Angela D'Amato

Cyclodextrin derivatives as chiral selectors for direct gas chromatographic separation of enantiomers in the essential oil, aroma and flavour fields

This article reviews papers published over the period 1995-1998 dealing with the application of cyclodextrin derivatives (CDs) as chiral selector for direct enantiomer GC separation of volatile optically active components in the essential oil, extract, flavour and aroma fields. For each application, the racemate analysed, the CD employed as chiral selector and the matrix investigated are reported. The applications are grouped by analytical technique employed: capillary gas chromatography and capillary gas chromatography-mass spectrometry (GC and GC-MS); two-dimensional gas chromatography (GC x GC); capillary gas chromatography-isotope ratio-mass spectrometry (GC-IRMS); liquid chromatography-capillary gas chromatography (LC-GC).

Improved method for the analysis of small amounts of essential oils by microdistillation followed by capillary gas chromatography

Abstract A method for the analysis of small amounts of essential oils by distillation in a microversion of a modified Marcusson apparatus followed by capillary gas chromatography is described. The analysis requires only very small amounts of plant material (0.2–3 g) and takes no more than 2 h, including sample preparation, distillation and capillary gas chromatography. The results of macroscale analysis by classical techniques were identical with those obtained with the microapparatus described in this paper. Some applications are given to illustrate this technique.

Cyclodextrin derivatives in the gas chromatographic separation of racemic mixtures of volatile compounds X. 2,3-Di-O-ethyl-6-O-tert.-butyldimethylsilyl-β- and −γ-cyclodextrins

Abstract 2,3-Di-O-ethyl-6-O-tert.-butyldimethylsilyl-β and −γ-cyclodextrins (ETTBS-β- and −γ-CDs) are proposed as stationary phases for GC separation of enantiomers. The influence of different polarity polysiloxanes (PS-347.5, PS-086, OV-1701) as diluting phase on the separation capacity of these CD derivatives was also investigated. The results of ifETTBS-β- and −γ-CDs are compared to those of if2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl-β- and−γ-cyclodextrins (ifMETBS-β- and−γ-CDs). The advantages of ETTBS-β- and −γ-CDs in terms of minimum opeative temperatures and separation capacity of the column are discussed. Each column coated with each of the new synthesized CD derivatives was evaluated by analysing a number of different racemates with different structures.

SFC-UV determination of diflubenzuron residues, teflubenzuron and triflumuron in apple and pear pulps for baby food

SummaryA method to determine residues of diflubenzuron (DFB), teflubenzuron (TFB), triflumuron (TFM) at 0.01 ppm with recoveries above 60% in apple and pear pulps for baby food is described. DFB, TFB and TFM are extracted with methanol, and cleaned up by SPE using C18 stationary phase and methanol mobile phase. Analysis of the three pesticides is by SFC-UV at 254 nm using a Diol column, and CO2 at 30 MPa and 40°C modified with acetonitrile (10%) mobile phase.

Cyclodextrin derivatives in the gas chromatographic separation of racemic mixtures of volatile compounds: VII. The use of 2,6-di-O-methyl-3-O-pentyl-β-cyclodextrin diluted in phases with different polarity in the separation of racemates in complex mixtures

Abstract In the GC separation of volatile racemates, cyclodextirin (CD) derivatives may be used either as such or diluted in polysiloxane. If diluting phases with different polarity are used, different interactions and as a consequence a different retention of each component in a complex mixture are produced. The combination of the retention indices from columns coated with a CD derivative diluted in different polysiloxane phases makes it possible to locate and to identify unambigously the enantiomers of an optically active compound in a complex mixture and hence from their areas to determine directly the enantiomeric excess (e.e.). Some examples in the fields of essential oils and aromas illustrate the abilities of 2,6-di-O-methyl-3-O-pentyl-β-CD diluted with different phases (PS-347.5, PS-086, OV-1701 and OV-1701-OH) to evaluate the e.e. of one or more optically active compounds in a complex mixture.

Determination of pyrrolizidine alkaloids in Senecio inaequidens D.C. by capillary gas chromatography.

A study of the toxic pyrrolizidine alkaloids contained in Senecio inaequidens D.C., an infestant species of the Senecio genus, widespread in the North East of Italy, is reported. Five of these compounds, senecivernine, senecionine, integerrimine, retrorsine and an analogue of retrorsine, were identified by means of capillary gas chromatography and capillary gas chromatography-mass spectrometry.

Chemical diversity of the contents from the secretory structures of Heracleum sphondylium subsp. Sphondylium

Abstract The lipophilic constituents of ‘companion canals’ and vittae co-occurring in fruits of Heracleum sphondylium L. subsp. sphondylium were investigated by microdissection and subsequent analysis by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The chemical composition of the two different types of secretory structures present in the fruits is different The canals, present in all of the aerial vegetative plant parts and in the fruits, are characterized by mono- and sesquiterpenoids, while the vittae, peculiar to the fruits, contain fatty acid aliphatic esters and furocoumarins.

Cyclodextrin Derivatives in GC Separation of Racemic Mixtures of Volatiles. Part XI. Some Applications of Cyclodextrin Derivatives in GC Enantioseparations of Essential Oil Components

Cyclodextrin derivatives (CDDs) are successful GC enantioselective stationary phases to evaluate essential oils through the enantiomeric composition of their optically active components. The most recent CDDs have greatly enlarged the number of separable racemates and, in many cases, it is now possible to evaluate origin and genuineness of an essential oil through several of its optically active components in a single GC run. Applications of this approach to lavender, lemon, peppermint, rose and iris oils are here described.

Cyclodextrin Derivatives in GC Separation of Racemic Mixtures of Volatiles. Part XIV: Some Applications of Thick‐Film Wide‐Bore Columns to Enantiomer GC Micropreparation

Representative examples of preparative GC isolation of pure enantiomers in amounts ranging from 0.5 to 2 mg, with thick-film wide-bore open tubular columns coated with cyclodextrin (CD) diluted in polysiloxanes, are described. Two 25 m×0.53 mm i.d. columns, coated with 3 μm of 30% 2,6-di-O-methyl-3-O-pentyl-β-CD/OV-1701 and 2 μm of 30% 2,3-di-O-acetyl-6-O-tert- butyldimethylsilyl-β-CD/PS-086 as stationary phases, were used. Methyl 3-hydroxyhexanoate, methyl 2-methylbutanoate, δ-hexalactone, δ-octalactone, and γ-decalactone (the latter from a nature-identical mango aroma), were submitted to automated micropreparative GC. Average yields of about 30% were achieved when amounts above 20 μg/μl were injected, and an enantiomeric purity above 90% was obtained.

Capillary GLC controls of some alpineArtemisiae and of the related liqueurs

SummaryArtemisia genipi Weber,Artemisia umbelliformis Lam. andArtemisia glacialis L. are plants of the Compositae family, traditionally employed in manufacturing a liqueur called “genepi”. Indiscriminate picking of these plants has increased their rarity. The aim of the present study was to evaluate whether it was possible to cultivate these three rare mountain plants, and to assess the quality of plants available commercially and also of manufactured liqueurs. The results of the gas chromatographic analyses of volatile components from both plants and liqueurs are reported. In the present investigation three different techniques were used: direct head-space analysis by capillary GC of plants and liqueurs, and capillary GC analysis of the volatile extracts of plants and liqueurs after two different microdistillation processes.