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  • Analytical Chemistry and Spectroscopy  (14)
  • Enantiomer separation  (4)
  • Chromatographic behavior  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Permethylated cyclodextrins in the GC separation of racemic mixtures of volatiles: Part 1 (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 301-305 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Enantiomeric resolution ; Permethylated cyclodextrins ; Chromatographic behavior ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chromatographic separation of racemic mixtures of volatile compounds by 2,3,6-trimethyl-α-, β- and γ-cyclodextrins is discussed. Columns were prepared by mixing the derivatized cyclodextrin with OV-1701 or hydroxy-terminated OV-1701 (OV-1701-OH) following Schurig's method [1]. About 130 racemates with widely differing structures were used to test the performances of 2,3,6-permethylated-α, β- and, γ-cyclodextrins mixed with the polysiloxane polymers in different ratios. The influence of the different types of cyclodextrin on racemate separation is shown, and some phenomena which might be helpful in the elucidation of the chromatographic behavior involved are also described. The influence both of the percentage of cyclodextrin in the polysiloxane, and of the operating conditions (carrier gas, flow rate, and temperature) in the separation of flavor and fragrance racemates is also evaluated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140502
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  • 2
    Electronic Resource
    Electronic Resource
    Cold on-column/sample split injection by a three-way press-fit device (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 649-651 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Cold on-column injection ; Sample split ; Three-way press-fit device ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130915
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    GC separation of the enantiomers of γ- and δ-lactones on a mixture of 2,6-dimethyl-3-trifluoroacetyl-γ-cyclodextrin and OV-1701Part II of the series “Cyclodextrin Derivatives in the GC Separation of Recemic Mixtures of Volatile Compounds” (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 701-704 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Enantiomer resolution ; Cyclodextrin derivatives ; Lactones ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240141016
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  • 4
    Electronic Resource
    Electronic Resource
    Cyclodextrin derivatives in the GC separation of racemic mixtures of volatile compounds: Part IV (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 655-658 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Derivatized cyclodextrins ; Enantiomer separation ; Chromatographic performance ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper reports the chromatographic performance of columns coated with 2,3,6-trimethyl-α-, β-, and γ-cyclodextrins (2,3,6-TriMe-α,- β-, and γ-CD) and their derivatives 2,6-dimethyl-3-trifluoroacetyl-α-, β-, and γ-cyclodextrins (2,6-DiMe-3-TFA-α-, β-, and γ-CD), all six diluted in polysiloxane, for the separation of the enantiomers of volatile compounds.The influence of column length and film thickness on separation is reported. Phenomena related to reproducibility and consistency, over a period of time, of columns prepared with these CD derivatives are also discussed, and a possible solution to some drawbacks reported here is proposed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240151005
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  • 5
    Electronic Resource
    Electronic Resource
    Cyclodextrin derivatives for the GC separation of racemic mixtures of volatile compounds. Part VI: The influence of the diluting phase on the enantioselectivity of 2,6-Di-O-methyl-3-O-pentyl-β-cyclodextrin (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 209-214 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Enantiomer separation ; Amorphous cyclodextrin derivatives ; Diluting stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As a continuation of previous studies on the use of cyclodextrin derivatives (CD) for the separation of volatile compounds by capillary GC, the influence of diluting phases other than OV-1701 or OV-1701-OH has been investigated.2,6-Di-O-methyl-3-O-pentyl-β-cyclodextrin (2,6-DiMe-3-Pe-β-CD) was taken as the reference CD derivative, because of the large number of volatile racemates it is able to separate; OV-1701 or OV-1701-OH was chosen as the reference diluting phase.The performance of a column coated with a 0.15 μm film of 10 % 2,6-DiMe-3-Pe-β-CD in OV-1701 was compared with that of analogous columns coated with films of the same thickness containing the same percentage of the CD derivative diluted with stationary phases of different polarity, i.e. PS-086, PS-347.5, and OV-225. Resolution values and separation factors of thirty racemates were used to evaluate the effect of different diluting phases on column performance.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160402
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  • 6
    Electronic Resource
    Electronic Resource
    HPLC - UV determination of pesticide residues at 0.01 ppm in apple and pear pulp used for baby food (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 105-110 
    Details
    ISSN: 0935-6304
    Keywords: HPLC-UV ; Baby food ; Apple pulp ; Pear pulp ; Diflubenzuron ; Ethiofencarb ; Teflubenzuron ; Triflumuron ; Triforine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two distinct methods are described for determination of residues of ethiofencarb and triforine, and of diflubenzuron, teflubenzuron, and triflumuron at the 0.01 ppm level in apple and pear pulp used for baby food;recoveries are above 50%. Diflubenzuron, teflubenzuron, and triflumuron are extracted with a 1:1 mixture of dichloromethane and acetone, and the extracts are cleaned by SPE using C18 as stationary phase and methanol as mobile phase. Ethiofencarb and triforine are extracted with dichloromethane, and the extracts cleaned using the same stationary phase but a 1:1 mixture of acetonitrile and water as mobile phase. Analysis of both groups of pesticides is by isocratic HPLC - UV at 210 nm using an RP-18 column and acetonitrile-water as mobile phase.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240190209
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  • 7
    Electronic Resource
    Electronic Resource
    Cold on-column - solvent split injection with a three-way press-fit device (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 155-159 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Three-way press-fit device ; Cold on-column injection ; Solvent split ; Early solvent vapor exit ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous paper we described the possibilities of cold on-column - sample split injection achieved by means of an inexpensive and simple three way press-fit device [1]. The same arrangement is proposed here for cold on-column - solvent split injection in which specific elimination of the solvent, without loss of any other sample components, is achieved by opening the splitting tube (or better, in this case, the early solvent vapor exit) during solvent elution, and then closing it during elution of the sample's other components.Discrimination between solvent and other sample components is achieved by means of a retention gap, a retaining precolumn, and an early vapor exit.The technique enables both selective enrichment of a sample, in order to record satisfactory mass and infrared spectra of minor components, and injection of large volumes (up to 100 μl) of dilute solutions which cannot be concentrated because of component volatility. Details of the assembly and tuning the system are given, together with some examples.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150304
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  • 8
    Electronic Resource
    Electronic Resource
    Cyclodextrin derivatives in the GC separation of racemic mixtures of volatile compounds, part V: Heptakis 2,6-dimethyl-3-pentyl-β-cyclodextrins (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 710-714 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Enantiomer separation ; Derivatized cyclodextrins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes an evaluation of the chromatographic performance of columns coated with amorphous cyclodextrin (CD) derivatives, in particular 2,3,6-tripentyl-β-CD (2,3,6-TriPe-β-CD), 2,6-dipentyl-3-methyl-β-CD (2,6-DiPe-3-Me-β-CD), and 2,6-dimethyl-3-pentyl-β-CD (2,6-DiMe-3-Pe-β-CD), all diluted in polysiloxane (OV-1701 or OV-1701-OH), for the separation of the enantiomers of volatile compounds. 2,6-DiMe-3-Pe-β-CD in OV-1701 offers performance comparable with (or better than) that of the other two CDs, and without their drawbacks (inconsistency of results, as described previously).This article compares the separating ability of 2,6-DiMe-3-Pe-β-CD and 2,3,6-TriMe-β-CD, and describes the influence of the CD derivative to polysiloxane ratio, the minimum operating temperatures of the columns, and the reproducibility and consistency of performance of columns coated with the former CD derivative diluted in polysiloxane.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240151104
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  • 9
    Electronic Resource
    Electronic Resource
    Identification of the constituents of a complex mixture by combined use of retention indices and specific multidetection responses (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 335-338 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Specific detectors ; ECD:NPD response ratio ; ECD:FPD response ratio ; Retention indices ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ratio of the responses of two different specific detectors to a single compound has, when used in conjunction with the compound's retention index, been investigated as an identification criterion for the compound. The ECD:NPD and ECD:FPD response ratios have been used for the identification of some pesticides. Analyses were performed with a single column - dual parallel detection - personal computer system.The reliability of the detector response ratio (DRR) was demonstrated by the consistency of detector response with time, and the influence of the quantity of analyte and of the chromatographic operating conditions. These factors were selected in the expectation that the technique could be used for routine trace analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240170510
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  • 10
    Electronic Resource
    Electronic Resource
    Cyclodextrin derivatives for GC separation of racemic mixtures of volatile compounds. Part VIII: 2,6-di-O-methyl-3-O-pentyl-γ-cyclodextrin and 2,6-di-O-methyl-3-O-(4-oxo-pentyl)- and 2,6-di-O-pentyl-3-O-(4-oxo-pentyl)-β-and -γ-cyclodextrins (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 295-298 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Enantiomer separation ; Differently derivatized cyclodextrins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In pre vious papers, 2,6-di-O-methyl-3-O-pentyl-β-cyclodextrin (CD) was demonstrated to be successful in separating volatile compounds, while avoiding the drawbacks of 2,3,6-tri-O-methyl-O-methyl-β-CD in terms of column stability and operating temperature.Since a CD chiral selector of universal use has not yet been found, and at least two (or more) columns coated with different CD derivatives are therefore necessary for routine work, the performance of 2,6-di-O-methyl-3-O-pentyl-γ-CD, 2,6-di-O-methyl-3-O-(4-oxopentyl)-γ-CD, 2,6-di-O-pentyl-3-O-(4-oxo-pentyl)-β-CD, and 2,6-di-O-pentyl-3-O-(-4-oxo-pentyl)-γ-CD diluted in polysiloxanes for the separation of volatile compounds in aromas and essential oils will be illustrated; each column coated with each of the newly synthesized CD derivatives was evaluated by analyzing more than 150 different recemates with different structures.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180506
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