Column parameters for ultra-low loaded glass bead columns in gas chromatography

Hawkes, Stephen J.; Nyberg, Donald G.

doi:10.1021/ac60281a011

Cited by 4 publications

(2 citation statements)

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“…Octoxy-, butoxy-, and benzoyl-derivatives of porous borosilicate glass were also superior to unmodified supports (732). Liquid loadings of less than 0.011% showed increasing adsorption, but loadings as low as 0.02% were practical for minimum time analyses (283). The optimum loading of other surface-textured beads for the separation of pesticides and other mixtures was found to range between 0.1 and 0.35% (436).…”

Section: Books and Reviewsmentioning

confidence: 93%

“…Further studies in low loaded columns also were conducted. Hawkes and Nyberg (283) studied column parameters for ultralow-loaded glass bead columns ranging in loading downward to 0.004% and found for Ballotini glass beads an increase in retention at loadings less than 0.011% owing to the increasing importance of adsorption. Other authors (314) have noted adsorption of solutes on low-loaded columns.…”

Section: Books and Reviewsmentioning

confidence: 99%

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Gas chromatography

Juvet¹,

Cram²

1970

Anal. Chem.

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Section: Books and Reviewsmentioning

confidence: 93%

Section: Books and Reviewsmentioning

confidence: 99%

Gas chromatography

Juvet¹,

Cram²

1970

Anal. Chem.

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Obstruction factors are flow sensitive

Hawkes¹

1972

Anal. Chem.

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Ultraviolet spectrophotometric determination of cyanide ion

Scoggins¹

1972

Anal. Chem.

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Elimination of D20 from deuterated 4 affords the abundant ion at m\e 270. As expected only one molecule of D20 is lost since the second hydroxyl group is attached to the aromatic ring. In contrast, the cardenolide, digitoxigenin (5), affords a CI(D20) spectrum containing peaks corresponding to the successive loss of D20 and HDO from the d2-5 + D+ion.In addition to the above examples, we have also obtained Cl (D20) spectra on a number of compounds containing one or more common organic functional groups. Our findings indicate that hydrogen bonded to heteroatoms in alcohols, phenols, carboxylic acids, amines, amides, and mercaptans undergoes essentially complete exchange in the ion source when D20 is employed as the reagent gas at a pressure of 0.4 Torr. Small amounts of deuterium incorporation (<15%) occur in some ketones, aldehydes, and esters but, in general, this does not complicate the analyses. At the usual sample pressures (<10"e Torr) unsaturated compounds such as benzene, stilbene, and 3,3-dimethyl-l-butene fail to undergo exchange in the ion source.In summary, the above results indicate that CIMS using D20 as the reagent gas provides a convenient method for determining the active hydrogen content of organic molecules.Abundant ions in the molecular weight region are usually observed in CI(D20) spectra and the method of exchange minimizes isotope and sample losses.

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Column parameters for ultra-low loaded glass bead columns in gas chromatography

Abstract: Well-cleaned Ballotini glass beads have strong adsorptive power for n-hydrocarbons which increases Ct catastrophically at low loads. Scanning electron micrographs of the bead surface show craters which would support a substantial amount of liquid phase. The

Cited by 4 publications

References 5 publications

Gas chromatography

Gas chromatography

Obstruction factors are flow sensitive

Ultraviolet spectrophotometric determination of cyanide ion

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