1
|
|
2
|
Development of a sensitive and selective Riboflavin sensor based on carbon ionic liquid electrode. Anal Chim Acta 2010; 674:176-81. [DOI: 10.1016/j.aca.2010.06.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 06/04/2010] [Accepted: 06/09/2010] [Indexed: 11/22/2022]
|
3
|
|
4
|
Mikheeva EV, Martynyuk OA, Slepchenko GB, Anisimova LS. Study of the voltammetric behavior of vitamin B2 and the development of a procedure for its determination in breast milk. JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1134/s1061934809070120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
5
|
Ibanez JG, Carreon-Alvarez A, Barcena-Soto M, Casillas N. Metals in alcoholic beverages: A review of sources, effects, concentrations, removal, speciation, and analysis. J Food Compost Anal 2008. [DOI: 10.1016/j.jfca.2008.06.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
6
|
Yantasee W, Timchalk C, Lin Y. Microanalyzer for biomonitoring lead (Pb) in blood and urine. Anal Bioanal Chem 2006; 387:335-41. [PMID: 17119936 DOI: 10.1007/s00216-006-0940-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 10/09/2006] [Accepted: 10/12/2006] [Indexed: 11/30/2022]
Abstract
Biomonitoring of lead (Pb) in blood and urine enables quantitative evaluation of human occupational and environmental exposures to Pb. State-of-the-art ICP-MS instruments can only analyze metals in laboratories, resulting in lengthy turnaround times, and they are expensive. In response to the growing need for a metal analyzer capable of on-site, real-time monitoring of trace toxic metals in individuals, we developed a portable microanalyzer based on flow-injection/stripping voltammetry (ASV), and validated the system using rat blood and urine spiked with known amounts of Pb. Fouling of electrodes by proteins often prevents the effective use of electrochemical sensors in biological matrices. Minimization of such fouling was accomplished with suitable sample pretreatment and by establishing turbulent flow of blood and urine containing Pb onto the electrode inside the microanalyzer, which resulted in no apparent electrode fouling even when the samples contained 50% urine or 10% blood by volume. No matrix effect was observed for the voltammetric Pb signals, even when the samples contained 10% blood or 10% urine. The microanalyzer offered linear concentration ranges relevant to Pb exposure levels in humans (0-20 ppb in 10% blood samples, 0-50 ppb in 50% urine samples). The device showed excellent sensitivity and reproducibility; Pb detection limits were 0.44 ppb and 0.46 ppb, and % R.S.D. was 4.9 and 2.4 in 50% urine and 10% blood samples, respectively. It gave similar Pb concentrations in blood and urine to those measured by ICP-MS. It offered high throughput (3 min per sample) and economical use of samples (60 microL per measurement) as well as low reagent consumption (1 microg of Hg per measurement), thus minimizing environmental concerns associated with mercury use. Since it is miniaturized, the microanalyzer is portable and field-deployable. Thus, it shows much promise as the next-generation analyzer for the biomonitoring of toxic metals.
Collapse
|
7
|
|
8
|
Maisonhaute E, Javier Del Campo F, Compton RG. Microelectrode study of single cavitational bubbles induced by 500 kHz ultrasound. ULTRASONICS SONOCHEMISTRY 2002; 9:275-283. [PMID: 12371205 DOI: 10.1016/s1350-4177(02)00074-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Insight is gained into about the processes governing cavitational activity and acoustic streaming induced by high frequency (500 kHz) ultrasound by the use of microelectrodes with short time resolution electrochemical equipment to allow monitoring of the activity of single cavitating bubbles. Current transients are interpreted as showing the flux of solution towards the electrode surface due to microstreaming. In order to explain the current amplitude, a simplified model is produced. Important parameters such as bubble size and shape on the surface as well as the boundary layer thickness for microstreaming are taken into account. This model leads to the amplitude of the oscillations of the cavitating bubble. Introducing realistic bubble sizes, this amplitude is found to be in the order of 1 micron. The conclusions arising from this work allow a further interpretation of previous observations at millimeter scale electrodes.
Collapse
Affiliation(s)
- Emmanuel Maisonhaute
- Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK
| | | | | |
Collapse
|
9
|
Floate S, Hyde M, Compton RG. Electrochemical and AFM studies of the electrodeposition of cobalt on glassy carbon: an analysis of the effect of ultrasound. J Electroanal Chem (Lausanne) 2002. [DOI: 10.1016/s0022-0728(02)00709-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
González-García J, Gallud F, Iniesta J, Montiel V, Aldaz A, Lasia A. Kinetics of Electrocrystallization of PbO2 on Glassy Carbon Electrodes. Influence of the Electrode Rotation. ELECTROANAL 2001. [DOI: 10.1002/1521-4109(200110)13:15<1258::aid-elan1258>3.0.co;2-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
11
|
Abstract
One of the most popular means for removal of organic water pollutants found in small concentrations is by adsorption. An important step in adsorption processes is the regeneration of the adsorbent as it does not only affect the adsorption-desorption cycle but also the expenses of the following process steps. State of the art regeneration of adsorbent resins is done by chemical methods. These require the use of organic solvents or inorganic chemicals and involve a difficult secondary separation step. Therefore, industry seeks for alternative methods to regenerate exhausted adsorbents. One of the discussed regeneration methods is desorption by ultrasound. Ultrasound does not only promote desorption but also enhances the mass transfer of sorption processes. We discuss the arising problems and basic effects when applying ultrasound during sorption processes in order to show the potentials of this desorption process. The focus is laid in particular on the influence of ultrasound frequency and intensity.
Collapse
Affiliation(s)
- M Breitbach
- Department of Chemical Engineering, University of Dortmund, Emil-Figge-Street 70, D-44221 Dortmund, Germany.
| | | |
Collapse
|
12
|
Hardcastle JL, Paterson CJ, Compton RG. Biphasic Sonoelectroanalysis: Simultaneous Extraction from, and Determination of Vanillin in Food Flavoring. ELECTROANAL 2001. [DOI: 10.1002/1521-4109(200107)13:11<899::aid-elan899>3.0.co;2-e] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
13
|
Kado Y, Atobe M, Nonaka T. Ultrasonic effects on electroorganic processes--Part 20. Photocatalytic oxidation of aliphatic alcohols in aqueous suspension of TiO2 powder. ULTRASONICS SONOCHEMISTRY 2001; 8:69-74. [PMID: 11326612 DOI: 10.1016/s1350-4177(00)00072-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ultrasonic effects in a suspension system were examined using the photocatalytic oxidation of 2-propanol to acetone and of ethanol to acetaldehyde in the aqueous suspension of TiO2 powder as a model reaction. The formation rate of acetone was significantly increased under ultrasonic irradiation. The oxidation reaction under ultrasonic irradiation was affected in a different manner from that in silence by reaction conditions such as ultrasonic power, stirring speed, amount of TiO2, concentration of 2-propanol, and pretreatment of the TiO2 powder. Furthermore, it was also observed that the particle size of the TiO2 photocatalyst powder was increased due to the particle agglomeration by ultrasonic irradiation, and consequently it was suggested that ultrasound activates the surface of the catalyst. These results are discussed on the basis of not only the activation of the photocatalyst but also ultrasonic enhancement of mass transport of 2-propanol molecules.
Collapse
Affiliation(s)
- Y Kado
- Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | | | | |
Collapse
|
14
|
|
15
|
Del Campo FJ, Melville J, Hardcastle JL, Compton RG. Differential Pulse and Chronoamperometric Studies of Insonated Systems: Acoustic Streaming and Cavitational Effects. J Phys Chem A 2000. [DOI: 10.1021/jp002948l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- F. Javier Del Campo
- Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, U.K
| | - James Melville
- Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, U.K
| | - Joanna L. Hardcastle
- Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, U.K
| | - Richard G. Compton
- Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, U.K
| |
Collapse
|
16
|
Hardcastle JL, Murcott GG, Compton RG. Sonoelectroanalysis: Ultrasonically Facilitated Liberation and Determination of Copper in Whole Blood. ELECTROANAL 2000. [DOI: 10.1002/(sici)1521-4109(200005)12:8<559::aid-elan559>3.0.co;2-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
17
|
Abstract
So far, the influence of sonication on the electrolytic current was studied only at solid or rather miniaturized mercury electrodes. The presented paper reports on sonoelectrochemical experiments at a liquid mercury pool electrode. Two sonoelectrochemical cells have been developed and tested. It was shown that during sonication, the electrolytic current increases in a number of individual peaks representing short local enhancements of current density due to vigorous local mass transfer and instantaneous increase of fresh electrode surface. Both these effects are caused by microjets of solution formed during violent unsymmetric collapses of cavitation bubbles in the close vicinity of the electrode surface. The newly formed electrode surface and the decrease in the diffusion layer thickness were estimated and discussed. An example is presented where the sonication is used for destruction of a film of products formed during electrolysis of cysteine, that otherwise rapidly inhibits continuation of the electrode process.
Collapse
|
18
|
Mikkelsen Ø, Schrøder K. Low Frequency Sound for Effective Sensitivity Enhancement in Staircase Voltammetry. ANAL LETT 2000. [DOI: 10.1080/00032710008543124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
19
|
Hardcastle JL, Ball JC, Hong Q, Marken F, Compton RG, Bull SD, Davies SG. Sonoelectrochemical and sonochemical effects of cavitation: correlation with interfacial cavitation induced by 20 kHz ultrasound. ULTRASONICS SONOCHEMISTRY 2000; 7:7-14. [PMID: 10643632 DOI: 10.1016/s1350-4177(99)00026-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Sonoelectrochemical measurements at macro-electrodes under extreme conditions with a very short distance between ultrasonic horn tip and electrode and different ultrasound intensity levels are shown to result in violent cavitation detected in form of current peaks superimposed on the average limiting current. Analysis of the current data obtained for the oxidation of ferrocene in dimethylformamide (0.1 M NBu4PF6) at a 4 mm diameter Pt disc electrode and for the reduction of Ru(NH3)6(3+) in aqueous 0.1 M KCl at a 6 mm diameter Pt disc electrode consistently indicate a change of the physicochemical nature of sonoelectrochemical processes under extreme conditions. The sonoelectrochemical measurement of the rate constant for the carbon bromide bond cleavage of a 3-bromobenzophenone radical anion electrogenerated at a glassy carbon electrode in dimethylformamide solution in the presence of power ultrasound is shown to yield evidence for a breakdown of the conventional mass transport model of a planar diffusion layer under extreme conditions. The change can be correlated to the number of current data points deviating more than 10% from the mean of the current due to violent cavitation processes superimposed onto the average limiting current. Further, a study of the sonochemical destruction of aqueous dilute cyanide solution (in 0.1 M NaOH) demonstrates a correlation between the electrochemically detected cavitation violence and the sonochemical activity. Factors that govern the violence of interfacial cavitation appear to be directly proportional to the factors that make cavitation in the bulk solution chemically efficient.
Collapse
Affiliation(s)
- J L Hardcastle
- Physical & Theoretical Chemistry Laboratory, Oxford University, UK
| | | | | | | | | | | | | |
Collapse
|
20
|
Saterlay AJ, Agra-Gutiérrez C, Taylor MP, Marken F, Compton RG. Sono-Cathodic Stripping Voltammetry of Lead at a Polished Boron-Doped Diamond Electrode: Application to the Determination of Lead in River Sediment. ELECTROANAL 1999. [DOI: 10.1002/(sici)1521-4109(199911)11:15<1083::aid-elan1083>3.0.co;2-i] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
BALL JC, COMPTON RG. Application of Ultrasound to Electrochemical Measurements and Analyses. ELECTROCHEMISTRY 1999. [DOI: 10.5796/electrochemistry.67.912] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
22
|
|
23
|
Perspectives in Modern Voltammetry: Basic Concepts and Mechanistic Analysis. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0065-3160(08)60006-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|