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1.
Anal Bioanal Chem ; 410(14): 3285-3296, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29549507

RESUMO

Baby foods are either a soft, liquid paste or an easily chewed food since babies lack developed muscles and teeth to chew effectively. Babies typically move to consuming baby food once nursing or formula is not sufficient for the child's appetite. Some commercial baby foods have been criticized for their contents. This article focuses on the simultaneous determination of organophosphorus pesticides and phthalates by means of a method based on ultrasound-vortex-assisted liquid-liquid microextraction coupled with gas chromatography-ion trap mass spectrometry (GC-IT/MS). The protocol developed allowed the determination of six phthalates [dimethyl phthalate, diethyl phthalate, dibutyl phthalate, isobutyl cyclohexyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate] and 19 organophosphorus pesticides. Freeze-dried product samples (0.1-0.2 g) were dissolved in 10 mL of warm distilled water along with 5 µL of an internal standard (anthracene at 10 mg mL-1 in acetone): the choice of extraction solvent was studied, with the most suitable being n-heptane, which is used for phthalate determination in similar matrices. The solution, held for 5 min in a vortex mixer and for 6 min in a 100-W ultrasonic bath to favor solvent dispersion and consequently analyte extraction, was centrifuged at 4000 rpm for 30 min. Then 1 µL was injected into the GC-IT/MS system (SE-54 capillary column; length 30 m, inner diameter 250 µm, film thickness 0.25 µm). All analytical parameters investigated are discussed in depth. The method was applied to real commercial freeze-dried samples: significant contaminant concentrations were not found. Graphical abstract Simultaneous and sensitive determination of organophosphorus pesticides and phthalates in baby foods by the ultrasound-vortex-assisted liquid-liquid microextraction Öªgas chromatography-ion trap mass spectrometry procedure. 1 methacrifos, 2 pirofos, 3 phorate, 4 seraphos, 5 diazinon, 6 etrimphos, 7 dichlofenthion, 8 chlorpyrifos-methyl, 9 pirimiphos-methyl, 10 malathion, 11 chlorpyrifos, 12 parathion-ethyl, 13 pirimiphos-ethyl, 14 bromophos, 15 chlorfenvinphos, 16 bromophos-ethyl, 17 stirophos, 18 diethion, 19 coumaphos, A dimethyl phthalate, B diethyl phthalate, C dibutyl phthalate, D butyl cyclohexyl phthalate, E benzyl butyl phthalate, F bis(2-ethylhexyl) phthalate, IS internal standard.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Alimentos Infantis/análise , Microextração em Fase Líquida/métodos , Compostos Organofosforados/análise , Praguicidas/análise , Ácidos Ftálicos/análise , Humanos , Recém-Nascido , Limite de Detecção , Sonicação/métodos
2.
Langmuir ; 31(12): 3627-34, 2015 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-25763603

RESUMO

The removal of the phenolic compound, caffeic acid, by photodegradation has been investigated using carbon-doped titanium dioxide particles as a photocatalyst under visible light. UV-vis absorption spectroscopy and gas chromatography-ion trap mass spectrometry analyses revealed a substrate concentration dependence of the removal of caffeic acid from a water solution. The k2 and t(0.5) parameters of each reaction were calculated by fitting kinetics data to a second-order kinetic adsorption model. To evaluate the photodegradation event, the effect of the adsorption process on the whole degradation was also monitored in the absence of light. Adsorption isotherm studies supported by ζ potential and scanning electron microscopy data demonstrated the pivotal role of the absorption mechanism. It was found that the whole photodegradation process is governed by a synergic mechanism in which adsorption and photodegradation are involved. This study, centered on the removal of caffeic acid from aqueous solutions, highlights the potential application of this technology for the elimination of phenolic compounds from olive mill wastewater, a fundamental goal in both the agronomical and environmental fields.

3.
J Sep Sci ; 37(4): 412-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24293137

RESUMO

In the previous part of this study, a significant improvement of the fundamental relationships that control GC resolution in a pressure-tunable assembly operating in isothermal conditions inside a single oven was made. A theoretical approach for the correct choice of the working temperature was proposed for the first time. In this second part of our report, a new interfacing device has been proposed for a rapid and reliable alignment of the two columns at the midpoint junction. Moreover, the results of a series of experimental tests have confirmed the validity of the proposed mathematical models.

4.
Anal Bioanal Chem ; 405(18): 6137-41, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23660693

RESUMO

This paper proposes a new method for quantitative analysis of acrylamide in cereal-based foods and potato chips. The method uses reaction with trifluoroacetic anhydride, and analyses the resulting derivative by use of gas chromatography with electron-capture detection (GC-ECD). The effects of derivatization conditions, including temperature, reaction time, and catalyst, on the acylation reaction were evaluated. Chromatographic analysis was performed on an SE-54 capillary column. Under the optimum conditions, good retention and peak response were achieved for the acrylamide derivative. The analytical method was fully validated by assessment of LODs and LOQs (1 ng g(-1) and 25 ng g(-1), with relative standard deviations (RSD) 2.1 and 3.6, respectively), linearity (R = 0.9935 over the range 0.03-10 µg g(-1)), and extraction recovery (>96%, with RSD below 2.0, for acrylamide spiked at 1, 20, 50, and 100 ng g(-1); 99.8% for acrylamide content >1000 ng g(-1)). The method requires no clean-up of the acrylamide derivative before injection. The method has been successfully used to determine acrylamide levels in different commercial cereal-based foods, French fries, and potato chips.


Assuntos
Acrilamida/análise , Cromatografia Gasosa/métodos , Grão Comestível/química , Contaminação de Alimentos/análise , Anidridos Acéticos/química , Cromatografia Gasosa/instrumentação , Fluoracetatos/química , Limite de Detecção
5.
J Sep Sci ; 36(14): 2260-7, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23640871

RESUMO

GC column selectivity can be continuously adapted to suit analytical needs using a flow-tuneable tandem system. Its application for the separation of complex mixtures requires a deep understanding of the theory in this area. Although a number of researchers have developed specific models, a general and exhaustive theory is still missing. In this paper, we have made an implementation of pre-existing models on tandem-column assemblies operated isothermally. In particular, we have investigated the effect of column length and diameter, phase thickness, and oven temperature on chromatographic parameters, such as capacity factor, selectivity, and intrinsic resolution. A new approach for the correct choice of the working temperature has been proposed.

6.
Foods ; 12(21)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37959034

RESUMO

In recent years, human populations' exposure to microplastics via foods is becoming a topic of concern. Although microplastics have been defined as "emerging contaminants", their occurrence in the environment and food is quite dated. This systematic review aims to investigate the discrepancies which are characterizing the research in the microplastics field in foods, with particular regard to sample preparations, microplastics' concentrations and their effect on humans. For the selection of papers, the PRISMA methodology was followed. Discrepancies in the methodological approaches emerged and in the expression of the results as well, underlying the urgency in the harmonization of the methodological approaches. Uncertainties are still present regarding the adverse effects of microplastics on the human body. The scientific evidence obtained thus far is, in fact, not sufficient to demonstrate a concrete negative effect. This review has clearly underlined the need to standardise laboratory approaches to obtain useful results for better food safety management.

7.
Anal Bioanal Chem ; 402(3): 1373-81, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22134492

RESUMO

A solid-phase extraction (SPE) method was developed for extraction and analysis of six phthalate esters in wine samples using Carbograph 1 sorbent. The SPE procedure allowed efficient recovery of the investigated phthalates ranging between 78% and 105% with a relative standard deviation (RSD) ≤6.5 for an ethanolic phthalic acid ester (PAE) standard solution and between 73-71% and 96-99% with a RSD ≤8.4 for red wine samples spiked with 20 and 50 ng mL(-1) of PAE, respectively. The adsorption isotherms and breakthrough curves for Carbograph 1/water solution were reported. Gas chromatography coupled with an ion-trap mass spectrometer detector (GC/IT-MS) was used for analysis. The instrumental analytical protocol was found to yield a linear calibration in the range 0.01-10.0 µg mL(-1) with R(2) values ≥0.9992. The limits of detection in GC/IT-MS (SIM mode) vary between 0.2 and 14 ng mL(-1) (RSD ≤5.6) whereas the limits of quantification range between 0.5 and 25 ng mL(-1) (RSD ≤5.9); the intra- and inter-day repeatabilities calculated as RSD for wine samples, were between 0.9-7.8 and 1.0-10.5, respectively. The analytical method developed was applied to several commercial wine samples. Furthermore, the investigated methods are simple, reliable, reproducible, and not expensive.

8.
Anal Bioanal Chem ; 404(5): 1517-27, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22760505

RESUMO

This paper shows an analytical methodology based on solid-phase extraction by XAD-2 adsorbent and gas chromatography (GC) coupled with nitrogen-phosphorus (NPD) and ion-trap mass spectrometry detectors (ITMS) in negative chemical ionization (NCI) mode analyses for investigating organophosphorus pesticides (OPs) at trace levels (in nanograms per cubic meter) in the atmosphere: in particular, we set up a procedure for analyzing 38 OPs. For the analytical methodology linearity responses have been obtained in GC-NPD (r > 0.9982) and GC-NCI/ITMS (r > 0.9974) in a large linearity range (0.10-500 pg µL(-1) in both cases) whereas the limits of detection range between 0.01 and 0.03 pg µL(-1) in both the techniques with a relative standard deviation (RSD) below 9.0 in both cases. Particular attention has been devoted to investigate the effect of different solvents (n-hexane, benzene, chloroform, carbon disulfide, acetonitrile) on the OP recovery as well the breakthrough volumes have been evaluated (100% recovery up to 4,286 L g(-1)). The study has also investigated the OP recoveries at different sampling flow rates (1.5 and 2.0 L min(-1)) for determining the optimal conditions for sample collection. Finally, the whole approach has been successfully applied to real samples collected in four different areas in the Molise region (Central Italy) during different seasons: the results show that parathion-ethyl, dimethoate, omethoate, and malathion are present in all periods at low levels (ranging between 70 and 10 ng m(-3)): their levels in such periods can be correlated with spraying as well atmospheric conditions favoring the dispersion/accumulation of these pollutants.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Atmosfera/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Organofosforados/isolamento & purificação , Praguicidas/isolamento & purificação , Poliestirenos/química , Extração em Fase Sólida/métodos , Adsorção , Itália , Limite de Detecção
9.
Data Brief ; 42: 108136, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35479420

RESUMO

This paper would like to show all the data related to an intensive field campaign focused on the characterization of the Polyaromatic Hydrocarbons (PAHs) composition profile in almost 60 honey samples collected in Central Italy. The analytical data here reported are the base for a study aimed to identify the pollution sources in a region. 22 PAHs were analyzed by means of ultrasound-vortex-assisted dispersive liquid-liquid micro-extraction (DLLME) procedure followed by a triple quadrupole gas chromatograph/mass spectrometer (GC-MS). A chemometrics approach has been carried out for evaluating all the data: in particular, principal component analysis and cluster analysis has been used both for the identification of the main natural/anthropogenic pollutants affecting a site and for evaluating the air quality.

10.
Food Chem ; 382: 132361, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35152011

RESUMO

The quality of honey is assessed through the determination of some commodity parameters: a certain importance is to be attributed to the absence of contaminating residues, in particular of Polycyclic Aromatic Hydrocarbons (PAHs). This paper deeply investigates the presence of 22 PAHs in 57 honey samples collected in Central Italy and identifies the possible source apportionment and fingerprint identification by DLLME-GC-MS analysis and a chemometric approach. Cluster Analysis and Principal Component Analysis have allowed to identify the main PAHs responsible of the contamination, benzo[a]anthracene and phenanthrene, characteristics pollutants of areas constantly exposed. The entire database has been compared to similar ones present in literature, particularly data from Serbia and Belgrado samples. The PCA applied to overall the data confirms the combustion to be the main contamination source in Italian samples whereas highlights the importance of the role of naphthalene, added during beekeeping practices in the other data-set.


Assuntos
Poluentes Ambientais , Mel , Hidrocarbonetos Policíclicos Aromáticos , Quimiometria , China , Monitoramento Ambiental , Poluentes Ambientais/análise , Mel/análise , Hidrocarbonetos Policíclicos Aromáticos/análise
11.
Anal Bioanal Chem ; 400(10): 3561-71, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21553216

RESUMO

This paper investigates the performance of some adsorbents, Carbopack B, Tenax-GC, and XAD-2, in a SPE and GC analytical method for sampling and determining some persistent organic pollutants such as benzene, toluene, o-, m-, and p-xylenes, naphthalene, anthracene, fluorene, fluoranthene, benzo(i,k)fluorene, pyrene and benzo(a)pyrene, aldrin, dieldrin, endrin, endosulfan, and PCB congeners (nos. 1, 15, 44, 77, and 209). Adsorbents evaluated in this study are Carbopack B, Tenax-GC, and XAD-2. Before applying the analytical method to air samples, it was widely investigated in laboratory: the sampler is constituted by a glass pyrex vial home-filled with 300 mg (sampling section) and 50 mg of adsorbent material (backup section). The re-extraction is performed by CS(2) (1-2 mL) and analysis is performed by GC-FID and GC-ECD. The evaluation of breakthrough volumes and desorption efficiencies shows the XAD-2 performance in the enrichment of different organic species present in atmosphere at trace levels (ppt) to be more advantageous than the other two materials in terms of analytical and technical parameters. One of the advantages is the high volume of sampled air with high concentration factor and limited loss of analytes (breakthrough volumes are higher than 5,000 L g(-1) for high-boiling compounds and higher than 400 L g(-1) for low-boiling solutes). Another advantage is the possibility of easy and speed re-extraction of analytes using small volumes of solvent (a few milliliters). The recoveries are about 100% with a RSD ≤ 2.3 for low-boiling compounds, and between 77% and 109% with a RSD ≤ 5.7% for high-boiling species. The XAD-2 adsorbent was applied to real air samples collected in different polluted areas (urban, industrial, rural, and remote locations) demonstrating the wide application of such methodology in various environmental situation.


Assuntos
Resinas de Troca Iônica/normas , Adsorção , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Polímeros/normas , Poliestirenos/normas
12.
Artigo em Inglês | MEDLINE | ID: mdl-33567749

RESUMO

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid-liquid extraction and static headspace) followed by gas chromatography-electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L-1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g-1), antimony (77.7 µg g-1), strontium (12,039 µg g-1) and zinc (103 µg g-1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g-1): the levels found in this paper (ranging between 1 and 5100 µg g-1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.


Assuntos
Compostos Orgânicos Voláteis , Poluentes Químicos da Água , Monitoramento Ambiental , Itália , Rios , Água , Poluentes Químicos da Água/análise
13.
Toxics ; 9(11)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34822670

RESUMO

The presence of phthalic acid esters (PAEs) in marine environments is an important issue. These chemicals are able to affect marine organisms, particularly marine turtles, and to act as endocrine disrupters. In this paper, for the first time, a simple and reproducible analytical method based on solid-phase extraction (SPE) coupled with gas chromatography-ion trap/mass spectrometry (GC-IT/MS) was developed for the extraction of phthalates from the blood of marine turtles. The extraction was obtained by using C18 phthalates-free as the stationary phase. In order to individuate the best working conditions for the extraction, the adsorption isotherms and breakthrough curves were studied. The overall analytical methodology was validated in terms of limit of detection (LOD, 0.08-0.6 ng mL-1), limit of quantification (LOQ, 0.4-0.8 ng mL-1), and correlation coefficients (>0.9933). By using this procedure, percentage recoveries ranging from 89 to 103% were achieved. The precision parameters (intra-day and inter-day) were studied, and the obtained values were smaller than 12.5%. These data confirm the goodness of the proposed analytical methodology, which is applied to real samples.

14.
Methods Protoc ; 3(1)2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32213842

RESUMO

In this paper, an analytical protocol was developed for the simultaneous determination of phthalates (di-methyl phthalate DMP, di-ethyl phthalate DEP, di-isobutyl phthalate DiBP, di-n-butyl phthalate DBP, bis-(2-ethylhexyl) phthalate DEHP, di-n-octyl phthalate DNOP) and bisphenol A (BPA). The extraction technique used was the ultrasound vortex assisted dispersive liquid-liquid microextraction (UVA-DLLME). The method involves analyte extraction using 75 µL of benzene and subsequent analysis by gas chromatography combined with ion trap mass spectrometry (GC-IT/MS). The method is sensitive, reliable, and reproducible with a limit of detection (LOD) below 13 ng g-1 and limit of quantification (LOQ) below 22 ng g-1 and the intra- and inter-day errors below 7.2 and 9.3, respectively. The method developed and validated was applied to six honey samples (i.e., four single-use commercial ones and two home-made ones. Some phthalates were found in the samples at concentrations below the specific migration limits (SMLs). Furthermore, the commercial samples were subjected to two different thermal stresses (24 h and 48 h at 40 °C) for evidence of the release of plastic from the containers. An increase in the phthalate concentrations was observed, especially during the first phase of the shock, but the levels were still within the limits of the regulations.

15.
Artigo em Inglês | MEDLINE | ID: mdl-32150918

RESUMO

Over the years, anthropogenic sources have increasingly affected food quality. One of the most sensitive and nutritional matrices affected by chemical contamination is honey, due to the use of acaricides. Recently, the attention has moved to the presence of phthalates (PAEs) and bisphenol A (BP-A), molecules present in plastic materials used both in the production phase and in the conservation of honey. In this study, an analytical method for the simultaneous determination of PAEs (dimethyl phthalate DMP, diethyl phthalate DEP, diisobutyl phthalate DiBP, dibutyl phthalate DBP, bis(2-ethylhexyl) phthalate DEHP, and di-n-octyl-phthalate DnOP) and BP-A was developed. The extraction technique is the ultrasound-vortex-assisted dispersive liquid-liquid microextraction (UVA-DLLME), using 150 µL of toluene as an extraction solvent, followed by the gas chromatography coupled with ion trap mass spectrometry analysis (GC-IT/MS). The developed method is sensitive, reliable, and reproducible: it shows high correlation coefficients (R > 0.999); limits of detection (LODs) less than 11 ng·g-1; limits of quantification (LOQs) less than 16 ng·g-1; repeatability below 3.6%, except BP-A (11.6%); and accuracy below 4.8%, except BP-A (17.6%). The method was applied to 47 nectar honey samples for evidencing similarities among them. The chemometric approach based on Hierarchical Cluster Analysis and Principal Component Analysis evidenced some similitudes about sample origin as well as marked differences between PAE and BP-A sources.


Assuntos
Mel , Ácidos Ftálicos , Plastificantes , Contaminação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Néctar de Plantas , Plastificantes/análise
16.
Nat Prod Res ; 33(7): 956-969, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26732127

RESUMO

The study and analysis of the materials employed in artistic paintings provide deeper knowledge about the history of the work of art, including restoration efforts made in the past, and the development of painting techniques through the centuries. Gas chromatography coupled to mass spectrometry is the main analytical technique employed, as it proved to be the most suitable technique for the analysis of complex mixtures, thanks to its combination of sensitivity, wide range of applicability and versatility. Further, µFT-IR technique has also been employed to get a preliminary screening of the samples taken from paintings. In this paper, the analytical protocol based on these two techniques has been applied for analysing natural terpenic resins; its performance has been tested on microsamples collected from paintings of valuable artistic interest.


Assuntos
Produtos Biológicos/análise , Pinturas , Adesivos/química , Arte , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resinas Vegetais/química , Manejo de Espécimes/métodos , Terpenos
17.
J Chromatogr A ; 1474: 1-7, 2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-28314431

RESUMO

This paper is focused on the determination of phthalates (PAEs), compounds "plausibly" endocrine disruptors, in baby food products by means of a method based on ultrasound-vortex-assisted liquid-liquid microextraction coupled with GC-IT/MS (UVALLME-GC-IT/MS). Particularly, the whole procedure allows the determination of six phthalates such as DMP, DEP, DBP, iBcEP, BBP and DEHP. After dissolution of 0.1g product sample and addition of anthracene as Internal Standard, 250µL of n-heptane are used as extraction solvent. The solution, held for 5min on the vortex mixer and for 6min in an ultrasonic bath at 100W for favoring the solvent dispersion and consequently the analyte extraction, is centrifuged at 4000rpm for 30min. About 100µL of heptane are recovered and 1µL is injected into the GC-IT/MS. All the analytical parameters investigated are deeply discussed: under the best conditions, the percentage recoveries range between 96.2 and 109.2% with an RSD ≤10.5% whereas the Limit of Detections (LODs) and the Limit of Quantifications (LOQs) are below 11 and 20ngg-1, respectively, for all the PAEs except for iBcEP (23 and 43ngg-1, respectively). The linear dynamic range of this procedure is between 10 and 5000ngg-1 with R2 ≥0.92. The method has been applied to real commercial freeze-dried samples (chicken and turkey meats) available on the Italian pharmaceutical market: three PAEs were preliminary identified, i.e. DEP (14ngg-1), DBP (11ngg-1) and DEHP (64ngg-1).


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Alimentos Infantis/análise , Microextração em Fase Líquida/métodos , Ácidos Ftálicos/análise , Animais , Antracenos/análise , Galinhas , Disruptores Endócrinos/análise , Liofilização , Heptanos/química , Limite de Detecção , Carne/análise , Padrões de Referência , Solventes/química , Fatores de Tempo , Perus , Ultrassom
18.
Ann Chim ; 95(3-4): 167-76, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16485658

RESUMO

Purpose of this scientific research is the physic and chemical characterization of two historical wax manufactures, made at the end of XIX century by Francesco Bianchi, a papal engraver. The chemical and analytical investigation was necessary to complete and to confirm the restorer's work. The IR Spectroscopy, X-Ray and GC-MS, the best technique to characterise wax, allowed us to obtain the following results. The two manufactures were made with commercial beeswax: in fact, the relative chromatograms showed unchanged peaks about esters of palmitic acid with C24 to C32 alcohol molecules; using standard beeswax we determined the same amount of hydrocarbons present in the wax manufactures. We found several hydrocarbons in these beeswax materials so that it is reasonable to think about successive modifications. ZnO (white zinc), a pigment, was added, probably due to its colour and covering capacity. Sb2S3, Anthimoniun vermilion, a red-orange pigment, was added to these manufactures to give them a soft pink-orange colour. By all used techniques we determined some modifications in the original beeswax; surely they were made to get a more malleable, mouldable, and then more able to be modelled wax.


Assuntos
Arte/história , Ceras/história , Cromatografia Gasosa-Espectrometria de Massas , História do Século XIX , História do Século XX , Itália , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura de Transição , Ceras/análise , Difração de Raios X
19.
Artigo em Inglês | MEDLINE | ID: mdl-12401371

RESUMO

We describe an analytical method that allows the determination of organophosphorus pesticides (OPs) in different human tissues. It involves an extraction procedure with ethanol-ethyl acetate, followed by gel permeation chromatography clean-up step and analysis by capillary gas chromatography-negative chemical ionization mass spectrometry in the selected ion monitoring mode. The method was tested for 37 OPs and the recoveries obtained vary between 60 and 106% with standard deviations ranging between +/-2 and +/-10. These values are independent of the analyzed tissue. Peak area repeatability as RSD for some OPs was < or =4.8% while a good linear relationship in the range 1.0-500 pg microl(-1) with r(2)> or =0.9878 was obtained. The limit of detection for the 37 OPs falls between 0.01 and 0.09 ng g(-1) with an RSD< or =9.5%. The analytical set up in this paper has been used to analyze different samples of human tissues (liver, healthy kidney, cancer kidney and adipose tissue) of 24 patients. The number of the identified OPs in the tissue samples is different (max. 20) according to the sample while their concentration ranges between the limit of detection and 28.0 ng g(-1). The highest concentrations have been determined in liver samples without any pathology (0.4-28.0 ng g(-1)) while the lowest concentrations have been determined in healthy kidney samples (0.01-1.50 ng g(-1)). In the cancer kidney samples OP concentrations vary between 0.03 and 4.6 ng g(-1): these concentrations are more elevated than those determined in healthy kidney samples. The comparison between the concentration of OPs determined in the healthy part, when possible, and those determined in the cancer part of the same kidney sample are very interesting: in fact, in the latter the OP concentration is generally 1-2-times higher than that in the former, an index of lower enzymatic activity in the cancer tissue.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Inseticidas/análise , Compostos Organofosforados , Resíduos de Praguicidas/análise , Tecido Adiposo/química , Calibragem , Humanos , Rim/química , Fígado/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Ann Chim ; 92(4): 469-76, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12073893

RESUMO

Lipids were extracted from lemon wax and fractionated into four classes on a silicic acid glass packed column by thin-layer chromatography (TLC). The free fatty acids, the fatty acid composition and the amount of each separated lipids were determined by capillary column gas chromatography (GC). Total lipids (TL) were 60 mg per 100 g raw weight and the ratio of nonpolar lipids (NPLs): glycolipids (GLs): phospholipids (PLs) was about 47:2:2. The main free fatty acids in lemon wax were hexadecanoic acid, cis-9-octadecenoic acid and cis,cis-9,12-octadecadienoic acid, while in the lipid fractions the main fatty acids were hexadecanoic acid in all the fractions, cis-cis-9,12-octadecadienoic and decanoic acids in triglyceride (TG) fraction, dodecanoic and cis-9-octadecenoic acids in diglyceride (DG) fraction and tetradecanoic, octadecanoic and cis-9-octadecenoic acids in GL and PL fractions. The ratio of unsaturated to saturated fatty acids showed a remarkable difference among these four lipid fractions. In PL and GL fractions this ratio was similar, 47.7% and 47.1% respectively, and in TG fraction it was 42.4% while in DG fraction this value was 23.5%.


Assuntos
Citrus/química , Ácidos Graxos/análise , Lipídeos/análise , Cromatografia Gasosa , Cromatografia em Camada Fina , Ceras/química
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