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:
Some papers from the latest issue:
Annealing of silica to reduce the concentration of isolated silanols and peak tailing in reverse phase liquid chromatography
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Josh J., Newby , Michael A., Legg , Benjamin, Rogers , Mary J., Wirth
Non-porous, colloidal silica particles were annealed at three different temperatures, 800, 900 and 1050°C. The adsorption of lysozyme, a probe of surface roughness, was consistent with progressively reduced surface roughness as temperature increased. The heat treated silica particles were rehydroxylated and then used to pack UHPLC columns. The cationic protein lysozyme was used to probe silanol activity, which exhibited progressively less tailing as the annealing temperature increased. FTIR spectroscopy confirmed that the abundance of isolated silanols on the surface was reduced by annealing at 900°C or 1050°C. FTIR also revealed that there was markedly increased hydrogen bonding of the isolated...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Josh J., Newby , Michael A., Legg , Benjamin, Rogers , Mary J., Wirth
Non-porous, colloidal silica particles were annealed at three different temperatures, 800, 900 and 1050°C. The adsorption of lysozyme, a probe of surface roughness, was consistent with progressively reduced surface roughness as temperature increased. The heat treated silica particles were rehydroxylated and then used to pack UHPLC columns. The cationic protein lysozyme was used to probe silanol activity, which exhibited progressively less tailing as the annealing temperature increased. FTIR spectroscopy confirmed that the abundance of isolated silanols on the surface was reduced by annealing at 900°C or 1050°C. FTIR also revealed that there was markedly increased hydrogen bonding of the isolated...
The inuence of the memory e_ect on preparative sep arations using the amylose tris(3,5-dimethylphenylcarbamate) stationary phase
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Joel, Putnam , Georges, Guiochon
Acid/base mobile phase modi_ers a_ect enantioseparations in ways that are not yet under6 stood for the lack of systematic studies, which makes the scale-up of preparative separations di_cult to predict. Shifts of the selectivity of certain pairs of enantiomers upon exposure of the column to these modi_ers is amply documented. Furthermore, once the modi_er has been removed from the mobile phase, the improved selectivity remains, this phenomenon has been named the memory e_ect. We selected four enantiomeric pairs for a systematic study of this memory e_ect. The selectivity of 4-chlorophenylalanine ethyl ester (4CPEE) improves after a solution of ethanesulfonic acid...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Joel, Putnam , Georges, Guiochon
Acid/base mobile phase modi_ers a_ect enantioseparations in ways that are not yet under6 stood for the lack of systematic studies, which makes the scale-up of preparative separations di_cult to predict. Shifts of the selectivity of certain pairs of enantiomers upon exposure of the column to these modi_ers is amply documented. Furthermore, once the modi_er has been removed from the mobile phase, the improved selectivity remains, this phenomenon has been named the memory e_ect. We selected four enantiomeric pairs for a systematic study of this memory e_ect. The selectivity of 4-chlorophenylalanine ethyl ester (4CPEE) improves after a solution of ethanesulfonic acid...
Application of multiwall carbon nanotubes-based matrix solid phase dispersion extraction for determination of hormones in butter by gas chromatography mass spectrometry
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Rui, Su , Xinghua, Wang , Xu, Xu , Ziming, Wang , Dan, Li , ...
The multiwall carbon nanotubes (MWCNTs)-based matrix solid phase dispersion (MSPD) was applied for the extraction of hormones, including 17-α-ethinylestradiol, 17-α-estradiol, estriol, 17-β-estradiol, estrone, medroxyprogesterone, progesterone and norethisterone acetate in butter samples. The method includes MSPD extraction of the target analytes from butter samples, derivatization of hormones with heptafluorobutyric acid anhydride-acetonitrile mixture, and determination by gas chromatography-mass spectrometry. The mixture containing 0.30g graphitized MWCNTs and 0.10g MWCNTs was selected as absorbent. Ethyl acetate was used as elution solvent. The elution solvent volume and flow rate were 12mL and 0.9mLmin−1 respectively. The recoveries of hormones obtained by analyzing the five spiked butter...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Rui, Su , Xinghua, Wang , Xu, Xu , Ziming, Wang , Dan, Li , ...
The multiwall carbon nanotubes (MWCNTs)-based matrix solid phase dispersion (MSPD) was applied for the extraction of hormones, including 17-α-ethinylestradiol, 17-α-estradiol, estriol, 17-β-estradiol, estrone, medroxyprogesterone, progesterone and norethisterone acetate in butter samples. The method includes MSPD extraction of the target analytes from butter samples, derivatization of hormones with heptafluorobutyric acid anhydride-acetonitrile mixture, and determination by gas chromatography-mass spectrometry. The mixture containing 0.30g graphitized MWCNTs and 0.10g MWCNTs was selected as absorbent. Ethyl acetate was used as elution solvent. The elution solvent volume and flow rate were 12mL and 0.9mLmin−1 respectively. The recoveries of hormones obtained by analyzing the five spiked butter...
Speciation analysis of arsenic compounds in edible oil by ion chromatography - inductively coupled plasma mass spectrometry
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Yun-Ling, Chu , Shiuh-Jen, Jiang
An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic in edible oil. The arsenic species studied include arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine. Gradient elution using (NH4)2CO3 and methanol at pH 8.5 allowed the chromatographic separation of all species in less than 8minutes. Effluents from the IC column were delivered to the nebulizer of ICP-MS for the determination of arsenic. The concentrations of arsenic species have been determined in several used and fresh vegetable oil samples. In this study, a microwave-assisted extraction method was used...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Yun-Ling, Chu , Shiuh-Jen, Jiang
An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic in edible oil. The arsenic species studied include arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine. Gradient elution using (NH4)2CO3 and methanol at pH 8.5 allowed the chromatographic separation of all species in less than 8minutes. Effluents from the IC column were delivered to the nebulizer of ICP-MS for the determination of arsenic. The concentrations of arsenic species have been determined in several used and fresh vegetable oil samples. In this study, a microwave-assisted extraction method was used...
Morphological analysis of physically reconstructed capillary hybrid silica monoliths and correlation with separation efficiency
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Stefan, Bruns , Takeshi, Hara , Bernd M., Smarsly , Ulrich, Tallarek
We report an experimental study on the structural (especially radial) heterogeneity of eleven 100μm i.d. capillary tetramethoxysilane-methyltrimethoxysilane hybrid silica monoliths with different pore and skeleton sizes, which were imaged by an optimized confocal laser scanning microscopy method. This method allows the optical sectioning of the monoliths, which is a prerequisite for quantitative morphological image analysis. Both radial porosity profiles and chord length distributions were calculated in the macropore domain for each column from at least 100 complete cross-sectional views along the column axis. The statistical approach visualized radial heterogeneities on different length scales in the monolithic structures. Chord length distributions...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Stefan, Bruns , Takeshi, Hara , Bernd M., Smarsly , Ulrich, Tallarek
We report an experimental study on the structural (especially radial) heterogeneity of eleven 100μm i.d. capillary tetramethoxysilane-methyltrimethoxysilane hybrid silica monoliths with different pore and skeleton sizes, which were imaged by an optimized confocal laser scanning microscopy method. This method allows the optical sectioning of the monoliths, which is a prerequisite for quantitative morphological image analysis. Both radial porosity profiles and chord length distributions were calculated in the macropore domain for each column from at least 100 complete cross-sectional views along the column axis. The statistical approach visualized radial heterogeneities on different length scales in the monolithic structures. Chord length distributions...
On-line concentration sample stacking coupled with water-in-oil microemulsion electrokinetic chromatography
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Hsi-Ya, Huang , Wan-Ling, Liu , Brenda, Singco , Shih-Huan, Hsieh , Yung-Han, Shih
This study describes for the first time, the ability of a normal stacking mode (NSM) on-line concentration step coupled with water-in-oil (W/O) microemulsion electrokinetic chromatography (MEEKC), using six common penicillin antibiotics (oxacillin, penicillin V, penicillin G, nafcillin, ampicillin, and amoxicillin) as test analytes. Optimization of penicillin separation in the conventional W/O MEEKC system demonstrated that change in the type and concentration of the oil phase (1-butanol) and column temperature had a pronounced effect on the separation. With the subsequent development of the NSM coupled with W/O MEEKC, improved separation and detection sensitivities were observed when an organic solvent plug (1-propanol;...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Hsi-Ya, Huang , Wan-Ling, Liu , Brenda, Singco , Shih-Huan, Hsieh , Yung-Han, Shih
This study describes for the first time, the ability of a normal stacking mode (NSM) on-line concentration step coupled with water-in-oil (W/O) microemulsion electrokinetic chromatography (MEEKC), using six common penicillin antibiotics (oxacillin, penicillin V, penicillin G, nafcillin, ampicillin, and amoxicillin) as test analytes. Optimization of penicillin separation in the conventional W/O MEEKC system demonstrated that change in the type and concentration of the oil phase (1-butanol) and column temperature had a pronounced effect on the separation. With the subsequent development of the NSM coupled with W/O MEEKC, improved separation and detection sensitivities were observed when an organic solvent plug (1-propanol;...
high-performance liquid chromatography COUPLED to direct analysis in real time mass spectrometry: INVESTIGATIONS ON GRADIENT ELUTION AND influence of complex matrices on signal intensities
01 June 2011, 20:35:51
Publication year: 2011
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Susanne, Beißmann , Wolfgang, Buchberger , Robert, Hertsens , Christian W., Klampfl
Direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) has been tested for its suitability as a detector for gradient elution HPLC. Thereby a strong dependency of signal intensity on the amount of organic solvent present in the eluent could be observed. Adding a make-up liquid (iso-propanol) post-column to the HPLC effluent greatly enhanced detection limits for early eluting compounds. Limits of detection achieved employing this approach were in the range of 7–27μgL−1 for the parabene test mixture and 15–87μgL−1 for the pharmaceuticals. In further investigations DART ionization was compared to several other widely used atmospheric pressure ionization methods...
Source: Journal of Chromatography A, In Press, Accepted Manuscript, Available online 1 June 2011
Susanne, Beißmann , Wolfgang, Buchberger , Robert, Hertsens , Christian W., Klampfl
Direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) has been tested for its suitability as a detector for gradient elution HPLC. Thereby a strong dependency of signal intensity on the amount of organic solvent present in the eluent could be observed. Adding a make-up liquid (iso-propanol) post-column to the HPLC effluent greatly enhanced detection limits for early eluting compounds. Limits of detection achieved employing this approach were in the range of 7–27μgL−1 for the parabene test mixture and 15–87μgL−1 for the pharmaceuticals. In further investigations DART ionization was compared to several other widely used atmospheric pressure ionization methods...
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