Flavio Belliardo

Identification of the volatile components of some Piedmontese honeys.

SummaryMultifloral and unifloral honeys produced in different years in Piedmont, Italy, were analysed for the components responsible for their flavours. Fifty-two volatile components were identified by capillary gas-liquid chromatography and gas-liquid chromatography/mass spectrometry and are reported here. A comparison of 4 different techniques for extraction of honey volatiles is reported.

Adsorption of organic compounds on porous carbon sorbents

Abstract Adsorption of model organic compounds from solutions in n-heptane, acetonitrile and an acetonitrile–water mixture (40/60 v/v) on the surface of new types of mesoporous carbon sorbents has been studied applying liquid chromatographic and static adsorption measurements. The values of specific retention volumes, absolute retention volumes, capacity factors and Henry constants of organic compounds on the surface of carbon sorbents have been determined. The influence of both the sorbent surface chemistry and the nature of the surrounding liquid on the adsorption and retention of organic compounds has been elucidated. The differences in the adsorption of probes on the carbon sorbent surface and on the hydroxylated silica surface is discussed.

HPLC determination of caffeine and theophylline in Paullinia cupana Kunth (Guarana) and Cola spp. samples

ZusammenfassungDie Anwendung einer RP-HPLC für die mengenmässige Bestimmung von Coffein und Theophyllin in Guarana-Proben (Droge aus den Samen desPaullinia cupana-Baumgewächses Kunth, Familie:Sapindaceae) des Amazonas-Gebiet und in Cola spp.-Proben wird beschrieben. Die analytische Methode ist einfach, nicht zeitaufwendig und erfordert nur ein Mindestmaß an analytischen Operationen für die Proben-Zubereitung. Der Vergleich von 5 verschiedenen Extraktionstechniken für Coffein wird ebenfalls erörtert. Außerdem wurde der Gehalt von Coffein und Theophyllin in fünf verschiedenen brasilianischen Guarana-Proben, zwei Proben diätetischer Erzeugnisse mit Guarana-Gehalt, zwei Cola-Extraktund drei Cola-Samen-Proben bestimmt.SummaryA reversed-phase high-performance liquid-chromatographic method for the determination of caffeine and theophylline in commercial guarana samples (drug obtained from the seeds ofPaulinia cupana Kunth,Sapindaceae of the Amazon Region) and inCola spp. samples is described and discussed.The methodology developed is simple and rapid with a minimum of samples preparation required. A comparision of five different techniques for the extraction of caffeine and theophylline is discussed. Furthermore the quantitative determination of caffeine and theophylline in five samples of Brasilian guarana, in two samples of dietetic products containing guarana, in two samples ofCola extract and in three ofCola seed powder are reported.

Quantitative Analysis of Carbohydrates and Organic Acids in Honeydew, Honey and Royal Jelly by Enzymic Methods

SummaryGlucose, fructose, sucrose, malic and citric acid were quantitatively determined in samples of honeydew, honey and royal jelly by means of enzymic UV tests. Preliminary qualitative analysis of carbohydrates present in the analysed samples was performed by silica gel thin-layer chromatography. The enzymic method employed shows appreciable advantages in specificity and ease of working.

Determination of α-Amanitin in Serum by HPLC

Abstract A reverse-phase high-performance liquid chromatographic method for the quantitative determination of α-amanitin in serum of poisoned patients is described and discussed. The methodology developed is simple and rapid with a minimum of sample preparation steps required. Detection is very sensitive, allowing quantitation of 25 ng of α-amanitin/ml of serum. The technique described is a useful tool to determine the severity of Amanita phalloides intoxication during the first 24 h after ingestion of poisonous mushrooms.

Simultaneous measurement of l-DOPA, its metabolites and carbidopa in plasma of Parkinsonian patients by improved sample pretreatment and high-performance liquid chromatographic determination☆

A procedure is described for the determination of L-3,4-dihydroxyphenylalanine (L-DOPA), its metabolites and carbidopa (CD) in plasma of Parkinsonian patients by high-performance liquid chromatography with dual working-electrode coulometric electrochemical detection. An efficient sample preparation scheme is presented for the isolation of L-DOPA, its metabolites and the catecholamines from the same plasma aliquot. After a simple deproteinization with methanol containing 2% of 0.5 M perchloric acid and evaporation of the solvent, L-DOPA, its metabolites and CD were separated with a 5-micron Nucleosil C18 column. Catecholamines were extracted from the supernatant of the deproteinized plasma by ion exchange on small columns and adsorption on alumina. Recoveries were close to 100% for L-DOPA, its metabolites and CD and 70% for catecholamines. The use of the same mobile phase for the concurrent assay of L-DOPA, its metabolites and catecholamines considerably increased the throughput of samples in the chromatographic system. The dual-electrode coulometric detector afforded peak identification by comparing current ratios. Monitoring of data from patients under L-DOPA therapy is reported.

Development and use of carbon adsorbents in the liquid chromatographic separation of isomers

Abstract Porous carbonaceous sorbents, prepared by a replicate method on a silica template, were examined under the liquid chromatographic conditions. The carbons were obtained by pyrolysis of two different organic precursors (a phenol—formaldehyde resin and saccharose) at 600°C. Columns packed with 15–20-μm particles were obtained by means of high-viscosity slurry techniques. The separation of some pairs of E/Z diastereomers is described and discussed.

Determination of Sulphonamide Residues in Honeys by High-Pressure Liquid Chromatography

SummaryA method was developed for determining 3 sulphonamide drug residues in honey at the level of 1 ppm. Residues were extracted with acetone, evaporated to dryness, redissolved in twice-distilled water containing sodium hydroxide, and then directly analysed by reverse-phase high-pressure liquid chromatography. The chromatographic conditions of the analyses and the degradation rates of sulphonamide residues in honey are described and discussed.

Micro-liquid chromatography method for the determination of ciclopiroxolamine after pre-column derivatization in topical formulations.

Ciclopiroxolamine is a broad-spectrum antimycotic drug. Neither the free acid (ciclopirox) nor its salt with ethanolamine (ciclopiroxolamine) can directly be quantified by liquid chromatography (LC) on both normal and reversed phases. This is due to the chelating function of the N-hydroxypyridone group that interacts strongly with stationary phases. Derivatization by alkylation forms a 1-alkyloxypirydone with regular chromatographic behaviour. A micro-LC method based on an isocratic elution reversed-phase system for quantification of ciclopiroxolamine in topical formulations is described. Chromatography was carried out using an LC Packings fused-silica capillary column (15 cm x 330 microns I.D.; Delta Pak, RP-18, 5 microns, 300 A) coupled to a Kontron 433 UV capillary detector. Data with respect to the derivatization reaction, recovery, reproducibility and limits of detection of the proposed method are reported and discussed.

Sesquiterpene lactones from Centaurea uniflora subsp. nervosa

Abstract Besides known compounds, the leaves of Centaurea uniflora subsp. nervosa afforded a new highly oxygenated guaianolide, whose structure was established by spectral data and chemical reactions.