1,721,145 research outputs found
Optimized use of a 50 um internal diameter secondary column in a comprehensive two dimensional gas chromatography system
No full textThe focus of the present research is directed toward the
development of a comprehensive two-dimensional gas
chromatography (GC × GC) method, characterized by a
greatly increased separation power, if compared with GC
× GC approaches using classical column combinations.
The analytical objective was achieved by using a 0.05 mm
internal diameter (i.d.) capillary as second dimension, a
split-flow approach reported in previous research (Tranchida,
P. Q.; Casilli, A.; Dugo, P.; Dugo, G.; Mondello,
L. Anal. Chem. 2007, 79, 2266-2275), and a twin-oven
GC × GC instrument. The column combination employed
was an orthogonal one: an apolar 30 m × 0.25 mm i.d.
column was linked, by means of a Y-union, to a flame
ionization detector (FID)-connected high-resolution 1 m
× 0.05 mm i.d. polar one and to a 0.20 m × 0.05 mm
i.d. uncoated capillary segment; the latter was connected
to a manually operated split valve, located on top of the
second GC. As previously shown, the generation of
optimum gas linear velocities in both dimensions can be
attained by splitting gas flows at the outlet of the first
dimension (Tranchida, P. Q.; Casilli, A.; Dugo, P.; Dugo,
G.; Mondello, L. Anal. Chem. 2007, 79, 2266-2275).
An optimized GC × GC method was developed and
exploited for the analysis of a complex petrochemical
sample. The satisfactory results attained were directly
compared with those observed using the same instrumentation,
equipped with what can be defined as a
classical GC × GC split-flow column set: the same primary
column was connected to an FID-linked 1 m × 0.10 mm
i.d. polar one and to a 0.30 m × 0.10 mm i.d. uncoated
capillary. It will be herein illustrated that there is still
room for significant progress in the GC × GC field
Enhanced resolution comprehensive two-dimensional gas chromatography applied to the analysis of roasted coffee volatiles
No full textThe present research is based on the full exploitation of the separation power of a 0.05mm internal
diameter (ID) capillary, as a comprehensive two-dimensional (2D) GC (GC×GC) secondary column, with
the objective of attaining very high-resolution second dimension separations. The aim was achieved by
using a split-flow system developed in previous research [P.Q. Tranchida, A. Casilli, P. Dugo, G. Dugo,
L. Mondello, Anal. Chem. 79 (2007) 2266], and a dual-oven GC×GC instrument. The column combination
employed consisted of a polar 30m×0.25mm ID column connected, by means of a T union, to a
detector-linked high-resolution 1.1m×0.05mm ID apolar analytical column and to a 0.33m×0.05mm
ID retention gap; the latterwas connected to a manually operated split valve. As previously demonstrated,
the use of a split valve enables the regulation of gas flows through both analytical columns, generating the
most appropriate gas linear velocities. Comprehensive 2D GC experiments were carried out on Arabica
roasted coffee volatiles (previously extracted by means of solid-phase microextraction) with the splitvalve
closed (equal to what can be defined as conventional GC×GC) and with the split-valve opened at
various degrees. The reasons why it is absolutely not effective to use a 0.05mm ID column as second
dimension in a conventional GC×GC instrument will be discussed and demonstrated. On the contrary,
the use of a 0.05mm ID column as second dimension, under ideal conditions in a split-flow, twin-oven
system, will also be illustrated and discussed
Heavy metals and persistent organic pollutants in marine organisms from two sicilian protected areas: Strait of Messina and Cape Peloro lakes
No full textThis paper reviews several scientific articles regarding levels of organic and inorganic contaminants in a variety of marine species coming from two Sicilian protected areas: the Strait of Messina and Cape Peloro lakes (Ganzirri and Faro). Moreover, different analytical techniques for the determinations of organic and inorganic contaminants, and the procedures adopted for the analyses, are summarized. Quantitative and qualitative determination of organic pollutants was performed by High Resolution Gas Chromatography-Electron Capture Detection and confirmed by Gas Chromatography-Mass Spectrometry. The concentrations of inorganic elements were determined by Atomic Absorption Spectrophotometry, derivative Stripping Chronopotentiometry, Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma - Mass Spectrometry. Results provide evidence that organic and inorganic residues found in some of the examined samples were mostly below the Maximum Residue Levels (MRLs). In conclusion, species analyzed in these studies were safe for human consumption and, consequently the investigated environments were estimated as free from toxicological risk
Un nuovo mini impianto gestibile nelle aziende agricole: prove sperimentali di estrazione olearia
No full textAdvance technology in virgin olive oil production from traditional and de-stoned pastes: influence of the introduction of a heat exhanger on oil quality
No full textAn experimental investigation was carried out to evaluate the quality of virgin olive oils obtained when a de-stoner were used for
the olive paste preparation in comparison to the use of a traditional stone mill. In order to improve the slightly differences of oil
yields due to the use of the de-stoner also a heat exchanger has been introduced in the processing line. The experimental data showed
that resistance to the oxidation, total phenols and pleasant volatile compounds were higher in the de-stoned olive oils than in the oils
obtained from the whole paste. Resistance to oxidation was assessed by Rancimat method and showed a positive correlation with
the amount of total phenols
Characterization of essential oil of Pummelo (cv. Chandler) by GC-MS, HPLC and physicochemical indices
No full text
Authentication of Bergamot Essential Oil by Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometer (GC-C-IRMS)
No full textThe quality assessment of bergamot essential oils was established employing the gas chromatography-combustion-isotope ratio mass spectrometer (GC-C-IRMS) technique. An authenticity range was obtained investigating the carbon stable isotope ratio of genuine Italian bergamot essential oils (harvest period 2008-2009), in order to compare the GC-C-IRMS data of several industrial, commercial and foreign bergamot essential oil samples. Moreover, with the aim to test the efficiency and the sensibility of IRMS device, self-adulterated in laboratory bergamot oil samples were analyzed. The data were compared with those achieved by conventional enantioselective gas chromatography (Es-GC) and high resolution gas chromatography (GC-FID). Results of this work indicated that GC-C-IRMS was able not only to detect the presence of adulterants in the samples, hut also to discriminate the bergamot oil samples according to their geographic provenance and the nature of the adulterants added
Advances of Modern Gas Chromatography and Hyphenated Techniques for Analysis of Plant Extracts
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