentration range of 1.0 Multiplication-Sign 10{sup -6}-1.0 Multiplication-Sign 10{sup -2} mol L{sup -1}, a detection limit of 5.5 Multiplication-Sign 10{sup -7} mol L{sup -1}, a short conditioning time, a fast response time (< 10 s), and high selectivity towards Dy(III) ion in contrast to other cations. The proposed sensor was successfully used as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also applied to the F{sup -} ion indirect determination of some mouth washing solutions and to the Dy{sup 3+} determination in binary mixtures. Highlights: Black-Right-Pointing-Pointer The novelty of this work is based on the high affinity of the ionophore toward the Dy{sup 3+} ions. Black-Right-Pointing-Pointer This technique is very simple, fast and inexpensive and it is not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer The newly developed sensor is superior to the formerly reported Dy{sup 3+} sensors in terms of selectivity.

  16. Potentiometric sensors for the selective determination of sulbutiamine.

    Science.gov (United States)

    Ahmed, M A; Elbeshlawy, M M

    1999-11-01

    Five novel polyvinyl chloride (PVC) matrix membrane sensors for the selective determination of sulbutiamine (SBA) cation are described. These sensors are based on molybdate, tetraphenylborate, reineckate, phosphotun gestate and phosphomolybdate, as possible ion-pairing agents. These sensors display rapid near-Nernstian stable response over a relatively wide concentration range 1x10(-2)-1x10(-6) M of sulbutiamine, with calibration slopes 28 32.6 mV decade(-1) over a reasonable pH range 2-6. The proposed sensors proved to have a good selectivity for SBA over some inorganic and organic cations. The five potentiometric sensors were applied successfully in the determination of SBA in a pharmaceutical preparation (arcalion-200) using both direct potentiometry and potentiometric titration. Direct potentiometric determination of microgram quantities of SBA gave average recoveries of 99.4 and 99.3 with mean standard deviation of 0.7 and 0.3 for pure SBA and arcalion-200 formulation respectively. Potentiometric titration of milligram quantities of SBA gave average recoveries of 99.3 and 98.7% with mean standard deviation of 0.7 and 1.2 for pure SBA and arcalion-200 formulation, respectively. PMID:10703998

  17. Permian potentiometric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Devary, J.L.

    1983-09-01

    Pacific Northwest Laboratory (PNL) was requested to analyze potentiometric data from the Wolfcamp Formation of the Permian System to evaluate the recommendations by the University of Texas/Bureau of Economic Geology (UT/BEG) that additional geohydrologic boreholes be drilled into the Wolfcamp. The UT/BEG recommended that two stratigraphic and two geohydrologic borings be drilled into the Permian System during FY83 and that several shallow hydrologic tests be made in the Dockum Formation. A geostatistical technique known as kriging was applied to objectively evaluate these geohydrologic borehole recommendations. The Deaf Smith County location appears to be an excellent choice for a borehole. No high quality potentiometric data are available from Deaf Smith County and a borehole location immediately upgradient from the candidate repository site is needed. Adding this borehole location to the potentiometric data base will significantly reduce field data uncertainty near the location being studied. The Swisher County location does not appear to be the best choice. High quality data values H2206 and H2360 are located immediately upgradient from the proposed repository site. The best placement of additional geohydrological boreholes in the Wolfcamp Formation depends strongly upon the proposed repository location. The variability of the potentiometric data causes estimation errors to rapidly increase away from locations of field measurements. Suggested locations for additional boreholes for the Deaf Smith investigations are in northwest Randall or central Potter Counties. Ideal borehole locations for the Swisher county studies appear to be in southeast Randall and Armstrong Counties.

  18. Permian potentiometric analysis

    International Nuclear Information System (INIS)

    Pacific Northwest Laboratory (PNL) was requested to analyze potentiometric data from the Wolfcamp Formation of the Permian System to evaluate the recommendations by the University of Texas/Bureau of Economic Geology (UT/BEG) that additional geohydrologic boreholes be drilled into the Wolfcamp. The UT/BEG recommended that two stratigraphic and two geohydrologic borings be drilled into the Permian System during FY83 and that several shallow hydrologic tests be made in the Dockum Formation. A geostatistical technique known as kriging was applied to objectively evaluate these geohydrologic borehole recommendations. The Deaf Smith County location appears to be an excellent choice for a borehole. No high quality potentiometric data are available from Deaf Smith County and a borehole location immediately upgradient from the candidate repository site is needed. Adding this borehole location to the potentiometric data base will significantly reduce field data uncertainty near the location being studied. The Swisher County location does not appear to be the best choice. High quality data values H2206 and H2360 are located immediately upgradient from the proposed repository site. The best placement of additional geohydrological boreholes in the Wolfcamp Formation depends strongly upon the proposed repository location. The variability of the potentiometric data causes estimation errors to rapidly increase away from locations of field measurements. Suggested locations for additional boreholes for the Deaf Smith investigations are in northwest Randall or central Potter Counties. Ideal borehole locations for the Swisher county studies appear to be in southeast Randall and Armstrong Counties

  19. The first 110 years of laboratory automation: technologies, applications, and the creative scientist.

    Science.gov (United States)

    Olsen, Kevin

    2012-12-01

    Prior to the widespread availability of electronic components after the Second World War, laboratory automation was constructed by end users and designed for specific tasks, mostly filtration, percolation, and washing operations. The earliest mention of automation in the chemical literature of the United States was in 1875, announcing a device to wash filtrates unattended. In the years that followed, a small number of commercial automated devices were sold, including large grinders for the preparation of coal samples. Around 1900, power stations began adopting automated carbon dioxide analysis. The development of electrical equipment for conductivity measurements enabled the first commercial, automated gas detection instruments for laboratory and field use around the time of the First World War. The growth of industrial production in the 1920s led to a desire for automated testing equipment, and the growing rubber industry was among the more successful early adapters. Photoelectric cells were first used in the early 1930s to create automatic titrators, and by the 1950s, automatic titration encompassed coulometric, potentiometric, and photometric devices. Combinations of chart recorders, photocells, and timers created other types of automated equipment such as stills and fraction collectors. The first true stand-alone automation for the laboratory included clinical chemistry analyzers, introduced during the 1950s. PMID:22893633

  20. Automated oxygen titration and weaning with FreeO2 in patients with acute exacerbation of COPD: a pilot randomized trial

    Directory of Open Access Journals (Sweden)

    Lellouche F

    2016-08-01

    Full Text Available François Lellouche,1 Pierre-Alexandre Bouchard,1 Maude Roberge,1 Serge Simard,1,2 Erwan L’Her,1,3 François Maltais,1 Yves Lacasse1 1Research Centre, 2Biostatistics Department, Quebec Heart and Lung Institute, Laval University, 3Emergency Medicine, Hôtel-Dieu de Lévis, Laval University, Quebec City, QC, Canada Introduction: We developed a device (FreeO2 that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen. Objective: The aim of this study was to evaluate the feasibility of using FreeO2 in patients hospitalized in the respiratory ward for an acute exacerbation of COPD. Methods: We conducted a randomized controlled trial comparing FreeO2 vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO2 as defined for each patient by the attending physician, the time with severe desaturation (SpO2 <85%, and the time with hyperoxia (SpO2 >5% above the target. We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O2 flow 2.0±1.0 L/min. Results: Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O2 administration systems. The percentage of time within the SpO2 target was significantly higher with FreeO2, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO2. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO2 and 8.4±6.0 days with usual oxygen administration (P=0.051. Conclusion: FreeO2 was deemed as an

  1. Polyelectrolyte assisted charge titration spectrometry: applications to latex and oxide nanoparticles

    OpenAIRE

    Mousseau, F.; Vitorazi, L.; Herrmann, L.; S Mornet; Berret, J. -F.

    2016-01-01

    The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation ...

  2. Surface Titrations of Perlite Suspensions.

    Science.gov (United States)

    Alkan; Do

    1998-11-01

    The surface charge behaviour of unexpanded and expanded perlite samples in KNO3 and NaCl solutions were investigated as a function of pH and ionic strength. The solutions of KNO3 and NaCl ranging from 10(-3) to 1.0 M were used. The potentiometric titration method was used to determine the surface charge of perlite samples. It was confirmed that the perlite samples had no the point of zero charge and was negatively charged in the pH range of 3-10. The double extrapolation method was used for determining the intrinsic equilibrium constants for simple ionization and complex ionization reactions. The values obtained are pKinta2 = 2.5 and p*KintK+ = 2.3 in KNO3 solutions and pKinta2 = 3.0 and p*KintNa+ = 2.4 in NaCl solutions for unexpanded perlite, and pKinta2 = 2.6 and p*KintK+ = 2.4 in KNO3 solutions and pKinta2 = 2.7 and pKintNa+ = 2.4 in NaCl solutions for expanded perlite. Copyright 1998 Academic Press.

  3. Surfactant/detergent titration analysis method and apparatus for machine working fluids, surfactant-containing wastewater and the like

    Science.gov (United States)

    Smith, D.D.; Hiller, J.M.

    1998-02-24

    The present invention is an improved method and related apparatus for quantitatively analyzing machine working fluids and other aqueous compositions such as wastewater which contain various mixtures of cationic, neutral, and/or anionic surfactants, soluble soaps, and the like. The method utilizes a single-phase, non-aqueous, reactive titration composition containing water insoluble bismuth nitrate dissolved in glycerol for the titration reactant. The chemical reaction of the bismuth ion and glycerol with the surfactant in the test solutions results in formation of micelles, changes in micelle size, and the formation of insoluble bismuth soaps. These soaps are quantified by physical and chemical changes in the aqueous test solution. Both classical potentiometric analysis and turbidity measurements have been used as sensing techniques to determine the quantity of surfactant present in test solutions. This method is amenable to the analysis of various types of new, in-use, dirty or decomposed surfactants and detergents. It is a quick and efficient method utilizing a single-phase reaction without needing a separate extraction from the aqueous solution. It is adaptable to automated control with simple and reliable sensing methods. The method is applicable to a variety of compositions with concentrations from about 1% to about 10% weight. It is also applicable to the analysis of waste water containing surfactants with appropriate pre-treatments for concentration. 1 fig.

  4. Using spectrophotometric titrations to characterize humic acid reactivity at environmental concentrations.

    Science.gov (United States)

    Janot, Noémie; Reiller, Pascal E; Korshin, Gregory V; Benedetti, Marc F

    2010-09-01

    Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM (>1 g/L) concentrations that are unrealistic compared to those found in natural waters (0.1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV-visible spectra of a diluted solution of purified Aldrich humic acid (5 mgDOC/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina.

  5. Using Spectrophotometric Titrations To Characterize Humic Acid Reactivity at Environmental Concentrations

    International Nuclear Information System (INIS)

    Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM (≥1 g/L) concentrations that are unrealistic compared to those found in natural waters (0. 1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV visible spectra of a diluted solution of purified Aldrich humic acid (5 mg(DOC)/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina. (authors)

  6. POTENTIOMETRIC BEHAVIOR OF CHELATING ION EXCHANGE RESIN IN WATER AND IN ETHANOL—WATER MIXTURES

    Institute of Scientific and Technical Information of China (English)

    DOUHuiyuan; WANGChangshou; 等

    1993-01-01

    The potentiometric behavior of the chelating ion exchange resin D751 containing iminodiacetic acid groups has been studied at 25℃ by batch titration with alkali and acid in water and in ethanol-water mixture solvent.The titrtion curves,the amount of chemically bound counter-ions and invasive electrolytes in the resin phase,and the solvent contents the resin have been investigated.

  7. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Andersen, Jens Enevold Thaulov; Reeve, John Ch;

    1997-01-01

    The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell.......The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell....

  8. Determination of total iron in iron ore by potentiometric titration with ascorbic acid as reducing titrant%以抗坏血酸作还原滴定剂电位滴定法测定铁矿石中全铁

    Institute of Scientific and Technical Information of China (English)

    戚淑芳; 张杰; 王莹; 宁松

    2011-01-01

    提出了以抗坏血酸作为还原滴定剂、全自动电位滴定仪判定滴定终点的测定铁矿石中全铁的方法.对滴定酸介质和酸度、温度、电位滴定仪参数进行了优化,对干扰元素的影响等进行了试验.结果表明,全铁可在铁矿石溶样的酸介质及酸度下滴定,无需进行酸度调节,滴定的温度范围为50~80℃.采用过氧化氢或过硫酸铵作预氧化剂,过量的预氧化剂煮沸数分钟即可除去,操作简便.铁矿石中大多数元素均不干扰测定,尤其是铜、钼、钒的允许量可达到5%(质量分数).测定结果相对标准偏差(RSD)小于0.2%.对两个铁矿石标准样品进行加标回收试验,得到加标回收率分别为99.6%和100.4%.%The determination method of total iron in iron ore using ascorbic acid as reducing titrant was development. The end point of titration was determined by full-automatic potential titrimeter. The titration acid medium and acidity, temperature, and potential titrimeter parameters were optimized.The influence of interference elements was tested. The results showed that titration of total iron could be carred out in the medium and acidity of dissolving iron ore samples without pH adjustment. The titration temperature range was 50 -80 ℃ . The hydrogen peroxide or ammonium persulfate was used as pre-oxidant. Since the excessive pre-oxidant could be removed by boiling for a few minutes, the operation was easy. The majority elements in iron ores did not intcrfcrc in the determination, especially the tolerant amount of copper, molybdenum and vanadium could be up to 5 % (mass fraction). The relative standard deviation (RSD) of determination results was less than 0. 2 % , and the recoveries for two samples were 99. 6% and 100. 4 % ,respectively.

  9. Galvanic cell without liquid junction for potentiometric determination of copper.

    Science.gov (United States)

    Migdalski, Jan; Błaz, Teresa; Zrałka, Barbara; Lewenstam, Andrzej

    2007-07-01

    This paper describes potentiometric measurements in an integrated galvanic cell with both indicator and reference electrodes. Both electrodes are conducting polymer-based. The copper-sensitive indicator electrode is made by using poly(3,4-ethylenedioxythiophene) (PEDOT) doped with 2-(o-arsenophenylazo)-1,8-dihydroxynaphthalene-3,6-disulphonic sodium salt (Arsenazo-I) as the electroactive substance in the film, while the reference electrode is based on PEDOT doped by 2-morpholineoethanesulfonic acid (MES). It is shown that the galvanic cell can be used for determination of copper both in non-aqueous media (where all PVC-based membranes failed) and in the presence of chloride ions, which disturb the signal of conventional copper ion-selective electrodes with solid-state membranes. It is further shown that the titration of copper ions can be successfully monitored using the described electrochemical cell.

  10. The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Jokić Anja B.

    2013-01-01

    Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

  11. 滴定分析在聚酰胺合成中的应用%The Application of Titration Analysis in Synthesis of Polyamide

    Institute of Scientific and Technical Information of China (English)

    蒋莹

    2012-01-01

    The analysis methods of the amine values of potentiometric titration were introduced emphasis, titration were discussed. and acid values of polyamide were provided. The application and the accuracy and influencing factors of potentiometric%总结了聚酰胺的酸值、胺值的分析方法。重点介绍了电位滴定法的应用。讨论了电位滴定法的精确度及其影响因素。

  12. Potentiometric studies on the complexes of tetracycline (TC) and oxytetracycline (OTC) with some metal ions

    International Nuclear Information System (INIS)

    The interaction of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pb(II), Al(III), and UO2(II) ions with tetracycline (TC) were studied by potentiometric pH titrations. The formation constants of the different binary complexes formed in such systems have been determined at 25±0.1 deg C and μ=0.1 moll-1 (NaNO3). Potentiometric pH equilibrium measurements have been made under the same conditions for the interaction of oxytetracycline (OTC) and Cu(II), Cd(II), Pb(II), and UO2(II). The formation of (1:1) binary complexes are inferred from the potentiometric pH titration curves. The protonation constants of TC and OTC were also determined under the same conditions and refined (ESAB2M computer program). The transition metal stability constants are consistent with the Irving-Williams series. (authors)

  13. Potentiometric application of boron- and phosphorus-doped glassy carbon electrodes

    Directory of Open Access Journals (Sweden)

    ZORAN V. LAUSEVIC

    2001-03-01

    Full Text Available Acomparative study was carried out of the potentiometric application of boronand phosphorus-doped and undoped glassy carbon samples prepared at the same heat treatment temperature (HTT 1000°C. The electrochemical activities of the obtained electrode materials were investigated on the example of argentometric titrations. It was found that the electrochemical behaviour of the doped glassy carbon samples are very similar to a Sigri (undoped glassy carbon sample (HTT 2400°C. The experiments showed that the potentiometric response depends on the polarization mode, the nature of the sample, the pretreatment of the electrode surface, and the nature of the supporting electrolyte. The amounts of iodide, bromide, and of chloridewere determined to be 1.27 mg, 0.80 mg and 0.54 mg, respectively, with a maximum relative standard deviation of less than 1.1%. The obtained results are in good agreement with the results of comparative potentiometric titrations using a silver indicator electrode. The titrationmethod was applied to the indirect determination of pyridoxine hydrochloride, i.e., vitamin B6.

  14. ''Titration'' polymerization of monovinylacetylene

    NARCIS (Netherlands)

    Mavinkurve, A; Visser, S; vandenBroek, W; Pennings, AJ

    1996-01-01

    A polymer consisting of a saturated carbon backbone with pendent acetylenic groups was prepared from monovinylacetylene. A titration was performed between the monomer and tertiary butyllithium, its lithiating agent. The charge transfer complex formed between the solvent THF and the tertiary butyllit

  15. Filtrates & Residues: Olfactory Titration.

    Science.gov (United States)

    Wood, John T.; Eddy, Roberta M.

    1996-01-01

    Presents an experiment that uses a unique acid-base indicator--the odor of raw onion--to indicate the end point of the titration of sodium hydroxide with hydrochloric acid. Allows the student to detect the completion of the neutralization reaction by olfaction rather than sight. (JRH)

  16. PK7300全自动血型分析仪测定ABO血型抗体效价的初步研究%A preliminary study on ABO blood type antibody titration by PK7300 automated blood typing analyzer

    Institute of Scientific and Technical Information of China (English)

    石绍川; 刘东; 李军; 田耘博; 陈鹏

    2014-01-01

    目的:探索使用PK7300全自动血型分析仪测定ABO血型抗体效价的方法,探讨献血者血型检测中与ABO血型抗体效价相关的影响因素及注意事项。方法仪器微板法测定抽样标本的ABO血型抗体效价;仪器微板法及手工试管法测定各血型混合血浆的ABO血型抗体效价;统计分析该中心2013年5~7月检测出的ABO血型抗体效价降低的情况。结果A型献血者与B型献血者的ABO血型抗体效价比较,差异无统计学意义(P>0.05),O型献血者的ABO血型抗体效价明显高于A型或B型献血者(P<0.05);手工试管法的灵敏度明显优于仪器微板法,而手工试管法二的灵敏度又明显优于手工试管法一(P<0.05);ABO血型抗体效价降低的A型献血者明显多于B型或O型(均P<0.01),ABO血型抗体效价降低的男性献血者明显多于女性(P<0.01)。结论仪器微板法测定ABO血型抗体效价操作简便、结果判读客观、重复性好,1∶1~1∶80的稀释比例范围能满足绝大多数标本的测定需要,采用梯度稀释有助于减小测定误差;血型、性别、年龄、亚型等因素可能与献血者ABO血型抗体效价降低相关。%Objective To explore the detection method of ABO blood type antibody titration by the PK7300 automated blood typing analyzer and to investigate the ABO blood type antibody titer‐related influencing factors and the matter needing attentions in blood typing test for blood donors .Methods The ABO blood type antibody titers of the samples were measured by the analyzer microplate method;the ABO blood type antibody titer of each mixed plas‐ma was respectively measured by the analyzer microplate method and by the manual tube method;the decrease situa‐tion of ABO blood type antibody titers detected in our center from May to July 2013 were statistically analyzed .Re‐sults There was no statistically significant difference in the ABO

  17. 自动电位滴定法测定工业铬酸酐中氯离子含量方法研究%The Research Method to Determine Chloride Ion Content in Chromium Trioxide for Industrial Use with Automatic Potentiometric Titration

    Institute of Scientific and Technical Information of China (English)

    胡清启; 孙宁

    2015-01-01

    用乙醇作还原剂,将铬酸酐中CrO42-还原为Cr3+,再用硝酸银标准溶液滴定,以电位变化率最大点确定反应终点,求出氯离子含量。就精密度和加标回收进行实验,并对方法展开分析与讨论,该方法的建立对工业生产铬酸酐中氯离子指标的控制具有指导意义。%Reduce the CrO42+to Cr3+in chromium trioxide with ethanol as the reductant ,then determine the content of chloride ion using AgNO3 standard solution to titrate to the end point that has a biggest change of potential. Conduct an experiment for calculating the precision and standard addition recovery of the method,and then analysis and discuss about the method.This method has a guiding significance for controlling the content of chloride ion in the industrial production of chromium trioxide.

  18. Physico chemical studies on the composition of complex arsenites of metals Part IV: conductometric and potentiometric studies on the composition of cadmium arsenite

    Directory of Open Access Journals (Sweden)

    M. S. Bhadraver

    1962-07-01

    Full Text Available The formation and precipitation of cadmium arsenite has been studied by conductometric and potentiometric titrations between cadmium nitrate and sodium arsenite (meta at different concentrations with either of the substances used as the reagent in titration. In the case of direct titrations (cadmium nitrate added to sodium arsenite in the conductivity cell, one distinct break in the curves is observed corresponding to the formation of the Cd (AsO/sub 2//sub 2/ where the molecular ratio is 2:1. The direct and reverse potentiometric titrations curves give one maxima in dE/dV at point corresponding to the formation of the complex Cd (AsO/sub/2/sub/2 where the molecular ratio of reactants Cd:AsO/sub/2 is 1:2. The composition has been arrived at by comparing the calculated values with observed values by conductometric and potentiometric titrations. The composition of cadmium arsenite arrived at both by conductometry and potentiometry is best representative as Cd(AsO/sub/2/sub/2

  19. Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

    Science.gov (United States)

    Moore, Dale E.; Goode, David R.; Seney, Caryn S.; Boatwright, Jennifer M.

    2016-01-01

    College chemistry faculties might not have considered including isothermal titration calorimetry (ITC) in their majors' curriculum because experimental data from this instrumental method are often analyzed via automation (software). However, the software-based data analysis can be replaced with a spreadsheet-based analysis that is readily…

  20. Host-Tailored Sensors for Leucomalachite Green Potentiometric Measurements

    Directory of Open Access Journals (Sweden)

    F. T. C. Moreira

    2013-01-01

    Full Text Available A new biomimetic sensor for leucomalachite green host-guest interactions and potentiometric transduction is presented. The artificial host was imprinted in methacrylic acid or acrylamido-2-methyl-1-propanesulfonic acid-based polymers. Molecularly imprinted particles were dispersed in 2-nitrophenyloctyl ether and trapped in poly(vinyl chloride. The potentiometric sensors exhibited a near-Nernstian response in steady state evaluations, with slopes and detection limits ranging from 45.8 to 81.2 mV decade-1 and 0.28 to 1.01 μg mL-1, respectively. They were independent from the pH of test solutions within 3 to 5. Good selectivity was observed towards drugs that may contaminate water near fish cultures, such as oxycycline, doxycycline, enrofloxacin, trimethoprim, creatinine, chloramphenicol, and dopamine. The sensors were successfully applied to field monitoring of leucomalachite green in river samples. The method offered the advantages of simplicity, accuracy, applicability to colored and turbid samples, and automation feasibility.

  1. Spectroscopic study on variations in illite surface properties after acid-base titration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    FT-IR, Raman microscopy, XRD, 29 Si and 27 Al MAS NMR, were used to investigate changes in surface properties of a natural illitesample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment withacid, then increased after hydroxide back titration. The varied ratio of signal intensity between Ⅳ Al and Ⅵ At species in 27 Al MAS NMRspectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure ofillite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illitesurfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of theaqueous illite.

  2. 手动滴定测定甲醛方法的改进%Improving of the Method of Formaldehyde Manual Titration

    Institute of Scientific and Technical Information of China (English)

    崔永乐

    2014-01-01

    The formaldehyde content analysis is very frequent in POM production . But there are more shortcomings in the formaldehyde manual titration . After the manual titration is substituted by the automatic potentiometric titration ,the analysis requirements can be met .%在聚甲醛的生产过程中,甲醛分析的频率很高,手动滴定存在局限性,改用自动电位滴定法,可满足分析要求。

  3. The determination of titratable acidity and total tannins in red wine

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2009-01-01

    Full Text Available Titration acidity and content of total tannins in mass-market red wines are analyzed in this paper. The content of total acids in wine, expressed through wine acid, was analyzed by potentiometric titration on 7.00 pH value. According to titratable acidity in analyzed wines, all wines (only with analyzed parameters according to Regulations about wine quality. The analysis of differential potentiometric curves shows that these curves can give the answer to the question if non organic substances, amino groups and phenols are present in wine in large quantity, as they are always present in wine. However it doesn't give the clear answer which substances are present in analyzed samples. The answer to this question can be received only by the method of ionic chromatography. The content of total tannins shows short time of storage in wine cellars so wine wasn't stored long enough, i.e. they are commercial wines made for mass market production and consumption. Although they have less content of total tannin materials of given values, wine taste gives the correlation with other polyphenol materials that only give odour, aroma and 'bouquet' to wine. The relative error of mean value is very low which indicates the reproduction of results and reliability of the method of determination of total tannins in red wine.

  4. Stuides on a Pb2+-selective electrode with a macrocyclic liquid membrane. Potentiometric determination of Pb2+ ions

    Directory of Open Access Journals (Sweden)

    MARIAN ISVORANU

    2006-12-01

    Full Text Available This paper presents experimental and theoretical data regarding the design, characterization and analytical applications of a non-expensive, liquid-membrane ion-selective electrode for Pb2+ ions. The membrane is a solution of the active complex formed by Pb2+ ions with dibenzo-18-crown-6-ionophore (DB-[18]-C-6 extracted in propylene carbonate (PC. The sucessful application of the developed electrode for the determination of Pb2+ ions in aqueos solution samples by direct potentiometry and potentiometric titration is presented. For the presented analytical results, there are insignificant systematic errors between the direct potentiometric method with the developed ion-selective electrode and atomic absorption spectrometry.

  5. Simple Potentiometric Determination of Reducing Sugars

    Science.gov (United States)

    Moresco, Henry; Sanson, Pedro; Seoane, Gustavo

    2008-01-01

    In this article a potentiometric method for reducing sugar quantification is described. Copper(II) ion reacts with the reducing sugar (glucose, fructose, and others), and the excess is quantified using a copper wire indicator electrode. In order to accelerate the kinetics of the reaction, working conditions such as pH and temperature must be…

  6. Automatic set-point titration for monitoring nitrification in SBRs.

    Science.gov (United States)

    Fiocchi, N; Ficara, E; Bonelli, S; Canziani, R; Ciappelloni, F; Mariani, S; Pirani, M; Ratini, P; Mazouni, D; Harmand, J

    2008-01-01

    Nitrification is usually the bottleneck of biological nitrogen removal processes. In SBRs systems, it is not often enough to monitor dissolved oxygen, pH and ORP to spot problems which may occur in nitrification processes. Therefore, automated supervision systems should be designed to include the possibility of monitoring the activity of nitrifying populations. Though the applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature, the possibility of an automated procedure is still at its early stage of industrial development. In this work, the use of an at-line automated titrator named TITAAN (TITrimetric Automated ANalyser) is presented. The completely automated sensor enables us to track nitrification rate trend with time in an SBR, detecting the causes leading to slower specific nitrification rates. It was also possible to perform early detection of toxic compounds in the influent by assessing their effect on the nitrifying biomass. Nitrifications rates were determined with average errors+/-10% (on 26 tests), never exceeding 20% as compared with UV-spectrophotometric determinations. PMID:18701782

  7. Determination of the Dissociation Constant of Some Substituted Phenols by Potentiometric Method in Acetonitrile-Water Mixtures

    OpenAIRE

    Ertokuş, Güzide Pekcan; Ahmet Hakan AKTAŞ

    2010-01-01

    Abstract: The dissociation constants of phenol, 2−methylphenol, 3−methylphenol, 4−methylphenol, and 4−ethylphenol have been determined by potentiometric titration in a electrochemical cell with glass electrode at 25 oC in water and in the mixtures of acetonitrile and water where the following volume fractions (before mixing) of acetonitrile were used: 0.10, 0.20, and 0.30. The ionic strength of the solutions was adjusted to be 0.1 mol dm−3 using KCl. The dissociation constants were ...

  8. Potentiometric determination of free acidity in presence of hydrolysable ions and a sequential determination of hydrazine.

    Science.gov (United States)

    Ganesh, S; Khan, Fahmida; Ahmed, M K; Pandey, S K

    2011-08-15

    A simple potentiometric method for the determination of free acidity in presence of hydrolysable ions and sequential determination of hydrazine is developed and described. Both free acid and hydrazine are estimated from the same aliquot. In this method, free acid is titrated with standard sodium carbonate solution after the metal ions in solutions are masked with EDTA. Once the end point for the free acid is determined at pH 3.0, an aliquot of formaldehyde is added to liberate the acid equivalent to hydrazine which is then titrated with the same standard sodium carbonate solution using an automatic titration system. The described method is simple, accurate and reproducible. This method is especially applicable to all ranges of nitric acid and heavy metal ion concentration relevant to Purex process used for nuclear fuel reprocessing. The overall recovery of nitric acid is 98.9% with 1.2% relative standard deviation. Hydrazine content has also been determined in the same aliquot with a recovery of nitric acid is 99% with 2% relative standard deviation. The major advantage of the method is that generation of corrosive analytical wastes containing oxalate or sulphate is avoided. Valuable metals like uranium and plutonium can easily be recovered from analytical waste before final disposal. PMID:21726724

  9. Study and Application of a New On—Line Titration Technique

    Institute of Scientific and Technical Information of China (English)

    朱建育; 施利毅; 等

    2002-01-01

    A new on-line titration method and device based on a new technique-continuous flow titration is described.By the means of electronically controlled switching of a solenoid valve,the main component of the system,the equivalent point of the titration is easily determined.Several kinds of mixing tools were examined.whereby a self-made mixing chamer with minimum volume gave best results and was therefore used in the dveice,The error of the titration is within 0.2% and the relative standard deviation(RSD) is below 1.2%,The results show no difference compared with a commercial device,meanwhile the new on-line titration system is cheaper and fully automated and thus easy to hand and less slovent consumption.

  10. Integration and global analysis of isothermal titration calorimetry data for studying macromolecular interactions.

    Science.gov (United States)

    Brautigam, Chad A; Zhao, Huaying; Vargas, Carolyn; Keller, Sandro; Schuck, Peter

    2016-05-01

    Isothermal titration calorimetry (ITC) is a powerful and widely used method to measure the energetics of macromolecular interactions by recording a thermogram of differential heating power during a titration. However, traditional ITC analysis is limited by stochastic thermogram noise and by the limited information content of a single titration experiment. Here we present a protocol for bias-free thermogram integration based on automated shape analysis of the injection peaks, followed by combination of isotherms from different calorimetric titration experiments into a global analysis, statistical analysis of binding parameters and graphical presentation of the results. This is performed using the integrated public-domain software packages NITPIC, SEDPHAT and GUSSI. The recently developed low-noise thermogram integration approach and global analysis allow for more precise parameter estimates and more reliable quantification of multisite and multicomponent cooperative and competitive interactions. Titration experiments typically take 1-2.5 h each, and global analysis usually takes 10-20 min.

  11. Direct Potentiometric Method for Human Stress Determination

    OpenAIRE

    Sakač, N.; Karnaš, M.; Grčić, M.

    2015-01-01

    The application of platinum redox electrode for potentiometric determination of salivary amylase activity as a stress biomarker is described. The candidates were divided into two groups, physical activity – medium intensity exercise (ten candidates), and psychical activity – student exam (thirteen candidates). The experimental data were compared with an adapted theoretical model where the sensor and analyte properties were optimized using Solver and the least-squares criterion to fit a theore...

  12. Flow injection potentiometric determination of pipazethate hydrochloride.

    Science.gov (United States)

    Abdel-Ghani, N T; Shoukry, A F; el Nashar, R M

    2001-01-01

    New plastic membrane electrodes for pipazethate hydrochloride based on pipazethatium phosphotungstate, pipazethatium phosphomolybdate and a mixture of the two were prepared. The electrodes were fully characterized in terms of composition, life span, pH and temperature and were then applied to the potentiometric determination of the pipazethate ion in its pure state and pharmaceutical preparations under batch and flow injection conditions. The selectivity of the electrodes towards many inorganic cations, sugars and amino acids was also tested. PMID:11205518

  13. A Porphyrin Based Potentiometric Sensor for Zn2+ Determination

    Directory of Open Access Journals (Sweden)

    H. Lang

    2003-07-01

    Full Text Available PVC based membranes of disodium salt of porphyrin 3,7,12,17-tetramethyl-8, 13-divinyl 2,18-porphine dipropionic acid (I as ionophore with sodium tetra phenyl borate (NaTPB as anion excluder and dibutyl phthalate (DBP, dioctyl phthalate (DOP, dibutyl butyl phosphonate (DBBP, tris(2- ethyl hexylphosphate (TEP, tri-n-butylphosphate (TBP and 1- chloronaphthalene (CN as plasticizing solvent mediators were prepared and constructed for determination of Zn(II. The PVC based membrane of (I with DBBP as plasticizer and having anion excluder, NaTPB in the ratio PVC: I: NaTPB: DBBP (150: 10: 2: 200 gave the best results in terms of working concentration range (1.3×10-5-1.0 ×10-1M with a Nernstian slope (30.0 mV/decade of activity. The useful pH range of the sensor is 3.0 –7.4, beyond which a drift in potential was observed. The response time of the sensor is 10s and the lifetime was about 2 months during which it could be used without any measurable divergence. It had good stability and reproducibility. The membrane worked satisfactorily in non-aqueous medium up to 40% (v/v non-aqueous content. The selectivity coefficient values indicate that the electrode is highly selective for Zn2+ over a number of other cations except Na+ and Cd2+. Although Na+ and Cd2+ are likely to cause some interference, they would not interfere if present at the concentrations < 1 ×10-5 and < 5 ×10-5 M, respectively. The electrode has been used as an indicator electrode to determine the end point in the potentiometric titration of Zn2+ with EDTA.

  14. Potentiometric studies on the complex formation of some Ln(III) ions with 4-nitrocatechol

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, B.C.; Dubey, S.N. (Kurukshetra Univ. (India). Dept. of Chemistry)

    1981-07-01

    The interaction of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Y(III) with 4-nitrocatechol has been investigated potentiometrically in aqueous medium at 25deg and at ionic strengths of 0.05, 0.1, 0.15 and 0.2M (KNO/sub 3/). The proton-ligand formation constants and metal-ligand formation constants have been calculated using the Calvin-Bjerrum titration technique as modified by Irving and Rossotti. The thermodynamic formation constants have also been determined. The order of stabilities of the lanthanide complexes with the above ligand is found to be: La(III) < Ce(III) approximately Pr(III) < Nd(III) < Sm(III) < Gd(III) < Y(III) < Tb(III) < Dy(III) < Ho(III).

  15. Cyclam Modified Carbon Paste Electrode as a Potentiometric Sensor For Determination of Cobalt(Ⅱ) Ions

    Institute of Scientific and Technical Information of China (English)

    Hamid Reza POURETEDAL; Mohammad Hossein KESHAVARZ

    2005-01-01

    A new modified carbon paste electrode based on cyclam as a modifier was prepared for the determination of Co(Ⅱ) ions. The proposed electrode shows a Nernstian slope 28.4 mV per decade over a wide concentration range 5.0×10-6_1.0×10-1 mol/L of Co2+ ions with detection limit 2.5×10-6 mol/L. The sensor exhibits good selectivities for Co2+ over a wide variety of other cations. It can be used as an indicator electrode in potentiometric titration of cobalt(Ⅱ) ions as well as in direct determination of cobalt(Ⅱ) ions in wastewater of acidic cobalt electroplating bath. The electrode shows Nernestian behavior in a solution of 25% ethanol.

  16. Fabrication a composite electrode based on MWCNT/Zeolite for potentiometric determination of Cr3+

    Directory of Open Access Journals (Sweden)

    Zahra Heidari

    2016-03-01

    Full Text Available A nanocomposite based on carbon paste electrode fabricated, by using zeolite as ion carrier .Functional multi-wall carbon nanotube was used for improvement of electrode response. The optimal composition of CPE was built from 65% graphite powder, 20 wt% paraffin oil, 5% ion carrier (zeolite, 10% MWCNTs. Electrode showed Nernstian response 19.88 (±0.2mVdecade−1 in the measuring range 10−7–10−2 mol L−1 and showed detection limit of 6.3×10-7 M. The sensor was successfully used for potentiometric titration Cr3+ with EDTA. The carbon paste electrode showed fast response time, good selectivity and applicable in the wide pH range of 3 -10.

  17. Liquid membrane ion-selective electrodes for potentiometric dosage of coper and nickel

    Directory of Open Access Journals (Sweden)

    MARIA PLENICEANY

    2005-02-01

    Full Text Available This paper presents experimental and theoretical data regarding the preparation and characterization of three liquid-membrane electrodes, which have not been mentioned in the specialized literature so far. The active substances, the solutions of which in nitrobenzene formed the membranes on a graphite rod, are simple complex combinations of Cu(II and Ni(II ions with an organic ligand belonging to the Schiff base class: N-[2-thienylmethilidene]-2-aminoethanol (TNAHE. The Cu2+ -selective and Ni2+ -selective electrodes were used to determine the copper and nickel ions in aqueous solutions, both by direct potentiometry and by potentiometric titration with EDTA. They were also used for the determination of Cu2+ and Ni2+ ions in industrial waters by direct potentiometry.

  18. Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2012-11-01

    Full Text Available In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM, high resolution transmission electron microscopy (HRTEM and X-ray diffraction (XRD techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

  19. Catalytic titrations of silver(I) applying the iodide-catalysed manganese(IV)-arsenic(III) indicator reaction in the presence of sulphuric acid

    OpenAIRE

    TIBOR J. PASTOR; VOJKA V. ANTONIJEVIC; FERENC T. PASTOR

    1999-01-01

    A new catalytic potentiometric titration method for the determination of silver(I), applying the iodide-catalysed manganese(IV)-arsenic(III) indicator reaction in the presence of sulphuric acid, has been developed. The effect of the concentration of sulphuric acid and different ions, and of the mole ratio of manganese(IV) to arsenic(III) in the titrated solution, as well as of the titrand temperature on the conditions for the determination of silver(I) in solutions of various concentrations, ...

  20. Potentiometric determination of uranium in organic extracts

    International Nuclear Information System (INIS)

    The potentimetric determination of uranium in organic extracts was studied. A mixture of 30% TBP, (tributylphosphate), in carbon tetrachloride was used, with the NBL (New Brunswick Laboratory) titrimetric procedure. Results include a comparative analysis performed on organic extracts of fissium alloys vs those performed on aqueous samples of the same alloys which had been treated to remove interfering elements. Also comparative analyses were performed on sample solutions from a typical scrap recovery operation common in the uranium processing industry. A limited number of residue type materials, calciner products, and presscakes were subjected to analysis by organic extraction. The uranium extraction was not hindered by 30% TBP/CCl4. To fully demonstrate the capabilities of the extraction technique and its compatibility with the NBL potentiometric uranium determination, a series of uranium standards was subjected to uranium extraction with 30% TBP/CCl4. The uranium was then stripped out of the organic phase with 40 mL of H3PO4, 15 mL of H20, and 1 mL of 1M FeSO4 solution. The uranium was then determined in the aqueous phosphoric phase by the regular NBL potentiometric method, omitting only the addition of another 40 mL of H3PO4. Uranium determinations ranging from approximately 20 to 150 mg of U were successfully made with the same accuracy and precision normally achieved. 8 tables

  1. Coulometric-potentiometric determination of autoprotolysis constant and relative acidity scale of water

    Directory of Open Access Journals (Sweden)

    Džudović Radmila M.

    2010-01-01

    Full Text Available The autoprotolysis constant and relative acidity scale of water were determined by applying the coulometric-potentiometric method and a hydrogen/palladium (H2/Pd generator anode. In the described procedure for the evaluation of autoprotolysis constant, a strong base generated coulometrically at the platinum cathode in situ in the electrolytic cell, in presence of sodium perchlorate as the supporting electrolyte, is titrated with hydrogen ions obtained by the anodic oxidation of hydrogen dissolved in palladium electrode. The titration was carried out with a glass-SCE electrode pair at 25.0±0.1°C. The value obtained pKw = 13.91 ± 0.06 is in agreement with literature data. The range of acidity scale of water is determined from the difference between the halfneutralization potentials of electrogenerated perchloric acid and that of sodium hydroxide in a sodium perchlorate medium. The halfneutralization potentials were measured using both a glass-SCE and a (H2/Pdind-SCE electrode pairs. A wider range of relative acidity scale of water was obtained with the glass-SCE electrode pair.

  2. Potentiometric and ³¹P NMR studies on inositol phosphates and their interaction with iron(III) ions.

    Science.gov (United States)

    Sala, Martin; Makuc, Damjan; Kolar, Jana; Plavec, Janez; Pihlar, Boris

    2011-03-01

    Potentiometric, conductometric and ³¹P NMR titrations have been applied to study interactions between myo-inositol hexakisphosphate (phytic acid), (±)-myo-inositol 1,2,3,5-tetrakisphosphate and (±)-myo-inositol 1,2,3-trisphosphate with iron(III) ions. Potentiometric and conductometric titrations of myo-inositol phosphates show that addition of iron increases acidity and consumption of hydroxide titrant. By increasing the Fe(III)/InsP(6) ratio (from 0.5 to 4) 3 mol of protons are released per 2 mol of iron(III). At first, phytates coordinate iron octahedrally between P2 and P1,3. The second coordination site represents P5 and neighbouring P4,6 phosphate groups. Complexation is accompanied with the deprotonation of P1,3 and P4,6 phosphate oxygens. At higher concentration of iron(III) intermolecular P-O-Fe-O-P bonds trigger formation of a polymeric network and precipitation of the amorphous Fe(III)-InsP(6) aggregates. (31)P NMR titration data complement the above results and display the largest chemical shift changes at pD values between 5 and 10 in agreement with strong interactions between iron and myo-inositol phosphates. The differences in T(1) relaxation times of phosphorous atoms have shown that phosphate groups at positions 1, 2 and 3 are complexated with iron(III). The interactions between iron(III) ions and inositol phosphates depend significantly on the metal to ligand ratio and an attempt to coordinate more than two irons per InsP(6) molecule results in an unstable heterogeneous system.

  3. Determination nitrogen in the Kjeldahl digests of plant samples by continuous flow analyzer in comparison with auto-mated distillation-titration instrument%连续流动分析仪与自动凯氏定氮仪测定小麦秸秆全氮含量之比较

    Institute of Scientific and Technical Information of China (English)

    温云杰; 李桂花; 黄金莉; 刘云霞; 高翔; 汪洪

    2015-01-01

    凯氏定氮法是测定植株全氮含量的经典方法,但费时费力。选择24个小麦秸秆样品,用浓 H2 SO4-H2 O2消煮,分别利用连续流动分析仪与全自动凯氏定氮仪测定消煮液中氮含量,比较了两种方法测定结果,探讨利用连续流动分析仪测定植株样品全氮含量的可行性。结果表明:两种仪器测定的小麦秸秆中全氮含量无明显差异,彼此间呈显著线性相关,回归直线方程为Y (连续流动分析仪-N)=0.892X (凯氏蒸馏滴定-N)+0.753,相关系数r=0.9421(n=24, P<0.01)。连续流动分析仪测定的回收率在96.6%~102.3%之间,对5个样品消煮液中氮浓度分别重复测定5次,相对标准偏差在5%以下。连续流动分析仪分析速度快,消耗试剂少,可用于大批量H2 SO4-H2 O2消煮的植株样品中全氮含量分析。研究结果为采用连续流动分析仪测定植株全氮含量提供了技术依据。%Kjeldahl distillation-titration has been used as a reference method for N determination in plants, but it is time consu-ming. This article aimed at establishing a time saving method for determining of plant N concentrations by continuous flow ana-lyzer ( CFA) . Twenty four of wheat plant samples were selected and digested with H2 SO4-H2 O2 . N contents in the digests were determined by CFA and an automated Kjeldahl distillation-titration ( AKDT) instrument, respectively. The test showed that there was no any significant difference of the plant N contents measured by the CFA and the AKDT method. A linear rela-tionship best described the measured N values generated by both methods: CFA-N=0. 892 AKDT-N +0. 753. The Pearson’s correlation coefficient was 0. 942 1 with a significance level (n=24, P<0. 01). The CFA method for plant N measurement had a high precision with relative standard deviation less than 5%. The standard recovery rate of feed samples with addition of ( NH4 ) 2 SO4 was 96. 6% ~102. 3%. It suggested that the CFA based on

  4. Recruitment Maneuvers and PEEP Titration.

    Science.gov (United States)

    Hess, Dean R

    2015-11-01

    The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation. PMID:26493593

  5. Risks and benefits of rapid clozapine titration

    Directory of Open Access Journals (Sweden)

    Jeannie D. Lochhead

    2016-05-01

    Full Text Available Clozapine is often considered the gold standard for the treatment of schizophrenia. Clinical guidelines suggest a gradual titration over 2 weeks to reduce the risks of adverse events such as seizures, hypotension, agranulocytosis, and myocarditis. The slow titration often delays time to therapeutic response. This raises the question of whether, in some patients, it may be safe to use a more rapid clozapine titration. The following case illustrates the potential risks associated with the use of multiple antipsychotics and rapid clozapine titration. We present the case of a young man with schizophrenia who developed life threatening neuroleptic malignant syndrome (NMS during rapid clozapine titration and treatment with multiple antipsychotics. We were unable to find another case in the literature of NMS associated with rapid clozapine titration. This case is meant to urge clinicians to carefully evaluate the risks and benefits of rapid clozapine titration, and to encourage researchers to further evaluate the safety of rapid clozapine titration. Rapid clozapine titration has implications for decreasing health care costs associated with prolonged hospitalizations, and decreasing the emotional suffering associated with uncontrolled symptoms of psychosis. Clozapine is considered the most effective antipsychotic available thus efforts should focus on developing strategies that would allow for safest and most efficient use of clozapine to encourage its utilization for treatment resistance schizophrenia.

  6. Determination of the acid dissociation constant of the biosurfactant monorhamnolipid in aqueous solution by potentiometric and spectroscopic methods.

    Science.gov (United States)

    Lebrón-Paler, Ariel; Pemberton, Jeanne E; Becker, Bridget A; Otto, William H; Larive, Cynthia K; Maier, Raina M

    2006-11-15

    The acid dissociation constant in water for a monorhamnolipid mixture extracted from Pseudomonas aeruginosa ATCC 9027 has been determined using potentiometry and two spectroscopic approaches at concentrations below and above the critical micelle concentration (cmc). Potentiometric titrations resulted in pKa values ranging from 4.28 +/- 0.16 to 5.50 +/- 0.06 depending on concentration. 1H NMR spectrochemical titrations at concentrations below the cmc revealed a pKa value of 4.39 +/- 0.06. ATR-FT-IR spectrochemical titrations on solutions well above the cmc gave a pKa value of 4.84 +/- 0.05. The value of 4.28 for the free rhamnolipid molecule for concentrations below the cmc differs markedly from that reported previously. However, the pKa of 5.50 for surface-adsorbed and solution aggregates correlates closely to that previously reported. Differences in these pKa values are rationalized in terms of the pH- and concentration-dependent aggregation behavior of rhamnolipids in aqueous solution.

  7. Design and fabrication of a miniaturization micro volume auto titrator coupled with electrochemical end-point detector for the determination of acidity of some fruit juice

    Directory of Open Access Journals (Sweden)

    Prinya Masawat

    2008-06-01

    Full Text Available A miniaturization micro volume auto titrator coupled with electrochemical end-point detector was designed and fabricated for the determination of acidity of some Thai citrus fruit juices collected in the northern area of Thailand. The method was based on on-line potentiometric titration of the acid contents with sodium hydroxide. Conditions such as volume of fruit juice sample, volume and concentration of potassium chloride used as supporting electrolyte and flow rate of titrant were optimized by using univariate optimization. A sample throughput of 83 samples h-1 at 0.28 mL/min was achieved with satisfactory results. The results obtained by the proposed method agreed with those obtained by using the standard classical titration method.

  8. New potentiometric transducer based on a Mn(II) [2-formylquinoline thiosemicarbazone] complex for static and hydrodynamic assessment of azides.

    Science.gov (United States)

    Kamel, Ayman H

    2015-11-01

    A new potentiometric transducer for selective recognition of azide is characterized and developed. The PVC plasticized based sensor incorporates Mn(II) [2-formylquinoline thiosemicarbazone] complex in the presence of tri dodecyl methyl ammonium chloride (TDMAC) as a lipophilic cationic additive. The sensor displayed a near-Nernstian response for azide over 1.0×10(-2)-1.0×10(-5) mol L(-1), with an anionic slope of -55.8±0.6 mV decade(-1) and lower limit of detection 0.34 µg mL(-1). The sensor was pH independent in the range 5.5-9 and presented good selectivity features towards several inorganic anions, and it is easily used in a flow injection system and compared with a tubular detector. The intrinsic characteristics of the detector in a low dispersion manifold were determined and compared with data obtained under a hydrodynamic mode of operation. This simple and inexpensive automation, with a good potentiometric detector, enabled the analysis of ~33 samples h(-1) without requiring pre-treatment procedures. The proposed method is also applied to the analysis of trace levels of azide in primer mixtures. Significantly improved accuracy, precision, response time, stability and selectivity were offered by these simple and cost-effective potentiometric sensor compared with other standard techniques. The method has the requisite accuracy, sensitivity and precision to determine azide ions. PMID:26452931

  9. Nap-titration : An effective alternative for continuous positive airway pressure titration

    NARCIS (Netherlands)

    Hoekema, A; Stegenga, B; Meinesz, AF; van der Hoeven, JH; Wijkstra, PJ

    2006-01-01

    When treating Obstructive Steep Apnea-Hypopnea Syndrome (OSAHS) several alternatives for standard (manual) continuous positive airway pressure (CPAP) titration are feasible. A practical alternative is titration without polysomnography during an afternoon nap (Nap-titration). The aim of the present s

  10. Discussion on Improvement of the Acid Standard Solution Titration Method%酸标准溶液标定方法改进探讨

    Institute of Scientific and Technical Information of China (English)

    谢鹏

    2012-01-01

    Objective: To improve the method for titration of standard acid solution. Methods According to interna- tional standard GB601 -2002, this experiment was used THAM as standard substance and applied the MATLAB Wavelet Toolbox functions to calculate the concentration of standard solution so as to determine the end point of ti- tration. The effectiveness of Potentiometric titration and Manual titration were compared. Results To use THAM as standard substance is feasible and the results dont reject the null hypothesis in the 95% confidence interval in both methods. Conclusion To determine the end point of titration, the Potentiometric titration -wavelet transform method is more accurate, easily manipulated and convenient than Manual titration.%目的:改进酸标准溶液标定方法。方法:在用GB601—2002方法配制时,尝试用三羟甲基氨基甲烷(THAM)作基准物,采用MATLAB小波工具箱函数确定滴定终点(化学计量点)并计算标准溶液浓度。结果:THAM作基准物可行,且电位滴定——小波变换法用于标定终点检测,其所得结果与手工滴定结果经统计分析,有95%的把握认为两种方法所得结果无显著差异。结论:电位滴定——小波变换法确定终点比手工指示剂法准确、简单、方便。

  11. Determination of Formation Constants of Co2+,Ni2+,Cu2+and Zn2+ Complexes with Humic and Fulvic Acids by Potentionmetric Titration Method

    Institute of Scientific and Technical Information of China (English)

    DUJIN-ZHOU; LUCHANG-QING; 等

    1994-01-01

    The formation constants of Co2+,Ni2+,Cu2+ and Zn2+ complexes with humic acid(HA) and fulvic acid(FA) in red soil wrer determined by the potentiometric titration method.The constants as a function of composition of the complexation solutions were obtained by two graphical approaches respetively,The formation constants decreased with increasing concentration of metal in the solution,The results provide unambiguous evidence for the heterogeneity of the function groups of humic substances,the formation constants of FA were much smaller than those of HA,and the formation constants of Cu2+ were much greater than those of Co2+ ,Ni2+ and Zn2+,The potentiometric titration methon for determining formation constants are also discussed in the article.

  12. New potentiometric sensor for the determination of iodine species

    Energy Technology Data Exchange (ETDEWEB)

    Kormosh, Zholt, E-mail: kormosh@univer.lutsk.ua; Savchuk, Tanya

    2012-12-01

    The characteristics, performance and application of novel triiodide potentiometric sensor based on ion-pair of Rhodamine B triiodide as a membrane carrier are described. The electrode has a linear dynamic range between 1 Multiplication-Sign 10{sup -6} and 1 Multiplication-Sign 10{sup -1} M, with a Nernstian slope of 68 {+-} 1 mV pC{sup -1} and detection limit of 3.9 Multiplication-Sign 10{sup -7} M. Fast and stable response, good reproducibility, long-term stability, very good selectivity over a large number of common organic and inorganic anions, applicability over a pH range of 2-10 are demonstrated. The proposed sensor has been applied for potentiometric determination of some iodine species. - Graphical abstract: Materials Science and Engineering C, Volume 000, Issue 0, Pages 0000-0000 (2012). New Potentiometric sensor for the Determination of Iodine Species. Zholt Kormosh, Tanya Savchuk. Highlights: Black-Right-Pointing-Pointer Triiodide potentiometric sensor based on an ion-pair of Rhodamine B triiodide as a membrane carrier Black-Right-Pointing-Pointer The electrode has a linear dynamic range between 1 Multiplication-Sign 10{sup -6} and 1 Multiplication-Sign 10{sup -1} M. Black-Right-Pointing-Pointer The Nernstian slope of 68 {+-} 1 mV pC{sup -1} and detection limit of 3.9 Multiplication-Sign 10{sup -7} M Black-Right-Pointing-Pointer Indicator electrode in potentiometric determination of some iodine species.

  13. Direct potentiometric determination of diastase activity in honey.

    Science.gov (United States)

    Sak-Bosnar, Milan; Sakač, Nikola

    2012-11-15

    A novel method for the determination of diastase activity is reported. The method is based on a direct potentiometric measurement of triiodide ion that is released when a starch-triiodide complex is hydrolysed by honey diastase. The increase of free triiodide ion concentration in a sample is found to be directly proportional to the diastase activity of the sample. A response mechanism of the platinum redox electrode is proposed, allowing a calculation of the diastase activity factor (F). The sensor and analyte parameters, including F, were obtained by least squares fitting of potentiometric data using the optimisation function of the Solver add-in of Microsoft Excel. The values of F obtained by the new direct potentiometric method were compared with those obtained using the standard Phadebas method (DN values), and the two values were found to agree within experimental error. Finally, the diastase activity of nine varieties of honey was determined using the novel method developed here. PMID:22868165

  14. Novel potentiometric sensor for monitoring beryllium based on naphto-9-crown-3.

    Science.gov (United States)

    Ganjali, Mohammad Reza; Daftari, Azadeh; Faal-Rastegar, Majid; Moghimi, Abolghasem

    2003-03-01

    A novel poly(vinyl chloride) (PVC) membrane electrode based on naphto-9-crown-3 was prepared and tested for the selective detection of beryllium ions. A suitable lipophilicity of the carrier and appropriate coordination ability were found to be essential for designing an electrode with good response characteristics. A PVC membrane with 9% naphtho-9-crown-3 carrier, 58% o-NPOE plasticizer, 3% tetraphenylborate anionic excluder and 30% poly(vinyl chloride) satisfied these requirements. The proposed sensor displayed a linear response to beryllium over a wide concentration range of 1.0 x 10(-1)-8.0 x 10(-6) M with a Nernstian slope of 29.5 mV per decade. The electrode showed very short response time (<15 s) and could be used in the pH range 3.5-9.0. The selectivity coefficient for alkali, alkaline earth, transition and heavy metal ions was smaller than 4.0 x 10(-4). The sensor was successfully used as an indicator electrode in the potentiometric titration of Be2+ with EDTA. The proposed Be(II) sensor was also used for the determination of Be2+ ions in binary mixtures.

  15. New triiodomercurate-modified carbon paste electrode for the potentiometric determination of mercury

    International Nuclear Information System (INIS)

    A new tetrazolium-triiodomercurate-modified carbon paste electrode has been described for the sensitive and selective determination of mercury. The electrode shows a stable, near-Nernstian response for 1x10-3 to 6x10-6 M [HgI3]- at 25 deg. C over the pH range of 4.0-9.0, with an anionic slope of 55.5±0.4 mV. The lower detection limit is 4x10-6 M with a fast response time of 30-50 s. Selectivity coefficients of a number of interfering anions and iodo complexes of some metal ions have been estimated. The interference from many of the investigated ions is negligible. The determination of 1-200 μg/ml of mercury in aqueous solutions shows an average recovery of 98.5% and a mean relative standard deviation of 1.6% at 50.0 μg/ml. The direct determination of mercury in spiked wastewater, metal amalgams and dental alloy gave results that compare favorably with those obtained by the cold vapor atomic absorption spectrometric method. Potentiometric titration of mercury and phenylmercury acetate with standard potassium iodide has been monitored using the developed triiodomercurate-carbon paste electrode (CPE) as an end point indicator electrode

  16. Aluminum(III) selective potentiometric sensor based on morin in poly(vinyl chloride) matrix.

    Science.gov (United States)

    Gupta, Vinod K; Jain, Ajay K; Maheshwari, Gaurav

    2007-06-15

    Al(3+) selective sensor has been fabricated from poly(vinyl chloride) (PVC) matrix membranes containing neutral carrier morin as ionophore. Best performance was exhibited by the membrane having composition as morin:PVC:sodium tetraphenyl borate:tri-n-butylphosphate in the ratio 5:150:5:150 (w/w, mg). This membrane worked well over a wide activity range of 5.0x10(-7) to 1.0x10(-1)M of Al(3+) with a Nernstian slope of 19.7+/-0.1mV/decade of Al(3+) activity and a limit of detection 3.2x10(-7)M. The response time of the sensor is approximately 5s and membrane could be used over a period of 2 months with good reproducibility. The proposed sensor works well over a pH range (3.5-5.0) and demonstrates good discriminating power over a number of mono-, di- and trivalent cations. The sensor can also be used in partially non-aqueous media having up to 20% (v/v) methanol, ethanol or acetone content with no significant change in the value of slope or working activity range. The sensor has also been used in the potentiometric titration of Al(3+) with EDTA and for its determination in zinc plating mud and red mud. PMID:19071785

  17. Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

    Science.gov (United States)

    Kaisheva, N. Sh.; Kaishev, A. Sh.

    2015-07-01

    The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.

  18. Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3

    Energy Technology Data Exchange (ETDEWEB)

    Toczydlowska, Diana; Kedra-Krolik, Karolina; Nejbert, Krzysztof; Preocanin, Tajana; Rosso, Kevin M.; Zarzycki, Piotr P.

    2015-05-29

    The role of surface electrostatics on the reductive dissolution of iron (III) oxides is poorly understood, despite its importance in controlling the amount of mobilized iron. We report the potentiometric titration of the a; y -Fe2O3 oxides exposed to reductants and complexing ligands (Fe(II), ascorbate, oxalate, malonate). We monitored in situ surface and potentials, the ratio of mobilized ferric to ferrous ions, and periodically analyzed nanoparticle crystal structure using X-ray diffraction. We found that addition of Fe2+ ions produces a response consistent with the iron solubilityactivity curve, whereas the presence of ascorbate significantly decreases the amount of mobilized Fe(III) due to reduction to Fe(II). In addition, XRD analysis proved that y-Fe2O3 particles remain structurally unchanged along the titration pathway despite iron cycling between aqueous and solid reservoirs. Our studies, suggest that the surface redoxactivity of iron oxides is primarily governed by the balance between Fe(III) and Fe(II) ions in aqueous phase, which may be easily altered by complexing and reducing agents.

  19. Plutonium titration by controlled potential coulometry

    International Nuclear Information System (INIS)

    The LAMMAN (Nuclear Materials Metrology Laboratory) is the support laboratory of the CETAMA (Analytical Method Committee), whose two main activities are developing analytic methods, and making and characterizing reference materials. The LAMMAN chose to develop the controlled potential coulometry because it is a very accurate analytical technique which allows the connection between the quantity of element electrolysed to the quantity of electricity measured thanks to the Faraday's law: it does not require the use of a chemical standard. This method was first used for the plutonium titration and was developed in the Materials Analysis and Metrology Laboratory (LAMM), for upgrading its performances and developing it to the titration of other actinides. The equipment and the material used were developed to allow the work in confined atmosphere (in a glove box), with all the restrictions involved. Plutonium standard solutions are used to qualify the method, and in particular to do titrations with an uncertainty better than 0.1 %. The present study allowed making a bibliographic research about controlled potential coulometry applied to the actinides (plutonium, uranium, neptunium, americium and curium). A full procedure was written to set all the steps of plutonium titration, from the preparation of samples to equipments storage. A method validation was done to check the full procedure, and the experimental conditions: working range, uncertainty, performance... Coulometric titration of the plutonium from pure solution (without interfering elements) was developed to the coulometric titration of the plutonium in presence of uranium, which allows to do accurate analyses for the analyses of some parts of the reprocessing of the spent nuclear fuel. The possibility of developing this method to other actinides than plutonium was highlighted thanks to voltammetric studies, like the coulometric titration of uranium with a working carbon electrode in sulphuric medium. (author)

  20. End-point construction and systematic titration error in linear titration curves-complexation reactions

    NARCIS (Netherlands)

    Coenegracht, P.M.J.; Duisenberg, A.J.M.

    1975-01-01

    The systematic titration error which is introduced by the intersection of tangents to hyperbolic titration curves is discussed. The effects of the apparent (conditional) formation constant, of the concentration of the unknown component and of the ranges used for the end-point construction are consid

  1. 全新在线滴定技术的研究与应用%Study and Application of a New On-Line Titration Technique

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new on-line titration method and device based on a new technique-continuous flow titration is described. By the meansofelectronically controlled switching of a solenoid valve, the main component of the system, the equivalent point of the titration is easilydetermined. Several kinds of mixing tools were examined, whereby a self-made mixing chamber with minimum volume gave best re-sults and was therefore used in the device. The error of the titration is within 0.2% and the relative standard deviation (RSD) isbe-low 1.2%. The results show no difference compared with a commercial device, meanwhile the new on-line titration system is cheaperand fully automated and thus easy to hand and less solvent consumption.

  2. Titulações espectrofotométricas de sistemas ácido-base utilizando extrato de flores contendo antocianinas Spectrophotometric titrations of acid-base systems using flower extracts containig anthocyanins

    Directory of Open Access Journals (Sweden)

    Mônica Souza Cortes

    2007-08-01

    Full Text Available Considering the attraction of the students' attention by the changes in the colors of vegetable crude extracts caused by the variation of the pH of the medium, the use of these different colors in order to demonstrate principles of spectrophotometric acid-base titrations using the crude extracts as indicators is proposed. The experimental setup consisted of a simple spectrophotometer, a homemade flow cell and a pump to propel the fluids along the system. Students should be stimulated to choose the best wavelength to monitor the changes in color during the titration. Since the pH of the equivalence point depends on the system titrated, the wavelength must be properly chosen to follow these changes, demonstrating the importance of the correct choice of the indicator. When compared with the potentiometric results, errors as low as 2% could be found using Rhododendron simsii (azalea or Tibouchina granulosa (Glory tree, quaresmeira as sources of the crude extracts.

  3. Titratable Acidity and Alkalinity of Red Soil Surfaces

    Institute of Scientific and Technical Information of China (English)

    SHAOZONG-CHEN; HEQUN; 等

    1993-01-01

    The surfaces of red soils have an apparent amphoteric character,carrying titratable acidity and titratable alkalinity simultaneously.The titratable acidity arises from deprotonation of hydroxyl groups of hydrous oxide-type surfaces and dissociation of weak-acid functional groups of soil organic matter,while the titratable alkalinity is derived from release of hydroxyl groups of hydrous oxide-type surfaces.The titratable acidity and titratable alkalinity mainly depended on the composition and content of iron and aluminum oxides in the soils.The results showed that the titratable acidity and titratable alkalinity were in significantly positive correlation not only with the content of amorphous aluminum oxide(Alo) and iron oxide(Feo) extracted with acid ammonium oxalate solution,free iron oxide(Fed) extracted with sodium dithionite-citrate-bicarbonate(DCB) and clays,but also with the zero point of charge (ZPC) of the samples.Organic matter made an important contribution to the titratable acidity.the titratable alkalinity was closely correlated with the amount of fluoride ions adsorbed.The titratable acidity and titratable alkalinity of red soils were influenced by parent materials,being in the order of red soil derived from basalt> that from tuff> that from granite.The titratable acidity and titratable alkalinity ware closely related with origination of the variable charges of red soils,and to a certain extent were responsible for variable negative and positive charges of the soils.

  4. Isothermal Titration Calorimetry in the Student Laboratory

    Science.gov (United States)

    Wadso, Lars; Li, Yujing; Li, Xi

    2011-01-01

    Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

  5. Limitations of potentiometric oxygen sensors operating at low oxygen levels

    DEFF Research Database (Denmark)

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels;

    2011-01-01

    The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10...... that gas phase mass transport processes were dominating. The time constant of the gas phase mass transport processes was found to be inversely proportional to the oxygen partial pressure. The response time of these processes therefore limits the oxygen partial pressure range in which potentiometric oxygen...

  6. Miniaturized ionophore-based potentiometric sensors for the flow-injection determination of metformin in pharmaceutical formulations and biological fluids.

    Science.gov (United States)

    Khaled, Elmorsy; Kamel, Manal S; Hassan, Hassan N; Abd El-Alim, Sameh H; Aboul-Enein, Hassan Y

    2012-12-01

    Miniaturized potentiometric sensors based on β-cyclodextrins (β-CDs) are described for determination of metformin (Mf) in pharmaceutical preparations and biological fluids. Electrode matrix compositions are optimized on the basis of the nature and content of sensing ionophore, ionic sites and plasticizers. Coated wire electrodes (CWEs) modified with heptakis(2,3,6-tri-O-methyl)-β-CD, sodium tetrakis(4-fluorophenyl)borate (NaTFPB) and 2-fluorophenyl 2-nitrophenyl ether (f-NPE), work satisfactorily in the concentration range from 10(-6) to 10(-1) mol L(-1) with Nernstian compliance (55.7 ± 0.4 mV per decade activity) and a detection limit of 8 × 10(-7) mol L(-1). Incorporation of β-CD as a molecular recognition element improved the electrode sensitivity and selectivity due to encapsulation of Mf into the β-CD cavity (host-guest interaction). The developed electrodes have been successfully applied for the potentiometric determination of Mf under batch and flow injection analysis (FIA). FIA allows analysis of 90 samples per h offering the advantages of simplicity, accuracy and automation feasibility. The dissolution profile for metformin pharmaceutical samples (Cidophage®) was monitored using the proposed electrode in comparison with the official spectrophotometric methods. Characterization of the formed Mf-β-CD inclusion complexes is discussed in detail.

  7. Strontium (II-Selective Potentiometric Sensor Based on Ester Derivative of 4-tert-butylcalix(8arene in PVC Matrix

    Directory of Open Access Journals (Sweden)

    Jitendra R. Raisoni

    2004-08-01

    Full Text Available Abstract: Membranes of 4-tert-butylcalix(8arene-octaacetic acid octaethyl ester (I as an electroactive material, sodium tetraphenyl borate (NaTPB as an anion excluder, and tri-n-butyl phosphate (TBP as a solvent mediator in poly(vinyl chloride (PVC matrix have been tried for a strontium-selective sensor. The best performance was exhibited by the membrane having a composition 5:100:150:2 (I: PVC: TBP: NaTPB (w/w. This sensor exhibits a good potentiometric response to Sr2+ over a wide concentration range (3.2 × 10 –5 –1.0 × 10 –1 M with a Nernstian slope (30 mV/ decade. The response time of the sensor is 10 s and it has been used for a period of four months without any drift in potentials. The selectivity coefficient values are in the order of 0.01 for mono-, bi-, and trivalent cations which indicate a good selectivity for Sr2+ over a large number of cations. The useful pH range for the sensor was found to be 3-10 and it works well in mixtures with non-aqueous content up to 25 % (v/v. The sensor has been used as an indicator electrode in the potentiometric titration of Sr2+ against EDTA.

  8. Application Of A Potentiometric Electronic Tongue For The Determination Of Free SO2 And Other Analytical Parameters In White Wines From New Zealand

    Science.gov (United States)

    Mednova, Olga; Kirsanov, Dmitry; Rudnitskaya, Alisa; Kilmartin, Paul; Legin, Andrey

    2009-05-01

    The present study deals with a potentiometric electronic tongue (ET) multisensor system applied for the simultaneous determination of several chemical parameters for white wines produced in New Zealand. Methods in use for wine quality control are often expensive and require considerable time and skilled operation. The ET approach usually offers a simple and fast measurement protocol and allows automation for on-line analysis under industrial conditions. The ET device developed in this research is capable of quantifying the free and total SO2 content, total acids and some polyphenolic compounds in white wines with acceptable analytical errors.

  9. Tandem electrochemical desalination-potentiometric nitrate sensing for seawater analysis.

    Science.gov (United States)

    Cuartero, Maria; Crespo, Gastón A; Bakker, Eric

    2015-08-18

    We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec(-1), limit of detection of 5 × 10(-7) M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater. PMID:26201537

  10. Titration Calorimetry Standards and the Precision of Isothermal Titration Calorimetry Data

    OpenAIRE

    Daumantas Matulis; Jurgita Matulienė; Vilma Petrikaitė; Lina Baranauskienė

    2009-01-01

    Current Isothermal Titration Calorimetry (ITC) data in the literature have relatively high errors in the measured enthalpies of protein-ligand binding reactions. There is a need for universal validation standards for titration calorimeters. Several inorganic salt co-precipitation and buffer protonation reactions have been suggested as possible enthalpy standards. The performances of several commercial calorimeters, including the VP-ITC, ITC200, and Nano ITC-III, were validated using these sug...

  11. An Olfactory Indicator for Acid-Base Titrations.

    Science.gov (United States)

    Flair, Mark N.; Setzer, William N.

    1990-01-01

    The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

  12. Home Automation

    OpenAIRE

    Ahmed, Zeeshan

    2010-01-01

    In this paper I briefly discuss the importance of home automation system. Going in to the details I briefly present a real time designed and implemented software and hardware oriented house automation research project, capable of automating house's electricity and providing a security system to detect the presence of unexpected behavior.

  13. Silver ion recognition using potentiometric sensor based on recently synthesized isoquinoline-1,3-dione derivatives

    Directory of Open Access Journals (Sweden)

    AJAR KAMAL

    2012-08-01

    Full Text Available The four derivatives of isoquinoline-1,3-dione based on β-lactum (I-IV, have been explored as neutral ionophores for preparing poly(vinylchloride based polymeric membrane electrodes (PME selective to silver(I ions. The addition of sodium tetraphenylborate (NaTPB and dioctylsebacate (DOS as a plasticizer was found to improve the performance of ion selective electrodes. The best performance was obtained with PME-1 based on ionophore I having composition: ionophore (9.2 mg, PVC (100.1 mg, DOS (201.1 mg and NaTPB (1.5 mg in 5 mL tetrahydrofuran. The electrode response was linear with Nernstian slope of 58.44 mV/decade in the concentration range of 1.0 x 10-1 M to 5.0 x 10-6 M and detection limit of 5.83 x 10-6 M. It performs satisfactorily over wide pH range of 1.0-5.5. The proposed sensor can be used over a period of more than three months without any significant drift in potential and shows good selectivity to silver(I ion over a number of cations especially with no interference of mercury(II ions. Sharp end point was obtained when the sensor was used as an indicator electrode for the potentiometric titration of silver(I ions with chloride ions and therefore this electrode (PME-1 could be used for quantitative determination of silver(I ion in synthetic water, silver foil and dental amalgam samples.

  14. Fabrication of new carbon paste electrodes based on gold nano-particles self-assembled to mercapto compounds as suitable ionophores for potentiometric determination of copper ions

    Directory of Open Access Journals (Sweden)

    Rasoul Pourtaghavi Talemi

    2013-12-01

    Full Text Available In the present study, we investigate the potentiometric behavior of Cu2+ carbon paste electrodes based on two mercapto compounds 2-ethylmino-5-mercapto-1,3,4-thiadiazole (EAMT and 2-acetylamino-5-mercapto-1,3,4-thiadiazole (AAMT self-assembled on gold nano-paricle (GNP as ionophore. Then, the obtained results from the modified electrodes are compared. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu2+, in which the sulfur and nitrogen atoms in their structure play a significant role as the effective coordination donor site for the copper ion. Among these electrodes, the best performance was obtained with the sensor with a EAMT/graphite powder/paraffin oil weight ratio of 4.0/68/28 with 200 µL of GNP which exhibits the working concentration range of 1.6×10−9 to 6.3×10−2 M and a nernstian slope of 28.9±0.4 mVdecade−1 of copper(II activity. The detection limit of electrode was 2.9(±0.2×10−10M and potential response was pH ; in other words, it was independent across the range of 2.8–6.3. The proposed electrode presented very good selectivity and sensitivity towards the Cu2+ ions over a wide variety of cations including alkali, alkaline earth, transition and heavy metal ions. Moreover, the proposed electrode was successfully applied as an indicator electrode in the potentiometric titration of Cu(II ions with EDTA and also the potentiometric determination of copper ions in spiked water samples.

  15. Potentiometric studies on ternary complexes involving some divalent transition metal ions, gallic acid and biologically abundant aliphatic dicarboxylic acids in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Abdelatty Mohamed Radalla

    2015-06-01

    Full Text Available Formation of binary and ternary complexes of the divalent transition metal ions, Cu2+, Ni2+, Co2+ and Zn2+ with gallic acid and the biologically important aliphatic dicarboxylic acids (adipic, succinic, malic, malonic, maleic, tartaric and oxalic acids were investigated by means of the potentiometric technique at 25 °C and I = 0.10 mol dm−3 NaNO3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of gallic acid and aliphatic dicarboxylic acids were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the above experimental conditions. The formation of the different 1:1 and 1:2 binary complexes and 1:1:1 ternary complexes are inferred from the corresponding potentiometric pH-metric titration curves. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The values of Δ log K, percentage of relative stabilization (%R.S. and log X were evaluated and discussed. The concentration distribution of the various complex species formed in solution was evaluated and discussed. The mode of chelation of ternary complexes formed was ascertained by conductivity measurements.

  16. A Novel Potentiometric Sensor Based on 1,2-Bis(N’-benzoylthioureido)benzene and Reduced Graphene Oxide for Determination of Lead (II) Cation in Raw Milk

    International Nuclear Information System (INIS)

    We have developed a highly sensitive and selective potentiometric PVC-membrane sensor for lead (II) cation. A glassy carbon electrode (GCE) was modified with synthesized 1,2-Bis(N’-benzoylthioureido) benzene (BBTB) as an ionophore and reduced graphene oxide (RGO), and this material was characterized by scanning electron microscopy. The sensor shows sensitive and highly selective response to Pb(II) ion with a linear range from 6.31 × 10−8 to 3.98 × 10−2 M, Nernstian slope of 30.37 ± 0.62 mV per decade and a detection limit of 2.51 × 10−8 M. The proposed sensor could be used in a pH range of 4.0–8.0. Selectivity coefficients were determined for known common cations by applying the match potential method (MPM). The sensor was successfully applied to monitor Pb(II) in raw milk and in potentiometric titration of Pb2+ ions. The structure of BBTB ligand and its complexation with some common cations were investigated by using quantum mechanical DFT calculations. Lead (II) cation showed prominent affinity to the BBTB carrier

  17. Digital movie-based on automatic titrations.

    Science.gov (United States)

    Lima, Ricardo Alexandre C; Almeida, Luciano F; Lyra, Wellington S; Siqueira, Lucas A; Gaião, Edvaldo N; Paiva Junior, Sérgio S L; Lima, Rafaela L F C

    2016-01-15

    This study proposes the use of digital movies (DMs) in a flow-batch analyzer (FBA) to perform automatic, fast and accurate titrations. The term used for this process is "Digital movie-based on automatic titrations" (DMB-AT). A webcam records the DM during the addition of the titrant to the mixing chamber (MC). While the DM is recorded, it is decompiled into frames ordered sequentially at a constant rate of 26 frames per second (FPS). The first frame is used as a reference to define the region of interest (ROI) of 28×13pixels and the R, G and B values, which are used to calculate the Hue (H) values for each frame. The Pearson's correlation coefficient (r) is calculated between the H values of the initial frame and each subsequent frame. The titration curves are plotted in real time using the r values and the opening time of the titrant valve. The end point is estimated by the second derivative method. A software written in C language manages all analytical steps and data treatment in real time. The feasibility of the method was attested by application in acid/base test samples and edible oils. Results were compared with classical titration and did not present statistically significant differences when the paired t-test at the 95% confidence level was applied. The proposed method is able to process about 117-128 samples per hour for the test and edible oil samples, respectively, and its precision was confirmed by overall relative standard deviation (RSD) values, always less than 1.0%. PMID:26592600

  18. Analysis of Cooperativity by Isothermal Titration Calorimetry

    OpenAIRE

    Alan Brown

    2009-01-01

    Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of coop...

  19. Use of Sequential Injection Analysis to construct a Potentiometric Electronic Tongue: Application to the Multidetermination of Heavy Metals

    Science.gov (United States)

    Mimendia, Aitor; Legin, Andrey; Merkoçi, Arben; del Valle, Manel

    2009-05-01

    An automated potentiometric electronic tongue (ET) was developed for the quantitative determination of heavy metal mixtures. The Sequential Injection Analysis (SIA) technique was used in order to automate the obtaining of input data, and the combined response was modeled by means of Artificial Neural Networks (ANN). The sensor array was formed by four sensors: two based on chalcogenide glasses Cd sensor and Cu sensor, and the rest on poly(vinyl chloride) membranes Pb sensor and Zn sensor. The Ion Selective Electrode (ISE) sensors were first characterized with respect to one and two analytes, by means of high-dimensionality calibrations, thanks to the use of the automated flow system; this characterization enabled an interference study of great practical utility. To take profit of the dynamic nature of the sensor's response, the kinetic profile of each sensor was compacted by Fast Fourier Transform (FFT) and the extracted coefficients were used as inputs for the ANN in the multidetermination applications. In order to identify the ANN which provided the best model of the electrode responses, some of the network parameters were optimized. Finally analyses were performed employing synthetic samples and water samples of the river Ebro; obtained results were compared with reference methods.

  20. A monosegmented-flow Karl Fischer titrator.

    Science.gov (United States)

    de Aquino, Emerson Vidal; Rohwedder, Jarbas José Rodrigues; Pasquini, Celio

    2007-02-28

    A monosegmented volumetric Karl Fischer titrator is described to mechanize the determination of water content in organic solvents. The system is based on the flow-batch characteristics of the monosegmented analysis concept and employs biamperometry to monitor the progress of the titration. The system shows accuracy and precision that are highly independent of the flow rate, does not require calibration, and is carried out in a closed system capable of minimizing contact of the sample and reagents with ambient moisture. Sample volumes in the range of 40-300muL are employed, depending on the water concentration. An automatic dilution is provided to deal with concentrated samples. The consumption of Karl Fischer reagent depends on the water content of the sample but is not larger than 100muL. The system was evaluated for determination of water in ethanol and methanol in the range 0.02-0.5% (w/w). The average relative precision estimated in that range (9-3%) is comparable to that obtained with a larger volume commercial system and no significant difference was observed between the results obtained for the two systems at the 95% confidence level. A complete titration can be performed in less than 5min employing the proposed system. PMID:19071447

  1. Potentiometric sensor for sensitive and selective detection of heparin

    Institute of Scientific and Technical Information of China (English)

    Yan Chen; Rong Ning Liang; Wei Qin

    2012-01-01

    A polymeric membrane ion-selective electrode for determination of heparin is described in this paper,protamine is incorporated into the organic membrane phase and functions as sensing element for selective recognition of heparin.The proposed membrane electrode exhibits high selectivity for heparin over lipophilic anions such as thiocyanide and salicylate.The potentiometric response to the concentration of heparin is linear in the range of 0.01-0.4 U/mL and a lower detection limit of 0.005 U/mL can be achieved.

  2. Neurochip Based on Light-addressable Potentiometric Sensor

    Institute of Scientific and Technical Information of China (English)

    Qingjun Liu; Hua Cai; Ying Xu; Lifeng Qin; Lijiang Wang; Ping Wang

    2006-01-01

    A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed. Using its light addressable characteristic. The problems of the limitations of restricted discrete active sites of current neurochips, such as microelectrode array and field effect transistor array can be settled easily. Based on the theoretical analysis of the interface between cells and LAPS, spontaneously discharges of hippocampal neurons induced by Mg2+-free media treatment were recorded by LAPS. The results demonstrate that this kind of neurochip has potential to monitor electrophysiology of cultured cells in a non-invasive way.

  3. Preparation and Application of Automatic Photometric Titration Analyzer Based on Reflective Photometric Sensor%基于反射式光度传感器的自动光度滴定仪的研制及应用

    Institute of Scientific and Technical Information of China (English)

    何艺; 周小锋; 马建丰

    2012-01-01

    研制了一种以颜色变化为滴定终点的自动光度滴定仪,仪器以光度传感器为核心,包括光度探头、滴定装置、AT89S52单片机、电磁阀、二极管和磁力搅拌器等部件。传感器采用开放设计,对溶液吸光度变化反应迅速。仪器用于红醋酸度的测定,所得结果与电位滴定分析法结果相符。%An automatic photometric titration analyzer with color change as end point of titration was prepared. The analyzer consisted of reflective photometric sensor (as core), photometric probe, titration device, AT89S52 monolithic circuit, electromagnetic valve, diode and magnetic stirrer. The open design of sensor leaded to detect the absorbance of solution without delay in titration. The analyzer was applied in the determination of acidity of red vinegar, and the results obtained were in consistency with those obtained by potentiometric titration.

  4. N′, N″, N‴-tris(2-pyridyloxymethyl) ethane as ionophore in potentiometric sensor for Pb(II) ions

    Indian Academy of Sciences (India)

    Pawan Kumar; Ashok Kumar S K; Susheel K Mittal

    2014-01-01

    N′,N″,N‴ tris(2-pyridyloxymethyl) ethane (TPOME) has been used as an ionophore in a polyvinylchloride (PVC)-based membrane. Membrane electrode with a composition 30:5:62:3 (PVC:TPOME: o-NPOE:NaTPB) exhibits Nernstian response towards Pb(II) ions with a slope of 30mV/decade, over a concentration range of 1 × 10−5 M to 1 × 10−1 M. Potential response remains almost unchanged over pH range of 3.7-6.4. The electrode shows fast response time of 15 ± 2 s and a lifetime of four months. It shows good selectivity for Pb(II) ions over other mono-, di- and trivalent cations. Electrode response is satisfactory in mixed solvent media up to 30% (v/v) non-aqueous contents. Selectivity of the ionophore for Pb(II) ions was determined by spectrophotometric method. The electrode can also be used as an indicator electrode in potentiometric titration of Pb(II) ions with standard chromate solution and its determination in real-life samples. Surface morphology of membrane electrode at different stages of its development and use is also discussed.

  5. Isothermal titration calorimetry: A thermodynamic interpretation of measurements

    International Nuclear Information System (INIS)

    Highlights: ► Literature review shows that many ITC utilizations are based on empirical rules. ► A proper and rigorous thermodynamic interpretation of heats of titration is proposed. ► Heats of titration are independent of the cell type using infinitesimal titrations. ► Heats of interaction between solutes require only two different titration runs. - Abstract: Isothermal titration calorimeters have been developed and in use since the 1960s and the number of applications based on empirical rules to use them steadily increases. In this paper a rigorous study of the physical interpretation of the titration heat and the thermodynamic framework underlying isothermal titration calorimetry are proposed. For infinitesimal titrations, the titration heat is independent of the cell type employed, and the interpretation of the titration heat depends on the titrant composition and on the experiment type. Moreover, for the study of the interaction between two solutes in solution, only a combination of two experiments is necessary, and the result is interpreted as the partial enthalpy of interaction at infinite dilution of the solute contained in the titrant solution.

  6. Improving the limits of detection in potentiometric sensors

    International Nuclear Information System (INIS)

    Potentiometric sensors will generally suffer from unwanted responses as a result to changing temperatures by generating an electromotive force. Typically, this voltage drift has a non-linear character and therefore it is difficult to compensate using linear algorithms implemented in the analogue domain. A solution is proposed to improve the sensor characteristics by combining the digitized output of two CO2 rubidium silver iodide sensors with a specially designed digital algorithm to improve the limits of detection (LOD). Experiments show that this method has the capability to improve the LOD of the sensor with a factor 4.5x during temperature variations of 22 °C over a measurement period of 22 h. It enables potentiometric sensors to be used in low power wireless sensor networks for long term air quality control. Furthermore, the influence of depletion of the rubidium silver iodide electrolyte layer can be effectively compensated by determining the decay of the active layer according to the Nernst equation. Knowing the function of depletion over time helps to correct the sensor output and thereby improves the accuracy of the sensor. (paper)

  7. Highly sensitive potentiometric immunosensor for hepatitis B surface antigen diagnosis

    Institute of Scientific and Technical Information of China (English)

    YUAN; Ruo; TANG; Dianping; CHAI; Yaqin; ZHANG; Lingyan; LI

    2005-01-01

    A highly sensitive potentiometric immunosensor for the diagnoses of epidemic diseases has been developed by means of self-assembly to immobilize hepatitis B surface antibody (HBsAb) for the detection of hepatitis B surface antigen (HBsAg) as a model. At first, the Nafion containing -SO3- groups was immobilized on a platinum electrode surface to absorb the -NH3+ groups of antibody molecules via the opposite-charged adsorption technique, in the meantime, hepatitis B surface antibodies were adsorbed onto the surface of Au nanoparticles, then hepatitis B surface antibodies and Au nanopartilces were entrapped into polyvinyl butyral on the surface of Nafion film. The modified procedure was further characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The influence and factors influencing the performance of resulting immunosensor were studied in detail. The resulting immunosensor exhibited sigmoid curve with log HBsAg concentrations, high sensitivity, wide linear range from 26 to 1280 ng·mL-1 with a detection limit of 3.1 ng·mL-1, rapid potentiometric response (4 months). Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays (ELISAs) method, implying a promising alternative approach for detecting HBsAg in the clinical diagnosis.

  8. Library Automation

    OpenAIRE

    Dhakne, B. N.; Giri, V. V; Waghmode, S. S.

    2010-01-01

    New technologies library provides several new materials, media and mode of storing and communicating the information. Library Automation reduces the drudgery of repeated manual efforts in library routine. By use of library automation collection, Storage, Administration, Processing, Preservation and communication etc.

  9. Potentiometric-level monitoring program: Mississippi and Louisiana. Annual status report for fiscal year 1984

    International Nuclear Information System (INIS)

    Potentiometric-level data presented in this report were collected from October 1983 through September 1984 at 79 wells in Mississippi and Louisiana. These wells are located near Richton and Cypress Creek Domes in Mississippi and Vacherie Dome in Louisiana. Fourteen wells were added to the program during this period. Two of these wells were not measurable. Two wells previously unmeasurable were located and measured. One well was destroyed during military maneuvers in the area. Analysis of the data indicated minimal, if any, change in potentiometric levels during the past year in the Citronelle, Hattiesburg, Cockfield, Sparta, and Wilcox Formations in Mississippi. A continuing decline in potentiometric levels, ranging from 0.3 to 0.6 foot per year, occurred in the wells screened in the caprock at Richton and Cypress Creek Domes. The Catahoula Formation experienced a continuing decline in potentiometric levels of about 2 feet per year. Two wells in the Cook Mountain Formation showed a continuing rise in potentiometric levels ranging from 8 to 30 ft during the past fiscal year. Wells screened in the Austin Formation in Louisiana showed a fall in potentiometric levels of 2 to 3 ft over the past fiscal year. Other formations in Louisiana generally showed no change in potentiometric levels over the past year. 26 refs., 2 figs., 3 tabs

  10. Process automation

    International Nuclear Information System (INIS)

    Process automation technology has been pursued in the chemical processing industries and to a very limited extent in nuclear fuel reprocessing. Its effective use has been restricted in the past by the lack of diverse and reliable process instrumentation and the unavailability of sophisticated software designed for process control. The Integrated Equipment Test (IET) facility was developed by the Consolidated Fuel Reprocessing Program (CFRP) in part to demonstrate new concepts for control of advanced nuclear fuel reprocessing plants. A demonstration of fuel reprocessing equipment automation using advanced instrumentation and a modern, microprocessor-based control system is nearing completion in the facility. This facility provides for the synergistic testing of all chemical process features of a prototypical fuel reprocessing plant that can be attained with unirradiated uranium-bearing feed materials. The unique equipment and mission of the IET facility make it an ideal test bed for automation studies. This effort will provide for the demonstration of the plant automation concept and for the development of techniques for similar applications in a full-scale plant. A set of preliminary recommendations for implementing process automation has been compiled. Some of these concepts are not generally recognized or accepted. The automation work now under way in the IET facility should be useful to others in helping avoid costly mistakes because of the underutilization or misapplication of process automation. 6 figs

  11. Carbon Nanotubes-Based Potentiometric Bio-Sensors for Determination of Urea

    Directory of Open Access Journals (Sweden)

    Ewa Jaworska

    2015-07-01

    Full Text Available The possibility of using disposable plastic-carbon potentiometric sensors as enzyme biosensors was examined. Urease enzyme was immobilized on poly(vinyl chloride based H+- or NH4+-selective membranes using cellulose acetate. This approach has resulted in a potentiometric response on changing the pH of the solution or NH4+ ion content due to an enzymatic reaction that occurs between urease and urea. Both types of potentiometric biosensors for urea were characterized by good analytical parameters as high sensitivity and fast response time.

  12. Isothermal Titration Calorimetry to Characterize Enzymatic Reactions.

    Science.gov (United States)

    Mazzei, Luca; Ciurli, Stefano; Zambelli, Barbara

    2016-01-01

    Isothermal titration calorimetry (ITC) is a technique that measures the heat released or absorbed during a chemical reaction as an intrinsic probe to characterize any chemical process that involves heat changes spontaneously occurring during the reaction. The general features of this method to determine the kinetic and thermodynamic parameters of enzymatic reactions (kcat, KM, ΔH) are described and discussed here together with some detailed applications to specific cases. ITC does not require any modification or labeling of the system under analysis, can be performed in solution, and needs only small amounts of enzyme. These properties make ITC an invaluable, powerful, and unique tool to extend the knowledge of enzyme kinetics to drug discovery.

  13. Isothermal Titration Calorimetry of Chiral Polymeric Nanoparticles.

    Science.gov (United States)

    Werber, Liora; Preiss, Laura C; Landfester, Katharina; Muñoz-Espí, Rafael; Mastai, Yitzhak

    2015-09-01

    Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titration calorimetry (ITC) to measure the chiral interactions and the energetics of the adsorption of enantiomers from aqueous solutions onto chiral polymeric nanoparticles. The characterization of chirality in nano-systems is a very challenging task; here, we demonstrate that ITC can be used to accurately determine the thermodynamic parameters associated with the chiral interactions of nanoparticles. The use of ITC to measure the energetics of chiral interactions and recognition at the surfaces of chiral nanoparticles can be applied to other nanoscale chiral systems and can provide further insight into the chiral discrimination processes of nanomaterials.

  14. Modeling potentiometric measurements in topological insulators including parallel channels

    Science.gov (United States)

    Hong, Seokmin; Diep, Vinh; Datta, Supriyo; Chen, Yong P.

    2012-08-01

    The discovery of spin-polarized states at the surface of three-dimensional topological insulators (TI) like Bi2Te3 and Bi2Se3 motivates intense interests in possible electrical measurements demonstrating unique signatures of these unusual states. Here we show that a three-terminal potentiometric set-up can be used to probe them by measuring the voltage change of a detecting magnet upon reversing its magnetization. We present numerical results using a nonequilibrium Green's function (NEGF)-based model to show the corresponding signal quantitatively in various transport regimes. We then provide an analytical expression for the resistance (the measured voltage difference divided by an applied current) that agrees with NEGF results well in both ballistic and diffusive limits. This expression is applicable to TI surface states, two-dimensional electrons with Rashba spin-split bands, and any combination of multiple channels, including bulk parallel states in TI, which makes it useful in analyzing experimental results.

  15. A Closer Look at Acid-Base Olfactory Titrations

    Science.gov (United States)

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  16. The coulometric titration of acids and bases in dimethylsulfoxide media

    NARCIS (Netherlands)

    Bos, M.; IJpma, S.T.; Dahmen, E.A.M.F.

    1976-01-01

    The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current densi

  17. Microscale pH Titrations Using an Automatic Pipet.

    Science.gov (United States)

    Flint, Edward B.; Kortz, Carrie L.; Taylor, Max A.

    2002-01-01

    Presents a microscale pH titration technique that utilizes an automatic pipet. A small aliquot (1-5 mL) of the analyte solution is titrated with repeated additions of titrant, and the pH is determined after each delivery. The equivalence point is determined graphically by either the second derivative method or a Gran plot. The pipet can be…

  18. CHEMICALLY MODIFIED FIELD-EFFECT TRANSISTORS - POTENTIOMETRIC AG+ SELECTIVITY OF PVC MEMBRANES BASED ON MACROCYCLIC THIOETHERS

    NARCIS (Netherlands)

    BRZOZKA, Z; COBBEN, PLHM; REINHOUDT, DN; EDEMA, JJH; KELLOGG, RM

    1993-01-01

    A chemically modified field-effect transistor (CHEMFET) with satisfactory Ag+ selectivity is described. The potentiometric Ag+ selectivities of CHEMFETs with plasticized PVC membranes based on macrocyclic thioethers have been determined. All the macrocyclic thioethers tested showed silver response a

  19. Improved Performance of the Potentiometric Biosensor for the Determination of Creatinine

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Zachau-Christiansen, Birgit

    2007-01-01

    The development of potentiometric biosensors for the determination of creatinine is attractive because it is a frequently analysed species in clinical chemistry. Contemporary methods of analysing creatinine engage chemicals harmful to the environment and generate large volumes of waste disposals....

  20. Synthesis and Non-Aqueous Medium Titrations of Some New 4-Benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives

    Directory of Open Access Journals (Sweden)

    Sule Bahceci

    2005-08-01

    Full Text Available The synthesis of 3-alkyl(aryl-4-(3-ethoxy-4-hydroxybenzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described.The acetylation and methylation reactions of the compounds 3 giving compounds of type4 and 5, respectively, were investigated. The newly synthesized compounds werecharacterized using elemental analyses and IR, 1H-NMR, 13C-NMR and UV spectral data.In addition, to investigate the effects of solvents and molecular structure upon acidity,compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide infour non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide. The half-neutralization potential values and the corresponding pKavalues were determined for all cases.

  1. Potentiometric-level monitoring program - Mississippi and Louisiana: annual status report for fiscal year 1983

    International Nuclear Information System (INIS)

    Potentiometric-level data presented in this report were collected from October 1982 to September 1983 at 62 wells in Mississippi and Louisiana near Richton and Vacherie Domes, respectively. Six wells were added to the monitoring program during this period, and one previously measured well was damaged and has been deleted from the monitoring program. Analysis of the data indicates that most of the potentiometric-level changes recorded during fiscal year 1983 were small (less than 2 feet) and attributable to seasonal fluctuations. Of the 62 wells monitored, 18 exhibited potentiometric-level changes in excess of 2 feet. In Mississippi, the data generally indicate that a long-term, potentiometric-level increase is occurring in the Sparta, Kosciusko, Hattiesburg, Wilcox, and Citronelle Formations. Only seasonal fluctuations in potentiometric levels were observed in the caprock, and in the Catahoula and Cockfield Formations. In Louisiana, a long-term, potentiometric-level decline was observed for the Lower Austin Formation while an increase was observed for the Sparta and Upper Austin Formations. Seasonal fluctuations were observed in the Wilcox, Carrizo, and Nacatoch Formations. This work is a continuation of that described in ONWI-478 for fiscal year 1982. 24 references, 2 figures, 3 tables

  2. Total Acid Value Titration of Hydrotreated Biomass Fast Pyrolysis Oil: Determination of Carboxylic Acids and Phenolics with Multiple End-Point Detection

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, E.; Alleman, T. L.; McCormick, R. L.

    2013-01-01

    Total acid value titration has long been used to estimate corrosive potential of petroleum crude oil and fuel oil products. The method commonly used for this measurement, ASTM D664, utilizes KOH in isopropanol as the titrant with potentiometric end point determination by pH sensing electrode and Ag/AgCl reference electrode with LiCl electrolyte. A natural application of the D664 method is titration of pyrolysis-derived bio-oil, which is a candidate for refinery upgrading to produce drop in fuels. Determining the total acid value of pyrolysis derived bio-oil has proven challenging and not necessarily amenable to the methodology employed for petroleum products due to the different nature of acids present. We presented an acid value titration for bio-oil products in our previous publication which also utilizes potentiometry using tetrabutylammonium hydroxide in place of KOH as the titrant and tetraethylammonium bromide in place of LiCl as the reference electrolyte to improve the detection of these types of acids. This method was shown to detect numerous end points in samples of bio-oil that were not detected by D664. These end points were attributed to carboxylic acids and phenolics based on the results of HPLC and GC-MS studies. Additional work has led to refinement of the method and it has been established that both carboxylic acids and phenolics can be determined accurately. Use of pH buffer calibration to determine half-neutralization potentials of acids in conjunction with the analysis of model compounds has allowed us to conclude that this titration method is suitable for the determination of total acid value of pyrolysis oil and can be used to differentiate and quantify weak acid species. The measurement of phenolics in bio-oil is subject to a relatively high limit of detection, which may limit the utility of titrimetric methodology for characterizing the acidic potential of pyrolysis oil and products.

  3. Titration procedure for low ethoxylated nonionic surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Buschmann, N. [Anorganisch-Chemisches Inst., Lehrstuhl fuer Analytische Chemie, Muenster Univ. (Germany); Huelskoetter, F. [Anorganisch-Chemisches Inst., Lehrstuhl fuer Analytische Chemie, Muenster Univ. (Germany)

    1997-01-01

    Highly lipophilic surfactants are frequently used as emulsifiers for preparing oil-in-water emulsions (e.g. coolants lubricants). Typical surfactants used for this purpose are low ethoxylated alcohols and ethoxylated alkylphenols. Due to the low degree of ethoxylation they cannot be analysed by conventional methods. The method described in this article is based on the introduction of an anionic group into the molecule by a derivatization reaction. The reaction product can be determined by conventional titration methods for anionic surfactants without any modification. The use of the new method for other nonionic surfactants like sorbitan esters, (ethoxylated) fatty acid amides or glycerol fatty acid partial esters is also described as well as the sample preparation for coolants lubricants. (orig.) [Deutsch] Lipophile Tenside werden haeufig zur Herstellung von Oel-in-Wasser-Emulsionen verwandt, wie sie beispielsweise in Kuehlschmiermitteln eingesetzt werden. Typische Vertreter dieser Tenside sind niedrig ethoxylierte Fettalkohole und Alkylphenole. Wegen ihres geringen Ethoxylierungsgrades koennen sie mit den konventionellen Methoden nicht analytisch bestimmt werden. Die hier beschriebene Analysenmethode beruht auf der Derivatisierung der Ethoxylate zu entsprechenden anionischen Tensiden (Ethersulfate). Diese koennen ohne weiteres mit den etablierten Titrationsverfahren bestimmt werden. Die Anwendung dieses neuen Verfahrens auf die Bestimmung anderer nichtionischer Tenside - Sorbitanester, (ethoxylierte) Fettsaeureamide und Partialglyceride - wird ebenso beschrieben wie die Probenvorbereitung fuer die Analyse von Kuehlschmiermitteln. (orig.)

  4. Titration and hysteresis in epigenetic chromatin silencing

    International Nuclear Information System (INIS)

    Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of this paper is to examine how the perturbations altering the activity of histone modifying enzymes affect the epigenetic states. We analyze the implications of having the total number of silencing proteins, given by the sum of proteins bound to the nucleosomes and the ones available in the ambient, to be constant. This constraint couples different regions of chromatin through the shared reservoir of ambient silencing proteins. We show that the response of the system to perturbations depends dramatically on the titration effect caused by the above constraint. In particular, for a certain range of overall abundance of silencing proteins, the hysteresis loop changes qualitatively with certain jump replaced by continuous merger of different states. In addition, we find a nonmonotonic dependence of gene expression on the rate of histone deacetylation activity of Sir2. We discuss how these qualitative predictions of our model could be compared with experimental studies of the yeast system under anti-silencing drugs. (paper)

  5. Proton conducting ceramics for potentiometric hydrogen sensors for molten metals

    Energy Technology Data Exchange (ETDEWEB)

    Borland, H.; Llivina, L.; Colominas, S.; Abellà, J., E-mail: jordi.abella@iqs.edu

    2013-10-15

    Highlights: • Synthesis and chemical characterization of proton conductor ceramics. • Qualification of ceramics for hydrogen sensors in molten lithium–lead. • Ceramics have well-defined grains with a wide distribution of sizes. • Good agreement with predictions obtained with BaZrY, BaCeZrY and SrFeCo ceramics. -- Abstract: Tritium monitoring in lithium–lead eutectic (Pb–15.7Li) is of great importance for the performance of liquid blankets in fusion reactors. Also, tritium measurements will be required in order to proof tritium self-sufficiency in liquid metal breeding systems. On-line hydrogen (isotopes) sensors must be design and tested in order to accomplish these goals. Potentiometric hydrogen sensors for molten lithium–lead eutectic have been designed at the Electrochemical Methods Lab at Institut Quimic de Sarria (IQS) at Barcelona and are under development and qualification. The probes are based on the use of solid state electrolytes and works as proton exchange membranes (PEM). In this work the following compounds: BaZr{sub 0.9}Y{sub 0.1}O{sub 3}, BaCe{sub 0.6}Zr{sub 0.3}Y{sub 0.1}O{sub 3−α}, Sr(Ce{sub 0.6}-Zr{sub 0.4}){sub 0.9}Y{sub 0.1}O{sub 3−α} and Sr{sub 3}Fe{sub 1.8}Co{sub 2}O{sub 7} have been synthesized in order to be tested as PEM H-probes. Potentiometric measurements of the synthesized ceramic elements at 500 °C have been performed at a fixed hydrogen concentration. The sensors constructed using the proton conductor elements BaZr{sub 0.9}Y{sub 0.1}O{sub 3}, BaCe{sub 0.6}Zr{sub 0.3}Y{sub 0.1}O{sub 3−δ} and Sr{sub 3}Fe{sub 1.8}Co{sub 0.2}O{sub 7−δ} exhibited stable output potential and its value was close to the theoretical value calculated with the Nernst equation (deviation around 60 mV). In contrast, the sensor constructed using the proton conductor element Sr(Ce{sub 0.6}–Zr{sub 0.4}){sub 0.9}Y{sub 0.1}O{sub 3−δ} showed a deviation higher than 100 mV between experimental an theoretical data.

  6. Automatic photometric titrations of calcium and magnesium in carbonate rocks

    Science.gov (United States)

    Shapiro, L.; Brannock, W.W.

    1955-01-01

    Rapid nonsubjective methods have been developed for the determination of calcium and magnesium in carbonate rocks. From a single solution of the sample, calcium is titrated directly, and magnesium is titrated after a rapid removal of R2O3 and precipitation of calcium as the tungstate. A concentrated and a dilute solution of disodium ethylenediamine tetraacetate are used as titrants. The concentrated solution is added almost to the end point, then the weak solution is added in an automatic titrator to determine the end point precisely.

  7. Automating Finance

    Science.gov (United States)

    Moore, John

    2007-01-01

    In past years, higher education's financial management side has been riddled with manual processes and aging mainframe applications. This article discusses schools which had taken advantage of an array of technologies that automate billing, payment processing, and refund processing in the case of overpayment. The investments are well worth it:…

  8. Beer classification by means of a potentiometric electronic tongue.

    Science.gov (United States)

    Cetó, Xavier; Gutiérrez-Capitán, Manuel; Calvo, Daniel; del Valle, Manel

    2013-12-01

    In this work, an electronic tongue (ET) system based on an array of potentiometric ion-selective electrodes (ISEs) for the discrimination of different commercial beer types is presented. The array was formed by 21 ISEs combining both cationic and anionic sensors with others with generic response. For this purpose beer samples were analyzed with the ET without any pretreatment rather than the smooth agitation of the samples with a magnetic stirrer in order to reduce the foaming of samples, which could interfere into the measurements. Then, the obtained responses were evaluated using two different pattern recognition methods, principal component analysis (PCA), which allowed identifying some initial patterns, and linear discriminant analysis (LDA) in order to achieve the correct recognition of sample varieties (81.9% accuracy). In the case of LDA, a stepwise inclusion method for variable selection based on Mahalanobis distance criteria was used to select the most discriminating variables. In this respect, the results showed that the use of supervised pattern recognition methods such as LDA is a good alternative for the resolution of complex identification situations. In addition, in order to show an ET quantitative application, beer alcohol content was predicted from the array data employing an artificial neural network model (root mean square error for testing subset was 0.131 abv).

  9. Potentiometric study of antioxidant activity: development and prospects.

    Science.gov (United States)

    Ivanova, A V; Gerasimova, E L; Brainina, Kh Z

    2015-01-01

    The increasing interest in the study of the antioxidant activity of different objects is caused by an unbalance between the formation of reactive oxygen species (ROS) and the performance of the antioxidant system in humans under certain conditions, which leads to oxidative stress and pathological states of the organism. This article presents a brief critical review of the methods that are used to measure integrated antioxidant activity (AOA). It is shown that the most promising methods for measuring AOA are electrochemical ones, particularly potentiometry, as it best fits the nature of the processes causing oxidative stress. The article gives the theoretical rational for requirements that an oxidizer of antioxidants (AO) should meet. The work presents the thermodynamic grounds for the use of an earlier proposed mediator system, kinetics of chemical reactions between AO and the mediator system. In order to confirm reliability and accuracy of the results, numerous correlation studies were conducted, aiming to compare the data obtained with the use the proposed method and independent analytical methods. The article presents the results of the potentiometric study of AOA for a variety of objects, including individual antioxidant → nutritional supplements → food → blood and blood fractions.

  10. A potentiometric biosensor for rapid on-site disease diagnostics.

    Science.gov (United States)

    Tarasov, Alexey; Gray, Darren W; Tsai, Meng-Yen; Shields, Niall; Montrose, Armelle; Creedon, Niamh; Lovera, Pierre; O'Riordan, Alan; Mooney, Mark H; Vogel, Eric M

    2016-05-15

    Quantitative point-of-care (POC) devices are the next generation for serological disease diagnosis. Whilst pathogen serology is typically performed by centralized laboratories using Enzyme-Linked ImmunoSorbent Assay (ELISA), faster on-site diagnosis would infer improved disease management and treatment decisions. Using the model pathogen Bovine Herpes Virus-1 (BHV-1) this study employs an extended-gate field-effect transistor (FET) for direct potentiometric serological diagnosis. BHV-1 is a major viral pathogen of Bovine Respiratory Disease (BRD), the leading cause of economic loss ($2 billion annually in the US only) to the cattle and dairy industry. To demonstrate the sensor capabilities as a diagnostic tool, BHV-1 viral protein gE was expressed and immobilized on the sensor surface to serve as a capture antigen for a BHV-1-specific antibody (anti-gE), produced in cattle in response to viral infection. The gE-coated immunosensor was shown to be highly sensitive and selective to anti-gE present in commercially available anti-BHV-1 antiserum and in real serum samples from cattle with results being in excellent agreement with Surface Plasmon Resonance (SPR) and ELISA. The FET sensor is significantly faster than ELISA (<10 min), a crucial factor for successful disease intervention. This sensor technology is versatile, amenable to multiplexing, easily integrated to POC devices, and has the potential to impact a wide range of human and animal diseases. PMID:26765531

  11. Acid Dissociation Constants of Functional Groups in Humic Substances:I.Affinity Spectrum Model Analysis of Potentiometric Data of Fulvic and Humic Acids Solutions from Weathered Coal and Dark Loessia

    Institute of Scientific and Technical Information of China (English)

    DUJIN-ZHOU; LUCHANG-QING; 等

    1994-01-01

    Potentiometric experiments were carried out on the proton binding equilibria of FA extracted from a weathered coal and HA and Fa extracted from a dark loessial soil.The affinity spectrum model was employed to treat the experimental data.The affinity spectrum model technique could“magnify” the heterogeneity of the proton binding equilibria.so it was useful for comparing and studying the characteristics of humic substances with similar properties.According to the affinity spectra,we also found that the direction of the titration could affect the properties of the equilibria of FA from the weathered coal,and the acidic functional groups contained in FA from the weathered coal were larger in quantity than those contained in HA and FA from the dark loessial soil.

  12. Analysis of the Purity of Cetrimide by Titrations

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Nielsen, Hans/Boye

    2006-01-01

    The purity of cetrimide, trimethyl tetradecyl ammonium bromide (TTAB), that is an important preservative of many cosmetic and pharmaceutical products, was determined by three independent methods of titration. Traditionally, cetrimide was analysed by an assay method of the European Pharmacopoeia (Ph....... Eur.), which showed consistently a low purity of cetrimide with large standard deviations associated, however. A systematic 3% bias of the Ph. Eur. assay method was identified by comparing the result with results of two alternative methods of titration that exhibited high precision and high accuracy....... Titration by perchloric acid showed a 99.69 ± 0.05 % purity of cetrimide and titration by silver nitrate showed a 99.85% ± 0.05 % purity while the traditional assay method predicted a purity of only 97.1 ± 0.4. It was found that the discrepancy could be identified as differences in selectivity during...

  13. A microcomputer-controlled system for titration analysis

    NARCIS (Netherlands)

    Boelema, Gerrit Jan

    1982-01-01

    This thesis deals with the results of the implementation of microprocessor technology in automatic titration equipment to obtain a versatile system for pharmaceutical, chemical analytical and optimization research purposes. ... Zie: Summary

  14. Microscope Titration and Extraction of DNA from Liver.

    Science.gov (United States)

    Mayo, Lois T.; And Others

    1993-01-01

    Describes a simple and inexpensive, one-period activity to extract DNA to make the study of DNA less abstract. A microscope titration is used to determine when cells are ready for DNA extraction. (PR)

  15. A Titration Technique for Demonstrating a Magma Replenishment Model.

    Science.gov (United States)

    Hodder, A. P. W.

    1983-01-01

    Conductiometric titrations can be used to simulate subduction-setting volcanism. Suggestions are made as to the use of this technique in teaching volcanic mechanisms and geochemical indications of tectonic settings. (JN)

  16. Reliability of home CPAP titration with different automatic CPAP devices

    OpenAIRE

    Lacasse Yves; Plante Julie; Sériès Frédéric

    2008-01-01

    Abstract Background CPAP titration may be completed by automatic apparatus. However, differences in pressure behaviour could interfere with the reliability of pressure recommendations. Our objective was to compare pressure behaviour and effective pressure recommendations between three Automatic CPAP machines (Autoset Spirit, Remstar Auto, GK 420). Methods Sixteen untreated obstructive sleep apnea patients were randomly allocated to one of the 3 tested machines for a one-week home titration tr...

  17. A large-scale radiometric micro-quantitative complement fixation test for serum antibody titration

    International Nuclear Information System (INIS)

    A micro-quantitative complement fixation (CF) procedure based on 51Cr release is described. The method employs 50% hemolysis as end point and the alternation equation to calculate the amount of complement involved in the hemolytic reaction. Compared to the conventional CF tests, the radiometric procedure described here is very precise and consistently reproducible. Also, since only 3 4-fold dilutions of sera are used for the titration of antibodies over a wide range of concentrations, the test is very concise and is economical to perform. Its format is amenable to automation and computerization. This radioimetric CF procedure is thus most useful for large-scale immunological research and epidemiological surveilance studies. (Auth.)

  18. Highly sensitive covalently functionalized light-addressable potentiometric sensor for determination of biomarker.

    Science.gov (United States)

    Liang, Jintao; Guan, Mingyuan; Huang, Guoyin; Qiu, Hengming; Chen, Zhengcheng; Li, Guiyin; Huang, Yong

    2016-06-01

    A biomarker is related to the biological status of a living organism and shows great promise for the early prediction of a related disease. Herein we presented a novel structured light-addressable potentiometric sensor (LAPS) for the determination of a model biomarker, human immunoglobulin G (hIgG). In this system, the goat anti-human immunoglobulin G antibody was used as recognition element and covalently immobilized on the surface of light-addressable potentiometric sensor chip to capture human immunoglobulin G. Due to the light addressable capability of light-addressable potentiometric sensor, human immunoglobulin G dissolved in the supporting electrolyte solution can be detected by monitoring the potential shifts of the sensor. In order to produce a stable photocurrent, the laser diode controlled by field-programmable gate array was used as the light emitter to drive the light-addressable potentiometric sensor. A linear correlation between the potential shift response and the concentration of human immunoglobulin G was achieved and the corresponding regression equation was ΔV (V)=0.00714ChIgG (μg/mL)-0.0147 with a correlation coefficient of 0.9968 over a range 0-150 μg/mL. Moreover, the light-addressable potentiometric sensor system also showed acceptable stability and reproducibility. All the results demonstrated that the system was more applicable to detection of disease biomarkers with simple operation, multiple-sample format and might hold great promise in various environmental, food, and clinical applications.

  19. Automation Security

    OpenAIRE

    Mirzoev, Dr. Timur

    2014-01-01

    Web-based Automated Process Control systems are a new type of applications that use the Internet to control industrial processes with the access to the real-time data. Supervisory control and data acquisition (SCADA) networks contain computers and applications that perform key functions in providing essential services and commodities (e.g., electricity, natural gas, gasoline, water, waste treatment, transportation) to all Americans. As such, they are part of the nation s critical infrastructu...

  20. Intrinsic thermodynamics of 4-substituted-2,3,5,6-tetrafluorobenzenesulfonamide binding to carbonic anhydrases by isothermal titration calorimetry.

    Science.gov (United States)

    Zubrienė, Asta; Smirnovienė, Joana; Smirnov, Alexey; Morkūnaitė, Vaida; Michailovienė, Vilma; Jachno, Jelena; Juozapaitienė, Vaida; Norvaišas, Povilas; Manakova, Elena; Gražulis, Saulius; Matulis, Daumantas

    2015-10-01

    Para substituted tetrafluorobenzenesulfonamides bind to carbonic anhydrases (CAs) extremely tightly and exhibit some of the strongest known protein-small ligand interactions, reaching an intrinsic affinity of 2 pM as determined by displacement isothermal titration calorimetry (ITC). The enthalpy and entropy of binding to five CA isoforms were measured by ITC in two buffers of different protonation enthalpies. The pKa values of compound sulfonamide groups were measured potentiometrically and spectrophotometrically, and enthalpies of protonation were measured by ITC in order to evaluate the proton linkage contributions to the observed binding thermodynamics. Intrinsic means the affinity of a sulfonamide anion for the Zn bound water form of CAs. Fluorination of the benzene ring significantly enhanced the observed affinities as it increased the fraction of deprotonated ligand while having little impact on intrinsic affinities. Intrinsic enthalpy contributions to the binding affinity were dominant over entropy and were more exothermic for CA I than for other CA isoforms. Thermodynamic measurements together with the X-ray crystallographic structures of protein-ligand complexes enabled analysis of structure-activity relationships in this enzyme ligand system.

  1. Functionalized β-cyclodextrin based potentiometric sensor for naproxen determination.

    Science.gov (United States)

    Lenik, Joanna; Łyszczek, Renata

    2016-04-01

    Potentiometric sensors based on neutral β-cyclodextrins: (2-hydroxypropyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin and anionic β-cyclodextrin: (2-hydroxy-3-N,N,N-trimethylamino)propyl-β-cyclodextrin chloride for naproxen are described. Inclusion complexes of naproxen with the above-mentioned cyclodextrins were studied using IR spectroscopy. The electrode surface was made from PVC membranes doped with the appropriate β-cyclodextrin as ionophores and quaternary ammonium chlorides as positive charge additives that were dispersed in plasticizers. The optimum membrane contains heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin, o-nitrophenyloctyl ether and tetraoctyl ammonium chloride as a lipophilic salt. The electrode is characterized by a Nernstian response slope of -59.0 ± 0.5 mV decade(-1) over the linear range of 5.0 × 10(-5)-1.0 × 10(-2) mol L(-1) and the detection limit 1.0 × 10(-5) mol L(-1), as well as the response time 10s. It can be used in the pH range 6.2-8.5 for 10 months without any considerable deterioration. Incorporation of β-cyclodextrins improved the electrode selectivity towards naproxen ions from several inorganic and organic interferents and some common drug excipients due to concovalent interactions (host molecule-guest molecule). The notable advantages of the naproxen-selective electrode include its high sensitivity, high selectivity, cost-effectiveness as well as accurate and comfortable application in drug analysis and milk samples. PMID:26838835

  2. Study of electrochemical phosphate sensing systems: Spectrometric, potentiometric and voltammetric evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kivlehan, Francine [Tyndall National Institute, Lee Maltings, University College, Cork (Ireland); Mace, Wade J. [Tyndall National Institute, Lee Maltings, University College, Cork (Ireland); Department of Chemistry, Analytical and Biological Chemistry Research Facility, University College, Cork (Ireland); Moynihan, Humphrey A. [Department of Chemistry, Analytical and Biological Chemistry Research Facility, University College, Cork (Ireland); Arrigan, Damien W.M. [Tyndall National Institute, Lee Maltings, University College, Cork (Ireland)], E-mail: damien.arrigan@tyndall.ie

    2009-02-28

    Characterization of the interaction of a urea-functionalized calix[4]arene ionophore and phosphate was undertaken by combination of nuclear magnetic resonance (NMR) spectrometry, potentiometric selectivity coefficient evaluation and voltammetric ion transfer at the interface between two immiscible electrolyte solutions (ITIES). NMR revealed that the urea protons were involved in complexation with the target anion and potentiometric separate solution selectivity data indicated selectivity for phosphate over chloride and sulphate. Voltammetry at the ITIES confirmed that the ionophore-facilitated transfer of monohydrogen phosphate occurred in preference to dihydrogen phosphate transfer. The results correlate with previously reported data on the potentiometric evaluation of this calixarene as an anionophore in PVC-membrane electrodes. The data provide the basis for development of amperometric monohydrogen phosphate sensors based on the ion-transfer principle.

  3. Potentiometric measurement of glucose concentration with an immobilized glucose oxidase/catalase electrode.

    Science.gov (United States)

    Wingard, L B; Liu, C C; Wolfson, S K; Yao, S J; Drash, A L

    1982-01-01

    A series of enzyme electrodes for measurement of glucose have been constructed. The electrodes contain glucose oxidase immobilized on platinum, either with or without co-immobilization of catalase. When placed in buffered glucose, the enzyme electrodes show a potentiometric response to glucose with respect to a Ag/AgCl reference electrode. This response is reproducible in the physiologic range of glucose concentrations. The immobilization technique, some of the environmental variables such as oxygen concentration and pH, and several compounds that might interfere with the selectivity of the enzyme electrodes for glucose have received preliminary study. This direct potentiometric approach is undergoing further evaluation to determine the basic electrochemical mechanism responsible for the potentiometric signal and whether it can be adapted for continuous in vivo monitoring of the glucose concentration in body fluids. PMID:7172983

  4. Automatic potentiometric titration determination red wine total acidity%自动电位滴定法测定红葡萄酒总酸度

    Institute of Scientific and Technical Information of China (English)

    李艳霞; 宣亚文; 秦珠红; 常利平; 王小果

    2007-01-01

    测定红葡萄酒总酸度时,采用自动电位滴定法控制反应终点,避免了因指示剂使用而带来的误差,简化了操作步骤,提高了测定准确度,用于实际酒样的测定,结果满意.

  5. Automatic potentiometric titration determination content of the iron ore%自动电位滴定法测定铁矿石中全铁含量

    Institute of Scientific and Technical Information of China (English)

    李艳霞; 李敏; 谢红; 欧阳丽

    2008-01-01

    采用自动电位滴定法控制SnCl2还原Fe3+为Fe2+反应的终点,达到了准确控制SnCl2用量的目的,从而避免了剧毒试剂HgCl2的引入,节约了试荆,有效避免了环境污染.用于铁矿石中铁含量的测定,结果满意.

  6. Determination of Food Moisture by Automatic Potentiometric Titrator%全自动电位滴定仪测定食物水分

    Institute of Scientific and Technical Information of China (English)

    文娜; 宋良辉; 韦子昂

    2014-01-01

    通过对使用全自动电位滴定仪卡尔费休法测定食物水分的实验研究,建立了几种食物水分测定的方法,重现性好,操作方便快捷,减小了人为误差,可以推广使用.

  7. Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Merroun, Mohamed L., E-mail: merroun@ugr.es [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Departamento de Microbiologia, Universidad de Granada, Campus Fuentenueva s/n 18071, Granada (Spain); Nedelkova, Marta [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Ojeda, Jesus J. [Cell-Mineral Interface Research Programme, Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Experimental Techniques Centre, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); Reitz, Thomas [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany); Fernandez, Margarita Lopez; Arias, Jose M. [Departamento de Microbiologia, Universidad de Granada, Campus Fuentenueva s/n 18071, Granada (Spain); Romero-Gonzalez, Maria [Cell-Mineral Interface Research Programme, Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Selenska-Pobell, Sonja [Institute of Radiochemistry, Helmholtz Centre Dresden-Rossendorf, Dresden (Germany)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Precipitation of uranium as U phosphates by natural bacterial isolates. Black-Right-Pointing-Pointer The uranium biomineralization involves the activity of acidic phosphatase. Black-Right-Pointing-Pointer Uranium bioremediation could be achieved via the biomineralization of U(VI) in phosphate minerals. - Abstract: This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U-bacterial interaction experiments were performed at low pH values (2.0-4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase.

  8. Geostatistical analysis of potentiometric data in Wolfcamp aquifer of the Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    This report details a geostatistical analysis of potentiometric data from the Wolfcamp aquifer in the Palo Duro Basin, Texas. Such an analysis is a part of an overall uncertainty analysis for a high-level waste repository in salt. Both an expected potentiometric surface and the associated standard error surface are produced. The Wolfcamp data are found to be well explained by a linear trend with a superimposed spherical semivariogram. A cross-validation of the analysis confirms this. In addition, the cross-validation provides a point-by-point check to test for possible anomalous data

  9. Study on Determination of Titratable Acidity in Fruits Using Automatic Potentiometric Titrator%应用自动电位滴定仪测定水果中的可滴定酸

    Institute of Scientific and Technical Information of China (English)

    李文生; 冯晓元; 王宝刚; 郭振忠; 杨军军; 张长松

    2009-01-01

    应用自动电位滴定仪的等量等当点滴定法,测定苹果、葡萄、草莓三类水果样品的可滴定酸.结果表明加标回收率为92.85%~96.65%,相对标准偏差为0.64%~1.84%,不受浸提液的颜色影响,准确度和精密度高,可以在水果品质测定中推广.

  10. 自动电位滴定法和两相滴定法测定DDAG含量的比较%Comparison of DDAC Concentration Measured by Automatic Potentiometric Titration Procedure and Two-phase Titration Procedure

    Institute of Scientific and Technical Information of China (English)

    韩玉杰; 宋常明; 唐镇忠

    2008-01-01

    DDAC含量是评定ACQ防腐木材性能的一项重要指标,本文通过对比自动电位滴定法和两相滴定法测定防腐材萃取液中DDAC的含量,得出结论:采用自动电位滴定仪可大大缩短操作时间,提高了检测的准确度.

  11. Reliability of home CPAP titration with different automatic CPAP devices

    Directory of Open Access Journals (Sweden)

    Lacasse Yves

    2008-07-01

    Full Text Available Abstract Background CPAP titration may be completed by automatic apparatus. However, differences in pressure behaviour could interfere with the reliability of pressure recommendations. Our objective was to compare pressure behaviour and effective pressure recommendations between three Automatic CPAP machines (Autoset Spirit, Remstar Auto, GK 420. Methods Sixteen untreated obstructive sleep apnea patients were randomly allocated to one of the 3 tested machines for a one-week home titration trial in a crossover design with a 10 days washout period between trials. Results The median pressure value was significantly lower with machine GK 420 (5.9 +/- 1.8 cm H2O than with the other devices both after one night and one week of CPAP titration (7.4 +/- 1.3 and 6.6 +/- 1.9 cm H2O. The maximal pressure obtained over the one-week titration was significantly higher with Remstar Auto (12.6 +/- 2.4 cm H2O, Mean +/- SD than with the two other ones (10.9 +/- 1.0 and 11.0 +/- 2.4 cm H2O. The variance in pressure recommendation significantly differed between the three machines after one night and between Autoset Spirit and the two other machines after 1 week. Conclusion Pressure behaviour and pressure recommendation significantly differ between Auto CPAP machines both after one night and one week of home titration.

  12. Complexometric titrations: new reagents and concepts to overcome old limitations.

    Science.gov (United States)

    Zhai, Jingying; Bakker, Eric

    2016-07-21

    Chelators and end point indicators are the most important parts of complexometric titrations. The most widely used universal chelator ethylenediamine tetraacetic acid (EDTA) and its derivatives can strongly coordinate with different metal ions. Their limited selectivity often requires the use of masking agents, and the multiple pKa values of the chelators necessitate a careful adjustment of pH during the procedure. Real world requirements for pH independent, selective and sensitive chelators and indicators call for a new design of these reagents. New concepts and structures of chelators and indicators have indeed recently emerged. We present here recent developments on chelators and indicators for complexometric titrations. Many of these advances were made possible only recently by moving the titration from a homogeneous to a heterogeneous phase using a new class of chelators and indicators based on highly selective ionophores embedded in ion-selective nanosphere emulsions. In view of achieving titrations in situ by complete instrumental control, thin layer electrochemistry has recently been shown to be an attractive concept that replaces the traditional cumbersome titration protocol with a direct reagent free sensing tool. PMID:27272695

  13. Potencialidades do dióxido de chumbo eletrodepositado como sensor potenciométrico Potentialities of electrodeposited lead dioxide as a potentiometric sensor

    Directory of Open Access Journals (Sweden)

    Milton Duffles Capelato

    1998-07-01

    Full Text Available This paper proposes an experiment to be performed in both instrumental analysis and experimental physical-chemistry curricular disciplines in order to open options to develop challenging basic research activities. Thus the experimental procedures and the results obtained in the preparation of electrodeposited lead dioxide onto graphite and its evaluation as potentiometric sensor for H3O+ and Pb2+ ions, are presented. The data obtained in acid-base titrations were compared with those of the traditional combination glass electrode at the same conditions. Although a linear sub-Nernstian response to free hydrogen ions was observed for the electrodeposited PbO2 electrode, a good agreement was obtained between them. Working as lead(II sensing electrode, the PbO2 showed a linear sub-Nernstian behavior at total Pb2+ concentrations ranging from 3,5 x 10-4 to 3,0 x 10-2 mol/L in nitrate media. For the redox couple PbO2/Pb(II the operational slope converges to the theoretical one, as the acidity of the working solution increases.

  14. The potentiometric and laser RAMAN study of the hydrolysis of uranyl chloride under physiological conditions and the effect of systematic and random errors on the hydrolysis constants

    International Nuclear Information System (INIS)

    The hydrolysis of uranyl ions in 0.15 mol/L (Na)C1 solution at 37 degrees Celsius has been studied by potentiometric titration. The results were consistent with the formation of (UO2)2(OH)2, (UO2)3(OH)4, (UO2)3(OH)5 and (UO2)4(OH)7. The stability constants, which were evaluated using a version of MINIQUAD, were found to be: log β22 = -5.693 ± 0.007, log β34 = -11.499 ± 0.024, log β35 = -16.001 ± 0.050, log β47 = -21.027 ± 0.051. Laser Raman spectroscopy has been used to identify the products including (UO2)4(OH)7 species. The difficulties in identifying the chemical species in solution and the effect of small errors on this selection has also been investigated by computer simulation. The results clearly indicate that small errors can lead to the selection of species that may not exist

  15. Potentiometric measurement of polymer-membrane electrodes based on lanthanum

    Science.gov (United States)

    Saefurohman, Asep; Buchari, Noviandri, Indra; Syoni

    2014-03-01

    Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm-1, 1031 cm-1 and 794.7 cm-1 for P=O stretching and stretching POC from group -OP =O. The result showed shift wave number for P =O stretching of the cluster (-OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm-1 indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R3P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10-3 M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10-5 and 10-1 M.

  16. Potentiometric measurement of polymer-membrane electrodes based on lanthanum

    Energy Technology Data Exchange (ETDEWEB)

    Saefurohman, Asep, E-mail: saefurohman.asep78@Gmail.com; Buchari,, E-mail: saefurohman.asep78@Gmail.com; Noviandri, Indra, E-mail: saefurohman.asep78@Gmail.com [Department of Chemistry, Bandung Institute of Technology (Indonesia); Syoni [Department of Metallurgy Engineering, Bandung Institute of Technology (Indonesia)

    2014-03-24

    Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm{sup −1}, 1031 cm{sup −1} and 794.7 cm{sup −1} for P=O stretching and stretching POC from group −OP =O. The result showed shift wave number for P =O stretching of the cluster (−OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm{sup −1} indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R{sub 3}P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10{sup −3} M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10{sup −5} and 10{sup −1} M.

  17. Optimal Oxygen Titration in Patients with Chronic Obstructive Pulmonary Disease: A Role for Automated Oxygen Delivery?

    Directory of Open Access Journals (Sweden)

    François Lellouche

    2013-01-01

    Full Text Available Oxygen therapy can be life-saving for patients with chronic obstructive pulmonary disease (COPD and is the backbone of any acute COPD treatment strategy. Although largely considered to be a benign drug, many publications have highlighted the need to accurately adjust oxygen delivery to avoid both hypoxemia and the problem of hyperoxia-induced hypercapnia. Recent clinical data have shown that the deleterious effects of excess oxygen treatment can not only alter carbon dioxide levels (which has been known for more than 60 years but can also lead to an increase in mortality. Nevertheless, despite the extensive literature, the risks associated with hyperoxia are often overlooked and published clinical recommendations are largely ignored. This failure in knowledge translation has become increasingly important not only because of the desire to reduce medical error, but in a society with limited health care resources, the economic burden of COPD is such that it cannot afford to make preventable medical mistakes. Recently, novel devices have been developed to automatically adjust oxygen flow rates to maintain stable oxygen saturations. These closed-loop oxygen delivery systems have the potential to reduce medical error, improve morbidity and mortality, and reduce health care costs. Preliminary data in this field are promising and will require a significant amount of research in the coming years to determine the precise indications for these systems. The importance of appropriate oxygen dosing and the current literature regarding novel oxygen delivery systems are reviewed.

  18. High-throughput Titration of Luciferase-expressing Recombinant Viruses

    OpenAIRE

    Garcia, Vanessa; Krishnan, Ramya; Davis, Colin; Batenchuk, Cory; Le Boeuf, Fabrice; Abdelbary, Hesham; Diallo, Jean-Simon

    2014-01-01

    Standard plaque assays to determine infectious viral titers can be time consuming, are not amenable to a high volume of samples, and cannot be done with viruses that do not form plaques. As an alternative to plaque assays, we have developed a high-throughput titration method that allows for the simultaneous titration of a high volume of samples in a single day. This approach involves infection of the samples with a Firefly luciferase tagged virus, transfer of the infected samples onto an appr...

  19. Automated Budget System

    Data.gov (United States)

    Department of Transportation — The Automated Budget System (ABS) automates management and planning of the Mike Monroney Aeronautical Center (MMAC) budget by providing enhanced capability to plan,...

  20. Potentiometric pH Measurements of Acidity Are Approximations, Some More Useful than Others

    Science.gov (United States)

    de Levie, Robert

    2010-01-01

    A recent article by McCarty and Vitz "demonstrating that it is not true that pH = -log[H+]" is examined critically. Then, the focus shifts to underlying problems with the IUPAC definition of pH. It is shown how the potentiometric method can provide "estimates" of both the IUPAC-defined hydrogen activity "and" the hydrogen ion concentration, using…

  1. BIOSENSOR FOR DIRECT DETERMINATION OF ORGANOPHOSPHATE NERVE AGENTS. 1. POTENTIOMETRIC ENZYME ELECTRODE. (R823663)

    Science.gov (United States)

    A potentiometric enzyme electrode for the direct measurement of organophosphate (OP)nerve agents was developed. The basic element of this enzyme electrode was a pH electrodemodified with an immobilized organophosphorus hydrolase (OPH) layer formed by cross-linkingOPH ...

  2. Lead in Hair and in Red Wine by Potentiometric Stripping Analysis: The University Students' Design.

    Science.gov (United States)

    Josephsen, Jens

    1985-01-01

    A new program for training upper secondary school chemistry teachers (SE 537 693) depends heavily on student project work. A project in which lead in hair and in red wine was examined by potentiometric stripping analysis is described and evaluated. (JN)

  3. Reversible potentiometric oxygen sensors based on polymeric and metallic film electrodes.

    Science.gov (United States)

    Yim, H S; Meyerhoff, M E

    1992-09-01

    Various materials and sensor configurations that exhibit reversible potentiometric responses to the partial pressure of oxygen at room temperature in neutral pH solution are examined. In one arrangement, platinum electrodes are coated with plasticized poly(vinyl chloride) films doped with a cobalt(II) tetraethylene pentamine complex. For such sensors, potentiometric oxygen response is attributed to a mixed potential originating from the underlying platinum electrode surface as well as a change in redox potential of the Co(II)-tetren-doped film as the complex binds oxygen reversibly. The response due to the platinum surface is prolonged by the presence of the Co(II)-tetren/PVC film. Alternately, thin films of metallic copper, electrochemically deposited on platinum and/or sputtered or vapor deposited on a single crystal silicon substrate, may be used for reversible oxygen sensing. The long-term reversibility and potentiometric stability of such copper film-based sensors is enhanced (up to 1 month) by preventing the formation of cuprous oxide on the surfaces via the application of an external nonpolarizing cathodic current through the working electrode or by specifically using sputtered copper films that have [100] preferred crystal structures as determined by X-ray diffraction. The implications of these findings in relation to fabricating analytically useful potentiometric oxygen sensors are discussed. PMID:1416035

  4. Interactions between oxovanadium (IV), glycylvaline and imidazoles: An aqueous potentiometric and spectroscopic study

    Indian Academy of Sciences (India)

    N Patel; V K Soni; K K Shukla; S Sharma; K B Pandeya

    2002-02-01

    Speciation has been determined in aqueous oxovanadium, glycylvaline and imidazoles at 25 ± 1° C and = 0.1M NaClO4 using a combination of potentiometry, and visible and EPR spectroscopy. Results of potentiometric and spectroscopic methods are consistent. Calculations of stability constants have been made using the SCOGS computer program.

  5. Disposable Miniaturized Screen‐Printed pH and Reference Electrodes for Potentiometric Systems

    DEFF Research Database (Denmark)

    Musa, Arnaud Emmanuel; del Campo, Francisco Javier; Abramova, Natalia;

    2011-01-01

    This work describes the development of a miniaturized potentiometric system comprising a miniaturized quasi‐reference electrode (QRE) coupled to a solid‐state ion‐selective electrode (ISE) for the monitoring of pH. We describe the optimization of materials and fabrication processes including scre...

  6. "Titration simulator"--Good assistant for titration analysis%滴定分析教学的好帮手"Titration simulator"

    Institute of Scientific and Technical Information of China (English)

    屠婕红

    2005-01-01

    @@ Titration simulator(滴定模拟器)软件是专门为滴定分析而设计的教学软件,它短小精悍,简洁实用,可以从Internet网上免费下载,网址为:http://www.chemonline.net/Truechemsoft/downsoft.asp?softID=1565该软件所占容量仅为72KB,是学生训练及化学教师的好助手.笔者在教学中尝试运用该软件辅助教学,效果良好,现将Titration simulator软件的主要功能、应用简要介绍如下:

  7. Complexation Effect on Redox Potential of Iron(III)-Iron(II) Couple: A Simple Potentiometric Experiment

    Science.gov (United States)

    Rizvi, Masood Ahmad; Syed, Raashid Maqsood; Khan, Badruddin

    2011-01-01

    A titration curve with multiple inflection points results when a mixture of two or more reducing agents with sufficiently different reduction potentials are titrated. In this experiment iron(II) complexes are combined into a mixture of reducing agents and are oxidized to the corresponding iron(III) complexes. As all of the complexes involve the…

  8. Highly sensitive covalently functionalized light-addressable potentiometric sensor for determination of biomarker.

    Science.gov (United States)

    Liang, Jintao; Guan, Mingyuan; Huang, Guoyin; Qiu, Hengming; Chen, Zhengcheng; Li, Guiyin; Huang, Yong

    2016-06-01

    A biomarker is related to the biological status of a living organism and shows great promise for the early prediction of a related disease. Herein we presented a novel structured light-addressable potentiometric sensor (LAPS) for the determination of a model biomarker, human immunoglobulin G (hIgG). In this system, the goat anti-human immunoglobulin G antibody was used as recognition element and covalently immobilized on the surface of light-addressable potentiometric sensor chip to capture human immunoglobulin G. Due to the light addressable capability of light-addressable potentiometric sensor, human immunoglobulin G dissolved in the supporting electrolyte solution can be detected by monitoring the potential shifts of the sensor. In order to produce a stable photocurrent, the laser diode controlled by field-programmable gate array was used as the light emitter to drive the light-addressable potentiometric sensor. A linear correlation between the potential shift response and the concentration of human immunoglobulin G was achieved and the corresponding regression equation was ΔV (V)=0.00714ChIgG (μg/mL)-0.0147 with a correlation coefficient of 0.9968 over a range 0-150μg/mL. Moreover, the light-addressable potentiometric sensor system also showed acceptable stability and reproducibility. All the results demonstrated that the system was more applicable to detection of disease biomarkers with simple operation, multiple-sample format and might hold great promise in various environmental, food, and clinical applications. PMID:27040210

  9. Modeling of titration experiments by a reactive transport model

    Institute of Scientific and Technical Information of China (English)

    Ma Hongyun; Samper Javier; Xin Xin

    2011-01-01

    Acid mine drainage (AMD) is commonly treated by neutralization with alkaline substances. This treatment is supported by titration experiments that illustrate the buffering mechanisms and estimate the base neutralization capacity (BNC) of the AMD. Detailed explanation of titration curves requires modeling with a hydro-chemical model. In this study the titration curves of water samples from the drainage of the As Pontes mine and the corresponding dumps have been investigated and six buffers are selected by analyzing those curves. Titration curves have been simulated by a reactive transport model to discover the detailed buffering mechanisms. These simulations show seven regions involving different buffering mechanism. The BNC is primarily from buffers of dissolved Fe, Al and hydrogen sulfate. The BNC can be approximated by: BNC = 3(CFe + CAl) + 0.05Csulfate, where the units are mol/L. The BNC of the sample from the mine is 9.25 × 10-3 mol/L and that of the dumps sample is 1.28 × 10-2 mol/L.

  10. A dipstick sensor for coulometric acid-base titrations

    NARCIS (Netherlands)

    Olthuis, W.; Schoot, van der B.H.; Chavez, F.; Bergveld, P.

    1989-01-01

    By performing an acid-base titration by coulometric generation of OH− or H+ ions at an inert electrode in close proximity to the pH-sensitive gate of an ISFET, it is possible to determine the acid or base concentration of a solution using the ISFET as an indicator device for the equivalence point in

  11. PVC Membrane Sensors for Potentiometric Determination of Acebutolol

    Directory of Open Access Journals (Sweden)

    Abdulrahman Al-Majed

    2007-12-01

    Full Text Available The construction and general performance characteristics of two novelpotentiometric membrane sensors responsive to the acebutolol are described. Thesensors are based on the use of ion-association complexes of acebutolol (AC withtetraphenylborate(TPB (I and phosphomolybdate(PM (II as exchange sites in a PVCmatrix. The sensors show a fast, stable and near- Nernstian for the mono charge cationof AC over the concentration range 1×10-3 - ~10-6 M at 25 °C over the pH range 2.0 -6.0 with cationic slope of 51.5 ± 0.5 and 53.0 ± 0.5 per concentration decade for AC-Iand AC-II sensors respectively. The lower detection limit is 6×10-6 M and 4×0-6 M withthe response time 20-30 s in the same order of both sensors. Selectivity coefficients ofAC related to a number of interfering cation and some organic compounds wereinvestigated. There are negligible interferences are caused by most of the investigatedspecies. The direct determination of 3 - 370 μg/ml of AC shows an average recovery of 99.4 and 99.5% and a mean relative standard deviation of 1 . 5 % at 100.0 μg/ml forsensor I and II respectively. The results obtained by determination of AC in tablets usingthe proposed sensors which comparable favorably with those obtained by the Britishpharmacopoeia method. In the present investigation the electrodes have been utilized asend point indicator for some precipitation titration reactions.

  12. Nano Structured Potentiometric Sensors Based on Polyaniline Conducting Polymer for Determination of Cr (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad-khah, Ali; Ansari, Reza; Delavar, Ali Fallah; Mosayebzadeh, Zahra [University of Guilan, Rasht (Iran, Islamic Republic of)

    2012-04-15

    In this paper, a potentiometric sensor based on polyaniline conducting polymer for potentiometric determination of Cr (VI) ions is reported. Polyaniline was synthesized electrochemically (cyclic voltammetry method) onto a micro pencil graphite electrode (0.7 mm diameter) in the presence of HCl and diphenylcarbazide (termed as (PGE/PAni/DPC). Some initial experiments were performed in order to find out the optimized conditions for preparation of the introduced Cr (VI) sensor electrode. The plot of E vs. log [Cr (VI)], showed a linear response in the range from 1.0 x 10{sup -6} to 1.0 x 10{sup -1} M. High repeatability with the detection limit of 8.0 x 10{sup -7} M was obtained

  13. Geostatistical analysis of potentiometric data in the Pennsylvanian aquifer of the Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    This report details a geostatistical analysis of potentiometric data from the Pennsylvanian aquifer in the Palo Duro Basin, Texas. Such an analysis is a part of an overall uncertainty analysis for a high-level waste repository in salt. Both an expected potentiometric surface and the associated standard error surface are produced. The Pennsylvanian data are found to be well explained by a linear trend with a superimposed spherical semivariogram. A cross-validation of the analysis confirms this. In addition, the cross-validation provides a point-by-point check to test for possible anomalous data. The analysis is restricted to that portion of the Pennsylvanian aquifer that lies to the southwest of the Amarillo Uplift. The Pennsylvanian is absent is some areas across the uplift and data to the northeast were not used in this analysis. The surfaces produced in that analysis are included for comparison. 9 refs., 15 figs

  14. Challenges in the enantioanalysis of fucose using stochastic and potentiometric microsensors

    Directory of Open Access Journals (Sweden)

    Iuliana Moldoveanu

    2014-08-01

    Full Text Available Fucose gained significant interest in the medical field since a large number of studies have been reported on the role of fucose – as tumor marker. Electrochemical enantioselective sensors based on monocrystalline diamond paste and carbon paste working on stochastic and potentiometric modes were proposed for the enantioanalysis of fucose in biological fluids. Porphyrins and polymeric surfactants were used as modifiers for the diamond and carbon pastes in the design of sensors. Stochastic sensors were able to determine simultaneously l- and d-fucose in whole blood samples (qualitative and quantitative, and potentiometric sensors were used for quantitative determination of fucose in the biological fluids. The main advantages of the utilization of the proposed sensors were: real time enantioanalysis of fucose, no sample preparation for the biological fluid, and high reliability of the determinations.

  15. Applications of isothermal titration calorimetry in protein science

    Institute of Scientific and Technical Information of China (English)

    Yi Liang

    2008-01-01

    During the past decade,isothermal titration calorimetry (ITC)has developed from a specialist method for understanding molecular interactions and other biological processes within cells to a more robust,widely used method.Nowadays,ITC is used to investigate all types of protein interactions,including protein-protein interactions,protein-DNA/RNA interactions,protein-small molecule interactions and enzyme kinetics;it provides a direct route to the complete thermodynamic characterization of protein interactions.This review concentrates on the new applications of ITC in protein folding and misfolding,its traditional application in protein interactions,and an overview of what can be achieved in the field of protein science using this method and what developments are likely to occur in the near future.Also,this review discusses some new developments of ITC method in protein science,such as the reverse titration of ITC and the displacement method of ITC.

  16. High-throughput titration of luciferase-expressing recombinant viruses.

    Science.gov (United States)

    Garcia, Vanessa; Krishnan, Ramya; Davis, Colin; Batenchuk, Cory; Le Boeuf, Fabrice; Abdelbary, Hesham; Diallo, Jean-Simon

    2014-01-01

    Standard plaque assays to determine infectious viral titers can be time consuming, are not amenable to a high volume of samples, and cannot be done with viruses that do not form plaques. As an alternative to plaque assays, we have developed a high-throughput titration method that allows for the simultaneous titration of a high volume of samples in a single day. This approach involves infection of the samples with a Firefly luciferase tagged virus, transfer of the infected samples onto an appropriate permissive cell line, subsequent addition of luciferin, reading of plates in order to obtain luminescence readings, and finally the conversion from luminescence to viral titers. The assessment of cytotoxicity using a metabolic viability dye can be easily incorporated in the workflow in parallel and provide valuable information in the context of a drug screen. This technique provides a reliable, high-throughput method to determine viral titers as an alternative to a standard plaque assay.

  17. Titrating Polyelectrolytes - Variational Calculations and Monte Carlo Simulations

    CERN Document Server

    Jönsson, B; Peterson, C; Sommelius, O; Söderberg, B

    1995-01-01

    Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. The Coulomb interactions are emulated by harmonic repulsive forces, the force constants being used as variational parameters to minimize the free energy. For the titrating charges, a mean field approach is used. The accuracy is tested against Monte Carlo data for up to 1000 monomers. For an unscreened chain, excellent agreement is obtained for the end-to-end distance and the apparent dissociation constant. With screening, the thermodynamical properties are invariably well described, although the structural agreement deteriorates. A very simple rigid-rod approximation is also considered, giving surprisingly good results for certain properties.

  18. Monitoring assembly of ribonucleoprotein complexes by isothermal titration calorimetry

    OpenAIRE

    Recht, Michael I.; Ryder, Sean P.; Williamson, James R.

    2008-01-01

    Isothermal titration calorimetry (ITC) is a useful technique to study RNA-protein interactions, as it provides the only method by which the thermodynamic parameters of free energy, enthalpy, and entropy can be directly determined. This chapter presents a general procedure for studying RNA-protein interactions using ITC, and gives specific examples for monitoring the binding of Caenorhabditis elegans GLD-1 STAR domain to TGE RNA and the binding of Aquifex aeolicus S6:S18 ribosomal protein hete...

  19. Titration of Human Coronaviruses Using an Immunoperoxidase Assay

    OpenAIRE

    Lambert, Francine; Jacomy, Helene; Marceau, Gabriel; J. Talbot, Pierre

    2008-01-01

    Calculation of infectious viral titers represents a basic and essential experimental approach for virologists. Classical plaque assays cannot be used for viruses that do not cause significant cytopathic effects, which is the case for strains 229E and OC43 of human coronavirus (HCoV). An alternative indirect immunoperoxidase assay (IPA) is herein described for the detection and titration of these viruses. Susceptible cells are inoculated with serial logarithmic dilutions of samples in a 96-wel...

  20. Predicting proton titration in cationic micelle and bilayer environments

    OpenAIRE

    Brian H. Morrow; Eike, David M.; Murch, Bruce P.; Koenig, Peter H.; Shen, Jana K.

    2014-01-01

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pKa’s in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pKa of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and l...

  1. Manufacturing and automation

    Directory of Open Access Journals (Sweden)

    Ernesto Córdoba Nieto

    2010-04-01

    Full Text Available The article presents concepts and definitions from different sources concerning automation. The work approaches automation by virtue of the author’s experience in manufacturing production; why and how automation prolects are embarked upon is considered. Technological reflection regarding the progressive advances or stages of automation in the production area is stressed. Coriat and Freyssenet’s thoughts about and approaches to the problem of automation and its current state are taken and examined, especially that referring to the problem’s relationship with reconciling the level of automation with the flexibility and productivity demanded by competitive, worldwide manufacturing.

  2. Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

    OpenAIRE

    Kasra Saeedfar; Lee Yook Heng; Tan Ling Ling; Majid Rezayi

    2013-01-01

    A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen...

  3. Challenges in the enantioanalysis of fucose using stochastic and potentiometric microsensors

    OpenAIRE

    Iuliana Moldoveanu; Raluca-Ioana Stefan-van Staden; Constantina P. Kapnissi-Cristodoulou; Jacobus Frederick van Staden; Aboul-Enein, Hassan Y.

    2014-01-01

    Fucose gained significant interest in the medical field since a large number of studies have been reported on the role of fucose – as tumor marker. Electrochemical enantioselective sensors based on monocrystalline diamond paste and carbon paste working on stochastic and potentiometric modes were proposed for the enantioanalysis of fucose in biological fluids. Porphyrins and polymeric surfactants were used as modifiers for the diamond and carbon pastes in the design of sensors. Stochastic sens...

  4. Highly efficient potentiometric glucose biosensor based on functionalized InN quantum dots

    OpenAIRE

    Alvi, Naveed ul Hassan; Soto Rodríguez, Paul; Gómez Hernández, Víctor Jesús; Kumar, Praveen; Amin, G.; Nur, O; Willander, Magnus; Nötzel, R.

    2012-01-01

    We present a fast, highly sensitive, and efficient potentiometric glucose biosensor based on functionalized InN quantum-dots (QDs). The InN QDs are grown by molecular beam epitaxy. The InN QDs are bio-chemically functionalized through physical adsorption of glucose oxidase (GOD). GOD enzyme-coated InN QDs based biosensor exhibits excellent linear glucose concentration dependent electrochemical response against an Ag/AgCl reference electrode over a wide logarithmic glucose concentration range ...

  5. Redox potential of shallow groundwater by 1-month continuous in situ potentiometric measurements

    Science.gov (United States)

    Ioka, Seiichiro; Muraoka, Hirofumi; Suzuki, Yota

    2016-06-01

    One-month continuous in situ potentiometric measurements of redox potential (Eh) were used to investigate the dominant redox processes in the shallow groundwater (i.e., fit was found between measured Eh values and Eh values calculated using thermodynamic data of fine-grained goethite. This suggests that Fe redox system is related to the Eh values of shallow groundwater in the Aomori City aquifer.

  6. Titrating and evaluating multi-drug regimens within subjects.

    Science.gov (United States)

    Shih, Margaret; Gennings, Chris; Chinchilli, Vernon M; Carter, Walter H

    2003-07-30

    The dosing of combination therapies is commonly undertaken empirically by practising physicians, and a coherent algorithm to approach the problem of combination dosing is currently lacking. Current methods of evaluating multiple drug combinations in clinical trials fail to provide information regarding the location of more effective doses when the combination is not found to differ from the standard, even though the absence of a difference does not necessarily mean the new combination is ineffective. Moreover, in studies where the new combination is found more effective, often a large proportion of the study participants obtain no benefit from the trial. Even with early stopping rules, the time these subjects spend on inferior treatments can have lasting detrimental effects, leading to problems with patient enrolment and adherence to study protocol. This paper describes an evolutionary operation (EVOP) direct-search procedure to titrate combination doses within individual patients. The Nelder-Mead simplex direct-search algorithm is used to titrate combinations of drugs within individual subjects. Desirability functions are utilized to define the main response of interest and additional responses or constraints. Statistical methodology for determining whether the titrated treatment combination has resulted in an improvement in subject response and for evaluating for therapeutic synergism is developed. Inferences can then be made about the efficacy of the combination or about the individual drugs that comprise the combination. The advantages of this approach include affording every patient the potential to benefit from the combination under study and permitting the consideration of multiple endpoints simultaneously. PMID:12854092

  7. A titration microcalorimeter and the vesicle of mixed surfactants

    Institute of Scientific and Technical Information of China (English)

    白光月[1; 王玉洁[2; 王金本[3; 杨冠英[4; 韩布兴[5; 闫海科[6

    2000-01-01

    A titration microcalorimeter with the sample cells of 1 mL and 3 mL volume was constructed by combining LKB-2107 ampule microcalorimeter with an improved Thermometric titration microcalorimeter. Its sensitivity and precision were tested with the baseline noise and stability, the measurement of energy equivalent, and the linear relation of electric energy and integral area as the function of voltage (V)-time (f). Its accuracy was demonstrated by measuring the dilution enthalpy of a concentrated sucrose solution and the micelle-forming enthalpy of sodium dodecyl sulfate (SDS) in aqueous solution respectively. At the same time, the enthalpy of interaction between SDS and didodecyldimethylammonium bromide (DDAB) was measured by using the titration microcalorimeter, and the phase behavior of SDS-DDAB aqueous mixture was discussed. The microcalorimetric results show that the enthalpy of interaction between SDS and DDAB micelles is -29.53 kJ/mol, the enthalpy of formation of 1:1 SDS-DDAB salt is -125.8 kJ/mol,

  8. A titration microcalorimeter and the vesicle of mixed surfactants

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A titration microcalorimeter with the sample cells of 1 mL and 3 mL volume was constructed by combining LKB-2107 ampule microcalorimeter with an improved Thermometric titration microcalorimeter. Its sensitivity and precision were tested with the baseline noise and stability, the measurement of energy equivalent, and the linear relation of electric energy and integral area as the function of voltage (V )-time (t ). Its accuracy was demonstrated by measuring the dilution enthalpy of a concentrated sucrose solution and the micelle-forming enthalpy of sodium dodecyl sulfate (SDS) in aqueous solution respectively. At the same time, the enthalpy of interaction between SDS and didodecyldimethylammonium bromide (DDAB) was measured by using the titration microcalorimeter, and the phase behavior of SDS-DDAB aqueous mixture was discussed. The microcalorimetric results show that the enthalpy of interaction between SDS and DDAB micelles is ?29.53 kJ/mol, the enthalpy of formation of 1:1 SDS-DDAB salt is ?125.8 kJ/mol, the vesicle-forming enthalpy of SDS-DDAB is 41.23 kJ/mol, and the enthalpy of phase transition from vesicles to SDS rich micelle is 32.10 kJ/mol.

  9. Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring.

    Science.gov (United States)

    Bandodkar, Amay J; Molinnus, Denise; Mirza, Omar; Guinovart, Tomás; Windmiller, Joshua R; Valdés-Ramírez, Gabriela; Andrade, Francisco J; Schöning, Michael J; Wang, Joseph

    2014-04-15

    This article describes the fabrication, characterization and application of an epidermal temporary-transfer tattoo-based potentiometric sensor, coupled with a miniaturized wearable wireless transceiver, for real-time monitoring of sodium in the human perspiration. Sodium excreted during perspiration is an excellent marker for electrolyte imbalance and provides valuable information regarding an individual's physical and mental wellbeing. The realization of the new skin-worn non-invasive tattoo-like sensing device has been realized by amalgamating several state-of-the-art thick film, laser printing, solid-state potentiometry, fluidics and wireless technologies. The resulting tattoo-based potentiometric sodium sensor displays a rapid near-Nernstian response with negligible carryover effects, and good resiliency against various mechanical deformations experienced by the human epidermis. On-body testing of the tattoo sensor coupled to a wireless transceiver during exercise activity demonstrated its ability to continuously monitor sweat sodium dynamics. The real-time sweat sodium concentration was transmitted wirelessly via a body-worn transceiver from the sodium tattoo sensor to a notebook while the subjects perspired on a stationary cycle. The favorable analytical performance along with the wearable nature of the wireless transceiver makes the new epidermal potentiometric sensing system attractive for continuous monitoring the sodium dynamics in human perspiration during diverse activities relevant to the healthcare, fitness, military, healthcare and skin-care domains. PMID:24333582

  10. Potentiometric determination of pantoprazole using an ion-selective sensor based on polypyrrole doped films.

    Science.gov (United States)

    Noronha, Bárbara V; Bindewald, Eduardo H; de Oliveira, Michelle C; Papi, Maurício A P; Bergamini, Márcio F; Marcolino-Jr, Luiz H

    2014-10-01

    The present work reports for the first time the use of polypyrrole (PPy) doped film for development of a potentiometric disposable sensor for determination of pantoprazole (PTZ), a drug used for ulcer treatment. Selective potentiometric response has been found by using a membrane of PPy doped with PTZ anions prepared under galvanostatic conditions at graphite pencil electrode (GPEM/PPy-PTZ) surface. Potentiometric response has been influenced for conditions adopted in polymerization and measurement step. After optimization of experimental (e.g. pH and time of conditioning) and instrumental parameters (e.g. current density and electrical charge) a linear analytical curve from 1.0 × 10(-5) to 1.1 × 10(-2) mol L(-1) with a slope of calibration of the 57.6 mV dec(-1) and limit of detection (LOD) of 6.9 × 10(-6) mol L(-1) was obtained. The determination of the PTZ content in pharmaceutical samples using the proposed methodology and official method recommended by Brazilian Pharmacopeia are in agreement at the 95% confidence level and within an acceptable range of error.

  11. Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring.

    Science.gov (United States)

    Bandodkar, Amay J; Molinnus, Denise; Mirza, Omar; Guinovart, Tomás; Windmiller, Joshua R; Valdés-Ramírez, Gabriela; Andrade, Francisco J; Schöning, Michael J; Wang, Joseph

    2014-04-15

    This article describes the fabrication, characterization and application of an epidermal temporary-transfer tattoo-based potentiometric sensor, coupled with a miniaturized wearable wireless transceiver, for real-time monitoring of sodium in the human perspiration. Sodium excreted during perspiration is an excellent marker for electrolyte imbalance and provides valuable information regarding an individual's physical and mental wellbeing. The realization of the new skin-worn non-invasive tattoo-like sensing device has been realized by amalgamating several state-of-the-art thick film, laser printing, solid-state potentiometry, fluidics and wireless technologies. The resulting tattoo-based potentiometric sodium sensor displays a rapid near-Nernstian response with negligible carryover effects, and good resiliency against various mechanical deformations experienced by the human epidermis. On-body testing of the tattoo sensor coupled to a wireless transceiver during exercise activity demonstrated its ability to continuously monitor sweat sodium dynamics. The real-time sweat sodium concentration was transmitted wirelessly via a body-worn transceiver from the sodium tattoo sensor to a notebook while the subjects perspired on a stationary cycle. The favorable analytical performance along with the wearable nature of the wireless transceiver makes the new epidermal potentiometric sensing system attractive for continuous monitoring the sodium dynamics in human perspiration during diverse activities relevant to the healthcare, fitness, military, healthcare and skin-care domains.

  12. Potentiometric detection in UPLC as an easy alternative to determine cocaine in biological samples.

    Science.gov (United States)

    Daems, Devin; van Nuijs, Alexander L N; Covaci, Adrian; Hamidi-Asl, Ezat; Van Camp, Guy; Nagels, Luc J

    2015-07-01

    The analytical methods which are often used for the determination of cocaine in complex biological matrices are a prescreening immunoassay and confirmation by chromatography combined with mass spectrometry. We suggest an ultra-high-pressure liquid chromatography combined with a potentiometric detector, as a fast and practical method to detect and quantify cocaine in biological samples. An adsorption/desorption model was used to investigate the usefulness of the potentiometric detector to determine cocaine in complex matrices. Detection limits of 6.3 ng mL(-1) were obtained in plasma and urine, which is below the maximum residue limit (MRL) of 25 ng mL(-1). A set of seven plasma samples and 10 urine samples were classified identically by both methods as exceeding the MRL or being inferior to it. The results obtained with the UPLC/potentiometric detection method were compared with the results obtained with the UPLC/MS method for samples spiked with varying cocaine concentrations. The intraclass correlation coefficient was 0.997 for serum (n =7) and 0.977 for urine (n =8). As liquid chromatography is an established technique, and as potentiometry is very simple and cost-effective in terms of equipment, we believe that this method is potentially easy, inexpensive, fast and reliable.

  13. Man-tailored biomimetic sensor of molecularly imprinted materials for the potentiometric measurement of oxytetracycline.

    Science.gov (United States)

    Moreira, Felismina T C; Kamel, Ayman H; Guerreiro, Joana R L; Sales, M Goreti F

    2010-10-15

    A novel biomimetic sensor for the potentiometric transduction of oxytetracycline is presented. The artificial host was imprinted in methacrylic acid and/or acrylamide based polymers. Different amounts of molecularly imprinted and non-imprinted polymers were dispersed in different plasticizing solvents and entrapped in a poly(vinyl chloride) matrix. Only molecularly imprinted based sensors allowed a potentiometric transduction, suggesting the existence of host-guest interactions. These sensors exhibited a near-Nernstian response in steady state evaluations; slopes and detection limits ranged 42-63 mV/decade and 2.5-31.3 μg/mL, respectively. Sensors were independent from the pH of test solutions within 2-5. Good selectivity was observed towards glycine, ciprofloxacin, creatinine, acid nalidixic, sulfadiazine, cysteine, hydroxylamine and lactose. In flowing media, the biomimetic sensors presented good reproducibility (RSD of ±0.7%), fast response, good sensitivity (65 mV/decade), wide linear range (5.0×10(-5) to 1.0×10(-2) mol/L), low detection limit (19.8 μg/mL), and a stable baseline for a 5×10(-3) M citrate buffer (pH 2.5) carrier. The sensors were successfully applied to the analysis of drugs and urine. This work confirms the possibility of using molecularly imprinted polymers as ionophores for organic ion recognition in potentiometric transduction. PMID:20688507

  14. Schiff's Bases and Crown Ethers as Supramolecular Sensing Materials in the Construction of Potentiometric Membrane Sensors

    Directory of Open Access Journals (Sweden)

    Siavash Riahi

    2008-03-01

    Full Text Available Ionophore incorporated PVC membrane sensors are well-established analyticaltools routinely used for the selective and direct measurement of a wide variety of differentions in complex biological and environmental samples. Potentiometric sensors have someoutstanding advantages including simple design and operation, wide linear dynamic range,relatively fast response and rational selectivity. The vital component of such plasticizedPVC members is the ionophore involved, defining the selectivity of the electrodes' complexformation. Molecular recognition causes the formation of many different supramolecules.Different types of supramolecules, like calixarenes, cyclodextrins and podands, have beenused as a sensing material in the construction of ion selective sensors. Schiff's bases andcrown ethers, which feature prominently in supramolecular chemistry, can be used assensing materials in the construction of potentiometric ion selective electrodes. Up to now,more than 200 potentiometric membrane sensors for cations and anions based on Schiff'sbases and crown ethers have been reported. In this review cation binding and anioncomplexes will be described. Liquid membrane sensors based on Schiff's bases and crownethers will then be discussed.

  15. Screen-printed sensor for batch and flow injection potentiometric chromium(VI) monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Moreno, Raul A.; Gismera, M.J.; Sevilla, M.T.; Procopio, Jesus R. [Facultad de Ciencias, Universidad Autonoma de Madrid, Departamento de Quimica Analitica y Analisis Instrumental, Madrid (Spain)

    2010-05-15

    A disposable screen-printed electrode was designed and evaluated for direct detection of chromium(VI) in batch and flow analysis. The carbon screen-printed electrode was modified with a graphite-epoxy composite. The optimal graphite-epoxy matrix contains 37.5% graphite powder, 12.5% diphenylcarbohydrazide, a selective compound for chromium(VI), and 50% epoxy resin. The principal analytical parameters of the potentiometric response in batch and flow analysis were optimized and calculated. The screen-printed sensor exhibits a response time of 20 {+-} 1 s. In flow analysis, the analytical frequency of sampling is 70 injections per hour using 0.1 M NaNO{sub 3} solution at pH 3 as the carrier, a flow rate of 2.5 mL.min{sup -1}, and an injection sample volume of 0.50 mL. The sensor shows potentiometric responses that are very selective for chromium(VI) ions and optimal detection limits in both static mode (2.1 x 10{sup -7} M) and online analysis (9.4 x 10{sup -7} M). The disposable potentiometric sensor was employed to determine toxicity levels of chromium(VI) in mineral, tap, and river waters by flow-injection potentiometry and batch potentiometry. Chromium(VI) determination was also carried out with successful results in leachates from municipal solid waste landfills. (orig.)

  16. Determination of Nelarabine by Nonaqueous Titration Method%非水滴定法测定奈拉滨原料药的含量

    Institute of Scientific and Technical Information of China (English)

    黄巧巧; 丁俊杰; 罗金文

    2012-01-01

    目的 建立奈拉滨原料药的含量测定方法.方法 以0.1 mol/L的高氯酸溶液为滴定液,采用非水滴定法测定,并比较了不同溶剂和不同指标剂对测定结果的影响.结果 以冰醋酸为溶剂,照电位滴定法滴定,终点明显,方法可行.连续测定5次,平均含量为99.8%(RSD=0.22%),测得结果与液相色谱法结果基本一致.结论该方法操作简便、精密度高,可作为奈拉滨原料药含量测定的方法.%Objective To establish a method for the determination of Nelarabine. Methods Nelarabine assay was performed by nonaque-ous titration metod, using 0. 1 mol/L perchloric acid VS as titrant. Effect of different dissolvents and indicators on the titration endpoint was compared in this paper. Results Using acetic acid as solvent and determining the endpoint potentiometrically 5 times, the average content of Nelarabine is 99. 8% (RSD = 0. 22% ), the result is consistent with HPLC. Conclusion The method is simplicity and precision, and can be used to determine the content of Nelarabine APIs.

  17. Configuration Management Automation (CMA)

    Data.gov (United States)

    Department of Transportation — Configuration Management Automation (CMA) will provide an automated, integrated enterprise solution to support CM of FAA NAS and Non-NAS assets and investments. CMA...

  18. Surface complexation of neodymium at the rutile-water interface: A potentiometric and modeling study in NaCl media to 250°C

    Science.gov (United States)

    Ridley, Moira K.; Machesky, Michael L.; Wesolowski, David J.; Palmer, Donald A.

    2005-01-01

    The adsorption of Nd 3+ onto rutile surfaces was examined by potentiometric titration from 25 to 250°C, in 0.03 and 0.30 m NaCl background electrolyte. Experimental results show that Nd 3+ sorbs strongly, even at low temperature, with adsorption commencing below the pH znpc of rutile. In addition, there is a systematic increase in Nd 3+ adsorption with increasing temperature. The experimental results were rationalized and described using surface oxygen proton affinities computed from the MUlti SIte Complexation or MUSIC model, coupled with a Stern-based three-layer description of the oxide/water interface. Moreover, molecular-scale information was incorporated successfully into the surface complexation model, providing a unique geometry for the adsorption of Nd 3+ on rutile. The primary mode of Nd 3+ adsorption was assumed to be the tetradentate configuration found for Y 3+ adsorption on the rutile (110) surface from previously described in situ X-ray standing wave experiments, wherein the sorbing cations bond directly with two adjacent "terminal" and two adjacent "bridging" surface oxygen atoms. Similarly, the adsorption of Na + counterions was also assumed to be tetradentate, as supported by MD simulations of Na + interactions with the rutile (110) surface, and by analogous X-ray standing wave results for Rb + adsorption on rutile. Fitting parameters for Nd 3+ adsorption included binding constants for the tetradentate adsorption complex and capacitance values for the inner-sphere binding plane. In addition, hydrolysis of the tetradentate adsorption complex was permitted and resulted in significantly improved model fits at higher temperature and pH values. The modeling results indicate that the Stern-based MUSIC surface-complexation model adequately accommodates molecular-scale information to uniquely rationalize and describe multivalent ion adsorption systematically into the hydrothermal regime.

  19. Potentiometric determination of trace amounts of aluminium utilizing polyvinyl chloride membrane and coated platinum sensors based on E-N'-(2-hydroxy-3-methoxybenzylidene) benzohydrazide.

    Science.gov (United States)

    Tajik, Somayeh; Taher, Mohammad Ali; Sheikhshoaie, Iran

    2013-01-01

    This paper describes the construction and performance characteristics of novel polyvinyl chloride membrane (PME) and coated platinum (CPtE) aluminium (Al) ion selective electrodes based on E-N'-(2-hydroxy-3-methoxybenzylidene) benzohydrazide. The electrodes exhibited linear responses with near Nernstian slopes of 19.9 +/- 0.3 (PME) and 20.1 +/- 0.4 (CPtE) mV/decade of activity within the Al3+ ion concentration range of 3.0 x 10(-7) to 1.0 x 10(-2) M for the PME and 1.0 x 10(-7)-1.0 x 10(-2) M for the CPtE. These sensors were applicable in a pH range of 3.0 to 7.0. The LODs of the PME and CPtE were 1.7 x 10(-7) and 5.6 x 10(-8) M, respectively. They had a response time of less than 10 s and could be used practically for a period of at least 2 months without measurable divergence in results. The isothermal temperature coefficient of the PME was 1.12 x 10(-3) V/degrees C, and it can tolerate partially nonaqueous media up to 25%. The electrodes showed excellent selectivity towards Al3+ ions in the presence of a wide range of alkali, alkaline earth, and transition metals ions. They were successfully applied for the direct determination of Al3+ ions in tap water, aqueduct water, mineral water, and Al-Mg syrup and as indicator electrodes in potentiometric titration of Al ions with EDTA.

  20. Workflow automation architecture standard

    Energy Technology Data Exchange (ETDEWEB)

    Moshofsky, R.P.; Rohen, W.T. [Boeing Computer Services Co., Richland, WA (United States)

    1994-11-14

    This document presents an architectural standard for application of workflow automation technology. The standard includes a functional architecture, process for developing an automated workflow system for a work group, functional and collateral specifications for workflow automation, and results of a proof of concept prototype.

  1. 电镀废水中硫氰酸根离子含量的自动电位滴定%Determination of Thiocyanate Ions in Electroplating Wastewater by Automatic Potentiometeric Titration

    Institute of Scientific and Technical Information of China (English)

    姚晓华; 丘圣; 丘山; 丘星初

    2011-01-01

    The condition and method to determine thiocyanate ion by automatic potentiometric titration was studied. The results show that, the selection of silver electrode as indicator electrode, the electrode 217 with double liquid junction as reference, this method has high selectivity in nitric acid medium to titrate thiocyanate ion. When used in electroplating wastewater analysis, the method is simple and fast, which can print out the results in 4 minutes.%研究了用自动电位滴定测定硫氰酸根离子的条件和方法.实验结果表明,选用银电极为指示电极,217型双液接电极为参比电极,在硝酸介质中滴定硫氰酸根离子,方法具有高选择性;应用于电镀废水分析,方法简便快捷,在4min内能打印出分析结果.

  2. Shoe-String Automation

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, M.L.

    2001-07-30

    Faced with a downsizing organization, serious budget reductions and retirement of key metrology personnel, maintaining capabilities to provide necessary services to our customers was becoming increasingly difficult. It appeared that the only solution was to automate some of our more personnel-intensive processes; however, it was crucial that the most personnel-intensive candidate process be automated, at the lowest price possible and with the lowest risk of failure. This discussion relates factors in the selection of the Standard Leak Calibration System for automation, the methods of automation used to provide the lowest-cost solution and the benefits realized as a result of the automation.

  3. A titration model for evaluating calcium hydroxide removal techniques

    Directory of Open Access Journals (Sweden)

    Mark PHILLIPS

    2015-02-01

    Full Text Available Objective Calcium hydroxide (Ca(OH2 has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH2 left after different endodontic irrigation methods. Material and Methods Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH2 followed by gross Ca(OH2 removal using hand files and randomized treatment of either: 1 Syringe irrigation; 2 Syringe irrigation with use of an apical file; 3 Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI, or 4 Syringe irrigation with apical file and PUI (n=12/group. Residual Ca(OH2 was dissolved with glycerin and titrated to measure residual Ca(OH2 left in the root. Results No method completely removed all residual Ca(OH2. The addition of 30 s PUI with or without apical file use removed Ca(OH2 significantly better than irrigation alone. Conclusions This technique allowed quantification of residual Ca(OH2. The use of PUI (with or without apical file resulted in significantly lower Ca(OH2 residue compared to irrigation alone.

  4. Titratable acidity of beverages influences salivary pH recovery

    Directory of Open Access Journals (Sweden)

    Livia Maria Andaló TENUTA

    2015-01-01

    Full Text Available A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively. Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

  5. Development of potentiometric urea biosensor based on urease immobilized in PVA-PAA composite matrix for estimation of blood urea nitrogen (BUN).

    Science.gov (United States)

    Jha, Sandeep Kumar; Topkar, Anita; D'Souza, Stanislaus F

    2008-04-24

    A urea biosensor was developed using the urease entrapped in polyvinyl alcohol (PVA) and polyacrylamide (PAA) composite polymer membrane. The membrane was prepared on the cheesecloth support by gamma-irradiation induced free radical polymerization. The performance of the biosensor was monitored using a flow-through cell, where the membrane was kept in conjugation with the ammonia selective electrode and urea was added as substrate in phosphate buffer medium. The ammonia produced as a result of enzymatic reaction was monitored potentiometrically. The potential of the system was amplified using an electronic circuit incorporating operational amplifiers. Automated data acquisition was carried by connecting the output to a 12-bit analog to digital converter card. The sensor working range was 1-1000 mM urea with a response time of 120 s. The enzyme membranes could be reused 8 times with more than 90% accuracy. The biosensor was tested for blood urea nitrogen (BUN) estimation in clinical serum samples. The biosensor showed good correlation with commercial Infinitytrade mark BUN reagent method using a clinical chemistry autoanalyzer. The membranes could be preserved in phosphate buffer containing dithiothreitol, beta-mercaptoethanol and glycerol for a period of two months without significant loss of enzyme activity. PMID:18329719

  6. Isothermal Titration Calorimetry: Assisted Crystallization of RNA-Ligand Complexes.

    Science.gov (United States)

    Da Veiga, Cyrielle; Mezher, Joelle; Dumas, Philippe; Ennifar, Eric

    2016-01-01

    The success rate of nucleic acids/ligands co-crystallization can be significantly improved by performing preliminary biophysical analyses. Among suitable biophysical approaches, isothermal titration calorimetry (ITC) is certainly a method of choice. ITC can be used in a wide range of experimental conditions to monitor in real time the formation of the RNA- or DNA-ligand complex, with the advantage of providing in addition the complete binding profile of the interaction. Following the ITC experiment, the complex is ready to be concentrated for crystallization trials. This chapter describes a detailed experimental protocol for using ITC as a tool for monitoring RNA/small molecule binding, followed by co-crystallization.

  7. Infrared Turbidimetric Titration Method for Sulfate Ions in Brackish Water

    Directory of Open Access Journals (Sweden)

    Benabadji Nouredine

    2012-12-01

    Full Text Available In this work an infrared turbidimetric titration method is described for the determination of sulfate ions in brackish water. A suspension of barium sulfate is produced in an aqueous solution and/or brackish water sample by the addition of barium chloride solution and the turbidity is monitored with the help of an immersed infrared sensor. The developed sensor utilizes an optical system to measure the evolution of turbidity during the titration. This sensor is a simple device designed in the laboratory, consisting of two infrared diodes (LED, the first is an emitter and the second is used as detector (receiver. The data acquisition system is made with the help of a dataloger made on the basis of the microcontroller 16F877/874 accompanied with adaptable software both of them are self made. Concentration over 60 µg/mL of sulfate expressed as, SO42- can be measured with high reproducibility, by this method without a preliminary treatment or dilution of the sample. The method determines SO42 - concentration of brackish water with RSD of < 1.2%.

  8. Characterization of protein-protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Velazquez-Campoy, Adrian; Leavitt, Stephanie A; Freire, Ernesto

    2015-01-01

    The analysis of protein-protein interactions has attracted the attention of many researchers from both a fundamental point of view and a practical point of view. From a fundamental point of view, the development of an understanding of the signaling events triggered by the interaction of two or more proteins provides key information to elucidate the functioning of many cell processes. From a practical point of view, understanding protein-protein interactions at a quantitative level provides the foundation for the development of antagonists or agonists of those interactions. Isothermal Titration Calorimetry (ITC) is the only technique with the capability of measuring not only binding affinity but the enthalpic and entropic components that define affinity. Over the years, isothermal titration calorimeters have evolved in sensitivity and accuracy. Today, TA Instruments and MicroCal market instruments with the performance required to evaluate protein-protein interactions. In this methods paper, we describe general procedures to analyze heterodimeric (porcine pancreatic trypsin binding to soybean trypsin inhibitor) and homodimeric (bovine pancreatic α-chymotrypsin) protein associations by ITC.

  9. Measuring the Kinetics of Molecular Association by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Vander Meulen, Kirk A; Horowitz, Scott; Trievel, Raymond C; Butcher, Samuel E

    2016-01-01

    The real-time power response inherent in an isothermal titration calorimetry (ITC) experiment provides an opportunity to directly analyze association kinetics, which, together with the conventional measurement of thermodynamic quantities, can provide an incredibly rich description of molecular binding in a single experiment. Here, we detail our application of this method, in which interactions occurring with relaxation times ranging from slightly below the instrument response time constant (12.5 s in this case) to as large as 600 s can be fully detailed in terms of both the thermodynamics and kinetics. In a binding titration scenario, in the most general case an injection can reveal an association rate constant (kon). Under more restrictive conditions, the instrument time constant-corrected power decay following each injection is simply an exponential decay described by a composite rate constant (kobs), from which both kon and the dissociation rate constant (koff) can be extracted. The data also support the viability of this exponential approach, for kon only, for a slightly larger set of conditions. Using a bimolecular RNA folding model and a protein-ligand interaction, we demonstrate and have internally validated this approach to experiment design, data processing, and error analysis. An updated guide to thermodynamic and kinetic regimes accessible by ITC is provided.

  10. Measuring Multivalent Binding Interactions by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Dam, Tarun K; Talaga, Melanie L; Fan, Ni; Brewer, Curtis F

    2016-01-01

    Multivalent glycoconjugate-protein interactions are central to many important biological processes. Isothermal titration calorimetry (ITC) can potentially reveal the molecular and thermodynamic basis of such interactions. However, calorimetric investigation of multivalency is challenging. Binding of multivalent glycoconjugates to proteins (lectins) often leads to a stoichiometry-dependent precipitation process due to noncovalent cross-linking between the reactants. Precipitation during ITC titration severely affects the quality of the baseline as well as the signals. Hence, the resulting thermodynamic data are not dependable. We have made some modifications to address this problem and successfully studied multivalent glycoconjugate binding to lectins. We have also modified the Hill plot equation to analyze high quality ITC raw data obtained from multivalent binding. As described in this chapter, ITC-driven thermodynamic parameters and Hill plot analysis of ITC raw data can provide valuable information about the molecular mechanism of multivalent lectin-glycoconjugate interactions. The methods described herein revealed (i) the importance of functional valence of multivalent glycoconjugates, (ii) that favorable entropic effects contribute to the enhanced affinities associated with multivalent binding, (iii) that with the progression of lectin binding, the microscopic affinities of the glycan epitopes of a multivalent glycoconjugate decrease (negative cooperativity), (iv) that lectin binding to multivalent glycoconjugates, especially to mucins, involves internal diffusion jumps, (bind and jump) and (v) that scaffolds of glycoconjugates influence their entropy of binding.

  11. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications.

  12. Comparison of VFA titration procedures used for monitoring the biogas process

    DEFF Research Database (Denmark)

    Lützhøft, Hans-Christian Holten; Boe, Kanokwan; Fang, Cheng;

    2014-01-01

    titration procedures. Currently, no standardized procedure is used and it is therefore difficult to compare the performance among plants. The aim of this study was to evaluate four titration procedures (for determination of VFA-levels of digested manure samples) and compare results with gas chromatographic...... (GC) analysis. Two of the procedures are commonly used in biogas plants and two are discussed in literature. The results showed that the optimal titration results were obtained when 40mL of four times diluted digested manure was gently stirred (200rpm). Results from samples with different VFA...... concentrations (1-11g/L) showed linear correlation between titration results and GC measurements. However, determination of VFA by titration generally overestimated the VFA contents compared with GC measurements when samples had low VFA concentrations, i.e. around 1g/L. The accuracy of titration increased when...

  13. Fusion of Potentiometric & Voltammetric Electronic Tongue for Classification of Black Tea Taste based on Theaflavins (TF) Content

    Science.gov (United States)

    Bhattacharyya, Nabarun; Legin, Andrey; Papieva, Irina; Sarkar, Subrata; Kirsanov, Dmitry; Kartsova, Anna; Ghosh, Arunangshu; Bandyopadhyay, Rajib

    2011-09-01

    Black tea is an extensively consumed beverage worldwide with an expanding market. The final quality of black tea depends upon number of chemical compounds present in the tea. Out of these compounds, theaflavins (TF), which is responsible for astringency in black tea, plays an important role in determining the final taste of the finished black tea. The present paper reports our effort to correlate the theaflavins contents with the voltammetric and potentiometric electronic tongue (e-tongue) data. Noble metal-based electrode array has been used for collecting data though voltammetric electronic tongue where as liquid filled membrane based electrodes have been used for potentiometric electronic tongue. Black tea samples with tea taster score and biochemical results have been collected from Tea Research Association, Tocklai, India for the analysis purpose. In this paper, voltammetric and potentiometric e-tongue responses are combined to demonstrate improvement of cluster formation among tea samples with different ranges of TF values.

  14. Direct Potentiometric Determination of Penicillamine in Real Samples by Using Copper ISE

    OpenAIRE

    Vukušić, Tina; Prkić, Ante; Giljanović, Josipa; Sokol, Vesna; Bošković, Perica

    2015-01-01

    Direct potentiometric method for determination of penicillamine in pharmaceuticals by using commercial copper ISE is described. Proposed method is very inexpensive, simple and reasonably fast method for determination of Pen in acetic buffer, pH = 4 without pretreatment of pharmaceuticals. Determination is based on the reaction between Pen and Cu2+ from electrode membrane. Described method has linear response range for Pen from 2×10−6 to 1×10−2 mol L−1 with limit of detection of 1.1×10−6 mol L...

  15. Analysis of Lead and Zinc by Mercury-Free Potentiometric Stripping Analysis

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1997-01-01

    A method is presented for trace-element analysis of lead and zinc by potentiometric stripping analysis (PSA) where both the glassy-carbon working electrode and the electrolyte are free of mercury. Analysis of zinc requires an activation procedure of the glassy-carbon electrode. The activation is...... performed by pre-concentrating zinc on glassy carbon at -1400 mV(SCE) in a mercury-free electrolyte containing 0.1 M HCl and 2 ppm Zn2+, followed by stripping at approx. -1050 mV. A linear relationship between stripping peak areas, recorded in the derivative mode, and concentration was found in the...

  16. Potentiometric sensor fabrication having 2D sarcosine memories and analytical features.

    Science.gov (United States)

    Özkütük, Ebru Birlik; Diltemiz, Sibel Emir; Avcı, Şeyma; Uğurağ, Deniz; Aykanat, Rabia Berna; Ersöz, Arzu; Say, Rıdvan

    2016-12-01

    In this study, a simple, rapid and sensitive method based on novel molecular imprinted polymeric sensor has been developed and validated for the determination of prostate cancer metabolite biomarker. The molecularly imprinted polymer (MIP) has been synthesized by emulsion polymerization, using sarcosine as template molecule, methacryloylamido histidine (MAH) as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The performance of the developed sarcosine sensor has been evaluated, and the results have indicated that a sensitive potentiometric sensor has been fabricated. The sarcosine sensor has showed high-selectivity, shorter response time (5.5months). PMID:27612708

  17. Indicator electrodes from d-elements for application in different types of potentiometric analytical methods

    OpenAIRE

    Z. Kunasheva; Dina Mendalieva; B. Seifullina

    2012-01-01

    The article covers the use of metal electrodes from titanium, tungsten, molybdenum as indicator electrodes at potentiometric method of analysis. The condition of measuring operation in dependence on pH, ionic strength of solutions is described in the article. Electrode potential of testing electrodes are measured in the interval of concentration of salts from 0,1∙10-1 mole/l till 0,1∙10-6 mole/l. The results of testing of electrical-analytical description of metal electrodes made of d-element...

  18. Complexation of Iron by Dopamine Analogs; A Spectrophotometric and Potentiometric Study

    OpenAIRE

    *T. Fiaz; N. Fatima; S. Z. A. Zaidi

    2013-01-01

    The chelation of Bio-essential metal, Iron, with dopamine analogs was studied at 30±2°C. Fe2+ formed intense color complex with these molecules with an absorbance maxima in visible region. A distinct peak of Fe-Carbidopa complex at 364nm with molar absorptivity of 1600 M-1 cm-1 was observed while that of Fe-Levodopa and Fe-Methyldopa were observed at 730nm with molar absorptivities of 306 M-1 cm-1 and 2300 M-1 cm-1, respectively. Potentiometric studies of the complex indicate that Fe(II) ...

  19. Development of miniaturized potentiometric nitrate- and ammonium selective electrodes for applications in water monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, J.; Kaden, H. [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e.V., Meinsberg (Germany); Pausch, G. [Umwelt- und Ingenieurtechnik GmbH, Dresden (Germany)

    2000-06-01

    Mobile analysis with potentiometric sensors is well suited for field measurements. Ion-selective electrodes (ISE) based on polymeric membranes for in-situ determination of nitrate and ammonium contents in ground water, drinking water and surface water have been developed. The ISE are integrated in a multisensor module (MSM) for monitoring these ions over longer time intervals. The receptor is a PVC-membrane with tridodecylammonium nitrate (TDDA) for nitrate- and nonactine for ammonium-electrodes as ionophores. As plasticizer dibutylphthalate (DBT) was used. The main parameters for assessing the efficiency of these ISE are presented. (orig.)

  20. Structural characterization of hexadecyltrimethylammonium-smectite composites and their potentiometric electrode applications

    Energy Technology Data Exchange (ETDEWEB)

    Cubuk, Osman [Department of Chemistry, Faculty of Arts and Sciences, Erzincan University, 24100 Erzincan (Turkey); Caglar, Bulent, E-mail: bcaglar55@gmail.com [Department of Chemistry, Faculty of Arts and Sciences, Erzincan University, 24100 Erzincan (Turkey); Topcu, Cihan; Coldur, Fatih; Sarp, Gokhan [Department of Chemistry, Faculty of Arts and Sciences, Erzincan University, 24100 Erzincan (Turkey); Tabak, Ahmet [Department of Chemistry, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, 53100 Rize (Turkey); Sahin, Erdal [Department of Chemistry, Faculty of Arts and Sciences, Erzincan University, 24100 Erzincan (Turkey)

    2015-05-30

    Graphical abstract: - Highlights: • Surfactant cations intercalated with different molecular arrangements into smectite layers. • The electrophoretic mobility values indicate that excess surfactant loadings also create positive charges on the organosmectites surfaces. • A novel potentiometric SCN{sup −} selective electrode was fabricated based on modified smectite. - Abstract: Organosmectites were prepared by the intercalation of hexadecyltrimethylammonium cations at various ratios into interlayer of Unye smectite. Structural, thermal, morphological and textural properties of the synthesized organosmectites were characterized. Afterwards, a novel potentiometric PVC-membrane thiocyanate selective electrode was prepared based on the obtained hexadecyltrimethylammonium modified smectites as electroactive material. The basal spacing values of organosmectites were observed in the range of 15.61 and 35.50 Å. Powder X-ray diffraction data show that the surfactant cations penetrated into the smectite layers with different molecular arrangements. Modification of smectite with hexadecyltrimethylammonium led to appreciable decreases in the intensities of the FTIR bands at 3402 and 1635 cm{sup −1} and the new characteristic vibrational bands at 2927, 2850, 1472 and 722 cm{sup −1} originating from the surfactant molecules appeared. The thermal analysis data showed that the decomposition of surfactant species occurred in the temperature range of 170–720 °C and the amount of dehydrated water gradually decreased with the increase in surfactant amount. The intercalation of surfactant species within the gallery spacing led gradually to smaller surface areas. In addition, the electrophoretic mobility values indicate that excess surfactant loadings also generate positive charges on the organosmectite surfaces. The most convenient membrane composition resulting in the best potentiometric performance was investigated. The optimum membrane composition was determined to

  1. Integrated potentiometric detector for use in chip-based flow cells

    Science.gov (United States)

    Tantra; Manz

    2000-07-01

    A new kind of potentiometric chip sensor for ion-selective electrodes (ISE) based on a solvent polymeric membrane is described. The chip sensor is designed to trap the organic cocktail inside the chip and to permit sample solution to flow past the membrane. The design allows the sensor to overcome technical problems of ruggedness and would therefore be ideal for industrial processes. The sensor performance for a Ba2+-ISE membrane based on a Vogtle ionophore showed electrochemical behavior similar to that observed in conventional electrodes and microelectrode arrangements. PMID:10905321

  2. Potentiometric study of polyaniline film synthesized with various dopants and composite-dopant: A comparative study

    Indian Academy of Sciences (India)

    P D Gaikwad; D J Shirale; V K Gade; P A Savale; K P Kakde; H J Kharat; M D Shirsat

    2006-08-01

    The potentiometric study of polyaniline (PANI) film synthesized with dopants viz. polyvinyl sulfonic acid (PVS), -toluene sulfonic acid (TS), dodecyl benzene sulfonic acid (DBS) and composite-dopants viz. PVS–TS and PVS–DBS, has been carried out. The synthesized PANI films were characterized by electrochemical technique, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and conductivity measurement. It was found that the PANI doped with PVS gives good electrochemical properties, conductivity as well as surface morphology as compared to TS and DBS, whereas in composite dopants the PANI doped with PVS–TS gives good polymer matrix as compared to PVS–DBS.

  3. 原位自动光度滴定法测定铁矿中铁含量%Study on application of photometric titration in the in situ determination of iron in iron ores

    Institute of Scientific and Technical Information of China (English)

    卢振国; 彭速标; 郑建国; 翟翠萍; 黄伟; 郭汉城; 邹振基

    2012-01-01

    利用自动电位滴定仪和DP5光度电极研究了原位自动光度滴定法在全铁测量中的应用.以HNO3、HCl和HF溶液为溶剂,采用密封微波消解系统分解试样.用NaOH溶液调节溶液酸度至pH 1.5,在原消解罐中以乙二胺四乙酸二钠盐(磺基水杨酸为指示剂)滴定铁.主要对滴定温度、试样的分解条件以及杂质对测定的干扰情况进行了研究.研究结果表明,称样量为0.05 g,溶剂为60%王水10 mL加1 mL HF(1 +99),温度为210℃,消解时间为20 min时溶样效果最好,50~60℃条件下,pH 1.5时进行滴定,结果准确可靠,能有效消除干扰.%The in situ determination of iron content in iron ores is presented with the automatic photometric titration method using an automatic potentiometric titrator and a DP5 photometric electrode. The samples are digested in closed vessels in a microwave oven with a mixture of nitric acid, hydrochloric acid and hydrofluoric acid solution. The resulting solution is diluted with water and adjusted to pHl. 5 with sodium hydroxide solution. Iron is determined in situ by automatic photometric titration with EDTA ( Sulfosalicylic acid as indicator). The conditions of titration temperature, sample decomposition and interferences are studied. The results show that optimal conditions are as follows, 0.05 g of samples, 10 mL of 60% aqua regia and 1 mL of (1+99) HF, digestion temperature of 210℃ , digestion time of 20 minutes, the titration solution at 50-60℃ and pH 1.5. The obtained results are accurate and reliable, and the interferences can be eliminated.

  4. Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles

    Science.gov (United States)

    Ali, A.; AlSalhi, M. S.; Atif, M.; Ansari, Anees A.; Israr, M. Q.; Sadaf, J. R.; Ahmed, E.; Nur, O.; Willander, M.

    2013-02-01

    The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness -500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ~42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.

  5. Correlation between Electrical Properties and Potentiometric Response of CS-Clay Nanocomposite Membranes

    Directory of Open Access Journals (Sweden)

    M. Oviedo Mendoza

    2015-01-01

    Full Text Available The aim of this work is to study the relationship between electrical, structure, and potentiometric response to nitrate anions using Ion Selective Electrodes (ISE. These ISE are based on chitosan-montmorillonite nanocomposite membranes with different content of montmorillonite. Membrane properties have been studied using SEM, FTIR, and impedance spectroscopy measurements. With the advent of impedance spectroscopy one is allowed to obtain the DC conductivity dependence on montmorillonite concentration and the percolation threshold. Additionally, the potentiometric response to nitrate anions of ISE based on chitosan-clay nanocomposite has been investigated. It is shown that the properties and performance of these membrane electrodes depend upon the clay wt% and that the best sensitivity to nitrate ions (with detection limit 7 × 10−5 M is obtained near the percolation concentration ca. 8 ± 2.5 wt% of clay. This observation is traceable to higher clay content (higher agglomeration that tends to decrease the intercalation and absorption of the number of chitosan chains in the interlayer space of montmorillonite.

  6. Potentiometric monitoring of cobalt in beer sample by solid contact ion selective electrode

    Directory of Open Access Journals (Sweden)

    Hilal Eren

    2014-12-01

    Full Text Available A new solid contact cobalt selective electrode was constructed with 4-tert-butylthiacalix[4]arene as ionophore. The best performance was observed with the membrane having an ionophore/polyvinyl chloride/sodium tetraphenylborate/nitrophenyl octyl ether ratio of 3.5:33:1.5:62 (w/w; mg. The electrode, under steady-state conditions, exhibited a working concentration range of 1 × 10−1 – 1 × 10−6 mol/L with a near-Nernstian slope of 25.3 mV/decade and a detection limit of 3.5 × 10−7 mol/L. The electrode had a very short response time (<10 seconds and good reproducibility at a working pH range of 4.0–6.5. The electrode was used for 4 months without any significant change in its sensitivity. The potentiometric performance of the electrode in partially nonaqueous medium [up to 20 % (v/v alcohol] was found satisfactory. The performance of the prepared electrode for the analysis of beer samples using direct potentiometric method is very encouraging.

  7. Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles

    International Nuclear Information System (INIS)

    The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness −500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ∼42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.

  8. Potentiometric urea biosensor based on multi-walled carbon nanotubes (MWCNTs)/silica composite material

    International Nuclear Information System (INIS)

    A novel potentiometric urea biosensor has been fabricated with urease (Urs) immobilized multi-walled carbon nanotubes (MWCNTs) embedded in silica matrix deposited on the surface of indium tin oxide (ITO) coated glass plate. The enzyme Urs was covalently linked with the exposed free -COOH groups of functionalized MWCNTs (F-MWCNTs), which are subsequently incorporated within the silica matrix by sol-gel method. The Urs/MWCNTs/SiO2/ITO composite modified electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and UV-visible spectroscopy. The morphologies and electrochemical performance of the modified Urs/MWCNTs/SiO2/ITO electrode have been investigated by scanning electron microscopy (SEM) and potentiometric method, respectively. The synergistic effect of silica matrix, F-MWCNTs and biocompatibility of Urs/MWCNTs/SiO2 made the biosensor to have the excellent electro catalytic activity and high stability. The resulting biosensor exhibits a good response performance to urea detection with a wide linear range from 2.18 x 10-5 to 1.07 x 10-3 M urea. The biosensor shows a short response time of 10-25 s and a high sensitivity of 23 mV/decade/cm2.

  9. New molecularly-imprinted polymer for carnitine and its application as ionophore in potentiometric selective membranes.

    Science.gov (United States)

    Moret, Joséphine; Moreira, Felismina T C; Almeida, Sofia A A; Sales, M Goreti F

    2014-10-01

    Carnitine (CRT) is a biological metabolite found in urine that contributes in assessingseveral disease conditions, including cancer. Novel quick screening procedures for CRT are therefore fundamental. This work proposes a novel potentiometric device where molecularly imprinted polymers (MIPs) were used as ionophores. The host-tailored sites were imprinted on a polymeric network assembled by radical polymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM). Non-imprinted polymers (NIPs) were produced as control by removing the template from the reaction media. The selective membrane was prepared by dispersing MIP or NIP particles in plasticizer and poly(vinyl chloride), PVC, and casting this mixture over a solid contact support made of graphite. The composition of the selective membrane was investigated with regard to kind/amount of sensory material (MIP or NIP), and the need for a lipophilic additive. Overall, MIP sensors with additive exhibited the best performance, with near-Nernstian response down to ~1×10(-4)mol L(-1), at pH5, and a detection limit of ~8×10(-5)mol L(-1). Suitable selectivity was found for all membranes, assessed by the matched potential method against some of the most common species in urine (urea, sodium, creatinine, sulfate, fructose and hemoglobin). CRT selective membranes including MIP materials were applied successfully to the potentiometric determination of CRT in urine samples. PMID:25175239

  10. Potentiometric urea biosensor based on multi-walled carbon nanotubes (MWCNTs)/silica composite material

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, Tarushee [National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K.S. Krishnan Road, New Delhi-110012 (India); Department of Applied Chemistry, Delhi College of Engineering, University of Delhi, Bawana Road, Delhi-110042 (India); Kumar, D. [Department of Applied Chemistry, Delhi College of Engineering, University of Delhi, Bawana Road, Delhi-110042 (India); Singh, Nahar; Biradar, A.M. [National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K.S. Krishnan Road, New Delhi-110012 (India); Rajesh, E-mail: rajesh_csir@yahoo.com [National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K.S. Krishnan Road, New Delhi-110012 (India)

    2011-03-12

    A novel potentiometric urea biosensor has been fabricated with urease (Urs) immobilized multi-walled carbon nanotubes (MWCNTs) embedded in silica matrix deposited on the surface of indium tin oxide (ITO) coated glass plate. The enzyme Urs was covalently linked with the exposed free -COOH groups of functionalized MWCNTs (F-MWCNTs), which are subsequently incorporated within the silica matrix by sol-gel method. The Urs/MWCNTs/SiO{sub 2}/ITO composite modified electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and UV-visible spectroscopy. The morphologies and electrochemical performance of the modified Urs/MWCNTs/SiO{sub 2}/ITO electrode have been investigated by scanning electron microscopy (SEM) and potentiometric method, respectively. The synergistic effect of silica matrix, F-MWCNTs and biocompatibility of Urs/MWCNTs/SiO{sub 2} made the biosensor to have the excellent electro catalytic activity and high stability. The resulting biosensor exhibits a good response performance to urea detection with a wide linear range from 2.18 x 10{sup -5} to 1.07 x 10{sup -3} M urea. The biosensor shows a short response time of 10-25 s and a high sensitivity of 23 mV/decade/cm{sup 2}.

  11. Potentiometric Multisensory Systems with Novel Ion-Exchange Polymer-Based Sensors for Analysis of Drugs

    Directory of Open Access Journals (Sweden)

    Olga V. Bobreshova

    2012-01-01

    Full Text Available This paper examines potentiometric multisensory systems that consist of novel cross-sensitive PD-sensors (Potential Donnan-sensors. The analytical signal of PD-sensors is the Donnan potential at the ion-exchange polymer/electrolyte test solution interface. The use of novel sensors for the quantitative analysis of multicomponent aqueous solutions of amino acids, vitamins and medical substances is based on protolytic and ion-exchange reactions at the interfaces of ion-exchangers and test solutions. The potentiometric sensor arrays consist of PD-sensors and ion-selective electrodes. Such systems were developed for the multicomponent quantitative analysis of lysine monohydrochloride, thiamine chloride and novocaine hydrochloride solutions that contained salts of alkaline and alkaline-earth metals, as well as for mixed solutions of nicotinic acid and pyridoxine hydrochloride. Multivariate methods of analysis were used for sensor calibration and the analysis of the total response of sensor arrays. The errors of measurement of the electrolytes in aqueous solutions did not exceed 10%. The developed multisensory systems were used to determine the composition of a therapeutic “Mineral salt with low content of sodium chloride” and to determine concentrations of novocaine in sewage samples from a dental clinic.

  12. Determination of Dimethylallylamine by Titration in Nonaqueous Solvent

    Institute of Scientific and Technical Information of China (English)

    LIU Li-hua; GONG Zhu-qing; ZHENG Ya-jie

    2004-01-01

    The content of dimethylallylamine was determined using glacial acetic acid as solvent, acetic-formic mixture as an anhydrite, perchloric acid-glacial acetic acid as titrant, and 1% crystal violet in acetic acid as indicator in the presence of methylamine and dimethylamine The influences of inert constituents and water on the titration were investigated, and a complete analytical method was determined. The results showed that the determination error of total amines increased with water increasing, while the effect of water on the determination of dimethylallylamine was little when the amount of water was within 5%, the relative error was generally within 1%, and that the end-point was acutely when about 10% chloroform was added. Compared with gas chromatography, this method is simple, convenient and accurate.

  13. Isothermal titration calorimetry of ion-coupled membrane transporters.

    Science.gov (United States)

    Boudker, Olga; Oh, SeCheol

    2015-04-01

    Binding of ligands, ranging from proteins to ions, to membrane proteins is associated with absorption or release of heat that can be detected by isothermal titration calorimetry (ITC). Such measurements not only provide binding affinities but also afford direct access to thermodynamic parameters of binding--enthalpy, entropy and heat capacity. These parameters can be interpreted in a structural context, allow discrimination between different binding mechanisms and guide drug design. In this review, we introduce advantages and limitations of ITC as a methodology to study molecular interactions of membrane proteins. We further describe case studies where ITC was used to analyze thermodynamic linkage between ions and substrates in ion-coupled transporters. Similar type of linkage analysis will likely be applicable to a wide range of transporters, channels, and receptors.

  14. Isothermal titration calorimetry of membrane proteins - progress and challenges.

    Science.gov (United States)

    Rajarathnam, Krishna; Rösgen, Jörg

    2014-01-01

    Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.

  15. Sailing on the "C": A Vitamin Titration with a Twist

    Science.gov (United States)

    Sowa, S.; Kondo, A. E.

    2003-05-01

    The experiment takes the traditional redox titration of vitamin C using iodine with starch as an indicator, and presents it to the student as a challenge in guided-inquiry format. Two versions, with different levels of difficulty, are provided, to accommodate students with varying levels of problem-solving skills. The "challenge" is both quantitative and qualitative: if you were an eighteenth-century sea captain packing for a voyage to the New World, would you take oranges, lemons, limes, or grapefruits to prevent your crew from getting scurvy? The challenge ties in history, nutrition, and health with chemistry, and provides students an opportunity to work with familiar food products in the laboratory.

  16. Automate functional testing

    Directory of Open Access Journals (Sweden)

    Ramesh Kalindri

    2014-06-01

    Full Text Available Currently, software engineers are increasingly turning to the option of automating functional tests, but not always have successful in this endeavor. Reasons range from low planning until over cost in the process. Some principles that can guide teams in automating these tests are described in this article.

  17. Automation in Warehouse Development

    NARCIS (Netherlands)

    Hamberg, R.; Verriet, J.

    2012-01-01

    The warehouses of the future will come in a variety of forms, but with a few common ingredients. Firstly, human operational handling of items in warehouses is increasingly being replaced by automated item handling. Extended warehouse automation counteracts the scarcity of human operators and support

  18. Work and Programmable Automation.

    Science.gov (United States)

    DeVore, Paul W.

    A new industrial era based on electronics and the microprocessor has arrived, an era that is being called intelligent automation. Intelligent automation, in the form of robots, replaces workers, and the new products, using microelectronic devices, require significantly less labor to produce than the goods they replace. The microprocessor thus…

  19. Library Automation Style Guide.

    Science.gov (United States)

    Gaylord Bros., Liverpool, NY.

    This library automation style guide lists specific terms and names often used in the library automation industry. The terms and/or acronyms are listed alphabetically and each is followed by a brief definition. The guide refers to the "Chicago Manual of Style" for general rules, and a notes section is included for the convenience of individual…

  20. Automation in immunohematology.

    Science.gov (United States)

    Bajpai, Meenu; Kaur, Ravneet; Gupta, Ekta

    2012-07-01

    There have been rapid technological advances in blood banking in South Asian region over the past decade with an increasing emphasis on quality and safety of blood products. The conventional test tube technique has given way to newer techniques such as column agglutination technique, solid phase red cell adherence assay, and erythrocyte-magnetized technique. These new technologies are adaptable to automation and major manufacturers in this field have come up with semi and fully automated equipments for immunohematology tests in the blood bank. Automation improves the objectivity and reproducibility of tests. It reduces human errors in patient identification and transcription errors. Documentation and traceability of tests, reagents and processes and archiving of results is another major advantage of automation. Shifting from manual methods to automation is a major undertaking for any transfusion service to provide quality patient care with lesser turnaround time for their ever increasing workload. This article discusses the various issues involved in the process.

  1. Automation in Immunohematology

    Directory of Open Access Journals (Sweden)

    Meenu Bajpai

    2012-01-01

    Full Text Available There have been rapid technological advances in blood banking in South Asian region over the past decade with an increasing emphasis on quality and safety of blood products. The conventional test tube technique has given way to newer techniques such as column agglutination technique, solid phase red cell adherence assay, and erythrocyte-magnetized technique. These new technologies are adaptable to automation and major manufacturers in this field have come up with semi and fully automated equipments for immunohematology tests in the blood bank. Automation improves the objectivity and reproducibility of tests. It reduces human errors in patient identification and transcription errors. Documentation and traceability of tests, reagents and processes and archiving of results is another major advantage of automation. Shifting from manual methods to automation is a major undertaking for any transfusion service to provide quality patient care with lesser turnaround time for their ever increasing workload. This article discusses the various issues involved in the process.

  2. Automation in immunohematology.

    Science.gov (United States)

    Bajpai, Meenu; Kaur, Ravneet; Gupta, Ekta

    2012-07-01

    There have been rapid technological advances in blood banking in South Asian region over the past decade with an increasing emphasis on quality and safety of blood products. The conventional test tube technique has given way to newer techniques such as column agglutination technique, solid phase red cell adherence assay, and erythrocyte-magnetized technique. These new technologies are adaptable to automation and major manufacturers in this field have come up with semi and fully automated equipments for immunohematology tests in the blood bank. Automation improves the objectivity and reproducibility of tests. It reduces human errors in patient identification and transcription errors. Documentation and traceability of tests, reagents and processes and archiving of results is another major advantage of automation. Shifting from manual methods to automation is a major undertaking for any transfusion service to provide quality patient care with lesser turnaround time for their ever increasing workload. This article discusses the various issues involved in the process. PMID:22988378

  3. Automation in Warehouse Development

    CERN Document Server

    Verriet, Jacques

    2012-01-01

    The warehouses of the future will come in a variety of forms, but with a few common ingredients. Firstly, human operational handling of items in warehouses is increasingly being replaced by automated item handling. Extended warehouse automation counteracts the scarcity of human operators and supports the quality of picking processes. Secondly, the development of models to simulate and analyse warehouse designs and their components facilitates the challenging task of developing warehouses that take into account each customer’s individual requirements and logistic processes. Automation in Warehouse Development addresses both types of automation from the innovative perspective of applied science. In particular, it describes the outcomes of the Falcon project, a joint endeavour by a consortium of industrial and academic partners. The results include a model-based approach to automate warehouse control design, analysis models for warehouse design, concepts for robotic item handling and computer vision, and auton...

  4. Advances in inspection automation

    Science.gov (United States)

    Weber, Walter H.; Mair, H. Douglas; Jansen, Dion; Lombardi, Luciano

    2013-01-01

    This new session at QNDE reflects the growing interest in inspection automation. Our paper describes a newly developed platform that makes the complex NDE automation possible without the need for software programmers. Inspection tasks that are tedious, error-prone or impossible for humans to perform can now be automated using a form of drag and drop visual scripting. Our work attempts to rectify the problem that NDE is not keeping pace with the rest of factory automation. Outside of NDE, robots routinely and autonomously machine parts, assemble components, weld structures and report progress to corporate databases. By contrast, components arriving in the NDT department typically require manual part handling, calibrations and analysis. The automation examples in this paper cover the development of robotic thickness gauging and the use of adaptive contour following on the NRU reactor inspection at Chalk River.

  5. Automated model building

    CERN Document Server

    Caferra, Ricardo; Peltier, Nicholas

    2004-01-01

    This is the first book on automated model building, a discipline of automated deduction that is of growing importance Although models and their construction are important per se, automated model building has appeared as a natural enrichment of automated deduction, especially in the attempt to capture the human way of reasoning The book provides an historical overview of the field of automated deduction, and presents the foundations of different existing approaches to model construction, in particular those developed by the authors Finite and infinite model building techniques are presented The main emphasis is on calculi-based methods, and relevant practical results are provided The book is of interest to researchers and graduate students in computer science, computational logic and artificial intelligence It can also be used as a textbook in advanced undergraduate courses

  6. Quick titration of pergolide in cotreatment with domperidone is safe and effective

    NARCIS (Netherlands)

    Jansen, PAF; Herings, RMC; Samson, MM; Schuurmans-Daemen, LMPJ; Hovestadt, A; Verhaar, HJJ; Van Laar, T; de Vreede, P.

    2001-01-01

    The purpose of the study was to analyze efficacy and safety of quick pergolide titration combined with domperidone. In an open-label prospective study, pergolide was titrated in 16 days to a maximum of 3 mg/d doses as adjunctive treatment to L-Dopa in 10 elderly patients with Parkinson's disease. Si

  7. Humic substance charge determination by titration with a flexible cationic polyelectrolyte

    NARCIS (Netherlands)

    Tan, Wen-Feng; Norde, Willem; Koopal, Luuk K.

    2011-01-01

    The anionic charge of humic substances (HS) plays a major role in the interaction of HS with other components. Therefore, the potential of the polyelectrolyte titration technique to obtain the charge density of HS in simple 1-1 electrolyte solutions has been investigated. Titrations are carried out

  8. Humic substance charge determination by titration with a flexible cationic polyelectrolyte

    NARCIS (Netherlands)

    Tan, W.F.; Norde, W.; Koopal, L.K.

    2011-01-01

    The anionic charge of humic substances (HS) plays a major role in the interaction of HS with other components. Therefore, the potential of the polyelectrolyte titration technique to obtain the charge density of HS in simple 1–1 electrolyte solutions has been investigated. Titrations are carried out

  9. The ion-sensitive field effect transistor in rapid acid-base titrations

    NARCIS (Netherlands)

    Bos, M.; Bergveld, P.; Veen-Blaauw, van A.M.W.

    1979-01-01

    Ion-sensitive field effect transistors (ISFETs) are used as the pH sensor in rapid acid—base titrations. Titration speeds at least five times greater than those with glass electrodes are possible for accuracies better than ±1%.

  10. A Laser-Pointer-Based Spectrometer for Endpoint Detection of EDTA Titrations

    Science.gov (United States)

    Dahm, Christopher E.; Hall, James W.; Mattioni, Brian E.

    2004-01-01

    A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations,…

  11. Polymeric membrane neutral phenol-sensitive electrodes for potentiometric G-quadruplex/hemin DNAzyme-based biosensing.

    Science.gov (United States)

    Wang, Xuewei; Ding, Zhaofeng; Ren, Qingwei; Qin, Wei

    2013-02-01

    The first potentiometric transducer for G-quadruplex/hemin DNAzyme-based biosensing has been developed by using potential responses of electrically neutral oligomeric phenols on polymeric membrane electrodes. In the presence of G-quadruplex/hemin DNAzyme and H(2)O(2), monomeric phenols (e.g., phenol, methylphenols, and methoxyphenols) can be condensed into oligomeric phenols. Because both substrates and products are nonionic under optimal pH conditions, these reactions are traditionally not considered in designing potentiometric biosensing schemes. However, in this paper, the electrically neutral oligomeric phenols have been found to induce highly sensitive potential responses on quaternary ammonium salt-doped polymeric membrane electrodes owing to their high lipophilicities. In contrast, the potential responses to monomeric phenolic substrates are rather low. Thus, the G-quadruplex/hemin DNAzyme-catalyzed oxidative coupling of monomeric phenols can induce large potential signals, and the catalytic activities of DNAzymes can be probed. A comparison of potential responses induced by peroxidations of 13 monomeric phenols indicates that p-methoxyphenol is the most efficient substrate for potentiometric detection of G-quadruplex/hemin DNAzymes. Finally, two label-free and separation-free potentiometric DNA assay protocols based on the G-quadruplex/hemin DNAzyme have been developed with sensitivities higher than those of colorimetric and fluorometric methods. Coupled with other features such as reliable instrumentation, low cost, ease of miniaturization, and resistance to color and turbid interferences, the proposed polymeric membrane-based potentiometric sensor promises to be a competitive transducer for peroxidase-mimicking DNAzyme-involved biosensing.

  12. Chef infrastructure automation cookbook

    CERN Document Server

    Marschall, Matthias

    2013-01-01

    Chef Infrastructure Automation Cookbook contains practical recipes on everything you will need to automate your infrastructure using Chef. The book is packed with illustrated code examples to automate your server and cloud infrastructure.The book first shows you the simplest way to achieve a certain task. Then it explains every step in detail, so that you can build your knowledge about how things work. Eventually, the book shows you additional things to consider for each approach. That way, you can learn step-by-step and build profound knowledge on how to go about your configuration management

  13. Single-cultivar extra virgin olive oil classification using a potentiometric electronic tongue.

    Science.gov (United States)

    Dias, Luís G; Fernandes, Andreia; Veloso, Ana C A; Machado, Adélio A S C; Pereira, José A; Peres, António M

    2014-10-01

    Label authentication of monovarietal extra virgin olive oils is of great importance. A novel approach based on a potentiometric electronic tongue is proposed to classify oils obtained from single olive cultivars (Portuguese cvs. Cobrançosa, Madural, Verdeal Transmontana; Spanish cvs. Arbequina, Hojiblanca, Picual). A meta-heuristic simulated annealing algorithm was applied to select the most informative sets of sensors to establish predictive linear discriminant models. Olive oils were correctly classified according to olive cultivar (sensitivities greater than 97%) and each Spanish olive oil was satisfactorily discriminated from the Portuguese ones with the exception of cv. Arbequina (sensitivities from 61% to 98%). Also, the discriminant ability was related to the polar compounds contents of olive oils and so, indirectly, with organoleptic properties like bitterness, astringency or pungency. Therefore the proposed E-tongue can be foreseen as a useful auxiliary tool for trained sensory panels for the classification of monovarietal extra virgin olive oils.

  14. Open ISEmeter: An open hardware high-impedance interface for potentiometric detection.

    Science.gov (United States)

    Salvador, C; Mesa, M S; Durán, E; Alvarez, J L; Carbajo, J; Mozo, J D

    2016-05-01

    In this work, a new open hardware interface based on Arduino to read electromotive force (emf) from potentiometric detectors is presented. The interface has been fully designed with the open code philosophy and all documentation will be accessible on web. The paper describes a comprehensive project including the electronic design, the firmware loaded on Arduino, and the Java-coded graphical user interface to load data in a computer (PC or Mac) for processing. The prototype was tested by measuring the calibration curve of a detector. As detection element, an active poly(vinyl chloride)-based membrane was used, doped with cetyltrimethylammonium dodecylsulphate (CTA(+)-DS(-)). The experimental measures of emf indicate Nernstian behaviour with the CTA(+) content of test solutions, as it was described in the literature, proving the validity of the developed prototype. A comparative analysis of performance was made by using the same chemical detector but changing the measurement instrumentation. PMID:27250474

  15. Potentiometric Electronic Tongue to Resolve Mixtures of Sulfide and Perchlorate Anions

    Directory of Open Access Journals (Sweden)

    Deivy Wilson

    2011-03-01

    Full Text Available This work describes the use of an array of potentiometric sensors and an artificial neural network response model to determine perchlorate and sulfide ions in polluted waters, by what is known as an electronic tongue. Sensors used have been all-solid-state PVC membrane selective electrodes, where their ionophores were different metal-phtalocyanine complexes with specific and anion generic responses. The study case illustrates the potential use of electronic tongues in the quantification of mixtures when interfering effects need to be counterbalanced: relative errors in determination of individual ions can be decreased typically from 25% to less than 5%, if compared to the use of a single proposed ion-selective electrode.

  16. Highly efficient potentiometric glucose biosensor based on functionalized InN quantum dots

    Science.gov (United States)

    Alvi, N. H.; Soto Rodriguez, P. E. D.; Gómez, V. J.; Kumar, Praveen; Amin, G.; Nur, O.; Willander, M.; Nötzel, R.

    2012-10-01

    We present a fast, highly sensitive, and efficient potentiometric glucose biosensor based on functionalized InN quantum-dots (QDs). The InN QDs are grown by molecular beam epitaxy. The InN QDs are bio-chemically functionalized through physical adsorption of glucose oxidase (GOD). GOD enzyme-coated InN QDs based biosensor exhibits excellent linear glucose concentration dependent electrochemical response against an Ag/AgCl reference electrode over a wide logarithmic glucose concentration range (1 × 10-5 M to 1 × 10-2 M) with a high sensitivity of 80 mV/decade. It exhibits a fast response time of less than 2 s with good stability and reusability and shows negligible response to common interferents such as ascorbic acid and uric acid. The fabricated biosensor has full potential to be an attractive candidate for blood sugar concentration detection in clinical diagnoses.

  17. Potentiometric stripping analysis of lead and cadmium leaching from dental prosthetic materials and teeth

    Directory of Open Access Journals (Sweden)

    GORAN M. NIKOLIC

    2004-07-01

    Full Text Available Potentiometric stipping analysis (PSA was applied for the determination of lead and cadmium leaching from dental prosthetic materials and teeth. The soluble lead content in finished dental implants was found to be much lower than that of the individual components used for their preparation. Cadmium was not detected in dental implants and materials under the defined conditions. The soluble lead and cadmium content of teeth was slightly lower than the lead and cadmium content in whole teeth (w/w reported by other researchers, except in the case of a tooth with removed amalgam filling. The results of this work suggest that PSA may be a good method for lead and cadmium leaching studies for investigation of the biocompatibility of dental prosthetic materials.

  18. Lanthanide recognition: A Ho3+ potentiometric membrane sensor as a probe for determination of terazosin

    International Nuclear Information System (INIS)

    In this study, complexation of N'-(1-pyridin-2-ylmethylene)-2-furohydrazide (NFH) with some metal ions was investigated by conductometry and spectroscopy. Then, a Ho3+ potentiometric membrane sensor was prepared based on the highly selective complexation between this ionophore and Ho3+. These new ionophores are more selective than the previously reported ones. In this work, for the first time, the proposed sensor was applied in indirect determination of the terazocine in its pharmaceutical formulation. The interest in constructing lanthanide sensors arises because they have similar ionic radii to calcium, but a higher charge density, which allows them to be used as probes to find the interactions between Ca2+ and biologically important molecules.

  19. Effect of temperature on the protonation of N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid in aqueous solutions: Potentiometric and calorimetric studies

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xingliang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Div.; China Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry; Zhang, Zhicheng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Div.; Endrizzi, Francesco [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Div.; Martin, Leigh R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Luo, Shunzhong [China Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry; Rao, Linfeng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Div.

    2015-06-01

    The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Komplexes) has been demonstrated in several pilot-scale operations to be effective at separating trivalent actinides (An3+) from trivalent lanthanides (Ln3+). However, fundamental studies have revealed undesired aspects of TALSPEAK, such as the significant partitioning of Na+, lactic acid, and water into the organic phase, thermodynamically unpredictable pH dependence, and the slow extraction kinetics. In the modified TALSPEAK process, the combination of the aqueous holdback complexant HEDTA (N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid) with the extractant HEH[EHP] (2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester) in the organic phase has been found to exhibit a nearly flat pH dependence between 2.5 and 4.5 and more rapid phase transfer kinetics for the heavier lanthanides. To help understand the speciation of Ln3+ and An3+ in the modified TALSPEAK, systematic studies are underway on the thermodynamics of major reactions in the HEDTA system under conditions relevant to the process (e.g., higher temperatures). Thermodynamics of the protonation and complexation of HEDTA with Ln3+ were studied at variable temperatures. Equilibrium constants and enthalpies were determined by a combination of techniques including potentiometry and calorimetry. This paper presents the protonation constants of HEDTA at T = (25 to 70) °C. The potentiometric titrations have demonstrated that, stepwise, the first two protonation constants decrease and the third one slightly increases with the increase of temperature. This trend is in good agreement with the enthalpy of protonation directly determined by calorimetry. The results of NMR analysis further confirm that the first two protonation reactions occur on the diamine nitrogen atoms, while the third protonation reaction occurs on the

  20. Synthesis, spectral, thermal, potentiometric and antimicrobial studies of transition metal complexes of tridentate ligand

    Directory of Open Access Journals (Sweden)

    Sarika M. Jadhav

    2014-01-01

    Full Text Available A series of metal complexes of Cu(II, Ni(II, Co(II, Fe(III and Mn(II have been synthesized with newly synthesized biologically active tridentate ligand. The ligand was synthesized by condensation of dehydroacetic acid (3-acetyl-6-methyl-(2H pyran-2,4(3H-dione or DHA, o-phenylene diamine and fluoro benzaldehyde and characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, 1H-NMR, UV–Vis spectroscopy and mass spectra. From the analytical data, the stoichiometry of the complexes was found to be 1:2 (metal:ligand with octahedral geometry. The molar conductance values suggest the non-electrolyte nature of metal complexes. The IR spectral data suggest that the ligand behaves as a dibasic tridentate ligand with ONN donor atoms sequence towards central metal ion. Thermal behaviour (TG/DTA and kinetic parameters calculated by the Coats–Redfern and Horowitz–Metzger method suggest more ordered activated state in complex formation. To investigate the relationship between stability constants of metal complexes and antimicrobial activity, the dissociation constants of Schiff bases and stability constants of their binary metal complexes have been determined potentiometrically in THF–water (60:40% solution at 25 ± 1 °C and at 0.1 M NaClO4 ionic strength. The potentiometric study suggests 1:1 and 1:2 complexation. Antibacterial and antifungal activities in vitro were performed against Staphylococcus aureus, Escherichia coli and Aspergillus niger, Trichoderma, respectively. The stability constants of the metal complexes were calculated by the Irving–Rosotti method. A relation between the stability constant and antimicrobial activity of complexes has been discussed. It is observed that the activity enhances upon complexation and the order of antifungal activity is in accordance with stability order of metal ions.

  1. Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

    Directory of Open Access Journals (Sweden)

    Kasra Saeedfar

    2013-12-01

    Full Text Available A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate (PnBA membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor’s sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor’s response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

  2. Real-Time Telemetry System for Amperometric and Potentiometric Electrochemical Sensors

    Directory of Open Access Journals (Sweden)

    Ching-Hsing Luo

    2011-09-01

    Full Text Available A real-time telemetry system, which consists of readout circuits, an analog-to-digital converter (ADC, a microcontroller unit (MCU, a graphical user interface (GUI, and a radio frequency (RF transceiver, is proposed for amperometric and potentiometric electrochemical sensors. By integrating the proposed system with the electrochemical sensors, analyte detection can be conveniently performed. The data is displayed in real-time on a GUI and optionally uploaded to a database via the Internet, allowing it to be accessed remotely. An MCU was implemented using a field programmable gate array (FPGA to filter noise, transmit data, and provide control over peripheral devices to reduce power consumption, which in sleep mode is 70 mW lower than in operating mode. The readout circuits, which were implemented in the TSMC 0.18-μm CMOS process, include a potentiostat and an instrumentation amplifier (IA. The measurement results show that the proposed potentiostat has a detectable current range of 1 nA to 100 μA, and linearity with an R2 value of 0.99998 in each measured current range. The proposed IA has a common-mode rejection ratio (CMRR greater than 90 dB. The proposed system was integrated with a potentiometric pH sensor and an amperometric nitrite sensor for in vitro experiments. The proposed system has high linearity (an R2 value greater than 0.99 was obtained in each experiment, a small size of 5.6 cm × 8.7 cm, high portability, and high integration.

  3. Bio-assisted potentiometric multisensor system for purity evaluation of recombinant protein A.

    Science.gov (United States)

    Voitechovič, Edita; Korepanov, Anton; Kirsanov, Dmitry; Jahatspanian, Igor; Legin, Andrey

    2016-08-15

    Recombinant proteins became essential components of drug manufacturing. Quality control of such proteins is routine task, which usually requires a lot of time, expensive reagents, specialized equipment and highly educated personnel. In this study we propose a new concept for protein purity evaluation that is based on application of bio-assisted potentiometric multisensor system. The model object for analysis was recombinant protein A from Staphylococcus aureus (SpA), which is commonly used for monoclonal antibody purification. SpA solutions with different amount of host cell related impurities (Escherichia coli, bacterial lysate) were analyzed. Two different bio-transducers were employed: proteinase K from Tritirachium album and baker's yeast Saccharomyces cerevisiae. It was shown that both bio-transducers are able to induce changes in pure and lysate-contaminated SpA samples. Different products of yeast digestion and proteolysis with proteinase of pure SpA and lysate were detected with size exclusion high-performance liquid chromatography (SE-HPLC). The induced changes of chemical composition are detectible with potentiometric multisensor system and can be related to SpA purity through projection on latent structures (PLS) regression technique. The proposed method allows for estimation of the impurity content with 12% accuracy using proteinase K and 16% accuracy using baker's yeast. The suggested approach could be useful for early contamination warning at initial protein purification steps. The analysis requires no expensive materials and equipment, no bio-material immobilization, and its duration time is comparable with other commonly used methods like chromatography or electrophoresis though the main part of this time is related to the sample preparation. PMID:27260439

  4. Characterization of membrane protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Situ, Alan J; Schmidt, Thomas; Mazumder, Parichita; Ulmer, Tobias S

    2014-10-23

    Understanding the structure, folding, and interaction of membrane proteins requires experimental tools to quantify the association of transmembrane (TM) helices. Here, we introduce isothermal titration calorimetry (ITC) to measure integrin αIIbβ3 TM complex affinity, to study the consequences of helix-helix preorientation in lipid bilayers, and to examine protein-induced lipid reorganization. Phospholipid bicelles served as membrane mimics. The association of αIIbβ3 proceeded with a free energy change of -4.61±0.04kcal/mol at bicelle conditions where the sampling of random helix-helix orientations leads to complex formation. At bicelle conditions that approach a true bilayer structure in effect, an entropy saving of >1kcal/mol was obtained from helix-helix preorientation. The magnitudes of enthalpy and entropy changes increased distinctly with bicelle dimensions, indicating long-range changes in bicelle lipid properties upon αIIbβ3 TM association. NMR spectroscopy confirmed ITC affinity measurements and revealed αIIbβ3 association and dissociation rates of 4500±100s(-1) and 2.1±0.1s(-1), respectively. Thus, ITC is able to provide comprehensive insight into the interaction of membrane proteins.

  5. Enzyme kinetics determined by single-injection isothermal titration calorimetry.

    Science.gov (United States)

    Transtrum, Mark K; Hansen, Lee D; Quinn, Colette

    2015-04-01

    The purposes of this paper are (a) to examine the effect of calorimeter time constant (τ) on heat rate data from a single enzyme injection into substrate in an isothermal titration calorimeter (ITC), (b) to provide information that can be used to predict the optimum experimental conditions for determining the rate constant (k2), Michaelis constant (KM), and enthalpy change of the reaction (ΔRH), and (c) to describe methods for evaluating these parameters. We find that KM, k2 and ΔRH can be accurately estimated without correcting for the calorimeter time constant, τ, if (k2E/KM), where E is the total active enzyme concentration, is between 0.1/τ and 1/τ and the reaction goes to at least 99% completion. If experimental conditions are outside this domain and no correction is made for τ, errors in the inferred parameters quickly become unreasonable. A method for fitting single-injection data to the Michaelis-Menten or Briggs-Haldane model to simultaneously evaluate KM, k2, ΔRH, and τ is described and validated with experimental data. All four of these parameters can be accurately inferred provided the reaction time constant (k2E/KM) is larger than 1/τ and the data include enzyme saturated conditions.

  6. Predicting proton titration in cationic micelle and bilayer environments

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Brian H.; Shen, Jana K. [Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201 (United States); Eike, David M.; Murch, Bruce P.; Koenig, Peter H. [Computational Chemistry, Modeling and Simulation GCO, Procter and Gamble, Cincinnati, Ohio 45201 (United States)

    2014-08-28

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pK{sub a}’s in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pK{sub a} of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pK{sub a} of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs.

  7. Predicting proton titration in cationic micelle and bilayer environments

    International Nuclear Information System (INIS)

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pKa’s in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pKa of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pKa of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs

  8. I-94 Automation FAQs

    Data.gov (United States)

    Department of Homeland Security — In order to increase efficiency, reduce operating costs and streamline the admissions process, U.S. Customs and Border Protection has automated Form I-94 at air and...

  9. Hydrometeorological Automated Data System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Office of Hydrologic Development of the National Weather Service operates HADS, the Hydrometeorological Automated Data System. This data set contains the last...

  10. Automated Vehicles Symposium 2015

    CERN Document Server

    Beiker, Sven

    2016-01-01

    This edited book comprises papers about the impacts, benefits and challenges of connected and automated cars. It is the third volume of the LNMOB series dealing with Road Vehicle Automation. The book comprises contributions from researchers, industry practitioners and policy makers, covering perspectives from the U.S., Europe and Japan. It is based on the Automated Vehicles Symposium 2015 which was jointly organized by the Association of Unmanned Vehicle Systems International (AUVSI) and the Transportation Research Board (TRB) in Ann Arbor, Michigan, in July 2015. The topical spectrum includes, but is not limited to, public sector activities, human factors, ethical and business aspects, energy and technological perspectives, vehicle systems and transportation infrastructure. This book is an indispensable source of information for academic researchers, industrial engineers and policy makers interested in the topic of road vehicle automation.

  11. Automated Vehicles Symposium 2014

    CERN Document Server

    Beiker, Sven; Road Vehicle Automation 2

    2015-01-01

    This paper collection is the second volume of the LNMOB series on Road Vehicle Automation. The book contains a comprehensive review of current technical, socio-economic, and legal perspectives written by experts coming from public authorities, companies and universities in the U.S., Europe and Japan. It originates from the Automated Vehicle Symposium 2014, which was jointly organized by the Association for Unmanned Vehicle Systems International (AUVSI) and the Transportation Research Board (TRB) in Burlingame, CA, in July 2014. The contributions discuss the challenges arising from the integration of highly automated and self-driving vehicles into the transportation system, with a focus on human factors and different deployment scenarios. This book is an indispensable source of information for academic researchers, industrial engineers, and policy makers interested in the topic of road vehicle automation.

  12. Disassembly automation automated systems with cognitive abilities

    CERN Document Server

    Vongbunyong, Supachai

    2015-01-01

    This book presents a number of aspects to be considered in the development of disassembly automation, including the mechanical system, vision system and intelligent planner. The implementation of cognitive robotics increases the flexibility and degree of autonomy of the disassembly system. Disassembly, as a step in the treatment of end-of-life products, can allow the recovery of embodied value left within disposed products, as well as the appropriate separation of potentially-hazardous components. In the end-of-life treatment industry, disassembly has largely been limited to manual labor, which is expensive in developed countries. Automation is one possible solution for economic feasibility. The target audience primarily comprises researchers and experts in the field, but the book may also be beneficial for graduate students.

  13. 沉淀滴定的林邦滴定曲线方程%Ringbom titration curve equation of precipitation titration

    Institute of Scientific and Technical Information of China (English)

    乔成立; 李文新

    2014-01-01

    Ionic strength effect,acid effect,precipitation effect and ligand effect were identified as side reactions of the main reaction,Ringbom titration curve equation of precipitation titration was derived by means of material balance, conditional stability constant and titration scores,etc,which can lay a solid foundation for researching precipitation titration analysis theory on the basis of Ringbom titration curve equation.%把离子强度效应、酸效应、沉淀效应、配位效应等看作是主反应发生的副反应,通过物料平衡、条件稳定常数和滴定分数等推导出沉淀滴定的林邦滴定曲线方程,为用林邦滴定曲线方程研究沉淀滴定分析理论打下坚实的基础。

  14. Instant Sikuli test automation

    CERN Document Server

    Lau, Ben

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A concise guide written in an easy-to follow style using the Starter guide approach.This book is aimed at automation and testing professionals who want to use Sikuli to automate GUI. Some Python programming experience is assumed.

  15. Automated security management

    CERN Document Server

    Al-Shaer, Ehab; Xie, Geoffrey

    2013-01-01

    In this contributed volume, leading international researchers explore configuration modeling and checking, vulnerability and risk assessment, configuration analysis, and diagnostics and discovery. The authors equip readers to understand automated security management systems and techniques that increase overall network assurability and usability. These constantly changing networks defend against cyber attacks by integrating hundreds of security devices such as firewalls, IPSec gateways, IDS/IPS, authentication servers, authorization/RBAC servers, and crypto systems. Automated Security Managemen

  16. Automated Lattice Perturbation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Monahan, Christopher

    2014-11-01

    I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.

  17. Spring point coverage for the potentiometric coverages for the Inyan Kara, Minnekahta, Minnelusa, Madison, and Deadwood Aquifers in the Black Hills Area, South Dakota

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset describes springs in the Black Hills area that were used to create potentiometric surface maps for the Inyan Kara, Minnekahta, Minnelusa, Madison, and...

  18. Regional potentiometric-surface contours by Bedinger and Harrill (2004), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The contours in this digital data set represent the regional potentiometric surface developed by Bedinger and Harrill (2004) to assess potential interbasin flow in...

  19. Estimated potentiometric surface by D'Agnese and others (1998), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — D'Agnese and others (1998) developed a potentiometric surface to conceptualize the regional ground-water flow system and to construct numerical flow models of the...

  20. Observation wells used in the creation of the generalized potentiometric surface of the Arikaree aquifer, Pine Ridge Indian Reservation and Bennett County, South Dakota

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set describes observation wells completed in the Arikaree aquifer that were used to create a map of the generalized potentiometric surface of the Arikaree...

  1. Titration of intravenous synthetic oxytocin post vaginal birth following induction or augmentation.

    Science.gov (United States)

    Lewis, Lucy; Hauck, Yvonne L; Pemberton, Alissa; Crichton, Caroline; Conwell, Marion

    2016-10-01

    Evidence exists for titration of intravenous oxytocin during induction and augmentation, whereas no evidence was identified for titration of intravenous oxytocin following vaginal birth, where management excluded oxytocin for postpartum haemorrhage (PPH). This retrospective cohort study explored this issue through patient case notes and computerised perinatal data. Analysis included 335 women comparing induction (n = 226, 67%) to augmentation (n = 109, 33%). The two groups differed in terms of: parity; oxytocin dosage; length of time on intravenous oxytocin; and the length of first and second stage labour. They had similar rates of PPH and titration of intravenous oxytocin following birth was rarely recorded. PMID:27634662

  2. On the Physical Meaning of the Isothermal Titration Calorimetry Measurements in Calorimeters with Full Cells

    Science.gov (United States)

    Grolier, Jean-Pierre E.; del Río, Jose Manuel

    2009-01-01

    We have performed a detailed study of the thermodynamics of the titration process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation Δ H = Winj + Q (where Winj is the work necessary to carry out the titration) than in terms of ΔH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution. PMID:20054472

  3. Titration Calorimetry Applied to the Thermokinetics Study of Consecutive First-order Reactions

    Institute of Scientific and Technical Information of China (English)

    SHI Jing-Yan; LI Jie; WANG Zhi-Yong; LIU Yu-Wen; WANG Cun-Xin

    2008-01-01

    The thermokinetic mathematical models for consecutive first-order reactions in titration period and the stopped-titration reaction period were proposed for titration calorimetry, based on which, thermodynamic parameters (reaction enthalpies, △rHm1 and △rHm2) and kinetic parameters (rate constants, k1 and k2) of the consecutive first-order reactions could be obtained by directly simulating the calorimetric curve from a single experiment with the method of nonlinear least squares regression (NLLS).The reliability of the model has been verified by investigating the reaction of the saponification of diethyl succinate in an aqueous ethanol solvent.

  4. 混合离子的沉淀准确滴定%Precipitation Titration for Multiple Ions

    Institute of Scientific and Technical Information of China (English)

    乔成立

    2016-01-01

    The absolute value of titration break in precipitation titration is deduced with the Ringbom titration curve equation, and the conditions for accurate precipitation titration are thus deduced with the absolute value of the titration break.%用沉淀滴定的林邦滴定曲线方程推导滴定突跃的绝对值,用滴定突跃的绝对值推导混合离子准确滴定的条件。

  5. Application of Ion-Association Titration for the Assay of Cyproheptadine Hydrochloride in Pharmaceuticals

    OpenAIRE

    kanakapura Basavaiah; Raghu, Madihalli S.

    2012-01-01

    Two simple and rapid titrimetric methods are described for the determination of cyproheptadine hydrochloride (CPH) in pharmaceuticals. The proposed methods are based on the solvent extraction-titration of CPH with two ion association reagents, sodium lauryl sulphate (SLS), (method A), and tetraphenylborate (TPB), (method B). In method A, SLS was used as titrant and the titration was carried out in the presence of dilute sulphuric acid and chloroform using dimethyl yellow as indicator, whereas...

  6. Use of Terminalia catappa fruit extract as an indicator in acid-base titrations

    Directory of Open Access Journals (Sweden)

    Untwal L

    2006-01-01

    Full Text Available Terminalia catappa L. (tropical almond, family Combretaceae, is a large deciduous tree, originally from India. It thrives as an ornamental tree in many tropical cities of the world. The present work highlights the use of the acidified methanol extract of the outer cover of Terminalia catappa fruits as an acid-base indicator in different types of acid-base titrations. It is found to be a very useful, economical, simple, and accurate indicator for said titrations.

  7. A practical protocol for titrating "optimal" PEEP in acute lung injury: recruitment maneuver and PEEP decrement.

    OpenAIRE

    Suh, Gee Young; Kwon, O Jung; Yoon, Jong Wook; Park, Sang Joon; Ham, Hyoung Suk; Kang, Soo Jung; Koh, Won-Jung; Chung, Man Pyo; Kim, Ho Joong

    2003-01-01

    This study was conducted to evaluate the effectiveness and safety of a practical protocol for titrating positive end-expiratory pressure (PEEP) involving recruitment maneuver (RM) and decremental PEEP. Seventeen consecutive patients with acute lung injury who underwent PEEP titration were included in the analysis. After baseline ventilation, RM (continuous positive airway pressure, 35 cm H2O for 45 sec) was performed and PEEP was increased to 20 cmH2O or the highest PEEP guaranteeing the mini...

  8. Development of potentiometric sensors for determining the concentration of ethan-1,2-dicarboxylic and 2-hydroxybenzoic acids

    OpenAIRE

    Matorina, Kateryna; Podpletnia, Olena

    2016-01-01

    The study suggests developed potentiometric sensors for determining the concentration of succinic and salicylic acids through using ion associates of succinic acid with safranin T and salicylic acid with safranin T as an electrode­active material of a plasticized film membrane. It is an important task of analytic practice to determine the contents of succinic and salicylic acids in samples with a complex matrix (the environment, foodstuffs, and pharmaceuticals). The research has revealed anal...

  9. Titration of strong and weak acids by sequential injection analysis technique.

    Science.gov (United States)

    Maskula, S; Nyman, J; Ivaska, A

    2000-05-31

    A sequential injection analysis (SIA) titration method has been developed for acid-base titrations. Strong and weak acids in different concentration ranges have been titrated with a strong base. The method is based on sequential aspiration of an acidic sample zone and only one zone of the base into a carrier stream of distilled water. On their way to the detector, the sample and the reagent zones are partially mixed due to the dispersion and thereby the base is partially neutralised by the acid. The base zone contains the indicator. An LED-spectrophotometer is used as detector. It senses the colour of the unneutralised base and the signal is recorded as a typical SIA peak. The peak area of the unreacted base was found to be proportional to the logarithm of the acid concentration. Calibration curves with good linearity were obtained for a strong acid in the concentration ranges of 10(-4)-10(-2) and 0.1-3 M. Automatic sample dilution was implemented when sulphuric acid at concentration of 6-13 M was titrated. For a weak acid, i.e. acetic acid, a linear calibration curve was obtained in the range of 3x10(-4)-8x10(-2) M. By changing the volumes of the injected sample and the reagent, different acids as well as different concentration ranges of the acids can be titrated without any other adjustments in the SIA manifold or the titration protocol. PMID:18967966

  10. Potentiometric and solubility studies of association quotients of aluminum malonate complexation in NaCl media to 75 C

    Energy Technology Data Exchange (ETDEWEB)

    Ridley, M.K.; Kettler, R.M. [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Geology; Palmer, D.A.; Wesolowski, D.J. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1998-07-01

    A potentiometric method was used to determine the formation quotients for aluminum-malonate (Al(Ma){sub y}{sup 3{minus}2y}, Ma = CH{sub 2}(CO{sub 2}){sub 2}{sup 2{minus}}) complexes from 5 to 75 C at four ionic strengths from 0.1 to 1.0 molal in aqueous NaCl media. Two mononuclear aluminum-malonate species, Al(Ma){sup +} and Al(Ma){sub 2}{sup {minus}}, were identified, and the formation quotients for these species were modeled by empirical equations to describe their temperature and ionic strength dependencies. Differentiation of the two empirical equations with respect to temperature provided thermodynamic quantities for the Al-malonate complexes. The thermodynamic quantities obtained for Al(Ma){sup +} and for Al(Ma){sub 2}{sup {minus}} indicate that Al(Ma){sup +}, a chelate complex, is much more stable than the equivalent monodentate Al-diacetate complex (Al(Ac){sub 2}{sup +}). A solubility study, which was undertaken to verify the 50 C potentiometric data, was performed by reacting powdered gibbsite (Al(OH){sub 3}) with malonic acid solutions at 0.1 molal ionic strength in aqueous NaCl media. The results of the solubility study are in excellent agreement with the potentiometric data.

  11. Materials Testing and Automation

    Science.gov (United States)

    Cooper, Wayne D.; Zweigoron, Ronald B.

    1980-07-01

    The advent of automation in materials testing has been in large part responsible for recent radical changes in the materials testing field: Tests virtually impossible to perform without a computer have become more straightforward to conduct. In addition, standardized tests may be performed with enhanced efficiency and repeatability. A typical automated system is described in terms of its primary subsystems — an analog station, a digital computer, and a processor interface. The processor interface links the analog functions with the digital computer; it includes data acquisition, command function generation, and test control functions. Features of automated testing are described with emphasis on calculated variable control, control of a variable that is computed by the processor and cannot be read directly from a transducer. Three calculated variable tests are described: a yield surface probe test, a thermomechanical fatigue test, and a constant-stress-intensity range crack-growth test. Future developments are discussed.

  12. Integrated, paper-based potentiometric electronic tongue for the analysis of beer and wine.

    Science.gov (United States)

    Nery, Emilia Witkowska; Kubota, Lauro T

    2016-04-28

    The following manuscript details the stages of construction of a novel paper-based electronic tongue with an integrated Ag/AgCl reference, which can operate using a minimal amount of sample (40 μL). First, we optimized the fabrication procedure of silver electrodes, testing a set of different methodologies (electroless plating, use of silver nanoparticles and commercial silver paints). Later a novel, integrated electronic tongue system was assembled with the use of readily available materials such as paper, wax, lamination sheets, bleach etc. New system was thoroughly characterized and the ion-selective potentiometric sensors presented performance close to theoretical. An electronic tongue, composed of electrodes sensitive to sodium, calcium, ammonia and a cross-sensitive, anion-selective electrode was used to analyze 34 beer samples (12 types, 19 brands). This system was able to discriminate beers from different brands, and types, indicate presence of stabilizers and antioxidants, dyes or even unmalted cereals and carbohydrates added to the fermentation wort. Samples could be classified by type of fermentation (low, high) and system was able to predict pH and in part also alcohol content of tested beers. In the next step sample volume was minimalized by the use of paper sample pads and measurement in flow conditions. In order to test the impact of this advancement a four electrode system, with cross-sensitive (anion-selective, cation-selective, Ca(2+)/Mg(2+), K(+)/Na(+)) electrodes was applied for the analysis of 11 types of wine (4 types of grapes, red/white, 3 countries). Proposed matrix was able to group wines produced from different varieties of grapes (Chardonnay, Americanas, Malbec, Merlot) using only 40 μL of sample. Apart from that, storage stability studies were performed using a multimeter, therefore showing that not only fabrication but also detection can be accomplished by means of off-the-shelf components. This manuscript not only describes new

  13. Automating the CMS DAQ

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.; et al.

    2014-01-01

    We present the automation mechanisms that have been added to the Data Acquisition and Run Control systems of the Compact Muon Solenoid (CMS) experiment during Run 1 of the LHC, ranging from the automation of routine tasks to automatic error recovery and context-sensitive guidance to the operator. These mechanisms helped CMS to maintain a data taking efficiency above 90% and to even improve it to 95% towards the end of Run 1, despite an increase in the occurrence of single-event upsets in sub-detector electronics at high LHC luminosity.

  14. Automated phantom assay system

    International Nuclear Information System (INIS)

    This paper describes an automated phantom assay system developed for assaying phantoms spiked with minute quantities of radionuclides. The system includes a computer-controlled linear-translation table that positions the phantom at exact distances from a spectrometer. A multichannel analyzer (MCA) interfaces with a computer to collect gamma spectral data. Signals transmitted between the controller and MCA synchronize data collection and phantom positioning. Measured data are then stored on disk for subsequent analysis. The automated system allows continuous unattended operation and ensures reproducible results

  15. Automated gas chromatography

    Science.gov (United States)

    Mowry, Curtis D.; Blair, Dianna S.; Rodacy, Philip J.; Reber, Stephen D.

    1999-01-01

    An apparatus and process for the continuous, near real-time monitoring of low-level concentrations of organic compounds in a liquid, and, more particularly, a water stream. A small liquid volume of flow from a liquid process stream containing organic compounds is diverted by an automated process to a heated vaporization capillary where the liquid volume is vaporized to a gas that flows to an automated gas chromatograph separation column to chromatographically separate the organic compounds. Organic compounds are detected and the information transmitted to a control system for use in process control. Concentrations of organic compounds less than one part per million are detected in less than one minute.

  16. Automated solvent concentrator

    Science.gov (United States)

    Griffith, J. S.; Stuart, J. L.

    1976-01-01

    Designed for automated drug identification system (AUDRI), device increases concentration by 100. Sample is first filtered, removing particulate contaminants and reducing water content of sample. Sample is extracted from filtered residue by specific solvent. Concentrator provides input material to analysis subsystem.

  17. Protokoller til Home Automation

    DEFF Research Database (Denmark)

    Kjær, Kristian Ellebæk

    2008-01-01

    computer, der kan skifte mellem foruddefinerede indstillinger. Nogle gange kan computeren fjernstyres over internettet, så man kan se hjemmets status fra en computer eller måske endda fra en mobiltelefon. Mens nævnte anvendelser er klassiske indenfor home automation, er yderligere funktionalitet dukket op...

  18. ELECTROPNEUMATIC AUTOMATION EDUCATIONAL LABORATORY

    OpenAIRE

    Dolgorukov, S. O.; National Aviation University; Roman, B. V.; National Aviation University

    2013-01-01

    The article reflects current situation in education regarding mechatronics learning difficulties. Com-plex of laboratory test benches on electropneumatic automation are considered as a tool in advancing through technical science. Course of laboratory works developed to meet the requirement of efficient and reliable way of practical skills acquisition is regarded the simplest way for students to learn the ba-sics of mechatronics.

  19. Building Automation Systems.

    Science.gov (United States)

    Honeywell, Inc., Minneapolis, Minn.

    A number of different automation systems for use in monitoring and controlling building equipment are described in this brochure. The system functions include--(1) collection of information, (2) processing and display of data at a central panel, and (3) taking corrective action by sounding alarms, making adjustments, or automatically starting and…

  20. Test Construction: Automated

    NARCIS (Netherlands)

    Veldkamp, Bernard P.

    2014-01-01

    Optimal test construction deals with automated assembly of tests for educational and psychological measurement. Items are selected from an item bank to meet a predefined set of test specifications. Several models for optimal test construction are presented, and two algorithms for optimal test assemb

  1. Test Construction: Automated

    NARCIS (Netherlands)

    Veldkamp, Bernard P.

    2016-01-01

    Optimal test construction deals with automated assembly of tests for educational and psychological measurement. Items are selected from an item bank to meet a predefined set of test specifications. Several models for optimal test construction are presented, and two algorithms for optimal test assemb

  2. Automated Web Applications Testing

    Directory of Open Access Journals (Sweden)

    Alexandru Dan CĂPRIŢĂ

    2009-01-01

    Full Text Available Unit tests are a vital part of several software development practicesand processes such as Test-First Programming, Extreme Programming andTest-Driven Development. This article shortly presents the software quality andtesting concepts as well as an introduction to an automated unit testingframework for PHP web based applications.

  3. Automated Student Model Improvement

    Science.gov (United States)

    Koedinger, Kenneth R.; McLaughlin, Elizabeth A.; Stamper, John C.

    2012-01-01

    Student modeling plays a critical role in developing and improving instruction and instructional technologies. We present a technique for automated improvement of student models that leverages the DataShop repository, crowd sourcing, and a version of the Learning Factors Analysis algorithm. We demonstrate this method on eleven educational…

  4. Myths in test automation

    Directory of Open Access Journals (Sweden)

    Jazmine Francis

    2015-01-01

    Full Text Available Myths in automation of software testing is an issue of discussion that echoes about the areas of service in validation of software industry. Probably, the first though that appears in knowledgeable reader would be Why this old topic again? What's New to discuss the matter? But, for the first time everyone agrees that undoubtedly automation testing today is not today what it used to be ten or fifteen years ago, because it has evolved in scope and magnitude. What began as a simple linear scripts for web applications today has a complex architecture and a hybrid framework to facilitate the implementation of testing applications developed with various platforms and technologies. Undoubtedly automation has advanced, but so did the myths associated with it. The change in perspective and knowledge of people on automation has altered the terrain. This article reflects the points of views and experience of the author in what has to do with the transformation of the original myths in new versions, and how they are derived; also provides his thoughts on the new generation of myths.

  5. Technical Note: Maximising accuracy and minimising cost of a potentiometrically regulated ocean acidification simulation system

    Science.gov (United States)

    MacLeod, C. D.; Doyle, H. L.; Currie, K. I.

    2014-05-01

    This article describes a potentiometric ocean acidification simulation system which automatically regulates pH through the injection of 100% CO2 gas into temperature-controlled seawater. The system is ideally suited to long-term experimental studies of the effect of acidification on biological processes involving small-bodied (10-20 mm) calcifying or non-calcifying organisms. Using hobbyist grade equipment, the system was constructed for approximately USD 1200 per treatment unit (tank, pH regulation apparatus, chiller, pump/filter unit). An overall accuracy of ±0.05 pHT units (SD) was achieved over 90 days in two acidified treatments (7.60 and 7.40) at 12 °C using glass electrodes calibrated with salt water buffers, thereby preventing liquid junction error. The accuracy of the system was validated through the independent calculation of pHT (12 °C) using dissolved inorganic carbon (DIC) and total alkalinity (AT) data taken from discrete acidified seawater samples. The system was used to compare the shell growth of the marine gastropod Zeacumantus subcarinatus infected with the trematode parasite Maritrema novaezealandensis with that of uninfected snails, at pH levels of 7.4, 7.6, and 8.1.

  6. Development of potentiometric equipment for the identification of altered dry-cured hams: A preliminary study.

    Science.gov (United States)

    Girón, Joel; Gil-Sánchez, Luís; García-Breijo, Eduardo; Pagán, M Jesús; Barat, José M; Grau, Raúl

    2015-08-01

    Microbiological contamination in dry-cured ham can occur in the early stages of the process, a large number of microorganisms involved in spoilage can produce alterations in the product. These include non-common odours, which are detected at the end of the process by a procedure called "cala", consisting of a sharp instrument punctured in every ham; this is smelled by an expert taster, who classifies hams as good and altered hams. An electronic device would be suitable for this process given the large amount of hams. The present research aims to develop objective equipment based on the potentiometry technique that identifies altered hams. A probe was developed, containing silver, nickel and copper electrodes, and was employed to classify altered and unaltered hams prior to classification by a tester. The results shown lower Ag and higher Cu potential values for altered hams. The differences in potentiometric response reveal a classification model, although further studies are required to obtain a reliable classification model.

  7. Manganese(III) porphyrin-based potentiometric sensors for diclofenac assay in pharmaceutical preparations.

    Science.gov (United States)

    Vlascici, Dana; Pruneanu, Stela; Olenic, Liliana; Pogacean, Florina; Ostafe, Vasile; Chiriac, Vlad; Pica, Elena Maria; Bolundut, Liviu Calin; Nica, Luminita; Fagadar-Cosma, Eugenia

    2010-01-01

    Two manganese(III) porphyrins: manganese(III) tetraphenylporphyrin chloride and manganese(III)-tetrakis(3-hydroxyphenyl)porphyrin chloride were tested as ionophores for the construction of new diclofenac-selective electrodes. The electroactive material was incorporated either in PVC or a sol-gel matrix. The effect of different plasticizers and additives (anionic and cationic) on the potentiometric response was studied. The best results were obtained for the PVC membrane plasticized with dioctylphtalate and having sodium tetraphenylborate as a lipophilic anionic additive incorporated. The sensor response was linear in the concentration range 3 × 10(-6) - 1 × 10(-2) M with a slope of -59.7 mV/dec diclofenac, a detection limit of 1.5 × 10(-6) M and very good selectivity coefficients. It was used for the determination of diclofenac in pharmaceutical preparations, by direct potentiometry. The results were compared with those obtained by the HPLC reference method and a good agreement was found between the two methods.

  8. A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng

    2010-11-01

    Full Text Available A new alcohol oxidase (AOX enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide [poly(nBA-NAS] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE. Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3. The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation and 1.11% RSD, respectively (n = 3. The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.

  9. Indicator electrodes from d-elements for application in different types of potentiometric analytical methods

    Directory of Open Access Journals (Sweden)

    Z. Kunasheva

    2012-05-01

    Full Text Available The article covers the use of metal electrodes from titanium, tungsten, molybdenum as indicator electrodes at potentiometric method of analysis. The condition of measuring operation in dependence on pH, ionic strength of solutions is described in the article. Electrode potential of testing electrodes are measured in the interval of concentration of salts from 0,1∙10-1 mole/l till 0,1∙10-6 mole/l. The results of testing of electrical-analytical description of metal electrodes made of d-elements, in particular, titanium, tungsten, molybdenum in solutions of cations of some metals and anions were mentioned. As ions of metal cations Cu2+, Cd2+, Zn2+, Pb2+ and anions Cl-, I-, F- were chosen.It is identified that titanic electrode has different response to ions of copper (II, zinc and cadmium. However, dependence of electrode potential on concentration of ions of metal is rectilinear, that is vequired of indicator electrodes in the direct potential metrics.  

  10. Generalized Potentiometric Surface of the Arikaree Aquifer, Pine Ridge Indian Reservation and Bennett County, South Dakota

    Science.gov (United States)

    Carter, Janet M.; Heakin, Allen J.

    2007-01-01

    INTRODUCTION The Pine Ridge Indian Reservation and Bennett County are located in southwest South Dakota. The Pine Ridge Indian Reservation includes all of Shannon County and the part of Jackson County south of the White River. Extensive Indian trust lands are in Bennett County. For purposes of this map, the Pine Ridge Indian Reservation and all of Bennett County are included in the study area (sheet 1). Ground water from wells and springs is the predominant source of public and domestic supply within the study area. The Arikaree aquifer is the largest source of ground water throughout this area. The Oglala Sioux Tribe is developing a ground-water management plan designed to ?preserve, protect and maintain the quality of ground water for living and future members and non-members of the Oglala Sioux Indian Tribe within the internal and external boundaries of the Pine Ridge Reservation? (Michael Catches Enemy, Oglala Sioux Tribe Natural Resources Regulatory Agency, oral commun., 2007). Hydrologic information about the Arikaree aquifer is important to managing this resource. In 1998, the U.S. Geological Survey (USGS) began working in cooperation with the Oglala Sioux Tribe to develop a potentiometric map of the Arikaree aquifer in Jackson and Shannon Counties, with a primary component of that effort being a well inventory in those counties. In 2003, the study area was expanded to include Bennett County.

  11. New Potentiometric Wireless Chloride Sensors Provide High Resolution Information on Chemical Transport Processes in Streams

    Science.gov (United States)

    Smettem, Keith; Harris, Nick; Cranny, Andy; Klaus, Julian; Pfister, Laurent

    2016-04-01

    Quantifying the travel times, pathways and dispersion of solutes moving through stream environments is critical for understanding the biogeochemical cycling processes that control ecosystem functioning. Validation of stream solute transport and exchange process models requires data obtained from in-stream measurement of chemical concentration changes through time. This can be expensive and time consuming, leading to a need for cheap distributed sensor arrays that respond instantly and record chemical transport at points of interest on timescales of seconds. To meet this need we apply new, low-cost (in the order of a euro per sensor) potentiometric chloride sensors used in a distributed array to obtain data with high spatial and temporal resolution. The application here is to monitoring in-stream hydrodynamic transport and dispersive mixing of an injected chemical, in this case NaCl. We present data obtained from the distributed sensor array under baseflow conditions for three stream reaches in Luxembourg. Sensor results are comparable to data obtained from more expensive electrical conductivity meters and allow spatial resolution of hydrodynamic mixing processes and identification of chemical 'dead zones' in the study reaches.

  12. Design and characterization of novel all-solid-state potentiometric sensor array dedicated to physiological measurements.

    Science.gov (United States)

    Toczyłowska-Mamińska, Renata; Kloch, Monika; Zawistowska-Deniziak, Anna; Bala, Agnieszka

    2016-10-01

    A novel construction of all-solid-state potentiometric sensor array designed for physiological measurements has been presented. The planar construction and elimination of liquid phase creates broad opportunities for the modifications in the sensing part of the sensor. The designed construction is based on all-solid-state ion-selective electrodes integrated with the ionic-liquid based reference electrode. Work parameters of the sensor arrays were characterized. It has been shown that presented sensor design indicates high sensitivity (55.2±1mV/dec, 56.3±2mV/dec, 58.4±1mV/dec and 53.5±1mV/pH for sodium-, potassium-, chloride- and pH-selective electrodes, respectively in 10(-5)-10(-1.5)M range of primary ions), low response time (t95 did not exceed 10s), high potential stability (potential drift in 28-h measurement was ca. ±2mV) and potential repeatability ca. ±1mV. The system was successfully applied to the simultaneous determination of K(+), Cl(-), Na(+) and pH in the model physiological solution and for the ion flux studies in human colon epithelium Caco-2 cell line as well.

  13. Technical Note: Maximising accuracy and minimising cost of a potentiometrically regulated ocean acidification simulation system

    Directory of Open Access Journals (Sweden)

    C. D. MacLeod

    2014-05-01

    Full Text Available This article describes a potentiometric ocean acidification simulation system which automatically regulates pH through the injection of 100% CO2 gas into temperature-controlled seawater. The system is ideally suited to long-term experimental studies of the effect of acidification on biological processes involving small-bodied (10–20 mm calcifying or non-calcifying organisms. Using hobbyist grade equipment, the system was constructed for approximately USD 1200 per treatment unit (tank, pH regulation apparatus, chiller, pump/filter unit. An overall accuracy of ±0.05 pHT units (SD was achieved over 90 days in two acidified treatments (7.60 and 7.40 at 12 °C using glass electrodes calibrated with salt water buffers, thereby preventing liquid junction error. The accuracy of the system was validated through the independent calculation of pHT (12 °C using dissolved inorganic carbon (DIC and total alkalinity (AT data taken from discrete acidified seawater samples. The system was used to compare the shell growth of the marine gastropod Zeacumantus subcarinatus infected with the trematode parasite Maritrema novaezealandensis with that of uninfected snails, at pH levels of 7.4, 7.6, and 8.1.

  14. Potentiometric studies and theoretical calculations of Some azo rhodanines and their metal complexes

    Directory of Open Access Journals (Sweden)

    K. A. Abu-Melha

    2015-12-01

    Full Text Available A series of 3-phenylazo-2-thioxo-4-thiazolidinone derivatives (H2L1 and H2L2 have been prepared and characterized by elemental analysis. The optimized bond lengths, bond angles and the calculated quantum chemical parameters for the ligands (H2L1 and H2L2 were investigated. Dissociation constants of (H2L1 and H2L2 and their metal-ligand stability constants of their complexes with (Cd2+, Fe2+, Fe3+, UO22+ and Zr4+ metal ions have been determined potentiometrically in 0.1M KCl and 40 % (by volume DMF-water mixture. The stability constants of the formed binary complexes were found to be Fe2+< Cd2+< Fe3+< UO22+< Zr4+. The effect of the substituents on the dissociation and stability constants was examined on the basis of the electron repelling property. The thermodynamic parameters (DG, DH and DS were reported for the ligands and complexes formation reactions. The enthalpy changes for the dissociation processes and complex systems are positive. The dissociation processes are nonspontaneous and entropically unfavorable. The metal complexes have been found to be spontaneous and entropically favorable.

  15. Manganese(III Porphyrin-based Potentiometric Sensors for Diclofenac Assay in Pharmaceutical Preparations

    Directory of Open Access Journals (Sweden)

    Eugenia Fagadar-Cosma

    2010-09-01

    Full Text Available Two manganese(III porphyrins: manganese(III tetraphenylporphyrin chloride and manganese(III-tetrakis(3-hydroxyphenylporphyrin chloride were tested as ionophores for the construction of new diclofenac−selective electrodes. The electroactive material was incorporated either in PVC or a sol−gel matrix. The effect of different plasticizers and additives (anionic and cationic on the potentiometric response was studied. The best results were obtained for the PVC membrane plasticized with dioctylphtalate and having sodium tetraphenylborate as a lipophilic anionic additive incorporated. The sensor response was linear in the concentration range 3 × 10−6 – 1 × 10−2 M with a slope of −59.7 mV/dec diclofenac, a detection limit of 1.5 × 10−6 M and very good selectivity coefficients. It was used for the determination of diclofenac in pharmaceutical preparations, by direct potentiometry. The results were compared with those obtained by the HPLC reference method and a good agreement was found between the two methods.

  16. A polyaniline based ultrasensitive potentiometric immunosensor for cardiac troponin complex detection.

    Science.gov (United States)

    Zhang, Qi; Prabhu, Alok; San, Avdar; Al-Sharab, Jafar F; Levon, Kalle

    2015-10-15

    An ultrasensitive immunosensor based on potentiometric ELISA for the detection of a cardiac biomarker, troponin I-T-C (Tn I-T-C) complex, was developed. The sensor fabrication involves typical sandwich ELISA procedures, while the final signal readout was achieved using open circuit potentiometry (OCP). Glassy carbon (GC) working electrodes were first coated with emulsion-polymerized polyaniline/dinonylnaphthalenesulfonic acid (PANI/DNNSA) and the coated surface was utilized as a transducer layer on which sandwich ELISA incubation steps were performed. An enzymatic reaction between o-phenylenediamine (OPD) and hydrogen peroxide (H2O2) was catalyzed by horseradish peroxidase (HRP) labeled on the secondary antibodies. The polymer transducer charged state was mediated through electron (e(-)) and charge transfers between the transducer and charged species generated by the same enzymatic reaction. Such a change in the polymer transducer led to potential variations against an Ag/AgCl reference electrode as a function of Tn I-T-C complex concentration during incubations. The sequence of OPD and H2O2 additions, electrochemical properties of the PANI/DNNSA layer and non-specific binding prevention were all crucial factors for the assay performance. Under optimized conditions, the assay has a low limit of detection (LOD) ( 6 orders of magnitude), high repeatability (coefficient of variance < 8% for all concentrations higher than 5 pg/mL) and a short detection time (< 10 min).

  17. Determination of the activity coefficient of neodymium in liquid aluminium by potentiometric methods

    Energy Technology Data Exchange (ETDEWEB)

    De Cordoba, G. [HLW/DFN/DE, CIEMAT, Avda. Complutense 22, Madrid 28040 (Spain)], E-mail: g.cordoba@ciemat.es; Laplace, A.; Conocar, O.; Lacquement, J. [DEN/DRCP/SCPS/LPP, CEA, Site de Marcoule. Bat. 399, BP 17171, 30207 Bagnols sur Ceze (France); Caravaca, C. [HLW/DFN/DE, CIEMAT, Avda. Complutense 22, Madrid 28040 (Spain)

    2008-12-30

    The activity coefficient of neodymium in liquid aluminium phase has been determined potentiometrically in the temperature range of 973-1073 K. To the author's knowledge, no data on this parameter has been published yet. Three different electrochemical methods have been tested: the cyclic voltammetry technique, the coulometric additions method and the direct use of an Al-Nd alloy. In addition, an experimental set-up has been designed which allows working with small amounts of solvent (30 g). The molten eutectic mixture CaCl{sub 2}-NaCl (52-48 mol%) has been selected as the electrolyte. From the results obtained, the variation of the activity coefficient of Nd in Al(l) as a function of the temperature can be expressed as follows: log {gamma}{sub Nd(Al)} = 9.81 - 17134/T(K), in the range 973-1073 K. It has been found a good agreement between the activity coefficient values obtained from the different methods tested. Hence, it can be stated that either of the techniques used allows determining reliable values for the activity coefficient.

  18. Titrated flow versus fixed flow Bubble Nasal CPAP for respiratory distress in preterm neonates.

    Directory of Open Access Journals (Sweden)

    Srinivas eMurki

    2015-10-01

    Full Text Available Background: The clinical effects of a pre-fixed flow of air-oxygen versus a flow titrated according to visible bubbling are not well understood.Objective: To compare the effects of a fixed flow (5 L/min and titrated flow ( flow just enough to ensure bubbling at different set pressures on delivered intra-prong pressure, gas exchange and clinical parameters in preterm infants on bubble CPAP for respiratory distress.Methods: Preterm infants less than 35 weeks gestation on bubble CPAP and less than 96 h of age, were enrolled in this cross over study. They were subjected to 30 minute periods of titrated flow and fixed flow. At the end of both epochs, gas flow rate, set pressure, FiO2, SpO2, Silverman retraction score, respiratory rate , abdominal girth, and blood gases were recorded. The delivered intra-prong pressure was measured by an electronic manometer. Results: Sixty nine recordings were made in 54 infants. For each of the set CPAP pressures (4, 5 and 6 cm H2O, the mean delivered pressure with a fixed flow of 5 L/min was higher than that delivered by the titrated flow. During the fixed flow epoch, the delivered pressure was closer to and higher than the set pressure resulting in higher PaO2 and lower PaCO2 as compared to titrated flow epoch. In the titrated flow period, the delivered pressure was consistently lower than the set pressure. Conclusion: In preterm infants on bubble CPAP with set pressures of 4 to 6 cm H2O, a fixed flow of 5 L/min is more effective than a flow titrated to ensure adequate visible bubbling. It achieves higher delivered pressures, better oxygenation and ventilation.

  19. Automating spectral measurements

    Science.gov (United States)

    Goldstein, Fred T.

    2008-09-01

    This paper discusses the architecture of software utilized in spectroscopic measurements. As optical coatings become more sophisticated, there is mounting need to automate data acquisition (DAQ) from spectrophotometers. Such need is exacerbated when 100% inspection is required, ancillary devices are utilized, cost reduction is crucial, or security is vital. While instrument manufacturers normally provide point-and-click DAQ software, an application programming interface (API) may be missing. In such cases automation is impossible or expensive. An API is typically provided in libraries (*.dll, *.ocx) which may be embedded in user-developed applications. Users can thereby implement DAQ automation in several Windows languages. Another possibility, developed by FTG as an alternative to instrument manufacturers' software, is the ActiveX application (*.exe). ActiveX, a component of many Windows applications, provides means for programming and interoperability. This architecture permits a point-and-click program to act as automation client and server. Excel, for example, can control and be controlled by DAQ applications. Most importantly, ActiveX permits ancillary devices such as barcode readers and XY-stages to be easily and economically integrated into scanning procedures. Since an ActiveX application has its own user-interface, it can be independently tested. The ActiveX application then runs (visibly or invisibly) under DAQ software control. Automation capabilities are accessed via a built-in spectro-BASIC language with industry-standard (VBA-compatible) syntax. Supplementing ActiveX, spectro-BASIC also includes auxiliary serial port commands for interfacing programmable logic controllers (PLC). A typical application is automatic filter handling.

  20. pH titrations of molluscan paramyosin at two different ionic strengths.

    Science.gov (United States)

    Cooley, L B; Krause, S

    1980-11-01

    Paramyosin extracted from the adductor muscle of Mercenaria mercenaria, the chowder clam, was titrated both in 0.3 M KCl and in 1 mM KCl. Both the presumed native form of the molecule, acid-R-paramyosin, and a slightly degraded form, beta-paramyosin, were studied. Titrations of both types of paramyosin were similar in 1 mM k+, except that the native paramyosin is more highly charged at pH 3.2 than beta-paramyosin, as postulated previously (DeLaney and Krause, 1976, Macromolecules, 9:455), and that more groups titrate on the native molecule than on beta-paramyosin, both between pH 3.2 and 3.3 and between pH 3.2 and 10. Titrations in 0.30 M KCl, unlike those in 1 mM K, depended on starting pH; long term exposure to alkali solutions during dialysis, previously shown to cause partial dephosphorylation of paramyosin (Cooley et al., 1979, J. Biol. Chem., 254:2195), apparently also leads to a change in intermolecular interactions sufficient to cause changes in the titration curves in 0.30 M KCl but not in 1 mM K+.

  1. 全自动电位滴定法测定混凝土中酸溶氯离子含量%DETERMINATION OF ACID-SOLUBLE CHLORIDE ION IN CONCRETE BY AUTOMATIC POTENTIOMETRIC TITRATION

    Institute of Scientific and Technical Information of China (English)

    吴双九; 徐晓云; 杨竞

    2009-01-01

    采用全自动电位滴定仪测定混凝土中氯离子含量,研究了实验相关影响因素.实验结果表明,pH值和AgNO3溶液浓度对试验结果无显著影响,在水溶液中加入乙醇有利于提高终点电位突跃,该方法加标回收率为96.9%~98.7%,测量结果的相对标准偏差为2.74%(n=6).

  2. Automatic Potentiometric Titration Determination of the Content of Ag in Ag2C2O4%自动电位滴定法测定草酸银中的银含量

    Institute of Scientific and Technical Information of China (English)

    王伟

    2015-01-01

    采用自动电位滴定法测定草酸银中的银含量,每个平行测定6次,滴定的相对标准偏差小于0.2%.方法的回收率为99.65 %~100.10%.经过对比实验证明,此方法操作简便快捷、准确可靠,不仅能满足生产过程中大批量草酸银中银含量的快速分析,而且不受干扰离子的影响.

  3. 电位滴定法测定氨酚伪麻片中盐酸伪麻黄碱的含量%POTENTIOMETRIC TITRATION IN QUANTITATIVE DETERMINATION OF PSEUDOEPHEDRINE HYDROCHLORIDE IN THE PARACETAMOL PSEUDOEPHEDRINE HYDROCHLORIDE COMPOUND TABLETS

    Institute of Scientific and Technical Information of China (English)

    屈爱桃; 孙利明; 刘笑融

    2004-01-01

    目的:建立氨酚伪麻片中盐酸伪麻黄碱电位滴定的测定方法.方法:用电位滴定法,以0.2 mol/LKCl溶液作离子强度调节剂,NaOH标准溶液滴定,测定其pH值,以强碱滴定弱酸计量点后之Gran函数对滴定体积作图直线外推求滴定终点.结果:平均回收率为100.8%,RSD=0.27%.结论:该法准确,精密度好,操作简便、快速.

  4. 甘蔗糖蜜有机酸总量的电位滴定分析方法研究%Determination of total organic acids in sugar cane molasses with potentiometric titration

    Institute of Scientific and Technical Information of China (English)

    曹家兴; 陆建平; 李郁; 童张法

    2010-01-01

    甘蔗糖蜜试样溶液用HCl调节至pH值为2,加入乙酸指示羧酸滴定起点,用标准NaOH溶液进行电位滴定,突跃指数曲线指示出羧酸的滴定突跃起点和突跃终点,两突跃之间消耗的标准碱量相当于样品中羧酸的总量.无机酸包括硫酸或磷酸不影响滴定结果.方法平均样品加标回收率100.1%,相对标准偏差2.3%.测定了广西几家糖厂的糖蜜羧酸根总量,结果约为0.64mol/kg.

  5. Rapid automated nuclear chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, R.A.

    1979-05-31

    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC.

  6. Automated theorem proving.

    Science.gov (United States)

    Plaisted, David A

    2014-03-01

    Automated theorem proving is the use of computers to prove or disprove mathematical or logical statements. Such statements can express properties of hardware or software systems, or facts about the world that are relevant for applications such as natural language processing and planning. A brief introduction to propositional and first-order logic is given, along with some of the main methods of automated theorem proving in these logics. These methods of theorem proving include resolution, Davis and Putnam-style approaches, and others. Methods for handling the equality axioms are also presented. Methods of theorem proving in propositional logic are presented first, and then methods for first-order logic. WIREs Cogn Sci 2014, 5:115-128. doi: 10.1002/wcs.1269 CONFLICT OF INTEREST: The authors has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:26304304

  7. ATLAS Distributed Computing Automation

    CERN Document Server

    Schovancova, J; The ATLAS collaboration; Borrego, C; Campana, S; Di Girolamo, A; Elmsheuser, J; Hejbal, J; Kouba, T; Legger, F; Magradze, E; Medrano Llamas, R; Negri, G; Rinaldi, L; Sciacca, G; Serfon, C; Van Der Ster, D C

    2012-01-01

    The ATLAS Experiment benefits from computing resources distributed worldwide at more than 100 WLCG sites. The ATLAS Grid sites provide over 100k CPU job slots, over 100 PB of storage space on disk or tape. Monitoring of status of such a complex infrastructure is essential. The ATLAS Grid infrastructure is monitored 24/7 by two teams of shifters distributed world-wide, by the ATLAS Distributed Computing experts, and by site administrators. In this paper we summarize automation efforts performed within the ATLAS Distributed Computing team in order to reduce manpower costs and improve the reliability of the system. Different aspects of the automation process are described: from the ATLAS Grid site topology provided by the ATLAS Grid Information System, via automatic site testing by the HammerCloud, to automatic exclusion from production or analysis activities.

  8. Rapid automated nuclear chemistry

    International Nuclear Information System (INIS)

    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC

  9. Microbiological titration of proteins and of single amino acid content in biological materials without purification and hydrolysis.

    Science.gov (United States)

    Puppo, S; Morpurgo, G; Nardi, S; Conti, G

    1978-04-01

    A method is described for the microbiological determination of the protein content of biological materials. This method can also be adopted to titrate the concentration of a single amino acid in the protein and has the following advantages: (1) titration can be done without purification and hydrolysis of proteins; (2) the titration graph is a straight line between 25 and 800 microgram/ml; (3) protein values agree with those obtained using the Kjeldhal method; and (4) each mutant requiring one amino acid may be used to titrate the concentration of a single amino acid of the protein. The leucine content of various kinds of flour was measured with this system.

  10. The role of DNA binding sites and slow unbinding kinetics in titration-based oscillators

    CERN Document Server

    Karapetyan, Sargis

    2015-01-01

    Genetic oscillators, such as circadian clocks, are constantly perturbed by molecular noise arising from the small number of molecules involved in gene regulation. One of the strongest sources of stochasticity is the binary noise that arises from the binding of a regulatory protein to a promoter in the chromosomal DNA. In this study, we focus on two minimal oscillators based on activator titration and repressor titration to understand the key parameters that are important for oscillations and for overcoming binary noise. We show that the rate of unbinding from the DNA, despite traditionally being considered a fast parameter, needs to be slow to broaden the space of oscillatory solutions. The addition of multiple, independent DNA binding sites further expands the oscillatory parameter space for the repressor-titration oscillator and lengthens the period of both oscillators. This effect is a combination of increased effective delay of the unbinding kinetics due to multiple binding sites and increased promoter ul...

  11. Purity of potassium hydrogen phthalate, determination with precision coulometric and volumetric titration--a comparison.

    Science.gov (United States)

    Recknagel, Sebastian; Breitenbach, Martin; Pautz, Joachim; Lück, Detlef

    2007-09-19

    The mass fraction of potassium hydrogen phthalate (KHP) from a specific batch was certified as an acidimetric standard. Two different analytical methods on a metrological level were used to carry out certification analysis: precision constant current coulometric and volumetric titration with NaOH. It could be shown that with a commercial automatic titration system in combination with a reliable software for the end-point detection it is possible to produce equivalent results with the same accuracy in comparison to a definite method handled by a fundamental apparatus for traceable precision coulometry. Prerequisite for titrations are that a high number of single measurement are applied which are calibrated with a high precision certified reference material. PMID:17870288

  12. Solubility increase of colloidal zinc hydroxide as revealed by isothermal titration calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Association between zinc (II) and dipicolylamine was studied by ITC. • Increasing heat release was observed as the titration proceeded. • Thermodynamics of the association was discussed. • The increasing heat release was ascribed to solubility increase of colloidal Zn(OH)2. - Abstract: In this study, association between zinc (II) and dipicolylamine was studied by isothermal titration calorimetry. At neutral of weakly alkaline conditions, with zinc (II) in cell and dipicolylamine in syringe, increasing heat release was observed as the titration proceeded. Considering the equilibrium between Zn2+ and Zn(OH)2 at these conditions, the increasing heat release is ascribed to the increasing solubilization of colloidal Zn(OH)2 followed by neutralization of OH- by the buffer. Though quantitative determination of the increase in solubility is not accomplished, to the best of our knowledge, this is the first report about solubility increase of colloidal zinc hydroxide using calorimetric method

  13. The Automated Medical Office

    OpenAIRE

    Petreman, Mel

    1990-01-01

    With shock and surprise many physicians learned in the 1980s that they must change the way they do business. Competition for patients, increasing government regulation, and the rapidly escalating risk of litigation forces physicians to seek modern remedies in office management. The author describes a medical clinic that strives to be paperless using electronic innovation to solve the problems of medical practice management. A computer software program to automate information management in a c...

  14. Automation in biological crystallization.

    Science.gov (United States)

    Stewart, Patrick Shaw; Mueller-Dieckmann, Jochen

    2014-06-01

    Crystallization remains the bottleneck in the crystallographic process leading from a gene to a three-dimensional model of the encoded protein or RNA. Automation of the individual steps of a crystallization experiment, from the preparation of crystallization cocktails for initial or optimization screens to the imaging of the experiments, has been the response to address this issue. Today, large high-throughput crystallization facilities, many of them open to the general user community, are capable of setting up thousands of crystallization trials per day. It is thus possible to test multiple constructs of each target for their ability to form crystals on a production-line basis. This has improved success rates and made crystallization much more convenient. High-throughput crystallization, however, cannot relieve users of the task of producing samples of high quality. Moreover, the time gained from eliminating manual preparations must now be invested in the careful evaluation of the increased number of experiments. The latter requires a sophisticated data and laboratory information-management system. A review of the current state of automation at the individual steps of crystallization with specific attention to the automation of optimization is given.

  15. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    Energy Technology Data Exchange (ETDEWEB)

    Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

    2010-07-01

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium

  16. Potentiometric CO2 Sensor Using Li Ion Conducting Li3PO4Thin Film Electrolyte

    Directory of Open Access Journals (Sweden)

    Jin Seong Park

    2005-11-01

    Full Text Available Li+ ion conducting Li3PO4 thin film electrolytes with thickness 300nm, 650nm and1.2μm were deposited on Al2O3 substrate at room temperature by thermal evaporation method.Reference and sensing electrodes were printed on Au interfaces by conventional screen printingtechnique. The overall dimension of the sensor was 3 x 3 mm and of electrodes were 1 x 1.5 mmeach. The fabricated solid state potentiometric CO2 sensors of type: CO2, O2, Au, Li2TiO3-TiO2 / Li3PO4 / Li2CO3, Au, CO2, O2 have been investigated for CO2 sensing properties. Theelectromotive force (emf and δemf/dec values of the sensors are dependent on the thickness ofthe electrolyte film. 1.2μm thickness deposited sensor has shown good sensing behavior than thesensors with less thickness. The δemf values of the sensor are linearly increased up to 460oCoperating temperature and became stable above 460oC. Between 460-500oC temperatures regionthe sensor has reached an equilibrium state and the experimentally obtained δemf values areabout 80% of the theoretically calculated values. A Nernst’s slope of -61mV/decade has beenobtained between 250 to 5000 ppm of CO2 concentration at 500oC temperature. The sensor issuitable for ease of mass production in view of its miniaturization and cost effectiveness aftersome further improvement.

  17. Computational prediction and experimental selectivity coefficients for hydroxyzine and cetirizine molecularly imprinted polymer based potentiometric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, Abolfazl; Javanbakht, Mehran, E-mail: mehranjavanbakht@gmail.com

    2014-02-17

    Graphical abstract: -- Highlights: •Possible configurations template/monomer complexes were designed and optimized. •Effect of the electrostatic force on the selectivity of MIPs was investigated. •A correlation between selectivity of sensors and a charge distribution was obtained. -- Abstract: In spite of the increasing usages number of molecularly imprinted polymers (MIPs) in many scientific applications, the theoretical aspects of participating intra molecular forces are not fully understood. This work investigates effects of the electrostatic force, the Mulliken charge and the role of cavity's backbone atoms on the selectivity of MIPs. Moreover, charge distribution, which is a computational parameter, was proposed for the prediction of the selectivity coefficients of MIP-based sensors. In the computational approaches and experimental study, methacrylic acid (MAA) was chosen as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linker for hydroxyzine and cetirizine imprinted polymers. Ab initio, DFT B3LYP method was carried out on molecular optimization. With regard to results obtained from molecules optimization and hydrogen bonding properties, possible configurations of 1:n (n ≤ 5) template/monomer complexes were designed and optimized. The binding energy for each complex in gas phase was calculated. Depending on the most stable configuration, hydroxyzine and cetirizine imprinted polymer models were designed. The calculations including the porogen were also investigated. The theoretical charge distributions for the template and some potential interfering molecules were calculated. The results showed a correlation between the selectivity coefficients and the theoretical charge distributions. The results surprisingly show that charge distribution based model was able to predict the selectivity coefficients of MIP based potentiometric sensors.

  18. Phenytoin speciation with potentiometric and chronopotentiometric ion-selective membrane electrodes.

    Science.gov (United States)

    Jansod, Sutida; Afshar, Majid Ghahraman; Crespo, Gastón A; Bakker, Eric

    2016-05-15

    We report on an electrochemical protocol based on perm-selective membranes to provide valuable information about the speciation of ionizable drugs, with phenytoin as a model example. Membranes containing varying amounts of tetradodecylammonium chloride (TDDA) were read out at zero current (potentiometry) and with applied current techniques (chronopotentiometry). Potentiometry allows one to assess the ionized form of phenytoin (pKa~8.2) that corresponds to a negatively monocharged ion. A careful optimization of the membrane components resulted in a lower limit of detection (~1.6 µM) than previous reports. Once the pH (from 9 to 10) or the concentration of albumin is varied in the sample (from 0 to 30 g L(-1)), the potentiometric signal changes abruptly as a result of reducing/increasing the ionized concentration of phenytoin. Therefore, potentiometry as a single technique is by itself not sufficient to obtain information about the concentration and speciation of the drug in the system. For this reason, a tandem configuration with chronopotentiometry as additional readout principle was used to determine the total and ionized concentration of phenytoin. In samples containing excess albumin the rate-limiting step for the chronopotentiometry readout appears to be the diffusion of ionized phenytoin preceded by comparatively rapid deprotonation and decomplexation reactions. This protocol was applied to measure phenytoin in pharmaceutical tables (100mg per tablet). This tandem approach can likely be extended to more ionizable drugs and may eventually be utilized in view of pharmacological monitoring of drugs during the delivery process.

  19. Potentiometric Sensors Based on Surface Molecular Imprinting: Detection of Cancer Biomarkers and Viruses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Zhang, Z; Jain, V; Yi, J; Mueller, S; Sokolov, J; Liu, Z; Levon, K; Rigas, B; Rafailovich, M

    2010-01-01

    The continuing discovery of cancer biomarkers necessitates improved methods for their detection. Molecular imprinting using artificial materials provides an alternative to the detection of a wide range of substances. We applied surface molecular imprinting using self-assembled monolayers to design sensing elements for the detection of cancer biomarkers and other proteins. These elements consist of a gold-coated silicon chip onto which hydroxyl-terminated alkanethiol molecules and template biomolecule are co-adsorbed, where the thiol molecules are chemically bound to the metal substrate and self-assembled into highly ordered monolayers, the biomolecules can be removed, creating the foot-print cavities in the monolayer matrix for this kind of template molecules. Re-adsorption of the biomolecules to the sensing chip changes its potential, which can be measured potentiometrically. We applied this method to the detection of carcinoembryonic antigen (CEA) in both solutions of purified CEA and in the culture medium of a CEA-producing human colon cancer cell line. The CEA assay, validated also against a standard immunoassay, was both sensitive (detection range 2.5-250 ng/mL) and specific (no cross-reactivity with hemoglobin; no response by a non-imprinted sensor). Similar results were obtained for human amylase. In addition, we detected virions of poliovirus in a specific manner (no cross-reactivity to adenovirus, no response by a non-imprinted sensor). Our findings demonstrate the application of the principles of molecular imprinting to the development of a new method for the detection of protein cancer biomarkers and to protein-based macromolecular structures such as the capsid of a virion. This approach has the potential of generating a general assay methodology that could be highly sensitive, specific, simple and likely inexpensive.

  20. The influence of Al, Mg, and Na on uranium analysis using potentiometric method

    International Nuclear Information System (INIS)

    The uranium concentration in uranyl nitrate solution from the dissolution of fuel element plate U3O8-Al has been analyzed using potentiometric method. The determination of uranium concentration is performed using redox method with ferro sulfate as the reductor and potassium bichromate as the oxidator. Uranyl nitrate solution obtained from the dissolution of fuel plate appears to contain impurities at relatively high concentration. To observe the influence of the impurities, sample preparation was performed employing heating with HClO4 and without heating. The results of uranium analysis in uranyl nitrate solution obtained from the dissolution of fuel elements plate with heating and without heating are 5.755 g/L and 5.105 g/L correspondingly. The difference in the analysis results is quite significant due to the presence of impurities Na, Mg and Al in the uranyl nitrate solution at rather high concentrations. The experiment results show that the influence of Al is noted at the concentrations of 8000 ppm and 10 000 ppm with accuracy of 95.06% and 87.09% respectively. The influence of Na is noted at the concentrations of 8000 ppm and 10 000 ppm with accuracy of 95.06% and 87.09%, respectively. The influence of Mg is noted at the concentration of 10 000 ppm with accuracy of 96.23%. The combined influence of the three elements commences at the concentrations of 1000 ppm, 2000 ppm, and 4000 ppm with accuracy of 94.37%, 94.97%, and 87.48% respectively. The combined influence at the concentration of 6000 ppm or higher cannot be measured. (author)

  1. Regional potentiometric surface of the Ozark aquifer in Arkansas, Kansas, Missouri, and Oklahoma, November 2014–January 2015

    Science.gov (United States)

    Nottmeier, Anna M.

    2015-12-21

    The Ozark aquifer, within the Ozark Plateaus aquifer system (herein referred to as the “Ozark system”), is the primary groundwater source in the Ozark Plateaus physiographic province (herein referred to as the “Ozark Plateaus”) of Arkansas, Kansas, Missouri, and Oklahoma. Groundwater from the Ozark system has historically been an important part of the water resource base, and groundwater availability is a concern in some areas; dependency on the Ozark aquifer as a water supply has caused evolving, localized issues. The construction of a regional potentiometric-surface map of the Ozark aquifer is needed to aid assessment of current and future groundwater use and availability. The regional potentiometric-surface mapping is part of the U.S. Geological Survey (USGS) Groundwater Resources Program initiative (http://water.usgs.gov/ogw/gwrp/activities/regional.html) and the Ozark system groundwater availability project (http://ar.water.usgs.gov/ozarks), which seeks to quantify current groundwater resources, evaluate changes in these resources over time, and provide the information needed to simulate system response to future human-related and environmental stresses.The Ozark groundwater availability project objectives include assessing (1) growing demands for groundwater and associated declines in groundwater levels as agricultural, industrial, and public supply pumping increases to address needs; (2) regional climate variability and pumping effects on groundwater and surface-water flow paths; (3) effects of a gradual shift to a greater surface-water dependence in some areas; and (4) shale-gas production requiring groundwater and surface water for hydraulic fracturing. Data compiled and used to construct the regional Ozark aquifer potentiometric surface will aid in the assessment of those objectives.

  2. Higher Order Inclusion Complexes and Secondary Interactions Studied by Global Analysis of Calorimetric Titrations

    DEFF Research Database (Denmark)

    Schönbeck, Jens Christian Sidney; Holm, René; Westh, Peter

    2012-01-01

    This paper investigates the use of isothermal titration calorimetry (ITC) as a tool for studying molecular systems in which weaker secondary interactions are present in addition to a dominant primary interaction. Such systems are challenging since the signal pertaining to the stronger primary......). The results are validated by a 13C NMR titration and negative controls with a bile salt with no secondary binding site (glycocholate) (K = 2.96 ± 0.01 × 103 M–1). The method proved useful for detailed analysis of ITC data and may strengthen its use as a tool for studying molecular systems by advanced binding...

  3. Determination of fluoride ions in water by condutometric titration with lanthanum nitrates

    International Nuclear Information System (INIS)

    An alternative method for determining fluoride ions in drinking water by condutometric titration using La(NO3)3 as titrant is presented. The method is based on previous separation of fluoride from sample by distillation at 1350C. The pH of the distillated is adjusted between 5,5 - 6,0; ethanol is adicioned in 50% titrating the resultant solution with La(NO3)3. In these conditions, fluoride ions are determined with accuracy respectively, 5% and 4%. Natural samples of drinking water were analysed by this method and by the ion selective method, with agreement among the results. (author)

  4. Using isothermal titration calorimetry to determine thermodynamic parameters of protein-glycosaminoglycan interactions.

    Science.gov (United States)

    Dutta, Amit K; Rösgen, Jörg; Rajarathnam, Krishna

    2015-01-01

    It has now become increasingly clear that a complete atomic description of how biomacromolecules recognize each other requires knowledge not only of the structures of the complexes but also of how kinetics and thermodynamics drive the binding process. In particular, such knowledge is lacking for protein-glycosaminoglycan (GAG) complexes. Isothermal titration calorimetry (ITC) is the only technique that can provide various thermodynamic parameters-enthalpy, entropy, free energy (binding constant), and stoichiometry-from a single experiment. Here we describe different factors that must be taken into consideration in carrying out ITC titrations to obtain meaningful thermodynamic data of protein-GAG interactions.

  5. Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

    Directory of Open Access Journals (Sweden)

    Claudia Mara Pereira

    2011-08-01

    Full Text Available This study proposes a method of direct and simultaneous determination of the amount of Ca2+ and Mg2+ present in soil extracts using a Calcium Ion-Selective Electrode and by Complexometric Titration (ISE-CT. The results were compared to those obtained by conventional analytical techniques of Complexometric Titration (CT and Flame Atomic Absorption Spectrometry (FAAS. There were no significant differences in the determination of Ca2+ and Mg2+ in comparison with CT and FAAS, at a 95 % confidence level. Additionally, results of this method were more precise and accurate than of the Interlaboratorial Control (IC.

  6. Highly selective electrode for potentiometric analysis of methadone in biological fluids and pharmaceutical formulations.

    Science.gov (United States)

    Ardeshiri, Moslem; Jalali, Fahimeh

    2016-06-01

    In order to develop a fast and simple procedure for methadone analysis in biological fluids, a graphite paste electrode (GPE) was modified with the ion-pair of methadone-phosphotungstic acid, and multiwalled carbon nanotubes (MWCNTs). Optimized composition of the electrode with respect to graphite powder:paraffin oil:MWCNTs:ion pair, was 58:30:8:4 (w/w%). The electrode showed a near-Nernstian slope of 58.9±0.3mV/decade for methadone in a wide linear range of 1.0×10(-8)-4.6×10(-3)M, with a detection limit of 1.0×10(-8)M. The electrode response was independent of pH in the range of 5-11, with a fast response time (~4s) at 25°C. The sensor showed high selectivity and was successfully applied to the determination of sub-micromolar concentrations of methadone in human blood serum and urine samples, with recoveries in the range of 95-99.8%. The average recovery of methadone from tablets (5mg/tablet) by using the proposed method was 98%. The life time of the modified electrode was more than 5months, due to the characteristic of GPE which can be cut off and fresh electrode surface be available. A titration procedure was performed for methadone analysis by using phosphotungstic acid, as titrating agent, which showed an accurate end point and 1:1 stoichiometry for the ion-pair formed (methadone:phosphotungstic acid). The simple and rapid procedure as well as excellent detection limit and selectivity are some of the advantages of the proposed sensor for methadone. PMID:27040192

  7. Crown-Ether Derived Graphene Hybrid Composite for Membrane-Free Potentiometric Sensing of Alkali Metal Ions

    DEFF Research Database (Denmark)

    Olsen, Gunnar; Ulstrup, Jens; Chi, Qijin

    2016-01-01

    surface coverage is achieved by the introduction of a flexible linking molecule. The resulting hybrid composite is highly stable and is capable of detecting potassium ions down to micromolar ranges with a selectivity over other cations (including Ca2+, Li+, Na+, NH4+) at concentrations up to 25 m......We report the design and synthesis of newly functionalized graphene hybrid material that can be used for selective membrane-free potentiometric detection of alkali metal ions, represented by potassium ions. Reduced graphene oxide (RGO) functionalized covalently by 18-crown[6] ether with a dense...

  8. Potentiometric studies on the chelation behaviour of lanthanons with 3-hydroxy-2-methyl-1.4-naphthoquinone (HMNQ)

    International Nuclear Information System (INIS)

    The chelation behaviour of complexes of La(III), Pr(III), Nd(III), Y(III), Sm(III) and Tb(III) with 3-hydroxy-2-methyl-1.4-naphthoquinone has been studied potentiometrically in 75% (v/v) aqueous dioxan medium at various ionic strengths. The method of Bjerrum and Calvin, as modified by Irving and Rossotti, has been used to find values of n-bar and pL. The stability constants and the values of Ssub(min) have been calculated. The order of stability constants was found to be: La < Pr < Nd < Sm < Tb. (Author)

  9. Development of a potentiometric EDTA method for determination of molybdenum. Use of the analysis for molybdenite concentrates

    Science.gov (United States)

    Khristova, R.; Vanmen, M.

    1986-01-01

    Based on considerations of principles and experimental data, the interference of sulfate ions in poteniometric titration of EDTA with FeCl3 was confirmed. The method of back complexometric titration of molybdenum of Nonova and Gasheva was improved by replacing hydrazine sulfate with hydrazine hydrochloride for reduction of Mo(VI) to Mo(V). The method can be used for one to tenths of mg of molybdenum with 0.04 mg standard deviation. The specific method of determination of molybdenum in molybdenite concentrates is presented.

  10. Development of a potentiometric EDTA method for determination of molybdenum. Use of the analysis for molybdenite concentrates

    International Nuclear Information System (INIS)

    Based on considerations of principles and experimental data, the interference of sulfate ions in poteniometric titration of EDTA with FeCl3 was confirmed. The method of back complexometric titration of molybdenum of Nonova and Gasheva was improved by replacing hydrazine sulfate with hydrazine hydrochloride for reduction of Mo(VI) to Mo(V). The method can be used for one to tenths of mg of molybdenum with 0.04 mg standard deviation. The specific method of determination of molybdenum in molybdenite concentrates is presented

  11. Automation in organizations: Eternal conflict

    Science.gov (United States)

    Dieterly, D. L.

    1981-01-01

    Some ideas on and insights into the problems associated with automation in organizations are presented with emphasis on the concept of automation, its relationship to the individual, and its impact on system performance. An analogy is drawn, based on an American folk hero, to emphasize the extent of the problems encountered when dealing with automation within an organization. A model is proposed to focus attention on a set of appropriate dimensions. The function allocation process becomes a prominent aspect of the model. The current state of automation research is mentioned in relation to the ideas introduced. Proposed directions for an improved understanding of automation's effect on the individual's efficiency are discussed. The importance of understanding the individual's perception of the system in terms of the degree of automation is highlighted.

  12. Automated Assessment, Face to Face

    OpenAIRE

    Rizik M. H. Al-Sayyed; Amjad Hudaib; Muhannad AL-Shboul; Yousef Majdalawi; Mohammed Bataineh

    2010-01-01

    This research paper evaluates the usability of automated exams and compares them with the paper-and-pencil traditional ones. It presents the results of a detailed study conducted at The University of Jordan (UoJ) that comprised students from 15 faculties. A set of 613 students were asked about their opinions concerning automated exams; and their opinions were deeply analyzed. The results indicate that most students reported that they are satisfied with using automated exams but they have sugg...

  13. Automation System Products and Research

    OpenAIRE

    Rintala, Mikko; Sormunen, Jussi; Kuisma, Petri; Rahkala, Matti

    2014-01-01

    Automation systems are used in most buildings nowadays. In the past they were mainly used in industry to control and monitor critical systems. During the past few decades the automation systems have become more common and are used today from big industrial solutions to homes of private customers. With the growing need for ecologic and cost-efficient management systems, home and building automation systems are becoming a standard way of controlling lighting, ventilation, heating etc. Auto...

  14. Test Automation of Online Games

    OpenAIRE

    Schoenfeldt, Alexander

    2015-01-01

    State of the art browser games are increasingly complex pieces of software with extensive code basis. With increasing complexity, a software becomes harder to maintain. Automated regression testing can simplify these maintenance processes and thereby enable developers as well as testers to spend their workforce more efficiently. This thesis addresses the utilization of automated tests in web applications. As a use case test automation is applied to an online-based strategy game for the bro...

  15. Mechatronic Design Automation

    DEFF Research Database (Denmark)

    Fan, Zhun

    This book proposes a novel design method that combines both genetic programming (GP) to automatically explore the open-ended design space and bond graphs (BG) to unify design representations of multi-domain Mechatronic systems. Results show that the method, formally called GPBG method, can...... successfully design analogue filters, vibration absorbers, micro-electro-mechanical systems, and vehicle suspension systems, all in an automatic or semi-automatic way. It also investigates the very important issue of co-designing plant-structures and dynamic controllers in automated design of Mechatronic...

  16. The automated medical office.

    Science.gov (United States)

    Petreman, M

    1990-08-01

    With shock and surprise many physicians learned in the 1980s that they must change the way they do business. Competition for patients, increasing government regulation, and the rapidly escalating risk of litigation forces physicians to seek modern remedies in office management. The author describes a medical clinic that strives to be paperless using electronic innovation to solve the problems of medical practice management. A computer software program to automate information management in a clinic shows that practical thinking linked to advanced technology can greatly improve office efficiency.

  17. AUTOMATED API TESTING APPROACH

    Directory of Open Access Journals (Sweden)

    SUNIL L. BANGARE

    2012-02-01

    Full Text Available Software testing is an investigation conducted to provide stakeholders with information about the quality of the product or service under test. With the help of software testing we can verify or validate the software product. Normally testing will be done after development of software but we can perform the software testing at the time of development process also. This paper will give you a brief introduction about Automated API Testing Tool. This tool of testing will reduce lots of headache after the whole development of software. It saves time as well as money. Such type of testing is helpful in the Industries & Colleges also.

  18. Titration of a Solid Acid Monitored by X-Ray Diffraction

    Science.gov (United States)

    Dungey, Keenan E.; Epstein, Paul

    2007-01-01

    An experiment is described to introduce students to an important class of solid-state reactions while reinforcing concepts of titration by using a pH meter and a powder X-ray diffractometer. The experiment was successful in teaching students the abstract concepts of solid-state structure and diffraction by applying the diffraction concepts learned…

  19. Effect of Spacers on CMCs and Micelle-forming Enthalpies of Gemini Surfactants by Titration Microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The critical micelle concentrations (CMC) and the micelle-forming enthalpies (D Hmic) of gemini surfactants were first measured by the precise titration microcalorimetry. The results showed that D Hmic values are negative, and there is an exothermal minimum between s=4 and s=6. Furthermore, the CMCs of the surfactants are in good agreement with literature values.

  20. Thermodynamic profiling of Peptide membrane interactions by isothermal titration calorimetry: a search for pores and micelles

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2011-01-01

    in mixed peptide-lipid micelles. We have investigated the mode of action of the antimicrobial peptide mastoparan-X using isothermal titration calorimetry (ITC) and cryo-transmission electron microscopy (cryo-TEM). The results show that mastoparan-X induces a range of structural transitions of POPC/POPG (3...

  1. A modelling approach to establish experimental parameters of a flow-through titration

    NARCIS (Netherlands)

    Reijnders, H.F.R.; Staden, J.J. van; Eelderink, G.H.B; Griepink, B.

    1980-01-01

    A flow-through titrimeter with optical detection and the flow-through titration of sulphate have been studied by using control engineering methods. Qualitative chemical descriptions and systems analysis yield a model covering different precipitation rates of barium sulphate. The validity of the mode

  2. Role of titrated low dose oral misoprostol solution in induction of labour

    Directory of Open Access Journals (Sweden)

    Sarvottma Antil

    2016-03-01

    Conclusions: For induction of labour in women with term gestation after cervical priming, low dose oral misoprostol solution in titrated doses and intravenous oxytocin were found to be comparable with each other in terms of labour outcomes, efficacy and adverse effects. [Int J Reprod Contracept Obstet Gynecol 2016; 5(3.000: 775-782

  3. 40 CFR Appendix A to Part 425 - Potassium Ferricyanide Titration Method

    Science.gov (United States)

    2010-07-01

    ... concentrations determined by EPA test procedure 376.1 (see 40 CFR 136.3, Table IB, parameter 66 (49 FR 43234... Method A Appendix A to Part 425 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Appendix A to Part 425—Potassium Ferricyanide Titration Method Source The potassium ferricyanide...

  4. Charge Density Quantification of Polyelectrolyte Polysaccharides by Conductometric Titration: An Analytical Chemistry Experiment

    Science.gov (United States)

    Farris, Stefano; Mora, Luigi; Capretti, Giorgio; Piergiovanni, Luciano

    2012-01-01

    An easy analytical method for determination of the charge density of polyelectrolytes, including polysaccharides and other biopolymers, is presented. The basic principles of conductometric titration, which is used in the pulp and paper industry as well as in colloid and interface science, were adapted to quantify the charge densities of a…

  5. Single-experiment displacement assay for quantifying high-affinity binding by isothermal titration calorimetry.

    Science.gov (United States)

    Krainer, Georg; Keller, Sandro

    2015-04-01

    Isothermal titration calorimetry (ITC) is the gold standard for dissecting the thermodynamics of a biomolecular binding process within a single experiment. However, reliable determination of the dissociation constant (KD) from a single titration is typically limited to the range 100 μM>KD>1 nM. Interactions characterized by a lower KD can be assessed indirectly by so-called competition or displacement assays, provided that a suitable competitive ligand is available whose KD falls within the directly accessible window. However, this protocol is limited by the fact that it necessitates at least two titrations to characterize one high-affinity inhibitor, resulting in considerable consumption of both sample material and time. Here, we introduce a fast and efficient ITC displacement assay that allows for the simultaneous characterization of both a high-affinity ligand and a moderate-affinity ligand competing for the same binding site on a receptor within a single experiment. The protocol is based on a titration of the high-affinity ligand into a solution containing the moderate-affinity ligand bound to the receptor present in excess. The resulting biphasic binding isotherm enables accurate and precise determination of KD values and binding enthalpies (ΔH) of both ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation, explore its potential and limitations with the aid of simulations and statistical analyses, and elaborate on potential applications to protein-inhibitor interactions.

  6. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  7. Determination of the aggregation number for micelles by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Holm, Rene; Westh, Peter

    2014-01-01

    Isothermal titration calorimetry (ITC) has previously been applied to estimate the aggregation number (n), Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of micellization. However, some difficulties of micelle characterization by ITC still remain; most micelles have aggregation numbers...

  8. Solvatochromic Dyes as pH-Independent Indicators for Ionophore Nanosphere-Based Complexometric Titrations.

    Science.gov (United States)

    Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric

    2015-12-15

    For half a century, complexometric titrations of metal ions have been performed with water-soluble chelators and indicators that typically require careful pH control. Very recently, ion-selective nanosphere emulsions were introduced that exhibit ion-exchange properties and are doped with lipophilic ionophores originally developed for chemical ion sensors. They may serve as novel, highly selective and pH independent complexometric reagents. While ion optode emulsions have been demonstrated as useful indicators for such titrations, they exhibit a pH cross-response that unfortunately complicates the identification of the end point. Here, we present pH-independent optode nanospheres as indicators for complexometric titrations, with calcium as an initial example. The nanospheres incorporate an ionic solvatochromic dye (SD), ion exchanger and ionophore. The solvatochromic dye will be only expelled from the core of the nanosphere into the aqueous solution at the end point at which point it results in an optical signal change. The titration curves are demonstrated to be pH-independent and with sharper end points than with previously reported chromoionophore-based optical nanospheres as indicator. The calcium concentration in mineral water was successfully determined using this method. PMID:26595520

  9. Hydrolysis-precipitation studies of aluminum (III) solutions. I. Titration of acidified aluminum nitrate solutions

    NARCIS (Netherlands)

    Vermeulen, A.C.; Geus, John W.; Stol, R.J.; Bruyn, P.L. de

    1975-01-01

    Acidified aluminum nitrate solutions were titrated with alkali (NaOH or KOH) over a temperature range of 24°C to 90°C. A homogeneous distribution of added base was achieved by: (i) in situ decomposition of urea (90°C); and (ii) a novel method involving injection through a capillary submerged in the

  10. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Science.gov (United States)

    Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic proc...

  11. An Exact Method to Determine the Conductivity of Aqueous Solutions in Acid-Base Titrations

    Directory of Open Access Journals (Sweden)

    Norma Rodríguez-Laguna

    2015-01-01

    Full Text Available Several works in the literature show that it is possible to establish the analytic equations to estimate the volume V of a strong base or a strong acid (Vb and Va, resp. being added to a solution of a substance or a mix of substances during an acid-base titration, as well as the equations to estimate the first derivative of the titration plot dpH/dV, and algebraic expressions to determine the buffer β capacity with dilution βdil. This treatment allows establishing the conditions of thermodynamic equilibria for all species within a system containing a mix of species from one or from various polyacid systems. The present work shows that it is possible to determine exactly the electric conductivity of aqueous solutions for these Brønsted acid-base titrations, because the functional relation between this property and the composition of the system in equilibrium is well known; this is achieved using the equivalent conductivity λi values of each of the ions present in a given system. The model employed for the present work confirms the experimental outcomes with the H2SO4, B(OH3, CH3COOH, and H3PO4 aqueous solutions’ titration.

  12. World-wide distribution automation systems

    Energy Technology Data Exchange (ETDEWEB)

    Devaney, T.M.

    1994-12-31

    A worldwide power distribution automation system is outlined. Distribution automation is defined and the status of utility automation is discussed. Other topics discussed include a distribution management system, substation feeder, and customer functions, potential benefits, automation costs, planning and engineering considerations, automation trends, databases, system operation, computer modeling of system, and distribution management systems.

  13. Hydrogen-ion titrations of amino acids and proteins in solutions containing concentrated electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Fergg, F. [Technische Universitaet Muenchen (Germany); Kuehner, D.E.; Blanch, H.W.; Prausnitz, J.M. [Lawrence Berkeley Lab., CA (United States)

    1994-12-01

    This report describes a first attempt to quantify the net charge as a function of solution pH for lysozyme and {alpha}-chymotrypsin at 0.1 M, 1.0 M and 3.0 M ionic strength, (IS). The calculations are based on the residue (titratable group) pK{sub a}`s in the amino-acid sequence of the protein. To determine these pK{sub a}`s, a simple theory was used which assumes that the pK{sub a}`s are independent from each other in the protein and are equal to their pK{sub a} values in free amino-acid solution (Independent-Site Theory, IST). Residue pK{sub a}`s were obtained from amino-acid hydrogen-ion titrations at three different KCl concentrations corresponding to 0.1M, 1.0M and 3.0M ionic strength. After construction of a suitable apparatus, the experimental procedure and data reduction were computerized to perform a large number of titrations. Most measured pK{sub a}`s showed high reproducibility (the difference of pK{sub a} values observed between two experiments was less than 0.05). For IS = 0.1M, observed pK{sub a}`s agreed with literature values to within a few hundredths of a pH unit. Furthermore, the ionic-strength dependence of the pK{sub a}`s followed the trends reported in the literature, viz. pK{sub a} values decrease with increasing ionic strength until they reach a minimum at about IS = 0.5M. At still higher IS, pK{sub a}`s increase as the ionic strength rises to 3M. The known pK{sub a}`s of all titratable groups in a protein were used with the IST to give a first approximation of how the protein net charge varies with pH at high ionic strength. A comparison of the titration curves based on the IST with experimental lysozyme and {alpha}-chymotrypsin titration data indicates acceptable agreement at IS = 0.1M. However, comparison of measured and calculated titration curves at IS = 1M and IS = 3M indicates only quantitative agreement.

  14. A nanoporous ruthenium oxide framework for amperometric sensing of glucose and potentiometric sensing of pH

    International Nuclear Information System (INIS)

    Nanoporous ruthenium oxide frameworks (L2-eRuO) were electrodeposited on gold substrates by repetitive potential cycling in solutions of ruthenium(III) ions in the presence of reverse neutral micelles. The L2-eRuO was characterized in terms of direct oxidation of glucose and potentiometric response to pH values. The surface structures and morphologies of the L2-eRuO were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and high-resolution transmission electron microscopy. Their surface area was estimated via underpotential deposition of copper. L 2-eRuO-modified electrodes showed a 17-fold higher sensitivity (40 μA mM-1 cm-2 towards glucose in 0-4 mM concentration in solution of pH 7.4) than a RuO electrode prepared in the absence of reverse micelles. Potential interferents such as ascorbic acid, 4-acetamidophenol, uric acid and dopamine displayed no effect. The new electrode also revealed improved potentiometric response to pH changes compared to a platinum electrode of the same type. (author)

  15. Potentiometric RuO2-Ta2O5 pH sensors fabricated using thick film and LTCC technologies.

    Science.gov (United States)

    Manjakkal, Libu; Zaraska, Krzysztof; Cvejin, Katarina; Kulawik, Jan; Szwagierczak, Dorota

    2016-01-15

    The paper reports on the preparation, properties and application of potentiometric pH sensors with thick film RuO2-Ta2O5 sensing electrode and Ag/AgCl/KCl reference electrode screen printed on an alumina substrate. Furthermore, it presents fabrication procedure and characterization of a new miniaturized pH sensor on LTCC (low temperature cofired ceramics) substrate, destined for wireless monitoring. The crystal structure, phase and elemental composition, and microstructure of the films were investigated by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Potentiometric characterization was performed in a wide pH range of 2-12 for different storage conditions and pH loops. The advantages of the proposed thick film pH sensors are: (a) low cost and easy fabrication, (b) excellent sensitivity close to the Nernstian response (56mV/pH) in the wide pH range, (c) fast response, (d) long lifetime, (e) good reproducibility, (f) low hysteresis and drift effects, and (g) low cross-sensitivity towards Li(+), Na(+) and K(+) as interfering ions. The applicability of the sensors for pH measurement of river, tap and distilled water, and some drinks was also tested.

  16. Application of original assemblies of polyelectrolytes, urease and electrodeposited polyaniline as sensitive films of potentiometric urea biosensors

    International Nuclear Information System (INIS)

    Highlights: • Elaboration of original polymer materials using self-assembly and electrochemistry. • In situ monitoring of the growth of the polymer materials. • Development of urea electrochemical sensors using a home-made mini-potentiostat. - Abstract: Original assemblies were prepared for use as sensitive films of potentiometric enzyme urea sensors, and compared to identify the more efficient structure with respect to stability. These films included electrodeposited polyaniline, used as transducer, urease, used as catalyst, and biocompatible polyelectrolytes, used as a matrix to preserve the integrity of the enzyme in the sensitive film. Two kinds of assemblies were done: the first one consisted in the adsorption of urease onto a polyaniline film followed by the adsorption of a chitosan-carboxymethylpullulan multilayer film, while the second one consisted in the adsorption of a urease-chitosan multilayer film onto an electrodeposited polyaniline film. The morphological features and growth of these assemblies were characterized by scanning electron microscopy and quartz crystal microbalance, respectively. This allowed us to demonstrate that the assemblies are successfully formed onto the electrodes of the sensors. The potentiometric responses of both assemblies were then measured as a function of urea concentration using a home-made portable potentiostat. The electrochemical response of resulting sensors was fast and sensitive for both types of assemblies, but the stability in time was much better for the films obtained from alternative adsorption of urease and chitosan onto a layer of urease adsorbed over electrodeposited polyaniline

  17. Protein Detection with Potentiometric Aptasensors: A Comparative Study between Polyaniline and Single-Walled Carbon Nanotubes Transducers

    Directory of Open Access Journals (Sweden)

    Ali Düzgün

    2013-01-01

    Full Text Available A comparison study on the performance characteristics and surface characterization of two different solid-contact selective potentiometric thrombin aptasensors, one exploiting a network of single-walled carbon nanotubes (SWCNTs and the other the polyaniline (PANI, both acting as a transducing element, is described in this work. The molecular properties of both SWCNT and PANI surfaces have been modified by covalently linking thrombin binding aptamers as biorecognition elements. The two aptasensors are compared and characterized through potentiometry and electrochemical impedance spectroscopy (EIS based on the voltammetric response of multiply charged transition metal cations (such as hexaammineruthenium, [Ru(NH36]3+ bound electrostatically to the DNA probes. The surface densities of aptamers were accurately determined by the integration of the peak for the reduction of [Ru(NH36]3+ to [Ru(NH36]2+. The differences and the similarities, as well as the transduction mechanism, are also discussed. The sensitivity is calculated as 2.97 mV/decade and 8.03 mV/decade for the PANI and SWCNTs aptasensors, respectively. These results are in accordance with the higher surface density of the aptamers in the SWCNT potentiometric sensor.

  18. Solid-contact potentiometric aptasensor based on aptamer functionalized carbon nanotubes for the direct determination of proteins.

    Science.gov (United States)

    Düzgün, Ali; Maroto, Alicia; Mairal, Teresa; O'Sullivan, Ciara; Rius, F Xavier

    2010-05-01

    A facile, solid-contact selective potentiometric aptasensor exploiting a network of single-walled carbon nanotubes (SWCNT) acting as a transducing element is described in this work. The molecular properties of the SWCNT surface have been modified by covalently linking aptamers as biorecognition elements to the carboxylic groups of the SWCNT walls. As a model system to demonstrate the generic application of the approach, a 15-mer thrombin aptamer interacts with thrombin and the affinity interaction gives rise to a direct potentiometric signal that can be easily recorded within 15 s. The dynamic linear range, with a sensitivity of 8.0 mV/log a(Thr) corresponds to the 10(-7)-10(-6) M range of thrombin concentrations, with a limit of detection of 80 nM. The aptasensor displays selectivity against elastase and bovine serum albumin and is easily regenerated by immersion in 2 M NaCl. The aptasensor demonstrates the capacity of direct detection of the recognition event avoiding the use of labels, mediators, or the addition of further reagents or analyte accumulation. PMID:20419254

  19. Potentiometric anion selectivity of polymer-membrane electrodes based on cobalt, chromium, and aluminum salens

    Energy Technology Data Exchange (ETDEWEB)

    Badr, Ibrahim H.A. [Department of Chemistry, Faculty of Science, Ain Shams University, P.O. Box 11566, Cairo (Egypt)]. E-mail: ibadr1@yahoo.com

    2006-06-16

    Metallo-salens of cobalt(II) (Co-Sal), chromium(III) (Cr-Sal), and aluminum(III) (Al-Sal) are used as the active ionophores within plasticized poly(vinyl chloride) membranes. It is shown that central metal-ion plays a critical role in directing the ionophore selectivity. Polymer-membrane electrodes based on Co-Sal, Cr-Sal, and Al-Sal are demonstrated to exhibit enhanced responses and selectivity toward nitrite/thiocyanate, thiocyanate, and fluoride anions, respectively. The improved anion selectivity of the three ionophore systems is shown to deviate significantly from the classical Hofmeister pattern that is based only on ion lipophilicity. For example, optimized membrane electrodes for nitrite ion based on Co-Sal exhibit logK{sub Nitrite,Anion}{sup pot} values of -5.22, -4.66, -4.48, -2.5 towards bromide, perchlorate, nitrate, and iodide anions, respectively. Optimized membrane electrodes based on Co-Sal and Cr-Sal show near-Nernstian responses towards nitrite (-57.9+/-0.9mV/decade) and thiocyanate (-56.9+/-0.8mV/decade), respectively, with fast response and recovery times. In contrast, Al-Sal based membrane electrodes respond to fluoride ion in a super-Nernstian (-70+/-3mV/decade) and nearly an irreversible mode. The operative response mechanism of Co-Sal, Cr-Sal, and Al-Sal membrane electrodes is examined using the effect of added ionic sites on the potentiometric response characteristics. It is demonstrated that addition of lipophilic anionic sites to membrane electrodes based on the utilized metallo-salens enhances the selectivity towards the primary ion, while addition of cationic sites resulted in Hofmeister selectivity patterns suggesting that the operative response mechanism is of the charged carrier type. Electron spin resonance (ESR) data indicates that Co(II) metal-ion center of Co-Sal ionophore undergoes oxidation to Co(III). This process leads to formation of a charged anion-carrier that is consistent with the response behavior obtained for Co

  20. Potentiometric Sensor for Real-Time Remote Surveillance of Actinides in Molten Salts

    Energy Technology Data Exchange (ETDEWEB)

    Natalie J. Gese; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson

    2012-07-01

    A potentiometric sensor is being developed at the Idaho National Laboratory for real-time remote surveillance of actinides during electrorefining of spent nuclear fuel. During electrorefining, fuel in metallic form is oxidized at the anode while refined uranium metal is reduced at the cathode in a high temperature electrochemical cell containing LiCl-KCl-UCl3 electrolyte. Actinides present in the fuel chemically react with UCl3 and form stable metal chlorides that accumulate in the electrolyte. This sensor will be used for process control and safeguarding of activities in the electrorefiner by monitoring the concentrations of actinides in the electrolyte. The work presented focuses on developing a solid-state cation conducting ceramic sensor for detecting varying concentrations of trivalent actinide metal cations in eutectic LiCl-KCl molten salt. To understand the basic mechanisms for actinide sensor applications in molten salts, gadolinium was used as a surrogate for actinides. The ß?-Al2O3 was selected as the solid-state electrolyte for sensor fabrication based on cationic conductivity and other factors. In the present work Gd3+-ß?-Al2O3 was prepared by ion exchange reactions between trivalent Gd3+ from GdCl3 and K+-, Na+-, and Sr2+-ß?-Al2O3 precursors. Scanning electron microscopy (SEM) was used for characterization of Gd3+-ß?-Al2O3 samples. Microfocus X-ray Diffraction (µ-XRD) was used in conjunction with SEM energy dispersive X-ray spectroscopy (EDS) to identify phase content and elemental composition. The Gd3+-ß?-Al2O3 materials were tested for mechanical and chemical stability by exposing them to molten LiCl-KCl based salts. The effect of annealing on the exchanged material was studied to determine improvements in material integrity post ion exchange. The stability of the ß?-Al2O3 phase after annealing was verified by µ-XRD. Preliminary sensor tests with different assembly designs will also be presented.

  1. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    International Nuclear Information System (INIS)

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-β(doubleprime)-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-β(doubleprime)-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in

  2. Automation from pictures

    International Nuclear Information System (INIS)

    The state transition diagram (STD) model has been helpful in the design of real time software, especially with the emergence of graphical computer aided software engineering (CASE) tools. Nevertheless, the translation of the STD to real time code has in the past been primarily a manual task. At Los Alamos we have automated this process. The designer constructs the STD using a CASE tool (Cadre Teamwork) using a special notation for events and actions. A translator converts the STD into an intermediate state notation language (SNL), and this SNL is compiled directly into C code (a state program). Execution of the state program is driven by external events, allowing multiple state programs to effectively share the resources of the host processor. Since the design and the code are tightly integrated through the CASE tool, the design and code never diverge, and we avoid design obsolescence. Furthermore, the CASE tool automates the production of formal technical documents from the graphic description encapsulated by the CASE tool. (author)

  3. Automated Test Case Generation

    CERN Document Server

    CERN. Geneva

    2015-01-01

    I would like to present the concept of automated test case generation. I work on it as part of my PhD and I think it would be interesting also for other people. It is also the topic of a workshop paper that I am introducing in Paris. (abstract below) Please note that the talk itself would be more general and not about the specifics of my PhD, but about the broad field of Automated Test Case Generation. I would introduce the main approaches (combinatorial testing, symbolic execution, adaptive random testing) and their advantages and problems. (oracle problem, combinatorial explosion, ...) Abstract of the paper: Over the last decade code-based test case generation techniques such as combinatorial testing or dynamic symbolic execution have seen growing research popularity. Most algorithms and tool implementations are based on finding assignments for input parameter values in order to maximise the execution branch coverage. Only few of them consider dependencies from outside the Code Under Test’s scope such...

  4. Automated Postediting of Documents

    CERN Document Server

    Knight, K; Knight, Kevin; Chander, Ishwar

    1994-01-01

    Large amounts of low- to medium-quality English texts are now being produced by machine translation (MT) systems, optical character readers (OCR), and non-native speakers of English. Most of this text must be postedited by hand before it sees the light of day. Improving text quality is tedious work, but its automation has not received much research attention. Anyone who has postedited a technical report or thesis written by a non-native speaker of English knows the potential of an automated postediting system. For the case of MT-generated text, we argue for the construction of postediting modules that are portable across MT systems, as an alternative to hardcoding improvements inside any one system. As an example, we have built a complete self-contained postediting module for the task of article selection (a, an, the) for English noun phrases. This is a notoriously difficult problem for Japanese-English MT. Our system contains over 200,000 rules derived automatically from online text resources. We report on l...

  5. Maneuver Automation Software

    Science.gov (United States)

    Uffelman, Hal; Goodson, Troy; Pellegrin, Michael; Stavert, Lynn; Burk, Thomas; Beach, David; Signorelli, Joel; Jones, Jeremy; Hahn, Yungsun; Attiyah, Ahlam; Illsley, Jeannette

    2009-01-01

    The Maneuver Automation Software (MAS) automates the process of generating commands for maneuvers to keep the spacecraft of the Cassini-Huygens mission on a predetermined prime mission trajectory. Before MAS became available, a team of approximately 10 members had to work about two weeks to design, test, and implement each maneuver in a process that involved running many maneuver-related application programs and then serially handing off data products to other parts of the team. MAS enables a three-member team to design, test, and implement a maneuver in about one-half hour after Navigation has process-tracking data. MAS accepts more than 60 parameters and 22 files as input directly from users. MAS consists of Practical Extraction and Reporting Language (PERL) scripts that link, sequence, and execute the maneuver- related application programs: "Pushing a single button" on a graphical user interface causes MAS to run navigation programs that design a maneuver; programs that create sequences of commands to execute the maneuver on the spacecraft; and a program that generates predictions about maneuver performance and generates reports and other files that enable users to quickly review and verify the maneuver design. MAS can also generate presentation materials, initiate electronic command request forms, and archive all data products for future reference.

  6. An Automated Electronic Tongue for In-Situ Quick Monitoring of Trace Heavy Metals in Water Environment

    Science.gov (United States)

    Cai, Wei; Li, Yi; Gao, Xiaoming; Guo, Hongsun; Zhao, Huixin; Wang, Ping

    2009-05-01

    An automated electronic tongue instrumentation has been developed for in-situ concentration determination of trace heavy metals in water environment. The electronic tongue contains two main parts. The sensor part consists of a silicon-based Hg-coated Au microelectrodes array (MEA) for the detection of Zn(II), Cd(II), Pb(II) and Cu(II) and a multiple light-addressable potentiometric sensor (MLAPS) for the detection of Fe(III) and Cr(VI). The control part employs pumps, valves and tubes to enable the pick-up and pretreatment of aqueous sample. The electronic tongue realized detection of the six metals mentioned above at part-per-billion (ppb) level without manual operation. This instrumentation will have wide application in quick monitoring and prediction the heavy metal pollution in lakes and oceans.

  7. Get smart! automate your house!

    NARCIS (Netherlands)

    Van Amstel, P.; Gorter, N.; De Rouw, J.

    2016-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will help you in reducing both energy usage and costs by automating your home. It gives an introduction to a number of home automation systems that every homeowner can install.

  8. Automated separation for heterogeneous immunoassays

    OpenAIRE

    Truchaud, A.; Barclay, J; Yvert, J. P.; Capolaghi, B.

    1991-01-01

    Beside general requirements for modern automated systems, immunoassay automation involves specific requirements as a separation step for heterogeneous immunoassays. Systems are designed according to the solid phase selected: dedicated or open robots for coated tubes and wells, systems nearly similar to chemistry analysers in the case of magnetic particles, and a completely original design for those using porous and film materials.

  9. Automated Test-Form Generation

    Science.gov (United States)

    van der Linden, Wim J.; Diao, Qi

    2011-01-01

    In automated test assembly (ATA), the methodology of mixed-integer programming is used to select test items from an item bank to meet the specifications for a desired test form and optimize its measurement accuracy. The same methodology can be used to automate the formatting of the set of selected items into the actual test form. Three different…

  10. Translation: Aids, Robots, and Automation.

    Science.gov (United States)

    Andreyewsky, Alexander

    1981-01-01

    Examines electronic aids to translation both as ways to automate it and as an approach to solve problems resulting from shortage of qualified translators. Describes the limitations of robotic MT (Machine Translation) systems, viewing MAT (Machine-Aided Translation) as the only practical solution and the best vehicle for further automation. (MES)

  11. Opening up Library Automation Software

    Science.gov (United States)

    Breeding, Marshall

    2009-01-01

    Throughout the history of library automation, the author has seen a steady advancement toward more open systems. In the early days of library automation, when proprietary systems dominated, the need for standards was paramount since other means of inter-operability and data exchange weren't possible. Today's focus on Application Programming…

  12. Potentiometric studies on complexation equilibria between some transition metal ions and 2-hydroxy-1-naphthaldehyde thiosemicarbazone in dioxane-water medium

    International Nuclear Information System (INIS)

    In continuation of our study on the metal complexes of biologically active o-hydroxynaphthaldehyde and its derivatives, potentiometric studies on the chelation behaviour of bivalent metal complexes of 2-hydroxy-1-naphthaldehyde thiosemicarbazone are described. (author). 11 refs., 2 tabs

  13. Automated Motivic Analysis

    DEFF Research Database (Denmark)

    Lartillot, Olivier

    2016-01-01

    Motivic analysis provides very detailed understanding of musical composi- tions, but is also particularly difficult to formalize and systematize. A computational automation of the discovery of motivic patterns cannot be reduced to a mere extraction of all possible sequences of descriptions....... The systematic approach inexorably leads to a proliferation of redundant structures that needs to be addressed properly. Global filtering techniques cause a drastic elimination of interesting structures that damages the quality of the analysis. On the other hand, a selection of closed patterns allows...... for lossless compression. The structural complexity resulting from successive repetitions of patterns can be controlled through a simple modelling of cycles. Generally, motivic patterns cannot always be defined solely as sequences of descriptions in a fixed set of dimensions: throughout the descriptions...

  14. Robust automated knowledge capture.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  15. Automated Electrostatics Environmental Chamber

    Science.gov (United States)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  16. Automated Standard Hazard Tool

    Science.gov (United States)

    Stebler, Shane

    2014-01-01

    The current system used to generate standard hazard reports is considered cumbersome and iterative. This study defines a structure for this system's process in a clear, algorithmic way so that standard hazard reports and basic hazard analysis may be completed using a centralized, web-based computer application. To accomplish this task, a test server is used to host a prototype of the tool during development. The prototype is configured to easily integrate into NASA's current server systems with minimal alteration. Additionally, the tool is easily updated and provides NASA with a system that may grow to accommodate future requirements and possibly, different applications. Results of this project's success are outlined in positive, subjective reviews complete by payload providers and NASA Safety and Mission Assurance personnel. Ideally, this prototype will increase interest in the concept of standard hazard automation and lead to the full-scale production of a user-ready application.

  17. Automated synthetic scene generation

    Science.gov (United States)

    Givens, Ryan N.

    Physics-based simulations generate synthetic imagery to help organizations anticipate system performance of proposed remote sensing systems. However, manually constructing synthetic scenes which are sophisticated enough to capture the complexity of real-world sites can take days to months depending on the size of the site and desired fidelity of the scene. This research, sponsored by the Air Force Research Laboratory's Sensors Directorate, successfully developed an automated approach to fuse high-resolution RGB imagery, lidar data, and hyperspectral imagery and then extract the necessary scene components. The method greatly reduces the time and money required to generate realistic synthetic scenes and developed new approaches to improve material identification using information from all three of the input datasets.

  18. Automated Essay Scoring

    Directory of Open Access Journals (Sweden)

    Semire DIKLI

    2006-01-01

    Full Text Available Automated Essay Scoring Semire DIKLI Florida State University Tallahassee, FL, USA ABSTRACT The impacts of computers on writing have been widely studied for three decades. Even basic computers functions, i.e. word processing, have been of great assistance to writers in modifying their essays. The research on Automated Essay Scoring (AES has revealed that computers have the capacity to function as a more effective cognitive tool (Attali, 2004. AES is defined as the computer technology that evaluates and scores the written prose (Shermis & Barrera, 2002; Shermis & Burstein, 2003; Shermis, Raymat, & Barrera, 2003. Revision and feedback are essential aspects of the writing process. Students need to receive feedback in order to increase their writing quality. However, responding to student papers can be a burden for teachers. Particularly if they have large number of students and if they assign frequent writing assignments, providing individual feedback to student essays might be quite time consuming. AES systems can be very useful because they can provide the student with a score as well as feedback within seconds (Page, 2003. Four types of AES systems, which are widely used by testing companies, universities, and public schools: Project Essay Grader (PEG, Intelligent Essay Assessor (IEA, E-rater, and IntelliMetric. AES is a developing technology. Many AES systems are used to overcome time, cost, and generalizability issues in writing assessment. The accuracy and reliability of these systems have been proven to be high. The search for excellence in machine scoring of essays is continuing and numerous studies are being conducted to improve the effectiveness of the AES systems.

  19. Automating the radiographic NDT process

    International Nuclear Information System (INIS)

    Automation, the removal of the human element in inspection, has not been generally applied to film radiographic NDT. The justication for automating is not only productivity but also reliability of results. Film remains in the automated system of the future because of its extremely high image content, approximately 8 x 109 bits per 14 x 17. The equivalent to 2200 computer floppy discs. Parts handling systems and robotics applied for manufacturing and some NDT modalities, should now be applied to film radiographic NDT systems. Automatic film handling can be achieved with the daylight NDT film handling system. Automatic film processing is becoming the standard in industry and can be coupled to the daylight system. Robots offer the opportunity to automate fully the exposure step. Finally, computer aided interpretation appears on the horizon. A unit which laser scans a 14 x 17 (inch) film in 6 - 8 seconds can digitize film information for further manipulation and possible automatic interrogations (computer aided interpretation). The system called FDRS (for Film Digital Radiography System) is moving toward 50 micron (*approx* 16 lines/mm) resolution. This is believed to meet the need of the majority of image content needs. We expect the automated system to appear first in parts (modules) as certain operations are automated. The future will see it all come together in an automated film radiographic NDT system (author)

  20. Electroanalytical measurements without electrolytes: conducting polymers as probes for redox titration in non-conductive organic media.

    Science.gov (United States)

    Lange, Ulrich; Mirsky, Vladimir M

    2012-09-26

    Electroanalytical methods have been applied only in conducting media. An application of conducting polymers allows to overcome this limitation. If such material is in electrochemical equilibrium with dissolved redox active species, its electrical conductivity depends on the redox potential of these species. Therefore, conductometric measurements with conducting polymers can provide about the same information as classical redox electrodes. The approach was applied for redox titration. Equivalent points obtained by this titration in aqueous and organic electrolytes were identical. Then the approach was applied for determination of bromine number by redox titration in non-conducting organic phase.

  1. Rapid determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration

    Institute of Scientific and Technical Information of China (English)

    XIAO Jun-ping; WANG Xue-feng; ZHOU Qing-xiang; FAN Xiao-yuan; SU Xian-fa; Bai Hua-hua; DUAN Hai-jing

    2007-01-01

    A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol could be transferred into a nitroso-compound by reacting with NaNO2. The titration end-point was obtained by the formation of a sharp cut in the oscillopolarographic with infinitesimal NaNO2 on double platinum electrodes. The results showed that phenol had an excellent linear relationship over the range of 4.82×10-6 -9.65×10-3 mol/L, the RSD of the proposed method was lower than 1.5%, and the spiked recoveries of three real water samples were in the range of 95.6%-106.9%.

  2. 滴定分析教学的好帮手"Titration simulator"

    Institute of Scientific and Technical Information of China (English)

    "Titration; simulator"--Good; assistant; for; titration; analysis

    2005-01-01

      Titration simulator(滴定模拟器)软件是专门为滴定分析而设计的教学软件,它短小精悍,简洁实用,可以从Internet网上免费下载,网址为:http://www.chemonline.net/Truechemsoft/downsoft.asp?softID=1565该软件所占容量仅为72KB,是学生训练及化学教师的好助手.笔者在教学中尝试运用该软件辅助教学,效果良好,现将Titration simulator软件的主要功能、应用简要介绍如下:……

  3. An automatic system for acidity determination based on sequential injection titration and the monosegmented flow approach.

    Science.gov (United States)

    Kozak, Joanna; Wójtowicz, Marzena; Gawenda, Nadzieja; Kościelniak, Paweł

    2011-06-15

    An automatic sequential injection system, combining monosegmented flow analysis, sequential injection analysis and sequential injection titration is proposed for acidity determination. The system enables controllable sample dilution and generation of standards of required concentration in a monosegmented sequential injection manner, sequential injection titration of the prepared solutions, data collecting, and handling. It has been tested on spectrophotometric determination of acetic, citric and phosphoric acids with sodium hydroxide used as a titrant and phenolphthalein or thymolphthalein (in the case of phosphoric acid determination) as indicators. Accuracy better than |4.4|% (RE) and repeatability better than 2.9% (RSD) have been obtained. It has been applied to the determination of total acidity in vinegars and various soft drinks. The system provides low sample (less than 0.3 mL) consumption. On average, analysis of a sample takes several minutes. PMID:21641455

  4. Determination of the catalytic activity of binuclear metallohydrolases using isothermal titration calorimetry.

    Science.gov (United States)

    Pedroso, Marcelo M; Ely, Fernanda; Lonhienne, Thierry; Gahan, Lawrence R; Ollis, David L; Guddat, Luke W; Schenk, Gerhard

    2014-03-01

    Binuclear metallohydrolases are a large and diverse family of enzymes that are involved in numerous metabolic functions. An increasing number of members find applications as drug targets or in processes such as bioremediation. It is thus essential to have an assay available that allows the rapid and reliable determination of relevant catalytic parameters (k cat, K m, and k cat/K m). Continuous spectroscopic assays are frequently only possible by using synthetic (i.e., nonbiological) substrates that possess a suitable chromophoric marker (e.g., nitrophenol). Isothermal titration calorimetry, in contrast, affords a rapid assay independent of the chromophoric properties of the substrate-the heat associated with the hydrolytic reaction can be directly related to catalytic properties. Here, we demonstrate the efficiency of the method on several selected examples of this family of enzymes and show that, in general, the catalytic parameters obtained by isothermal titration calorimetry are in good agreement with those obtained from spectroscopic assays.

  5. Successful management of a difficult cancer pain patient by appropriate adjuvant and morphine titration

    Directory of Open Access Journals (Sweden)

    Shiv PS Rana

    2011-01-01

    Full Text Available Morphine has been used for many years to relieve cancer pain. Oral morphine (in either immediate release or modified release form remains the analgesic of choice for moderate or severe cancer pain. The dose of oral morphine is titrated up to achieve adequate relief from pain with minimal side effects. Antidepressant and anticonvulsant drugs, when used in addition to conventional analgesics, give excellent relief from cancer pain. Most cancer pain responds to pharmacological measures with oral morphine but some pain like neuropathic and bony pain, pain in children and elderly age group, and advanced malignancy pain are very difficult to treat. Here, we report the management of a similar patient of severe cancer pain and the difficulty that we came across during dose titration of oral morphine and adjuvant analgesic.

  6. Titratable macroions in multivalent electrolyte solutions: Strong coupling dressed ion approach

    Science.gov (United States)

    Adžić, Nataša; Podgornik, Rudolf

    2016-06-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macroions. The model system consists of two point-like macroions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a dressed ion strong coupling theory, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, pH of the solution, and salt concentration) through a simple charge regulation model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macroions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  7. Titratable Macroions in Multivalent Electrolyte Solutions: Strong Coupling Dressed Ion Approach

    CERN Document Server

    Adzic, Natasa

    2016-01-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macro-ions. The model system consists of two point-like macro-ions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a {\\em dressed ion strong coupling theory}, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt, and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, $pH$ of the solution, salt concentration) through a simple {\\em charge regulation} model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macro-ions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  8. Automated Fluid Interface System (AFIS)

    Science.gov (United States)

    1990-01-01

    Automated remote fluid servicing will be necessary for future space missions, as future satellites will be designed for on-orbit consumable replenishment. In order to develop an on-orbit remote servicing capability, a standard interface between a tanker and the receiving satellite is needed. The objective of the Automated Fluid Interface System (AFIS) program is to design, fabricate, and functionally demonstrate compliance with all design requirements for an automated fluid interface system. A description and documentation of the Fairchild AFIS design is provided.

  9. A Geochemical Reaction Model for Titration of Contaminated Soil and Groundwater at the Oak Ridge Reservation

    Science.gov (United States)

    Zhang, F.; Parker, J. C.; Gu, B.; Luo, W.; Brooks, S. C.; Spalding, B. P.; Jardine, P. M.; Watson, D. B.

    2007-12-01

    This study investigates geochemical reactions during titration of contaminated soil and groundwater at the Oak Ridge Reservation in eastern Tennessee. The soils and groundwater exhibits low pH and high concentrations of aluminum, calcium, magnesium, manganese, various trace metals such as nickel and cobalt, and radionuclides such as uranium and technetium. The mobility of many of the contaminant species diminishes with increasing pH. However, base additions to increase pH are strongly buffered by various precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior and associated geochemical effects is thus critical to evaluate remediation performance of pH manipulation strategies. This study was undertaken to develop a practical but generally applicable geochemical model to predict aqueous and solid-phase speciation during soil and groundwater titration. To model titration in the presence of aquifer solids, an approach proposed by Spalding and Spalding (2001) was utilized, which treats aquifer solids as a polyprotic acid. Previous studies have shown that Fe and Al-oxyhydroxides strongly sorb dissolved Ni, U and Tc species. In this study, since the total Fe concentration is much smaller than that of Al, only ion exchange reactions associated with Al hydroxides are considered. An equilibrium reaction model that includes aqueous complexation, precipitation, ion exchange, and soil buffering reactions was developed and implemented in the code HydroGeoChem 5.0 (HGC5). Comparison of model results with experimental titration curves for contaminated groundwater alone and for soil- water systems indicated close agreement. This study is expected to facilitate field-scale modeling of geochemical processes under conditions with highly variable pH to develop practical methods to control contaminant mobility at geochemically complex sites.

  10. Positive End-expiratory Pressure Titration after Alveolar Recruitment Directed by Electrical Impedance Tomography

    Institute of Scientific and Technical Information of China (English)

    Yun Long; Da-Wei Liu; Huai-Wu He; Zhan-Qi Zhao

    2015-01-01

    Background:Electrical impedance tomography (EIT) is a real-time bedside monitoring tool,which can reflect dynamic regional lung ventilation.The aim of the present study was to monitor regional gas distribution in patients with acute respiratory distress syndrome (ARDS) during positive-end-expiratory pressure (PEEP) titration using EIT.Methods:Eighteen ARDS patients under mechanical ventilation in Department of Critical Care Medicine of Peking Union Medical College Hospital from January to April in 2014 were included in this prospective observational study.After recruitment maneuvers (RMs),decremental PEEP titration was performed from 20 cmH2O to 5 cmH2O in steps of 3 cmH2O every 5-10 min.Regional over-distension and recruitment were monitored with EIT.Results:After RMs,patient with arterial blood oxygen partial pressure (PaO2) + carbon dioxide partial pressure (PaCO2) >400 mmHg with 100% of fractional inspired oxygen concentration were defined as RM responders.Thirteen ARDS patients was diagnosed as responders whose PaO2 + PaCO2 were higher than nonresponders (419 ± 44 mmHg vs.170 ± 73 mmHg,P < 0.0001).In responders,PEEP mainly increased recruited pixels in dependent regions and over-distended pixels in nondependent regions.PEEP alleviated global inhomogeneity of tidal volume and end-expiratory lung volume.PEEP levels without significant alveolar derecruitment and over-distension were identified individually.Conclusions:After RMs,PEEP titration significantly affected regional gas distribution in lung,which could be monitored with EIT.EIT has the potential to optimize PEEP titration.

  11. The coulometric titration of acids and bases in m-cresol medium

    NARCIS (Netherlands)

    Bos, M.; Dahmen, E.A.M.F.

    1974-01-01

    A method is described for the coulometric titration of acids and bases in the solvent m-cresol. The method is suitable for bases with pKa values greater than 11 in m-cresol, or for acids with pKa values below 13 in m-cresol. Amounts of 5–50 μeq of acid or base can be determined with a relative accur

  12. PEEP titration guided by ventilation homogeneity: a feasibility study using electrical impedance tomography

    OpenAIRE

    Zhao, Zhanqi; Steinmann, Daniel; Frerichs, Inéz; Guttmann, Josef; Möller, Knut

    2010-01-01

    Introduction Lung protective ventilation requires low tidal volume and suitable positive end-expiratory pressure (PEEP). To date, few methods have been accepted for clinical use to set the appropriate PEEP. The aim of this study was to test the feasibility of PEEP titration guided by ventilation homogeneity using the global inhomogeneity (GI) index based on electrical impedance tomography (EIT) images. Methods In a retrospective study, 10 anesthetized patients with healthy lungs mechanically ...

  13. AMPHOTERIC BEHAVIOR OF COMPLEX SYSTEMS : II. TITRATION OF SULFANILIC ACID-GLYCINE MIXTURES.

    Science.gov (United States)

    Stearn, A E

    1926-11-20

    Electrometric titrations of glycine, sulfanilic acid, and various mixtures of the two have been made. These mixtures are shown to give a curve which, between their respective isoelectric points, is different from that of either substance. These mixtures have a maximum buffering power at a pH which can be theoretically calculated, and which has the characteristics of an "isoelectric point of the system." Other pairs of ampholytes are shown to act in an analogous manner.

  14. Automatic nasal continuous positive airway pressure titration in the laboratory: patient outcomes

    OpenAIRE

    Stradling, J. R.; Barbour, C.; Pitson, D. J.; Davies, R J

    1997-01-01

    BACKGROUND: Manual titration of nasal continuous positive airway pressure (NCPAP) treatment for obstructive sleep apnoea (OSA) is time consuming and expensive. There are now "intelligent" NCPAP machines that try to find the ideal pressure for a patient by monitoring a combination of apnoeas, hypopnoeas, inspiratory flow limitation, and snoring. Although these machines usually find similar pressures to skilled technicians, it is not clear if their use in the sleep laboratory influences s...

  15. Revisiting the streptavidin-biotin binding by using an aptamer and displacement isothermal calorimetry titration.

    Science.gov (United States)

    Kuo, Tai-Chih; Tsai, Ching-Wei; Lee, Peng-Chen; Chen, Wen-Yih

    2015-03-01

    The association constant of a well-known streptavidin-biotin binding has only been inferred from separately measured kinetic parameters. In a single experiment, we obtained Ka 1 × 10(12)  M(-1) by using a streptavidin-binding aptamer and ligand-displacement isothermal titration calorimetry. This study explores the challenges of determining thermodynamic parameters and the derived equilibrium binding affinity of tight ligand-receptor binding.

  16. Importance of anticomplement immunofluorescence antibody titration for diagnosing varicella-zoster virus infection in Bell's palsy.

    OpenAIRE

    Shigeta, S; Baba, M.; Ogata, M; Nozaki, H.; Okuaki, A; Nakamura, S.

    1986-01-01

    Anticomplement Immunofluorescence was used for antibody titration against varicella-zoster virus (VZV) in 43 patients with peripheral facial palsy. Nine of 31 patients (29%) with Bell's palsy and eight of 12 patients (75%) with Ramsey-Hunt syndrome had anticomplement immunofluorescence antibody titres of greater than or equal to 1/10. On the other hand, none of 14 patients with herpes simplex virus (HSV) infection and 51 healthy adults showed anticomplement immunofluorescence antibody titres ...

  17. Clinical predictors of central sleep apnea evoked by positive airway pressure titration

    Science.gov (United States)

    Moro, Marilyn; Gannon, Karen; Lovell, Kathy; Merlino, Margaret; Mojica, James; Bianchi, Matt T

    2016-01-01

    Purpose Treatment-emergent central sleep apnea (TECSA), also called complex apnea, occurs in 5%–15% of sleep apnea patients during positive airway pressure (PAP) therapy, but the clinical predictors are not well understood. The goal of this study was to explore possible predictors in a clinical sleep laboratory cohort, which may highlight those at risk during clinical management. Methods We retrospectively analyzed 728 patients who underwent PAP titration (n=422 split-night; n=306 two-night). Demographics and self-reported medical comorbidities, medications, and behaviors as well as standard physiological parameters from the polysomnography (PSG) data were analyzed. We used regression analysis to assess predictors of binary presence or absence of central apnea index (CAI) ≥5 during split-night PSG (SN-PSG) versus full-night PSG (FN-PSG) titrations. Results CAI ≥5 was present in 24.2% of SN-PSG and 11.4% of FN-PSG patients during titration. Male sex, maximum continuous positive airway pressure, and use of bilevel positive airway pressure were predictors of TECSA, and rapid eye movement dominance was a negative predictor, for both SN-PSG and FN-PSG patients. Self-reported narcotics were a positive predictor of TECSA, and the time spent in stage N2 sleep was a negative predictor only for SN-PSG patients. Self-reported history of stroke and the CAI during the diagnostic recording predicted TECSA only for FN-PSG patients. Conclusion Clinical predictors of treatment-evoked central apnea spanned demographic, medical history, sleep physiology, and titration factors. Improved predictive models may be increasingly important as diagnostic and therapeutic modalities move away from the laboratory setting, even as PSG remains the gold standard for characterizing primary central apnea and TECSA. PMID:27555802

  18. Titration mit oralem transmukosalem Fentanylcitrat und Morphinsulfat zur Dosisfindung einer Behandlung mit transdermalem Fentanylpflaster

    OpenAIRE

    Eimer, Sebastian

    2012-01-01

    Patients who needed a treatment with opioids of WHO level 3 due to increasing pain were included in this study. We compared oral transmucosal fentanyl citrate (OTCF) with immediate release morphine (IRM) for the dose finding of a transdermal fentanyl (TF) treatment. Up to now commonly morphine either orally, subcutaneously or via Patient Controlled Analgesia (PCA) intravenously was used for dose titration. However, conversion ratio tables were necessary to calculate the ratio of morphine to T...

  19. Continuous flow thin layer headspace (TLHS) analysis. Pt. 4. Indirect potentiometric determination of volatile organic halogens (VOX) in water

    Energy Technology Data Exchange (ETDEWEB)

    Kozlowski, E.; Gorecki, T.; Sienkowska-Zyskowska, E. (Technical Univ. of Gdansk (Poland). Inst. of Inorganic Chemistry, Technology and Corrosion)

    1991-08-01

    The paper presents two methods of potentiometric VOX determination in drinking water utilizing the previously developed TLHS method for the isolation of the volatile analytes from aqueous samples. Halogen mineralization products are converted with the use of silver oxyiodide into iodine equivalent, reduced subsequently to iodide ions using ascorbic acid or sodium sulphite solutions. An iodine ion-selective electrode and Ag/AgI electrodes have been used for the final determination of iodides in the washing solution. Both methods proved to be very precise and accurate, the detection limit being lower in the case of the Ag/AgI electrode (of the order of hundreds of pg/ml). The derived compact form of the general equation describing the recovery of the volatile analyte enabled an easy estimation of the flattening of the recovery curve around the maximum, determining the magnitude of the effect of gas flow rate variations on the accuracy and precision of the determination. (orig.).

  20. Accuracy of potentiometric oxygen sensors with Bi/Bi2O3 reference electrode for use in liquid LBE

    Science.gov (United States)

    Lim, J.; Mariën, A.; Rosseel, K.; Aerts, A.; Van den Bosch, J.

    2012-10-01

    Potentiometric oxygen sensors fabricated with yttria partially stabilized zirconia (YPSZ) and a Bi/Bi2O3 reference electrode were tested in oxygen saturated lead-bismuth eutectic (LBE) and oxygen saturated tin (Sn), respectively, in order to estimate the accuracy of the oxygen sensors prior to applying them to R&D work for MYRRHA. The accuracy of these sensors was estimated in the temperature range of 673-733 K by measuring the electromotive force (emf) of eight sensors. The standard deviation on the measured emf data was about 0.79 mV in the case of oxygen saturated LBE and was about 1.25 mV in the case of oxygen saturated Sn. These values result in a standard deviation of 4% on the oxygen concentration in LBE which is calculated from the measured emf.