Elvira M.S.M. Gaspar

Organic metabolites in exhaled human breath—A multivariate approach for identification of biomarkers in lung disorders

The gas chromatographic profiles of exhaled air from lung cancer patients have been investigated. The breath from healthy volunteers, smokers and non-smokers, and lung cancer patients without treatment and under radio and/or chemotherapy, was collected using Tedlar bags. Different profiles for healthy people and cancer patients could be recognized by multivariate analysis and significant diagnostic compounds could be established. Target compounds showed to be linear and branched hydrocarbons between C(14) and C(24). Solid phase microextraction (SPME) coupled to gas chromatography mass spectrometry GC-(TOF)-MS was used. The method showed good precision (RSD below 26%) and limit of detection ranged from 0.04 to 8.0ppb. These findings show a high potential for establishment of laboratorial screening methods. Validation studies in a larger number of patients are being done.

Steroidal constituents from mature wheat straw

Abstract From the neutral fraction of the acetone extract of mature wheat straw ( Triticum aestivum ) two new steroid ketones: (24 R )-14α-methyl-5α-ergostan-3-one and 14α-methyl-5α-cholestan-3-one and two new tetracyclic triterpenoids: cycloart-5-ene-3β,25-diol and cycloart-3β,25-diol together with the known compounds: cholesterol, ergosterol, campesterol, stigmasterol, sitosterol, spinasterol and stigmastanol were identified.

Simultaneous chromatographic separation of enantiomers, anomers and structural isomers of some biologically relevant monosaccharides

A one-step chiral high-performance liquid chromatography (HPLC) method was developed to separate anomers and enantiomers of some carbohydrates--glucose, fructose, arabinose, ribose, fucose, mannose, lyxose and xylose, using a Chiralpak AD-H column. The method allows the carbohydrate identification and determination of the absolute configuration (D or L) and simultaneously also determine the configuration of the anomeric center (alpha or beta) of the monosaccharide. The method was applied to matrices involved in food chain and human health, as part of a general strategy for the structure determination of their constituents, due to the extreme importance of sugars since they are involved in food authenticity and nutritional characteristics and the biological role depends on the enantiomer and the anomeric form of a given monosaccharide.

Gas chromatography mass spectrometry determination of acaricides from honey after a new fast ultrasonic-based solid phase micro-extraction sample treatment.

A method is reported for the determination of acaricides (amitraz, bromopropylate, coumaphos and fluvalinate) from honey by gas chromatography mass spectrometry after a new fast solid phase micro-extraction, SPME, procedure. Six different fibers were assessed for micro-extraction purpose studying the following variables: (i) SPME coating, (ii) extraction temperature, (iii) extraction time, (iv) desorption conditions and (v) agitation conditions. The new ultrasonic bath technology providing different sonication frequencies (35 and 130kHz) and different working modes (Sweep, Standard and Degas) was studied and optimized for speeding up the acaricide micro-extraction. The best extraction results were achieved with the polyacrylate fiber. The extraction process was done in 30min using the ultrasonic bath at 130kHz in the Standard mode. Quality parameters of the proposed method show a good precision (<11%) and detection and quantitation limits lower than 6 and 15ng/g, respectively, except for fluvalinate. Eleven Portuguese commercial honey samples were analyzed with the developed method in order to assess the performance of the method with real samples and to determine whether the concentration of acaricides in honey exceed their maximum residue levels (MRLs). Acaricide residues detected were lower than those established by the legislation.

Optimization of pressurized liquid extraction (PLE) of dioxin-furans and dioxin-like PCBs from environmental samples

Pressurized liquid extraction (PLE) applying three extraction cycles, temperature and pressure, improved the efficiency of solvent extraction when compared with the classical Soxhlet extraction. Polychlorinated-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like PCBs (coplanar polychlorinated biphenyls (Co-PCBs)) in two Certified Reference Materials [DX-1 (sediment) and BCR 529 (soil)] and in two contaminated environmental samples (sediment and soil) were extracted by ASE and Soxhlet methods. Unlike data previously reported by other authors, results demonstrated that ASE using n-hexane as solvent and three extraction cycles, 12.4 MPa (1800 psi) and 150 degrees C achieves similar recovery results than the classical Soxhlet extraction for PCDFs and Co-PCBs, and better recovery results for PCDDs. ASE extraction, performed in less time and with less solvent proved to be, under optimized conditions, an excellent extraction technique for the simultaneous analysis of PCDD/PCDFs and Co-PCBs from environmental samples. Such fast analytical methodology, having the best cost-efficiency ratio, will improve the control and will provide more information about the occurrence of dioxins and the levels of toxicity and thereby will contribute to increase human health.

Simple gas chromatographic method for furfural analysis

A new, simple, gas chromatographic method was developed for the direct analysis of 5-hydroxymethylfurfural (5-HMF), 2-furfural (2-F) and 5-methylfurfural (5-MF) in liquid and water soluble foods, using direct immersion SPME coupled to GC-FID and/or GC-TOF-MS. The fiber (DVB/CAR/PDMS) conditions were optimized: pH effect, temperature, adsorption and desorption times. The method is simple and accurate (RSD<8%), showed good recoveries (77-107%) and good limits of detection (GC-FID: 1.37 microgL(-1) for 2-F, 8.96 microgL(-1) for 5-MF, 6.52 microgL(-1) for 5-HMF; GC-TOF-MS: 0.3, 1.2 and 0.9 ngmL(-1) for 2-F, 5-MF and 5-HMF, respectively). It was applied to different commercial food matrices: honey, white, demerara, brown and yellow table sugars, and white and red balsamic vinegars. This one-step, sensitive and direct method for the analysis of furfurals will contribute to characterise and quantify their presence in the human diet.

Emission profiles of polychlorinated dibenzodioxins, polychlorinated dibenzofurans (PCDD/Fs), dioxin-like PCBs and hexachlorobenzene (HCB) from secondary metallurgy industries in Portugal.

This paper reports, for the first time, a study of dioxin emissions from 10 siderurgies and metallurgies, secondary copper, aluminum and lead metallurgies, in Portugal. The study reports the emission factors and total emission amounts of PCDD/Fs, dioxin-like PCBs and hexachlorobenzene (HCB). The congener patterns were characterized and are discussed. The results showed that the total amount of PCDFs is higher than PCDDs in flue gas of each industrial unit. The toxic equivalent emission factors of pollutants emitted are 3098-3338 ngI-TEQt(-1) for PCDD/Fs and 597-659 ng I-TEQt(-1) for dioxin-like PCBs in siderurgies production (total estimated emission amounts released to atmosphere of 3.9-4.5 g I-TEQyr(-1)), 50-152 ng I-TEQt(-1) for PCDD/Fs and 24-121 ng I-TEQt(-1) for dioxin-like PCBs in ferrous foundries production (total estimated emission amounts released to atmosphere of 0.0010-0.0016 g I-TEQyr(-1)) and 5.8-5715 ng I-TEQt(-1) for PCDD/Fs and 0.49-259 ng I-TEQt(-1) for dioxin-like PCBs in non-ferrous foundries production (total estimated emission amounts released to atmosphere of 0.00014-0.12 g I-TEQyr(-1)). The HCB emission from siderurgies production is 0.94-3.2 mg t(-1) (total estimated emission amounts released 0.94-3.8 g yr(-1)), being much smaller, residual, in the emissions of the other types of plants (0.0012-0.026 mg t(-1) production and total estimated emission amounts released to atmosphere of 0.013-1.7 mg yr(-1)).

Mercury determination by FI-CV-AAS after the degradation of organomercurials with the aid of an ultrasonic field : The important role of the hypochlorite ion

Due to new findings, the methodology based on room-temperature ultrasonic irradiation (sonolysis) for conversion of organomercurials into inorganic mercury [J.L. Capelo, I. Lavilla, C. Bendicho, Anal. Chem. 72 (2000) 4979-4984.] is further investigated. Inorganic mercury is selectively determined by Flow Injection-Cold Vapour Atomic Absorption Spectrometry (FI-CV-AAS) using SnCl(2)/HCl. Complete oxidation of methyl-mercury can be accomplished within 90 s whilst phenyl and diphenyl-mercury can be degraded within 10s using a 50% sonication amplitude (100 W nominal power) provided by a probe ultrasonic device (20.5 kHz frequency) and a 1 mol L(-1) HCl liquid medium with the presence of hypochlorite ion. The importance of hypochlorite in reduction of organomercurials by stannous chloride is highlighted. Oxidation kinetics indicated a pseudo first-order reaction for methyl-mercury, phenyl-mercury, and diphenyl-mercury.

New pentasaccharide macrolactone from the European Convolvulaceae Calystegia soldanella

Abstract A new nonlinear pentasaccharide resin glycoside Soldanelline A ( 1 ) has been isolated from a Portuguese Convolvulaceae Calystegia soldanella . The structure of compound 1 was elucidated using high-field NMR spectroscopy, mass spectrometry and chemical studies.

Soldanelline B − The First Acylated Nonlinear Tetrasaccharide Macrolactone from the European ConvolvulaceaeCalystegia soldanella

The first acylated nonlinear tetrasaccharide resin glycoside, soldanelline B (1), and its fatty acid derivative soldanellic acid B (2), have been isolated from a Portuguese Convolvulaceae Calystegia soldanella. The structures were elucidated using high-field NMR spectroscopy, FAB mass spectrometry and chemical studies.