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This blog has been set up for editors, reviewers, authors and readers of Elsevier's Analytical Chemistry Journals - all of which can be seen below. It will be updated from Monday to Friday with general news and announcements concerning the titles listed on this page. It should be noted that the views or claims made in the news items and feeds are not necessarily those of the Publisher.
World Congress on Biosensors 2014
Biosensors 2014
Wednesday, 7 December 2011
Tuesday, 6 December 2011
Just Published: Spectrochimica Acta Part B: Atomic Spectroscopy
Selected papers from the latest issue:
Solid sampling in analysis of animal organs by two-jet plasma atomic emission spectrometry
30 November 2011, 01:59:44
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 November 2011
Natalia P. Zaksas, Georgy A. Nevinsky
A study of high-power two-jet plasma capabilities for the direct multi-elemental analysis of animal organs was undertaken. The experimental conditions chosen allow the direct analysis of different animal organs after drying and grinding to powder (particle size 20–200 μm). It was found that evaporation efficiency of the samples depends on the particle size and thermal stability of tissues and can be improved by reduction of a carrier gas flow. Calibration samples based on graphite powder and a tenfold dilution of powdered samples with buffer (graphite powder containing 15% NaCl) were used. 5–10 mg of the sample was quite enough to get the detection limits of elements at the level of 0.1-10 μg g. A prior carbonization procedure (not ashing) makes it possible to decrease the detection limits of elements by an order of magnitude. The validation of the techniques was confirmed by the analysis of certified reference materials NIST 8414, BCR 278R and NCS ZC 81001 as well as by using different sample preparation procedures.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 November 2011
Natalia P. Zaksas, Georgy A. Nevinsky
A study of high-power two-jet plasma capabilities for the direct multi-elemental analysis of animal organs was undertaken. The experimental conditions chosen allow the direct analysis of different animal organs after drying and grinding to powder (particle size 20–200 μm). It was found that evaporation efficiency of the samples depends on the particle size and thermal stability of tissues and can be improved by reduction of a carrier gas flow. Calibration samples based on graphite powder and a tenfold dilution of powdered samples with buffer (graphite powder containing 15% NaCl) were used. 5–10 mg of the sample was quite enough to get the detection limits of elements at the level of 0.1-10 μg g. A prior carbonization procedure (not ashing) makes it possible to decrease the detection limits of elements by an order of magnitude. The validation of the techniques was confirmed by the analysis of certified reference materials NIST 8414, BCR 278R and NCS ZC 81001 as well as by using different sample preparation procedures.
Highlights
► A two-jet plasma was used for direct analysis of powdered animal organs. ► The analysis of powders with particles 20–200 μm in size was possible. ► Calibration samples based on graphite powder were used. ► Carbonization of the sample allows decreasing detection limits of elements.Laser Induced Breakdown Spectroscopy Library for the Martian Environment
28 October 2011, 20:46:38
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
A. Cousin, O. Forni, S. Maurice, O. Gasnault, C. Fabre, ...
The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in spa ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
A. Cousin, O. Forni, S. Maurice, O. Gasnault, C. Fabre, ...
The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in spa ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results.
Highlights
► Chemcam: First Laser Induced Breakdown Spectroscopy technique on Mars. ► Creation of a LIBS specific database to ChemCam on Mars. ► Data reduction scheme is proposed. ► Best signal under Martian conditions. ► LIBS emission lines database: subset of NIST database for Martian geochemistry.Flow injection-chemical vapor generation atomicfluorescence spectrometry hyphenated system for organic mercury determination: A step forward
28 October 2011, 20:46:38
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
Valeria Angeli, Simona Biagi, Silvia Ghimenti, Massimo Onor, Alessandro D'Ulivo, ...
Monomethylmercury and ethyl mercury were determined on line using flow injection-chemical vapour generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethyl mercury were detected by atomic fluorescence spectrometry in a Ar/H2miniaturized flame after sodium borohydride reduction to Hg, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H2microflame was investigated.The behavior of inorganic mercury, monomethylmercury and ethyl mercury and their cysteine-complexes was also studied by continuous flow - chemical vapour generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethyl mercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethyl mercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 mol L), thus allowing the organic/inorganic mercury speciation.The detection limits of the flow injection- chemical vapour generation atomic fluorescence spectrometry method were about 45 nmol L(as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol Lwere obtained. Recoveries of monomethylmercury and ethyl mercury with respect to inorganic mercury were never less than 91%. Flow injection- chemical vapour generation atomic fluorescence spectrometry method was validated by analyzing the TORT-1 certificate reference material, which contains only monomethylmercury, and obtaining 83 ± 5% of monomethylmercury recovered, respectively. This method was also applied to the determination of monomethylmercury in saliva samples.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
Valeria Angeli, Simona Biagi, Silvia Ghimenti, Massimo Onor, Alessandro D'Ulivo, ...
Monomethylmercury and ethyl mercury were determined on line using flow injection-chemical vapour generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethyl mercury were detected by atomic fluorescence spectrometry in a Ar/H2miniaturized flame after sodium borohydride reduction to Hg, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H2microflame was investigated.The behavior of inorganic mercury, monomethylmercury and ethyl mercury and their cysteine-complexes was also studied by continuous flow - chemical vapour generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethyl mercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethyl mercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 mol L), thus allowing the organic/inorganic mercury speciation.The detection limits of the flow injection- chemical vapour generation atomic fluorescence spectrometry method were about 45 nmol L(as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol Lwere obtained. Recoveries of monomethylmercury and ethyl mercury with respect to inorganic mercury were never less than 91%. Flow injection- chemical vapour generation atomic fluorescence spectrometry method was validated by analyzing the TORT-1 certificate reference material, which contains only monomethylmercury, and obtaining 83 ± 5% of monomethylmercury recovered, respectively. This method was also applied to the determination of monomethylmercury in saliva samples.
Highlights
► Monomethylmercury and ethyl mercury were determined on line using FI-CVG-AFS. ► No oxidation to Hgis required for MeHg and EtHg determination. ► No complexing agents are needed for their conversion to volatile species detectable by AFS. ► LOD was about 45 nmol L(as mercury) for all the species considered.Analytical Technology is Awarded Prestigious Framework Agreement with Yorkshire Water
Specialist electrochemical sensor manufacturer Analytical Technology Inc. today announces that it has been awarded a framework agreement to supply and install bufferless chlorine monitoring systems to Yorkshire Water. An in-depth technical evaluation was carried out by Yorkshire Water, in which Analytical Technology’s products were compared with a competitor’s against benchmark buffered units. Following this extensive process, Analytical Technology secured the agreement and commenced an asset replacement scheme for over 450 chlorine monitors.
The evaluation period lasted eight months and Analytical Technology’s bufferless chlorine monitors were tested using a wide variety of water types at four different water treatment works. During this time, the Analytical Technology monitors required very little maintenance and calibration, reflecting the company’s vast experience with membrane technology. This trial established that the monitor’s membranes would not need replacing for at least six months at all but a small minority of sites with high manganese levels.
Yorkshire Water continually monitors water from its 59 treatment plants with samples taken from 363 reservoirs where treated water is stored. In a typical year, more than 500,000 tests are carried out on water samples to ensure it meets exacting standards. The first phase of Analytical Technology’s framework agreement has been successfully completed with 75 chlorine monitors installed at 12 Yorkshire Water sites in the North and Dales areas. This includes a mixture of buffered, bufferless and pH corrected units, which are deployed depending on water quality and expected pH range. Additionally, funding for the second phase has recently been approved, in which a region wide asset replacement of chlorine monitors will be completed. This will include the installation of 377 chlorine monitors into an additional 31 water treatment plants and 20 secondary chlorination sites.
Rod Black, Asset Reliability Manager at Yorkshire Water said: “The instruments have performed well with little or no issues; chlorine control has been good and has not contributed to any call outs. It is nice to have standard instruments which can be calibrated and cleaned easily.” Alan Henson, Project Manager at Yorkshire Water commented: “Analytical Technology came out comfortably the best performer in our rigorous selection process, and the company’s vast experience with membrane technology places them ahead of most of their competitors who are only just adopting the technology. Once the roll-out has been completed, the scheme will have realised around £335K of OPEX savings per annum for Yorkshire Water and operators will no longer have to manhandle 25 litre containers of buffer around our sites. Analytical Technology has provided an excellent service and it is a pleasure working with a company who are very customer focussed.”
Dr. Michael Strahand, General Manager Europe at Analytical Technology added: “This agreement confirms that Analytical Technology’s chlorine monitors are unrivalled in the market, maintaining our position as one of the leading suppliers of water monitoring systems in the UK
Analytical Technology is a UK UK
For more information on Analytical Technology’s water and gas monitoring instrumentation, please call +44(0)1457 873 318, e-mail sales@atiuk.com or visit http://www.analyticaltechnology.com/.
Monday, 5 December 2011
Just Published: Journal of Chromatography A
A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
A Reversed-Flow Differential Flow Modulator for Comprehensive Two-Dimensional Gas Chromatography
04 December 2011, 21:44:19
Publication year: 2011
Source: Journal of Chromatography A, Available online 3 December 2011
James F. Griffith, William L. Winniford, Kefu Sun, Rob R. Edam, Jim C. Luong
A simple and reliable differential flow modulator has been demonstrated which reverses the flow during the flush step. The modulator is constructed with commercially available capillary flow technology tees which simplifies the apparatus and permits wide range of column dimensions to be used because the modulator volume is adjustable. Using a reverse flush arrangement the tailing of the peak at the base (baseline rise between modulations) is reduced 10-20 fold as compared to forward flush modulation. This is most easily observed for peaks overloaded in the first dimension. Excellent reproducibility (<2% RSD) of area measurements has been demonstrated with a complex fragrance sample as well as the capacity to handle significant overloading without loss of resolution in the second dimension. Further demonstrating the flexibility of this modulator, separation of C1-6 alkanes and olefins are demonstrated with two porous layer open tubular columns.
Source: Journal of Chromatography A, Available online 3 December 2011
James F. Griffith, William L. Winniford, Kefu Sun, Rob R. Edam, Jim C. Luong
A simple and reliable differential flow modulator has been demonstrated which reverses the flow during the flush step. The modulator is constructed with commercially available capillary flow technology tees which simplifies the apparatus and permits wide range of column dimensions to be used because the modulator volume is adjustable. Using a reverse flush arrangement the tailing of the peak at the base (baseline rise between modulations) is reduced 10-20 fold as compared to forward flush modulation. This is most easily observed for peaks overloaded in the first dimension. Excellent reproducibility (<2% RSD) of area measurements has been demonstrated with a complex fragrance sample as well as the capacity to handle significant overloading without loss of resolution in the second dimension. Further demonstrating the flexibility of this modulator, separation of C1-6 alkanes and olefins are demonstrated with two porous layer open tubular columns.
Highly Sensitive Detection of Neodymium Ion in Small Amount of Spent Nuclear Fuel Samples Using Novel Fluorescent Macrocyclic Hexadentate Polyaminocarboxylate Probe in Capillary Electrophoresis-Laser-Induced Fluorescence Detection
04 December 2011, 21:44:19
Publication year: 2011
Source: Journal of Chromatography A, Available online 3 December 2011
Shingo Saito, Yoshiyuki Sato, Tomoko Haraga, Yuta Nakano, Shiho Asai, ...
A rapid and high-sensitive detection method for the total concentration of Nd ion (total Nd) in a small amount of a spent nuclear fuel sample is urgently required since the precise quantification of total Nd ion makes it possible for burnup (degree of fuel consumption) to be determined. In this work, a capillary electrophoresis-laser-induced fluorescent detection method (CE-LIF) is proposed for the analysis of total Nd in a spent fuel sample solution, with the use of a newly synthesized metal fluorescent probe which has a fluorescein and a macrocylic hexadentate chelating group, FTC-ABNOTA, for lanthanide (Ln) ions. Ln ions were derivatized to form a strongly fluorescent complex with the probe to suppress the quenching of the ligand-centered emission. The detection of Ln complexes in the CE-LIF indicated that the interaction between Ln ions and the FTC-ABNOTA was strong enough not to dissociate during migration. The mutual separation among the Ln-FTC-ABNOTA complexes in CE-LIF was achieved by pH control providing a dynamic ternary complexation (DTC) with hydroxide ions. Using the DTC separation mode, a high resolution of Nd from other Ln ions with high resolution of 1.3-1.9 and a theoretical plate number of 68,000, and a very low detection limit of 22 pM (3.2 ppt, 0.11 atto mol amount basis) were successfully obtained. A simulated spent fuel sample containing various metal ions was examined in this method with a good quantification result of 102.1% recovery obtained even with a large excess of U.
Source: Journal of Chromatography A, Available online 3 December 2011
Shingo Saito, Yoshiyuki Sato, Tomoko Haraga, Yuta Nakano, Shiho Asai, ...
A rapid and high-sensitive detection method for the total concentration of Nd ion (total Nd) in a small amount of a spent nuclear fuel sample is urgently required since the precise quantification of total Nd ion makes it possible for burnup (degree of fuel consumption) to be determined. In this work, a capillary electrophoresis-laser-induced fluorescent detection method (CE-LIF) is proposed for the analysis of total Nd in a spent fuel sample solution, with the use of a newly synthesized metal fluorescent probe which has a fluorescein and a macrocylic hexadentate chelating group, FTC-ABNOTA, for lanthanide (Ln) ions. Ln ions were derivatized to form a strongly fluorescent complex with the probe to suppress the quenching of the ligand-centered emission. The detection of Ln complexes in the CE-LIF indicated that the interaction between Ln ions and the FTC-ABNOTA was strong enough not to dissociate during migration. The mutual separation among the Ln-FTC-ABNOTA complexes in CE-LIF was achieved by pH control providing a dynamic ternary complexation (DTC) with hydroxide ions. Using the DTC separation mode, a high resolution of Nd from other Ln ions with high resolution of 1.3-1.9 and a theoretical plate number of 68,000, and a very low detection limit of 22 pM (3.2 ppt, 0.11 atto mol amount basis) were successfully obtained. A simulated spent fuel sample containing various metal ions was examined in this method with a good quantification result of 102.1% recovery obtained even with a large excess of U.
Efficiency in supercritical fluid chromatography with different superficially porous and fully porous particles ODS bonded phases
04 December 2011, 21:44:19
Publication year: 2011
Source: Journal of Chromatography A, Available online 3 December 2011
E. Lesellier
The chromatographic efficiency, in terms of plate number per second, was dramatically improved by the introduction of sub- two microns particles with ultra-high pressure liquid chromatography (UHPLC). On the other hand, the recent development of superficially porous particles, called core-shell or fused-core particles, appears to allow the achievement of the same efficiency performances at higher speed without high pressure drops.CO2-based mobile phases exhibiting much lower viscosities than aqueous based mobile phases allow better theoretical efficiencies, even with 3 to 5 μm particles, but with relative low pressure drops. They also allow much higher flow rates or much longer columns while using conventional instruments capable to operate below 400 bar. Moreover, the use of superficially porous particles in SFC could enhance the chromatographic performances even more. The kinetic behavior of ODS phases bonded on these particles was studied, with varied flow rates, outlet (and obviously inlet) pressures, temperatures, by using a homologous series (alkylbenzenes) with 10% modifier (methanol or acetonitrile) in the carbon dioxide mobile phase. Results were also compared with classical fully porous particles, having different sizes, from 2.5 to 5 μm.Superior efficiency (N) and reduced h were obtained with these new ODS-bonded particles in regards to classical ones, showing their great interest for use in SFC. However, surprising behavior were noticed, i.e. the increase of the theoretical plate number vs. the increase of the chain length of the compounds. This behavior, opposite to the one classically reported vs. the retention factor, was not depending on the outlet pressure, but on the flow rate and the temperature changes. The lower radial trans-column diffusion on this particle typescould explain these results. This diffusion reduction with these ODS-bonded superficially porous particles seems to decrease with the increase of the residence time of compounds.
Source: Journal of Chromatography A, Available online 3 December 2011
E. Lesellier
The chromatographic efficiency, in terms of plate number per second, was dramatically improved by the introduction of sub- two microns particles with ultra-high pressure liquid chromatography (UHPLC). On the other hand, the recent development of superficially porous particles, called core-shell or fused-core particles, appears to allow the achievement of the same efficiency performances at higher speed without high pressure drops.CO2-based mobile phases exhibiting much lower viscosities than aqueous based mobile phases allow better theoretical efficiencies, even with 3 to 5 μm particles, but with relative low pressure drops. They also allow much higher flow rates or much longer columns while using conventional instruments capable to operate below 400 bar. Moreover, the use of superficially porous particles in SFC could enhance the chromatographic performances even more. The kinetic behavior of ODS phases bonded on these particles was studied, with varied flow rates, outlet (and obviously inlet) pressures, temperatures, by using a homologous series (alkylbenzenes) with 10% modifier (methanol or acetonitrile) in the carbon dioxide mobile phase. Results were also compared with classical fully porous particles, having different sizes, from 2.5 to 5 μm.Superior efficiency (N) and reduced h were obtained with these new ODS-bonded particles in regards to classical ones, showing their great interest for use in SFC. However, surprising behavior were noticed, i.e. the increase of the theoretical plate number vs. the increase of the chain length of the compounds. This behavior, opposite to the one classically reported vs. the retention factor, was not depending on the outlet pressure, but on the flow rate and the temperature changes. The lower radial trans-column diffusion on this particle typescould explain these results. This diffusion reduction with these ODS-bonded superficially porous particles seems to decrease with the increase of the residence time of compounds.
Silanol suppressing potency of alkyl-imidazolium ionic liquids on C18 stationary phases
04 December 2011, 21:44:19
Publication year: 2011
Source: Journal of Chromatography A, Available online 3 December 2011
J.J. Fernández-Navarro, J.R. Torres-Lapasió, M.J. Ruiz-Ángel, M.C. García-Álvarez-Coque
Residual silanols on C18 columns yield undesirable slow-kinetics ion-exchange interactions with positively charged basic compounds that result in asymmetrical peaks, low efficiencies and long retention times. The purity of the silica employed as supporting material, and the technique used to form the bonded phase, which varies with the brand and manufacturer, give rise to different amounts of residual silanols in the packings, and consequently, different chromatographic performance. One of the most efficient and widespread strategies to reduce or even eliminate the different performance among columns is the addition of a reagent to the mobile phase to block the silanol sites. However, the intrinsic nature of both stationary phase and additive leads to particular results. In this work, a group of basic compounds were analysed using six C18 stationary phases (Zorbax SB-C18, X-Terra MS C18, Kromasil, Lichrospher, Nucleosil, and Spherisorb) and acetonitrile-water mixtures. Two ionic liquids (ILs), 1—butyl- and 1-hexyl-3-methyl-imidazolium tetrafluoroborates, were added to the mobile phases to evaluate their silanol suppressing potency, based on the decreased retention of the basic compounds when the silanols are blocked (described by the Horváth equation), and the improvement in peak profile (described by the plots of the peak half–widths at diverse retention times). The suppressing potency based on the retention can be misleading when the adsorption of the IL anion is not negligible, since the anion attracts the cationic basic compounds increasing the retention. However, the accessibility of basic compounds to the silanols is prevented by both IL cation and anion, improving the peak profiles for all stationary phases. This was especially remarkable for Spherisorb, which in the absence of additive yielded by far the worst performance. 1–Hexyl-3-methyl-imidazolium tetrafluoroborate was the best additive in terms of retention and peak profile (width and asymmetry).
Source: Journal of Chromatography A, Available online 3 December 2011
J.J. Fernández-Navarro, J.R. Torres-Lapasió, M.J. Ruiz-Ángel, M.C. García-Álvarez-Coque
Residual silanols on C18 columns yield undesirable slow-kinetics ion-exchange interactions with positively charged basic compounds that result in asymmetrical peaks, low efficiencies and long retention times. The purity of the silica employed as supporting material, and the technique used to form the bonded phase, which varies with the brand and manufacturer, give rise to different amounts of residual silanols in the packings, and consequently, different chromatographic performance. One of the most efficient and widespread strategies to reduce or even eliminate the different performance among columns is the addition of a reagent to the mobile phase to block the silanol sites. However, the intrinsic nature of both stationary phase and additive leads to particular results. In this work, a group of basic compounds were analysed using six C18 stationary phases (Zorbax SB-C18, X-Terra MS C18, Kromasil, Lichrospher, Nucleosil, and Spherisorb) and acetonitrile-water mixtures. Two ionic liquids (ILs), 1—butyl- and 1-hexyl-3-methyl-imidazolium tetrafluoroborates, were added to the mobile phases to evaluate their silanol suppressing potency, based on the decreased retention of the basic compounds when the silanols are blocked (described by the Horváth equation), and the improvement in peak profile (described by the plots of the peak half–widths at diverse retention times). The suppressing potency based on the retention can be misleading when the adsorption of the IL anion is not negligible, since the anion attracts the cationic basic compounds increasing the retention. However, the accessibility of basic compounds to the silanols is prevented by both IL cation and anion, improving the peak profiles for all stationary phases. This was especially remarkable for Spherisorb, which in the absence of additive yielded by far the worst performance. 1–Hexyl-3-methyl-imidazolium tetrafluoroborate was the best additive in terms of retention and peak profile (width and asymmetry).
Just Published: Trends in Analytical Chemistry
A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Recent developments in fluorescent sensors for trace-level determination of toxic-metal ions
26 November 2011, 01:44:35
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 25 November 2011
Mili Dutta, Debasis Das
The literature on the use of fluorescent sensors for the trace-level determination of toxic cations is highly significant. Among different analytical methods, fluorescence is the most attractive due to its robustness, high sensitivity, selectivity, rapidity, ease of measurement and non-destructive methodology. Here, we illustrate different fluorescent probes developed for detection and estimation of toxic cations, including their molecular structure, sensing mechanism, analytical figures of merit and their applications. We provide a critical survey of the fluorescent sensors of each toxic element (i.e. Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni). A separate section contains the sensors that can detect several toxic elements simultaneously, so-called multi-element sensors. We briefly describe the merits and the demerits of the methods. Finally, we outline future prospects in this field.
Source: TrAC Trends in Analytical Chemistry, Available online 25 November 2011
Mili Dutta, Debasis Das
The literature on the use of fluorescent sensors for the trace-level determination of toxic cations is highly significant. Among different analytical methods, fluorescence is the most attractive due to its robustness, high sensitivity, selectivity, rapidity, ease of measurement and non-destructive methodology. Here, we illustrate different fluorescent probes developed for detection and estimation of toxic cations, including their molecular structure, sensing mechanism, analytical figures of merit and their applications. We provide a critical survey of the fluorescent sensors of each toxic element (i.e. Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni). A separate section contains the sensors that can detect several toxic elements simultaneously, so-called multi-element sensors. We briefly describe the merits and the demerits of the methods. Finally, we outline future prospects in this field.
Highlights
► Different fluorescent sensors selective for toxic cations have been illustrated. ► Sensors selective for cationsviz.Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni discussed. ► Advantages and limitations of each fluorescent probe have been critically analysed. ► Analytical and biological applications of the sensors have been thoroughly discussed. ► We have confined our discussion on the topic over the literature for last 10 years.A review of sensor-based methods for monitoring hydrogen sulfide
21 November 2011, 00:38:10
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Sudhir Kumar Pandey, Ki-Hyun Kim, Kea-Tiong Tang
We review sensor-based methods commonly employed for monitoring hydrogen sulfide (H2S), including recent developments in H2S-sensing instrumentation.We evaluate the basic quality-assurance parameters of different sensor types for quantifying H2S in terms of major operational criteria (e.g., response time, limit of detection, common operating range of concentrations, and stability). We also describe the applicability of these sensor-based methods with respect to practicality in various environmental settings. Finally, we highlight the limitations and the future prospects of these sensor-based methods.
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Sudhir Kumar Pandey, Ki-Hyun Kim, Kea-Tiong Tang
We review sensor-based methods commonly employed for monitoring hydrogen sulfide (H2S), including recent developments in H2S-sensing instrumentation.We evaluate the basic quality-assurance parameters of different sensor types for quantifying H2S in terms of major operational criteria (e.g., response time, limit of detection, common operating range of concentrations, and stability). We also describe the applicability of these sensor-based methods with respect to practicality in various environmental settings. Finally, we highlight the limitations and the future prospects of these sensor-based methods.
Highlights
► In this work, the emerging sensor-based methodologies for H2S analysis are explored. ► The common sensor types are grouped by their material type and/or sensing principle. ► The efficacy of different sensors is evaluated in terms of QA for real world application. ► Discussion is provided with respect to their advantages, limitations, and future prospects.Metabolite identification and quantitation in LC-MS/MS-based metabolomics
21 November 2011, 00:38:10
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Jun Feng Xiao, Bin Zhou, Habtom Ressom
Metabolomics aims at detection and quantitation of all metabolites in biological samples. The presence of metabolites with a wide variety of physicochemical properties and different levels of abundance challenges existing analytical platforms used for identification and quantitation of metabolites. Significant efforts have been made to improve analytical and computational methods for metabolomics studies.This review focuses on the use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) for quantitative and qualitative metabolomics studies. It illustrates recent developments in computational methods for metabolite identification, including ion annotation, spectral interpretation and spectral matching. We also review selected reaction monitoring and high-resolution MS for metabolite quantitation. We discuss current challenges in metabolite identification and quantitation as well as potential solutions.
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Jun Feng Xiao, Bin Zhou, Habtom Ressom
Metabolomics aims at detection and quantitation of all metabolites in biological samples. The presence of metabolites with a wide variety of physicochemical properties and different levels of abundance challenges existing analytical platforms used for identification and quantitation of metabolites. Significant efforts have been made to improve analytical and computational methods for metabolomics studies.This review focuses on the use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) for quantitative and qualitative metabolomics studies. It illustrates recent developments in computational methods for metabolite identification, including ion annotation, spectral interpretation and spectral matching. We also review selected reaction monitoring and high-resolution MS for metabolite quantitation. We discuss current challenges in metabolite identification and quantitation as well as potential solutions.
Highlights
► A review of LC-MS/MS based quantitative and qualitative metabolomics studies. ► A framework summarizing computational methods for improved metabolite identification. ► LC-SRM-MS/MS and LC-HRMS-based metabolite quantitation. ► Challenges and future perspectives in metabolite identification and quantitation.Recent developments in fluorescent sensors for trace-level determination of toxic-metal ions
26 November 2011, 01:44:35
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 25 November 2011
Mili Dutta, Debasis Das
The literature on the use of fluorescent sensors for the trace-level determination of toxic cations is highly significant. Among different analytical methods, fluorescence is the most attractive due to its robustness, high sensitivity, selectivity, rapidity, ease of measurement and non-destructive methodology. Here, we illustrate different fluorescent probes developed for detection and estimation of toxic cations, including their molecular structure, sensing mechanism, analytical figures of merit and their applications. We provide a critical survey of the fluorescent sensors of each toxic element (i.e. Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni). A separate section contains the sensors that can detect several toxic elements simultaneously, so-called multi-element sensors. We briefly describe the merits and the demerits of the methods. Finally, we outline future prospects in this field.
Source: TrAC Trends in Analytical Chemistry, Available online 25 November 2011
Mili Dutta, Debasis Das
The literature on the use of fluorescent sensors for the trace-level determination of toxic cations is highly significant. Among different analytical methods, fluorescence is the most attractive due to its robustness, high sensitivity, selectivity, rapidity, ease of measurement and non-destructive methodology. Here, we illustrate different fluorescent probes developed for detection and estimation of toxic cations, including their molecular structure, sensing mechanism, analytical figures of merit and their applications. We provide a critical survey of the fluorescent sensors of each toxic element (i.e. Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni). A separate section contains the sensors that can detect several toxic elements simultaneously, so-called multi-element sensors. We briefly describe the merits and the demerits of the methods. Finally, we outline future prospects in this field.
Highlights
► Different fluorescent sensors selective for toxic cations have been illustrated. ► Sensors selective for cationsviz.Hg, Ag, Cd, Cr, Pb, Tl, Co and Ni discussed. ► Advantages and limitations of each fluorescent probe have been critically analysed. ► Analytical and biological applications of the sensors have been thoroughly discussed. ► We have confined our discussion on the topic over the literature for last 10 years.A review of sensor-based methods for monitoring hydrogen sulfide
21 November 2011, 00:38:10
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Sudhir Kumar Pandey, Ki-Hyun Kim, Kea-Tiong Tang
We review sensor-based methods commonly employed for monitoring hydrogen sulfide (H2S), including recent developments in H2S-sensing instrumentation.We evaluate the basic quality-assurance parameters of different sensor types for quantifying H2S in terms of major operational criteria (e.g., response time, limit of detection, common operating range of concentrations, and stability). We also describe the applicability of these sensor-based methods with respect to practicality in various environmental settings. Finally, we highlight the limitations and the future prospects of these sensor-based methods.
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Sudhir Kumar Pandey, Ki-Hyun Kim, Kea-Tiong Tang
We review sensor-based methods commonly employed for monitoring hydrogen sulfide (H2S), including recent developments in H2S-sensing instrumentation.We evaluate the basic quality-assurance parameters of different sensor types for quantifying H2S in terms of major operational criteria (e.g., response time, limit of detection, common operating range of concentrations, and stability). We also describe the applicability of these sensor-based methods with respect to practicality in various environmental settings. Finally, we highlight the limitations and the future prospects of these sensor-based methods.
Highlights
► In this work, the emerging sensor-based methodologies for H2S analysis are explored. ► The common sensor types are grouped by their material type and/or sensing principle. ► The efficacy of different sensors is evaluated in terms of QA for real world application. ► Discussion is provided with respect to their advantages, limitations, and future prospects.Metabolite identification and quantitation in LC-MS/MS-based metabolomics
21 November 2011, 00:38:10
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Jun Feng Xiao, Bin Zhou, Habtom Ressom
Metabolomics aims at detection and quantitation of all metabolites in biological samples. The presence of metabolites with a wide variety of physicochemical properties and different levels of abundance challenges existing analytical platforms used for identification and quantitation of metabolites. Significant efforts have been made to improve analytical and computational methods for metabolomics studies.This review focuses on the use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) for quantitative and qualitative metabolomics studies. It illustrates recent developments in computational methods for metabolite identification, including ion annotation, spectral interpretation and spectral matching. We also review selected reaction monitoring and high-resolution MS for metabolite quantitation. We discuss current challenges in metabolite identification and quantitation as well as potential solutions.
Source: TrAC Trends in Analytical Chemistry, Available online 19 November 2011
Jun Feng Xiao, Bin Zhou, Habtom Ressom
Metabolomics aims at detection and quantitation of all metabolites in biological samples. The presence of metabolites with a wide variety of physicochemical properties and different levels of abundance challenges existing analytical platforms used for identification and quantitation of metabolites. Significant efforts have been made to improve analytical and computational methods for metabolomics studies.This review focuses on the use of liquid chromatography with tandem mass spectrometry (LC-MS/MS) for quantitative and qualitative metabolomics studies. It illustrates recent developments in computational methods for metabolite identification, including ion annotation, spectral interpretation and spectral matching. We also review selected reaction monitoring and high-resolution MS for metabolite quantitation. We discuss current challenges in metabolite identification and quantitation as well as potential solutions.
Highlights
► A review of LC-MS/MS based quantitative and qualitative metabolomics studies. ► A framework summarizing computational methods for improved metabolite identification. ► LC-SRM-MS/MS and LC-HRMS-based metabolite quantitation. ► Challenges and future perspectives in metabolite identification and quantitation.Product Thermal Characterization Using Freeze Drying Microscopy
SP Scientific, a world leader in freeze drying technology, has announced a new LyoLearn webinar entitled 'The practical application of freeze drying microscopy in product thermal characterization'.
Presented by Ruben J Nieblas from McCrone Microscopes - the 28th November 2011 webinar is targeted at anyone involved in the development, quality control, scale-up, transfer, or production of freeze-dried products that has at some point in their career, been required to accurately thermally characterise a sample in order to optimize the freeze drying cycle.
This webinar will introduce participants to the components of a freeze drying microscope and discuss its use in determination of thermal characteristics of products to be lyophilized. Light microscopy techniques such as phase contrast and polarized light will be demonstrated. The webinar will discuss and demonstrate how with a Freeze Drying Microscope it is possible to quickly and accurately determine collapse and eutectic temperature and intricately investigate freeze dried structure of complex samples.
SP Scientific's program of free educational webinars delivered by industry experts are devoted to freeze-drying topics, and follow a 30-minute format for the presentations with a Q&A session immediately afterwards. To register for the November 28th, 2011 webinar please visit the SP Scientific website* or contact the company on +1-845-255-5000 (+44-1473-240000 in Europe).
Presented by Ruben J Nieblas from McCrone Microscopes - the 28th November 2011 webinar is targeted at anyone involved in the development, quality control, scale-up, transfer, or production of freeze-dried products that has at some point in their career, been required to accurately thermally characterise a sample in order to optimize the freeze drying cycle.
This webinar will introduce participants to the components of a freeze drying microscope and discuss its use in determination of thermal characteristics of products to be lyophilized. Light microscopy techniques such as phase contrast and polarized light will be demonstrated. The webinar will discuss and demonstrate how with a Freeze Drying Microscope it is possible to quickly and accurately determine collapse and eutectic temperature and intricately investigate freeze dried structure of complex samples.
SP Scientific's program of free educational webinars delivered by industry experts are devoted to freeze-drying topics, and follow a 30-minute format for the presentations with a Q&A session immediately afterwards. To register for the November 28th, 2011 webinar please visit the SP Scientific website* or contact the company on +1-845-255-5000 (+44-1473-240000 in Europe).
Cell Culture 2012
Select Biosciences is delighted to announce its Select Biosciences is proud to announce Cell Culture 2012. This event will take place at the Crowne Plaza in San Diego and is co-located with Circulating Tumor Cells and Stem Cells 2012.
Designed specifically to provide scientists with an opportunity to learn the latest techniques and technologies being used to overcome the common problems associated with producing cell culture. An added bonus to attendees is the extensive exhibition full of equipment vendors being run in parallel with the scientific programme.
I hope that you find this of interest, please send any editorial inclusions directly to myself..
If you would like any additional information or would be interested in speaking with someone from Select Biosciences Ltd, then please feel free to contact either Hannah Tweed or Sam Marsden.
Hannah Tweed,
Conference Producer
Direct Line +44 (0)1787 315124
h.tweed@selectbiosciences.com
www.SelectBiosciences.com
Designed specifically to provide scientists with an opportunity to learn the latest techniques and technologies being used to overcome the common problems associated with producing cell culture. An added bonus to attendees is the extensive exhibition full of equipment vendors being run in parallel with the scientific programme.
I hope that you find this of interest, please send any editorial inclusions directly to myself..
If you would like any additional information or would be interested in speaking with someone from Select Biosciences Ltd, then please feel free to contact either Hannah Tweed or Sam Marsden.
Hannah Tweed,
Conference Producer
Direct Line +44 (0)1787 315124
h.tweed@selectbiosciences.com
www.SelectBiosciences.com
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