CYTOPATHOLOGY, Issue 2006
M. A. Lynch
Liquid based cytology (LBC) has improved cell visualization and preservation in cervical cytology. There has been a reduction in inadequate rate and some data to suggest an increase in sensitivity for dyskaryosis. Training for LBC has focused on differences in distribution of abnormal cells, but in most cases the morphological appearance of the dyskaryotic cells themselves is similar to that seen in conventional cytology. We are describing a new presentation of dyskaryosis which may be a cause of false negative cytology. We have referred to this as ,Bland dyskaryosis' because cells appear deceptively bland on low power examination, and can be misinterpreted as metaplastic or endocervical cells. Bland dyskaryosis cells are seen in groups. The architecture of the group is very disorganized, and adjacent cells show variation in size. Cells have a high nuclear/cytoplasmic ratio and smooth nuclear membranes. Chromatin is finely granular and evenly distributed. This is an unusual presentation of high-grade dyskaryosis and we feel that there is a learning curve in laboratories converting to liquid based cytology. The spectrum of appearances of squamous dyskaryosis needs to be delineated to allow further increases in sensitivity for dyskaryosis. [source]

O-13 ENDOMETRIAL CARCINOMA DETECTED WITH SUREPATH LIQUID BASED CERVICAL CYTOLOGY: COMPARISON WITH CONVENTIONAL CERVICAL CYTOLOGY

CYTOPATHOLOGY, Issue 2006
C. J. Patel
Introduction:, Conventional Pap Smear (CPS) has had little impact on the detection of endometrial carcinoma (MC). Although Liquid Based Cytology (LBC) is replacing CPS in the UK, experience with identification of endometrial cancers with this is limited. A few studies of ThinPrep LBC show promise with reported increased detection rate, but to date, there has been no reported study of detection with SurePath LBC. Aim:, The purpose of this 2-year retrospective study was to compare the accuracy of the SurePath LBC with that of conventional smear in detecting endometrial cancers. Methods:, Our study group consisted of all SurePath cases of endometrial atypia/carcinoma diagnosed between 1st Jan 2004 and 31st Dec 2005, following 100% conversion of our laboratory to the SurePath system in 2001. Conventional smears reported over a 6-year period (1993,1998), comprised the control group. Histological follow up was obtained. Results:, Endometrial lesions were reported in 95 (0.07%) of 130352 SurePath LBC smears. These included 70 (0.053%) reports of endometrial atypia, 05 (0.003%) suspicious and 20 (0.015%) diagnostic of endometrial carcinoma. A total of 58 (0.014%) cases of 409495 CPS were diagnosed as endometrial carcinoma. Adequate histological follow up was available in 47 (49.5%) SurePath LBC and 52 (89.6%) conventional cases. In these, the positive predictive value (PPV) for endometrial carcinoma of SurePath LBC was 73.3% compared to 55.4% of CPS. The PPV for endometrial carcinoma of the atypical and suspicious LBC categories was 14.3% and 40% respectively. No categorisation as atypical or suspicious in the conventional study was available for comparison. The sensitivity of the SurePath LBC, calculated from retrograde analysis of histologically diagnosed endometrial cancers during the same period was 40%. Conclusion:, The SurePath LBC is at least an as accurate and sensitive method for detecting endometrial cancer as CPS. [source]

P-11 THE IMPACT OF INTRODUCING LIQUID BASED CYTOLOGY INTO A ROUTINE SCREENING LABORATORY

CYTOPATHOLOGY, Issue 2006
L. Gregory
With the exception of information from the liquid based cytology (LBC) pilot site there has been limited data to date on the impact of the introduction of SurePathÔ LBC in the NHSCSP. We will present data to show the impact on a medium sized laboratory (42 000 requests per annum) over the first phases of rollout. Data from before, during and post conversion, a period of 28 months, shows the following trends: (1) A significant fall in the inadequate rate (2) A slight decrease in the borderline / mild dyskaryosis rate (3) A small increase in the high-grade squamous dyskaryosis reporting rate (4) An increase in both the number and specificity of glandular lesions reported (5) A largely unchanged positive predictive value for high-grade abnormalities (6) A significant increase in laboratory productivity, unrelated to inadequate rate but through increased speed of screening. Although our experience is not directly comparable to the experience of the LBC pilot, our observations may well reflect that we were fortunate to be trained by staff from one of the LBC sites and thereby benefited directly from their experience. [source]

IS IT REALITY OR AN ILLUSION THAT LIQUID-BASED CYTOLOGY IS BETTER THAN CONVENTIONAL CERVICAL SMEARS?

CYTOPATHOLOGY, Issue 2 2002
Robin Moseley
No abstract is available for this article. [source]

IS IT REALITY OR AN ILLUSION THAT LIQUID-BASED CYTOLOGY IS BETTER THAN CONVENTIONAL CERVICAL SMEARS?

CYTOPATHOLOGY, Issue 1 2002
J. Linder
No abstract is available for this article. [source]

PRODUCTION OF LIQUID AND WHITE SOLID PEKMEZ IN TURKEY

JOURNAL OF FOOD QUALITY, Issue 5-6 2005
ALI BATU
ABSTRACT The research was carried out to evaluate gelling and bleaching agents for white solid pekmez production. Grape juice with 26% total soluble solids as °Brix was used for the production of pekmez. Acidity was reduced with the application of sterile white soil containing 70.4% CaCO3, followed by tannin,gelatin clarification and filtration. The grape juice was concentrated to 76% total soluble solids by vacuum. Gelling treatments were designed to produce a solid pekmez by adding high or low methoxyl pectins or carboxymethylcellulose (CMC). It was found that sufficient gelling could be achieved using less than 0.5% CMC and 1% for either pectin. Also, a desirable white color was obtained with 1.5% soapwort juice and 3% egg white with the combination of 1% pectins. [source]

A CRITICAL LOOK AT PAP ADEQUECY: ARE OUR CRITERIA SATISFACTORY?

CYTOPATHOLOGY, Issue 2006
D.R. Bolick
Liquid based Pap (LBP) specimen adequacy is a highly documented, yet poorly understood cornerstone of our GYN cytology practice. Each day, as cytology professionals, we make adequacy assessments and seldom wonder how the criteria we use were established. Are the criteria appropriate? Are they safe? What is the scientific data that support them? Were they clinically and statistically tested or refined to achieve optimal patient care? In this presentation, we will take a fresh look at what we know about Pap specimen adequacy and challenge some of the core assumptions of our daily practice. LBP tests have a consistent, well-defined surface area for screening, facilitating the quantitative estimates of slide cellularity. This provides an unprecedented opportunity to establish reproducible adequacy standards that can be subjected to scientific scrutiny and rigorous statistical analysis. Capitalizing on this opportunity, the TBS2001 took the landmark step to define specimen adequacy quantitatively, and set the threshold for a satisfactory LBP at greater than 5,000 well visualized squamous epithelial cells. To date, few published studies have attempted to evaluate the validity or receiver operator characteristics for this threshold, define an optimal threshold for clinical utility or assess risks of detection failure in ,satisfactory' but relatively hypocellular Pap specimens. Five years of cumulative adequacy and cellularity data of prospectively collected Pap samples from the author's laboratory will be presented, which will serve as a foundation for a discussion on ,Pap failure'. A relationship between cellularity and detection of HSIL will be presented. Risk levels for Pap failure will be presented for Pap samples of different cellularities. The effect of different cellularity criterion on unsatisfactory Pap rates and Pap failure rates will be demonstrated. Results from this data set raise serious questions as to the safety of current TBS2001 adequacy guidelines and suggest that the risk of Pap failure in specimens with 5,000 to 20 000 squamous cells on the slide is significantly higher than those assumed by the current criteria. TBS2001 designated all LBP to have the same adequacy criterion. Up to this point, it has been assumed that ThinPrep, SurePath, or any other LBP would be sufficiently similar that they should have the same adequacy criteria. Data for squamous cellularity and other performance characteristics of ThinPrep and SurePath from the author's laboratory will be compared. Intriguing data involving the recently approved MonoPrep Pap Test will be reviewed. MonoPrep clinical trial data show the unexpected finding of a strong correlation between abundance of endocervical component and the detection of high-grade lesions, provoking an inquiry of a potential new role for a quantitative assessment of the transition zone component. The current science of LBP adequacy criteria is underdeveloped and does not appear to be founded on statistically valid methods. This condition calls us forward as a body of practitioners and scientists to rigorously explore, clarify and define the fundamental nature of cytology adequacy. As we forge this emerging science, we will improve diagnostic performance, guide the development of future technologies, and better serve the patients who give us their trust. Reference:, Birdsong GG: Pap smear adequacy: Is our understanding satisfactory? Diagn Cytopathol. 2001 Feb; 24(2): 79,81. [source]

DEFINING DYSKARYOSIS , THE BSCC CLASSIFICATION IN 2006

CYTOPATHOLOGY, Issue 2006
K. Denton
The terminology used for reporting cervical samples in the UK is the BSCC classification, which has evolved over many years. In 2002 the BSCC held a consensus conference to review the BSCC classification, with the intention of providing clearer results for women, improving concordance with other terminologies and facilitating consistency with new scientific developments and technologies. The consensus conference was well attended and robust. In the intervening years there have also been other further advances on morphometry, data on outcomes, data from EQA and other sources. Liquid Based cytology (LBC) has been implemented by the NHS CSP. All of these developments have impacted on the proposed classification, which will be presented in full. The term ,dyskaryosis' will be retained and several of the current reporting categories will be relatively unchanged, though additional information on LBC will be provided. The major proposed changes are: (1) A move to a single category of ,High Grade Dyskaryosis' to replace the existing categories of moderate and severe dyskaryosis. (2) Sub-division of Borderline change into three categories. Borderline change in glandular cells Borderline change ?high grade Borderline change, NOS (3) The current grades of Mild Dyskaryosis and Borderline change with Koilocytosis to be merged. Details of these proposals, together with illustrations and the evidence base for change will be presented. [source]

O-12 BLAND DYSKARYOSIS: A NEW PITFALL IN THINPREP® LIQUID BASED CYTOLOGY

O-13 ENDOMETRIAL CARCINOMA DETECTED WITH SUREPATH LIQUID BASED CERVICAL CYTOLOGY: COMPARISON WITH CONVENTIONAL CERVICAL CYTOLOGY

Liquid-based cytology: the evidence is out there?

CYTOPATHOLOGY, Issue 2 2006
Philip O G Wilson
No abstract is available for this article. [source]

Liquid-based cytology: applying international experience to the United Kingdom

CYTOPATHOLOGY, Issue 3 2004
K. J. Denton
No abstract is available for this article. [source]

Liquid-based cytology: is this the way forward for cervical screening?

CYTOPATHOLOGY, Issue 2 2002
R. P. MOSELEY
Liquid-based cytology: is this the way forward for cervical screening? Liquid-based cytology (LBC) is currently being marketed as an alternative methodology to replace the conventional PAP smear in cervical cytology. A substantial body of literature exists in support of LBC, some of which is at least partially sponsored by product manufacturers. The majority of published literature in support of LBC employs Bethesda reporting terminology. In this study we have analysed published raw data and presented this in NHSCSP terminology. Claims relating to sensitivity, specificity and smear adequacy have then been considered with reference to this data. Our analysis of existing data does not support the nationwide implementation of LBC at present. Further studies are recommended in order to evaluate the place of this technology within the NHSCSP. [source]

Liquid-based cytology , an alternative international view

CYTOPATHOLOGY, Issue 3 2001
M. Broadstock
No abstract is available for this article. [source]

Liquid-based cytology for cervical screening

CYTOPATHOLOGY, Issue 6 2000
N. Payne
England and Wales' new National Institute for Clinical Excellence (NICE) has completed the first of its appraisals and issued guidance on a diagnostic technique rather than a therapeutic intervention.1 It was directed to examine the use of liquid-based cytology (LBC) for cervical screening and took evidence from a wide variety of sources. LBC is a new method of preparing cervical samples for cytological examination. Unlike the conventional ,smear' preparation it involves making a suspension of cells from the sample and this is used to produce a thin layer of cells on a slide. [source]

Human papillomavirus prevalence and cytopathology correlation in young Ugandan women using a low-cost liquid-based pap preparation

DIAGNOSTIC CYTOPATHOLOGY, Issue 8 2010
Janis M. Taube M.D.
Abstract Screening for HPV-driven cervical dysplasia and neoplasia is a significant public health concern in the developing world. The purpose of this study was to use a manual, low-cost liquid-based Pap preparation to determine HPV prevalence in HIV-positive and HIV-negative young women in Kampala, Uganda and to correlate cervical cytopathology with HPV-DNA genotype. About 196 post-partum women aged 18,30 years underwent rapid HIV testing and pelvic examination. Liquid-based cervical cytology samples were processed using a low-cost manual technique. A DNA collection device was used to collect specimens for HPV genotyping. HIV and HPV prevalence was 18 and 64%, respectively. Overall, 49% of women were infected with a high-risk HPV genotype. The most common high-risk HPV genotypes were 16 (8.2%), 33 (7.7%), 35 (6.6%), 45 (5.1%), and 58 (5.1%). The prevalence of HPV 18 was 3.6%. HIV-positive women had an HPV prevalence of 86% compared to 59% in HIV-negative women (P = 0.003). The prevalence of HPV 16/18 did not differ by HIV status. HIV-positive women were infected with a significantly greater number of HPV genotypes compared to HIV-negative women. By multivariate analysis, the main risk factor for HPV infection was coinfection with HIV. HIV-positive women were four times more likely to have abnormal cytology than HIV-negative women (43% vs. 11.6%, P < 0.001). These data highlight that HIV infection is a strong risk factor for HPV infection and resultant abnormal cervical cytology. Notably, the manual low-cost liquid-based Pap preparation is practical in this setting and offers an alternate method for local studies of HPV vaccine efficacy. Diagn. Cytopathol. 2010;38:555,563. 2009 Wiley-Liss, Inc. [source]

Comparison of the sensitivity of conventional cytology and the ThinPrep Imaging System for 1,083 biopsy confirmed high-grade squamous lesions,

DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2010
C.T. (A.S.C.), C.T. (I.A.C.), J. A. Halford B.App.Sc.
Abstract Liquid-based cytology continues to be utilized as an adjunct to conventional cytology in most Australian laboratories, even though a direct-to-vial ThinPrep protocol has been introduced in many countries with established cervical screening programs. Manual screening of ThinPrep slides has been widely practiced for more than 10 years and the recent introduction of the ThinPrep Imaging System (TPI) has been reported as being more sensitive than the conventional smear (CS) in the identification of high-grade cervical disease. We report our experience with ThinPrep Imaging since its introduction into our routine gynecological cytology service. 87,284 split sample pairs reported using the Imaging System demonstrated a decrease in unsatisfactory reports (3.65% for CS and 0.87% for TPI) and an increase in possible high grade and definite high-grade squamous reports (1.57% for CS and 1.62% for TPI). For 1,083 biopsy confirmed high-grade lesions, the correct diagnosis of high grade or possible high-grade squamous disease was made on the ThinPrep imaged slide in 61.0% (661/1,083) of cases and on the CS in 59.4% (643/1,083). This was not statistically significant. When all abnormalities identified on cytology were considered, including possible low grade and definite low-grade abnormalities, the difference in sensitivity for Thinprep imaged slides of 96.0% (1,040/1,083) and CSs of 91.6% (992/1,083) was statistically significant. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source]

Development of a Glucose Biosensor Using Advanced Electrode Modified by Nanohybrid Composing Chemically Modified Graphene and Ionic Liquid

ELECTROANALYSIS, Issue 11 2010
Ho Yang
Abstract Nanohybrids of chemically modified graphene (CMG) and ionic liquid (IL) were prepared by sonication to modify the electrode. The modified CMG-IL electrodes showed a higher current and smaller peak-to-peak potential separation than a bare electrode due to the promoted electron transfer rate. Furthermore, the glucose oxidase (GOx) immobilized on the modified electrode displayed direct electron transfer rate and symmetrical redox potentials with a linear relationship at different scan rates. The fabricated GOx/CMG-IL electrodes were developed selective glucose biosensor with respect to a sensitivity of 0.64,,A mM,1, detection limit of 0.376,mM, and response time of <5,s. [source]

Green Synthesis of Silver Nanoparticles Using Ionic Liquid and Application for the Detection of Dissolved Oxygen

ELECTROANALYSIS, Issue 6 2010
Tsung-Hsuan Tsai
Abstract The electrochemical synthesis of silver nanoparticles (nano-Ag) has been successfully carried out on glassy carbon electrode (GCE) and indium tin oxide electrode (ITO) using 1-butyl-3-methylimidazolium tetrafluoroborate (BMT) as green electrolytes. Further the electrodeposited nano-Ag modified ITO electrode has been examined using atomic force microscopy (AFM), and X-ray diffraction studies (XRD). The electrodeposited Ag nanoparticles on ITO were found in the size range of 5 to 35,nm. The nano-Ag film modified GCE was further coated with nafion (Nf) and BMT (1,:,1 ratio) mixture and found to be stable in BMT and in pH,7 phosphate buffer solution (PBS). The nano-Ag/BMT-Nf film modified GCE successfully applied for the oxygen reduction reaction in neutral pH (pH,7.0 PBS). The proposed film modified GCE successfully reduces the over potential and show well defined reduction peaks for the detection of dissolved oxygen using cyclic voltammetry (CV) and rotating disc voltammetry (RDE). The film also applied for the detection of dissolved oxygen using electrochemical impedance spectroscopic studies (EIS). [source]

Electrogenerated Chemiluminescence Sensor Based on Tris(2,2,-bipyridine)ruthenium(II)-Immobilized Natural Clay and Ionic Liquid

ELECTROANALYSIS, Issue 2 2010
Ping Jiang
Abstract A novel electrogenerated chemiluminescence (ECL) sensor based on natural clay and ionic liquid was fabricated. Tris(2,2,-bipyridine)ruthenium(II) (Ru(bpy)32+) was immobilized on natural clay surface through simple adsorption. An ECL sensor was prepared by mixing Ru(bpy)32+ -incorporated clay, graphite powder and an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) as the binder. The electrochemical behavior and ECL of the immobilized Ru(bpy)32+ was investigated. It was observed that the ECL of immobilized Ru(bpy)32+ was activated by the ionic liquid. The proposed ECL sensor showed high sensitivity to tri- n -propylamine (TPrA) and the detection limit was found to be 20,pM. In addition, the ECL sensor displayed good stability for TPrA detection and long-term storage stability. [source]

Quantitative Analysis of Prometrine Herbicide by Liquid,Liquid Extraction Procedures Coupled to Electrochemical Measurements

ELECTROANALYSIS, Issue 6 2009
V. Juarez
Abstract A sensitive method is proposed for the preconcentration and quantification of the herbicide Prometrine (PROM) at a liquid-liquid interface employing square-wave voltammetry. The preconcentration stage was based on liquid-liquid extraction methodology and the PROM quantification was carried out from the peak current of square-wave voltammograms. Under the experimental conditions employed, linear calibration curves in the concentration range 1.0×10,6,M,5.0×10,5,M, with detection limit equal to 1.5×10,6,M were obtained without pretreatment of the samples. This linear range, as well as detection limit could be extended towards lower concentrations when a pretreatment procedure was employed. In this way, linearity of calibration curves between 8.0×10,8,M and 2.4×10,7,M and detection limit of 1.0×10,7,M, were observed. On the other hand, the standard addition method was also used as an alternative and an appropriated quantification technique for this system. A linear concentration range between 1.0×10,6,M and 2.7×10,5,M, with a correlation coefficient of 0.997, was obtained. This procedure has also a promising application in the separation of herbicides from other interferents, present in real samples, previous to their quantification. [source]

Direct Electrochemistry and Electrocatalysis of Hemoglobin in Lipid Film Incorporated with Room-Temperature Ionic Liquid

ELECTROANALYSIS, Issue 20 2008
Gaiping Li
Abstract A facile phospholipid/room-temperature ionic liquid (RTIL) composite material based on dimyristoylphosphatidylcholine (DMPC) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) was exploited as a new matrix for immobilizing protein. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were adopted to characterize this composite film. Hemoglobin (Hb) was chosen as a model protein to investigate the composite system. UV-vis absorbance spectra showed that Hb still maintained its heme crevice integrity in this composite film. By virtue of the Hb/DMPC/[bmim]PF6 composite film-modified glassy carbon electrode (GCE), a pair of well-defined redox peaks of Hb was obtained through the direct electron transfer between protein and underlying GCE. Moreover, the reduction of O2 and H2O2 at the Hb/DMPC/[bmim]PF6 composite film-modified GCE was dramatically enhanced. [source]

Fabrication, Characterization, and Application of ,Sandwich-Type' Electrode Based on Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid

ELECTROANALYSIS, Issue 17 2008
Xuzhi Zhang
Abstract The much-enhanced electrochemical responses of potassium ferricyanide and methylene blue (MB) were firstly explored at the glassy carbon electrode modified with single-walled carbon nanotubes (SWNT/GCE), indicating the distinct electrochemical activity of SWNTs towards electroactive molecules. A hydrophobic room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), was used as electrode modification material, which presented wide electrochemical windows, proton permeation and selective extraction ability. In consideration with the advantages of SWNTs and RTIL in detecting target molecules (TMs), a novel strategy of ,sandwich,type' electrode was established with TMs confined by RTIL between the SWNT/GCE and the RTIL membrane. The strategy was used for electrochemical detection of ascorbic acid (AA) and dopamine (DA), and detection limits of 400 and 80 fmol could be obtained, respectively. The selective detection of DA in the presence of high amount of AA could also be realized. This protocol presented many attractive advantages towards voltammetric detection of TMs, such as low sample demand, low cost, high sensitivity, and good stability. [source]

Facilitated Transfer of Alkali Metal Ions by a Tetraester Derivative of Thiacalix[4]arene at the Liquid,Liquid Interface

ELECTROANALYSIS, Issue 12 2008
Akgemci, Emine Guler
Abstract The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28-tetraethoxycarbonylmethoxy-thiacalix[4]arene across the water/1,2-dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half-wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2-dichloroethane interface, the facilitated transfers were observed by formation of 1,:,1 (metal:ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1,:,2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log ,1°), and 8.36 (log ,2°), respectively. [source]

Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA Detection

ELECTROANALYSIS, Issue 12 2008
Xuzhi Zhang
Abstract A paste electrode (SWNT&RTIL PE) has been prepared using carboxylic group-functionalized short single-walled carbon nanotubes (SWNTs) mixed with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, one kind of room temperature ionic liquid, RTIL). Its electrochemical behavior was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the paste electrode using mineral oil as a binder. Results highlighted the advantages of the paste electrode: not only higher conductivity, but also lower potential separation (,Ep), higher peak current (ip) and better reversibility towards dopamine (DA), methylene blue (MB) and K3[Fe(CN)6]. The SWNT&RTIL PE could be used to detect the number of guanine bases and adenine bases contents in per mol oligonucleotides according to the current response in the range of 0.05,2.0,nM. Based on the current response of guanine bases, oligonucleotides could be detected sensitively in the B,R buffer solution with a detection limit of 9.9,pM. The heterogeneous electron transfer rate constant (ks) of guanine bases contents in the oligonucleotides was investigated and its value was 0.90,s,1. In essence the SWNT&RTIL PE showed high sensitivity, reliability, stability and reproducibility for the detection of DNA. [source]

Dramatic Effects of Ionic Liquid on Platinum Electrode Surface and Electron-Transfer Rates of meso -Tetraphenylporphyrins

ELECTROANALYSIS, Issue 12 2006
Afsaneh Safavi
Abstract The effect of addition of a room temperature ionic liquid, 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim][PF6], on the electrochemical behavior of different free-base para-substituted meso -tetraphenylporphyrins in dichloromethane solution has been studied using cyclic voltammetric technique. It has been found that the ionic liquid has the ability to regenerate platinum electrode surface and improves the reversibility of electrode processes. This has been true for the case of all the porphyrins studied. [source]

Ultrasound-Assisted Synthesis of CuO Nanorods in a Neat Room-Temperature Ionic Liquid

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2009
Tarek Alammar
Abstract CuO nanorods were prepared via ultrasound-assisted synthesis in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] as a reaction medium. The structure and morphology of CuO nanorods were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), vibrational and UV/Vis absorption spectroscopy. The synthesized CuO nanocrystals are of rod like shape with lengths from 30 to 100 nm and diameters of about 10 nm. Quantum size effects were observed as the bandgap of the CuO nanorods was determined to 2.41 eV from UV/Vis absorption measurements, which is significantly larger than the bulk value. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Synthesis of the Clathrate-II K8.6(4)Ge136 by Oxidation of K4Ge9 in an Ionic Liquid

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2009
Arnold M. Guloy
Abstract The new clathrate-II K8.6(4)Ge136 has been synthesized by mild oxidation of K4Ge9 in the ionic liquid n -dodecyltrimethylammonium chloride (DTAC)/AlCl3 at 300 °C and subsequent annealing at 370 °C. Refinement of the crystal structure from X-ray powder diffraction data revealed the composition K8.6(4)Ge136 [space group Fdm, a = 15.302(1) Å], which was also confirmed by energy-dispersive X-ray spectrometry (EDXS), transmission electron microscopy, and scanning electron microscopy on the bulk material. K atoms preferably occupy the larger Ge28 cages rather than the Ge20 cages in the clathrate-II structure. K8.6(4)Ge136 is metastable and was found to decompose exothermically at 471 °C. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

The Use of N -Type Ligands in the Enantioselective Liquid,Liquid Extraction of Underivatized Amino Acids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2010
Bastiaan J. V. Verkuijl
Abstract The first palladium based extraction system using chiral N -based ligands in the enantioselective liquid,liquid extraction (ELLE) of underivatized amino acids, is presented. The system shows the highest selectivity for the ELLE of methionine with metal complexes as hosts reported to date. Furthermore, the host can be prepared in situ from commercially available compounds. The dependency of the system on parameters such as pH, organic solvent, and temperature has been established. The intrinsic selectivity was deduced by determination of the association constants of the palladium complex with the tryptophan enantiomers. [source]

Metal-Free Air Oxidation of Thiols in Recyclable Ionic Liquid: A Simple and Efficient Method for the Synthesis of Disulfides

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2010
Devender Singh
Abstract An efficient procedure for the oxidative coupling of alkyl, aryl and heteroaryl thiols with atmospheric oxygen is reported. The methodology utilizes BMIM-BF4 as a recyclable solvent and does not require support materials or metal salts. Symmetric disulfides are obtained in excellent yields. [source]