Solvent Trapping during Large Volume Injection with an Early Vapor Exit, Part 1: Description of the Flooding Process

Boselli, Emanuele; Grolimund, Beat; Grob, Konrad; Lercker, Giovanni; Amadò, Renato

doi:10.1002/(sici)1521-4168(19980601)21:6<355::aid-jhrc355>3.0.co;2-b

Cited by 29 publications

(7 citation statements)

References 29 publications

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“…Finally, the LC-GC injection of a standard solution of n-alkanes under the same conditions as described earlier provided for a recovery of >97% of C 16 hydro-carbon without using a retaining precolumn. This result was in agreement with previous work (Boselli et al, 1998). Thus, short-chain F-acids such as diMeF(7,5) should be efficiently recovered if present in samples.…”

Section: Resultssupporting

confidence: 93%

Determination of Furan Fatty Acids in Extra Virgin Olive Oil

Boselli

Grob

Lercker

2000

J. Agric. Food Chem.

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The presence of 4 different furan fatty acids (F-acids) was detected in 18 samples of transmethylated monovarietal extra virgin olive oil: methyl 10,13-epoxy-11,12-dimethyloctadeca-10,12-dienoate [diMeF(9,5)], methyl 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoate [diMeF(11,5)] and both olefinic derivatives of diMeF(11,5) with one unsaturation on the side chains conjugated with the furan ring. Transmethylated oils were analyzed by normal phase high-performance liquid chromatography coupled on-line with capillary gas chromatography. After the gas chromatographic separation step, a more selective detection of F-acids was achieved by using a photoionization detector mounted in series with a flame ionization detector. The concentration of F-acids ranged between 50 ppb (detection limit of the method) and 2.1 ppm in the oil. The olefinic derivatives of diMeF(11,5) acids detected were not artifacts created during the sample preparation or during the chromatographic analysis.

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Section: Resultssupporting

confidence: 93%

Determination of Furan Fatty Acids in Extra Virgin Olive Oil

Boselli

Grob

Lercker

2000

J. Agric. Food Chem.

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“…This zone is defined as the length of retention gap that is occupied by the solvent film (in cmgL-1). This was firstly reported by Boselli et al [12], who reported flooded zones of about 4 cm 1 gL-for large-volume injections into a 0.53 mm I. D. retention gap [13] which is confirmed by our findings. The occurrence of prepeaks [16] was used to determine the flooded zone.…”

Section: Evaporation Profile For Large-volume Injectionssupporting

confidence: 92%

“…There are several optimisation procedures. In another study where no retaining precolumn was used between the retention gap and the SVE [13] losses were also observed. With a particular set-up of retention gap, retaining precolumn and analytical GC column, the evaporation rate is determined by the pressure used and the length of the individual capillaries.…”

Section: Introductionmentioning

confidence: 86%

Investigations on analyte losses in systems suited for large-volume on-column injections

et al. 2001

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Use o~ a large-volume injection system with a solvent vapour exit (SVE) requires optimisation. An appropriate strategy is to determine the evaporation rate by increasing the injection time at a fixed injection speed, injection temperature and head pressure. When measuring the flow rate in the carrier gas supply line to the on-column injector, optimisation can be very rapid: some five injections of pure solvent will be sufficient.When working under pa~ially concurrent solveni evaporation conditions, loss of volatiles is often observed if no retaining precolumn is used be~een the retention gap and the SVE. To investigate the requirements (length anct stationary phase) of the retaining precolumn, C8-C18 n-alkanes in n-hexane were used. The minimum length of the retaining precolumn (0.32 mm diameter) needed to prevent substantial losses of volatiles was 2 m. Experiments with retaining precolumns with ancl without stationary phase gave identical results. This shows that there is no need to coat the capillary as it only acts as a restrictor.

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“…In the meantime, on-line-coupled LC-GC evolved [11,12]. While the retention gap technique using the on-column interface remained the method of choice for the on-column transfer of fractions containing volatile components [13][14][15], concurrent eluent evaporation for fractions without volatile compounds, such as the wax esters, was increasingly performed also by the on-column interface [12,16]. This enabled to perform the two on-line LC-GC transfer techniques by a single interface and to use the same techniques as for largevolume on-column injection by syringe.…”

Section: Introductionmentioning

confidence: 99%

Wax ester fraction of edible oils: Analysis by on‐line LC‐GC‐MS and GC×GC‐FID

Biedermann¹,

Haase‐Aschoff²,

Grob³

2008

Euro J Lipid Sci & Tech

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The wax ester fraction of various plant oils was isolated by normal-phase HPLC (NPLC) on-line coupled to GC via the on-column interface and applying concurrent eluent evaporation. The esters were analyzed by on-line NPLC-GC-MS and by comprehensive two-dimensional GC with flame ionization detection (GC6GC-FID) off-line combined with NPLC-GC. GC6GC-FID enables to group the various classes of wax esters, in particular the phytol esters, geranylgeraniol esters and the straight-chain esters of palmitic acids and the unsaturated C 18 acids. Optimization of the GC6GC columns and the conditions must take into account the limited thermostability of the diterpene esters. Chromatograms are shown for a range of oils, with particular focus on the various classes of wax esters in olive oil and the geranylgeraniol esters 22:0 and 24:0 in a variety of oils.

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Solvent Trapping during Large Volume Injection with an Early Vapor Exit, Part 1: Description of the Flooding Process

Cited by 29 publications

References 29 publications

Determination of Furan Fatty Acids in Extra Virgin Olive Oil

Determination of Furan Fatty Acids in Extra Virgin Olive Oil

Investigations on analyte losses in systems suited for large-volume on-column injections

Wax ester fraction of edible oils: Analysis by on‐line LC‐GC‐MS and GC×GC‐FID

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