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  • 1
    Electronic Resource
    Electronic Resource
    Development of Microchannel Thin-Layer Chromatography with Infrared Microspectroscopic Detection (1994)
    s.l. : American Chemical Society
    Analytical chemistry 66 (1994), S. 1937-1940 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00085a003
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Hexamethyldisiloxane as a mobile phase component for normal phase liquid chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 647-653 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hexamethyldisiloxane ; Mobile phase component ; Silica column
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Hexamethyldisiloxane (HMDX) has been evaluated as a modifier solvent for the normal phase separation of substituted naphthalene componds as well as aromatics such as nitrobenzene, acetophenone, benzonitrile, and aniline. It is found to be a weaker eluting solvent than n-butyl ether and other commonly used normal phase solvents filling a niche in the eluotropic series. HMDX exhibited an unusual retention factor (k′) profile as a function of mobile phase composition in hexane. In a range from 0 to 40 %, thek′ values remained quite constant with increasing HMDX composition. As the concentration of HMDX progressed to 100 %, thek′ values actually increased in a generally linear fashion. This trend ink′ is due to longer solute retention not just a change in the retention time of the unretained component. Although slight silanization of the silica column may occur with initial use of HMDX, retention of these analytes on a commerical C-1 silica column is much lower with no positivek′ slope with increasing HMDX. The chromatographic data provide evidence that HMDX is likely adsorbed to the silica surface and a solute partitioning mechanism may be operative.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02292982
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Mixed-mode liquid chromatography of aliphatic anionic surfactants with a naphthalenetrisulfonate mobile phase (1995)
    Springer
    Chromatographia 40 (1995), S. 237-246 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Mixed mode stationary phases ; Indirect photometric and fluorometric detection ; Conductimetric detection ; Alkyl-sulphates, and sulphonat-phosphates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Separation of three classes of anionic surfactants (alkyl sulfates, alkanesulfonates, and alkyl phosphates) are achieved on a mixed-mode reversed phase (RP) phenyl/-anion exchange column using a naphthalenetrisulfonate (NTS)-acetonitrile (ACN) mobile phase via indirect photometric, indirect fluorometric, direct or indirect conductivity detection. Mixtures of C5−C18 sulfates, C6−C18 sulfonates, and C1−C4 phosphates (mono- and di-ester) can be separated in less than 20, 24, and 20 min respectively. Although hydrophobic effects are more pronounced in mixed-mode chromatography, equivalent-per-equivalent exchange of analysis and eluent ion is still required for sensitive indirect photometric, fluorometric, or conductivity detection. The detection limits of alkyl sulfates and alkanesulfonates are in the range of 3–15 pmoles which are at least an order of magnitude better than suppressed conductivity detection. The determination of surfactants in a variety of real samples is also presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290352
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Ion-exchange chromatography using vanadyl and vandate salts as mobile phases with indirect detection (1990)
    Springer
    Chromatographia 29 (1990), S. 139-143 
    Details
    ISSN: 1612-1112
    Keywords: Ion exchange chromatography ; Vanadyl and vanadate salt eluents ; Indirect photometric and electrochemical detection ; Li+, Na+, NH 4 + and K+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Vanadyl sulfate, VOSO4, was characterized as the mobile phase for the ion exchange separation of Li+, Na+, NH 4 + , and K+ using indirect photometric detection at 254 nm. Detection limits ranged from 0.2 ppm for Li+ to 1 ppm for K+. Indirect electrochemical detection of these separated cations by reduction of VO (II) to V3+ was compared to spectrophotometric detection. The potential of the vanadate species, HVO 4 2− , for the separation of F−, Cl−, and SO 4 2− , with indirect photometric detection was also demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02268700
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison study between indirect photometric and direct conductivity detection for anion exchange chromatography using naphthalenesulfonate derivatives as mobile phases (1992)
    Springer
    Chromatographia 33 (1992), S. 25-31 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion exchange ; Indirect photometric and direct conductivity detection ; Naphthalenesulfonate ; Inorganic anions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Indirect photometric and unsuppressed direct conductivity detection modes are examined using naphthalene mono-, di-, and tri-sulfonate as mobile phases for the separation of several anions such as F−, Cl−, NO2 −, Br−, NO3 −, SO4=,I−, and SCN− using a commercial anion exchange column. With all three mobile phases, conductivity detection shows better sensitivities and detection limits than indirect photometry. Conductivity detection is 5 to 16 times more sensitive than indirect photometry for all analytes. Detection limits achieved using these mobile phases are, for example, 0.04 ng and 0.1 ng for chloride ion with conductivity and indirect photometry, respectively. Both detection modes give wide linear ranges extending from at least 100 ppm to the detection limit of each anion which is generally about 0.02 ppm. Sulfur oxide anions such as dithionate and tetrathionate are separated using flow programming with naphthalenetrisulfonate as the mobile phase in less than 20 minutes. With both detection modes, desired chromatographic performance of these three eluents is achieved without pH adjustment of the mobile phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02276846
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of hydrazine and 1,1-dimethylhydrazine as salicyldehyde derivates by liquid chromatography with electrochemical detection (1984)
    Springer
    Chromatographia 18 (1984), S. 125-128 
    Details
    ISSN: 1612-1112
    Keywords: Liquid chromatography ; Electrochemical detection ; Hydrazine derivatives ; Derivatization with salicylaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Determination of hydrazine and 1,1-dimethylhydrazine after derivatization with salicylaldehyde was done using high-performance liquid chromatography with electrochemical detection. The oxidation of the phenolic group of salicylaldazine (S-HY) and salicylaldehyde-1,1-dimethylhydrazone (S-UDMH) was optimized with respect to ionic strength, pH, and applied potential. Less than 5 ng of S-HY and S-UDMH could be detected. The detection limits for hydrazine and 1,1-dimethylhydrazine solutions were estimated to be 0.025 and 0.20 ppm, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02258767
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    Paper (German National Licenses)
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