Induktive, CC-hyperkonjugative und frangomere Effekte bei solvolytischen Fragmentierungsreaktionen

Grob, C. A.; Bolleter, Martin; Kunz, Walter

doi:10.1002/ange.19800920909

Cited by 15 publications

(5 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results agree with those of Grob and Neukom [12]. The hot needle method was better than that of solvent flush as shown previously [13].…”

Section: Resultssupporting

confidence: 93%

“…The septum was shown to be a problem and aseptum-less injection system was developed [ l 11. Injection techniques were studied with particular emphasis on the evaporation of the sample from the needle under different conditions [12,13] and a cooling system for the inlet end of the column was described [ 141. "Procedural" and "instrumental" errors in handling the syringe were reported [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Direct injection on capillary columns for gas chromatography

Chauhan

Darbre

1981

J. High Resol. Chromatogr.

View full text Add to dashboard Cite

SummaryDiscrimination may occur when injecting samples onto gas chromatography capillary columns, whereby peak areas for higher boiling point compounds are smaller than they should be compared to lower boiling compounds. This problem is most important in quantitative work on solutes having a wide range of volatility. An all-glass inlet system was used. Injections were made with a 10-1.11 syringe onto a column without an injection point heater and with the column oven about 20°C below the boiling point of the solvent used for the solutes. Discrimination did not occur in a range of CI2 to C36 n-alkanes.

show abstract

“…These results agree with those of Grob and Neukom [12]. The hot needle method was better than that of solvent flush as shown previously [13].…”

Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Direct injection on capillary columns for gas chromatography

Chauhan

Darbre

1981

J. High Resol. Chromatogr.

View full text Add to dashboard Cite

show abstract

“…He also used mixtures of HMDS and DPTMDS [3,4]. The difference between these two reagents was not very clear and the expected improvement in wettability not very pronounced.…”

Section: Introductionmentioning

confidence: 99%

A CP‐MAS NMR study of some deactivation methods in capillary gas chromatography

Rutten

Ven

Haan

et al. 1984

J. High Resol. Chromatogr.

View full text Add to dashboard Cite

The effect of temperature, water content, and the type of reagent on the silylation of fused silica capillaries was studied by 29Si and 13C CP‐MAS NMR. Fumed silica (Cab‐O‐Sil M5), which is essentially a highly dispersed vitreous quartz with a surface comparable to that of fused silica capillary columns, was selected as a model material. Hexamethyldisilazane (HMDS) and 1,2‐diphenyl‐1,1,3,3‐tetraphenyldisilazane (DPTMDS), which were used as silylation reagents, yielded trimethyl‐ and dimethylphenylsilyl surface groups respectively at lower temperatures (< 350°C and <250°C respectively). At higher temperatures, increasingly more dimethylsilyl groups are formed, with the silicon bound to two oxygen atoms. This process occurs for DPTMDS at a considerably lower temperature than for HMDS. The formation of silyl groups on the surface and the disappearance of hydroxyl groups are followed independently. The 13C NMR and GC‐MS of the reaction products showed that with DPTMDS, the formation of two Si‐O‐Si links is accompanied by a loss of phenyl groups rather than of methyl groups. After the Cab‐O‐Sil had been dried over P2O5, the formation of these double links occurred for HMDS only at temperatures above 460°C and for DPTMDS at 400°C. Thus we concluded that water supplies oxygen atoms for double Si‐O‐Si links (possibly crosslinks) necessary for efficient deactivation. This may explain the less successful silanization of fused silica capillaries because their water content is lower than that of glass capillaries.

show abstract

“…The capillaries were leached and dehydrated according to Grob et a/. [2,3]. Pieces 10 m long were used in the following experiments.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore the demand for information concerning the metabolism of these pesticides is growing. Present methods for the quantitative determination of metabolites include radioactive labeled material and thin layerchromatographic methods [1,2]. These methods are time consuming and do not fulfill the requirements of speed, low cost, and high sensitivity important when analyzing large numbers of samples.…”

Section: Introductionmentioning

confidence: 99%