RESUMO: Os objetivos deste estudo foram verificar a ocorrência de álcool furfurílico (FA) e compostos carbonílicos (acetaldeído, acroleína, carbamato de etila (CE), formaldeído e furfural) em espumantes e avaliar, pela primeira vez, se o consumo das amostras em estudo poderia representar risco para a saúde do consumidor. Esses compostos são eletrofílicos e, portanto, podem se ligar covalentemente ao DNA, o que pode resultar em mutagenicidade. CE e formaldeído foram encontrados em baixos níveis (<1μg/L) em todas as amostras. Acetaldeído, furfural e acroleína também foram encontrados em baixos níveis (<1,5; 1,4 e 1,0μg L-1, respectivamente) em 57, 71 e 76% das amostras. Nas demais amostras, os níveis de acetaldeído, furfural e acroleína variaram de 5,2 a 54,8, 10,5 a 41,0 e 20,3 a 36,7μg L-1, respectivamente. O álcool furfurílico também foi encontrado em todas as amostras em níveis de 10,4 a 33,5μg L-1. A acroleína foi o único composto encontrado em níveis suficientes para representar risco à saúde, que ocorreu em 24% das amostras. Uma avaliação focada na origem da acroleína merece atenção, investigando a influência da concentração dos precursores e o papel da fermentação na formação do aldeído, além da avaliação da possível contaminação ambiental das uvas durante o cultivo.

ABSTRACT: The goals of this study were to verify the occurrence of furfuryl alcohol (FA) and carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate (EC), formaldehyde and furfural) in sparkling wines and to evaluate, for the first time, whether the consumption of the samples under study could represent risk to consumers health. These compounds are electrophilic; and therefore, may covalently bind to DNA, which may result in mutagenicity. EC and formaldehyde were present at low levels (<1μg L-1) in all samples. Acetaldehyde, furfural and acrolein were also found in low levels (<1.5, 1.4 and 1.0μg L-1, respectively) in 57, 71 and 76% of samples. In the other samples, levels of acetaldehyde, furfural and acrolein ranged from 5.2 to 54.8, 10.5 to 41.0 and 20.3 to 36.7μg L-1, respectively. Furfuryl alcohol was also reported in all samples in levels from 10.4 to 33.5μg L-1. Acrolein was the only compound reported at levels sufficient to represent risk to health, which occurred in 24% of the samples. A study focused on the origin of acrolein deserves attention, investigating the influence of the concentration of precursors and the role of fermentation in the formation of this aldehyde, besides the evaluation of possible environmental contamination of grapes during cultivation.

A cromatografia gasosa bidimensional abrangente (GC×GC) é uma técnica analítica relativamente nova, que tem sido amplamente empregada para análise de vários tipos de amostras complexas. A GC×GC proporciona maior capacidade de pico, sensibilidade e resolução, quando comparada à cromatografia gasosa monodimensional (1D-GC). Além disso, a estruturação dos cromatogramas bidimensionais auxilia na identificação de classes de compostos. No que diz respeito à análise de alimentos e bebidas, a eficiência superior da GC×GC resulta em benefícios únicos quando comparada às técnicas analíticas disponíveis para os mais variados objetivos de análise: separação de grupos de compostos aroma-ativos, verificação de perfil cromatográfico, análise de compostos alvo ou identificação de componentes desconhecidos. Quando compostos aroma-ativos estão presentes em nível de traços, a GC×GC também pode ser empregada como uma técnica de alto potencial devido a sua sensibilidade superior. Tendo em vista que a fração volátil de muitos alimentos e bebidas pode determinar a aceitação ou rejeição destes produtos por parte do consumidor, a caracterização da mesma pode ser feita com base na composição destes compostos voláteis. Neste trabalho, as aplicações da GC×GC para análise de voláteis em alimentos e bebidas são apresentadas, desde a fase inicial de sua implementação até 2010. Alguns tópicos relacionados aos princípios da GC×GC foram também discutidos.

Comprehensive two-dimensional gas chromatography (GC×GC) is a relatively new analytical technique, which has been widely used for the analysis of a variety of complex samples. GC×GC offers increased peak capacity, higher sensitivity, and improved resolution when compared to conventional one-dimensional gas chromatography (1D-GC). In addition, it generates structured two-dimensional chromatograms, which aids in the identification of compound classes. The enhanced separation provided by GC×GC has been a distinctive benefit when it is compared to other available analytical techniques that deal with the analysis of food and beverages, irrespective of the goal of the analysis, i.e. aroma group-type separation and fingerprinting, target-volatile compound analysis or identification of unknowns. When trace amounts of aroma active compounds are present, GC×GC may also be used as a very powerful tool for their analysis due to its higher sensitivity. As volatile fractions may determine the acceptance or rejection of many foods and beverages by the consumer, the characterization of these products may be done having volatile composition as a basis. Applications of GC×GC for the analysis of volatiles of foods and beverages were revised since the emergence of this technique until 2010. Some topics related to principles of GC×GC were also discussed.

Analysis of seven pesticides in sediments was successfully achieved using comprehensive two-dimensional gas chromatography with micro-electron capture detection, as it provided higher sensitivity and less matrix interference. Repeatability and intermediate precision of peak areas and heights were less than 4% and the recovery percentage for the analytes ranged from 52 to 115%. Instrumental LOD and LOQ were in the range of 0.60 to 2.31 μg L-1 and 1.83 to 5.62 μg L-1, respectively. Concentrations of 3.34 μg kg-1 (dry basis) for trifloxystrobin and azoxystrobin (below the LOQ) were found in a sediment sample.

The development of analytical methods for determination of eight pesticides of different chemical classes (trichlorfon, propanil, fipronil, propiconazole, trifloxystrobin, permethrin, difenoconazole and azoxystrobin) in sediments with gas chromatography-micro-electron capture detector (GC/µECD) and comprehensive two-dimensional gas chromatography with micro-electron capture detector (GCxGC/µECD) is described. These methods were applied to real sediment samples, and the best results were obtained using a 5% diphenyl-methylpolysiloxane column for 1D-GC. For GCxGC the same column was employed in the first dimension and a 50%-phenyl-methylpolysiloxane stationary phase was placed in the second dimension. Due to the superior peak capacity and selectivity of GCxGC, interfering matrix peaks were separated from analytes, showing a better performance of GCxGC.

Neste trabalho foram comparados perfis cromatográficos dos óleos provenientes de hidrodestilação de folhas de Baccharis punctulata, Baccharis dracunculifolia e Eupatorium laevigatum e os perfis cromatográficos obtidos utilizando-se HS-SPME. Várias plantas nativas do Brasil ainda não foram estudadas quanto à sua composição química. Técnicas convencionais de extração como a hidrodestilção, podem resultar em alterações da composição química original destes óleos. O uso da HS-SPME provê uma alternativa mais branda de extração, prevenindo transformações químicas e resultando em informações complementares sobre a composição de voláteis das plantas. Pela primeira vez, cumarina e cumaran foram identificados no "headspace" de folhas de E. laevigatum, após dano mecânico, por HS-SPME. As semelhanças e diferenças na composição dos voláteis, verificadas através de ambas as técnicas de extração, são discutidas, mostrando a complementaridade destas técnicas, as possíveis implicações destes resultados no que diz respeito a compostos infoquímicos e as possíveis transformações químicas durante o processo de hidrodestilação.

In this work the qualitative chromatographic profiles of the volatile oil obtained with fresh chopped leaves of Baccharis punctulata, Baccharis dracunculifolia and Eupatorium laevigatum, using HS-SPME were compared with their hydrodistilled oils. Several Brazilian native plant species have not yet been studied regarding their volatile compounds composition. Conventional techniques employed for the investigation of volatile compounds, such as hydrodistillation, may impart chemical changes to the original oil composition. The use of HS-SPME provides alternative milder extraction conditions, preventing chemical transformations and supplying complementary information about volatiles composition. Coumarin and coumaran were detected by the first time among volatile components of E. laevigatum leaves after mechanical damage, only when using HS-SPME. Differences and similarities perceived between volatile compounds profiles using both extraction techniques are discussed, showing that they are complementary and may bring insight about fresh leaf volatiles playing infochemical roles and about chemical transformations caused by hydrodistillation.

Comprehensive Multidimensional Chromatography is a relatively new analytic technique, which is receiving growing attention in many parts of the world, including recently in Brazil. This work presents terms in Portuguese which are commonly used in Comprehensive Multidimensional Chromatography in order to help standardize the vocabulary employed in this area in the scientific literature. It also includes some symbols, their nominations, and explanation of some terms, whenever necessary. This proposal does not intend to be comprehensive or definitive; on the contrary, it intends to be a first step in the process of establishing a standardized nomenclature, serving as a base for a further sound discussion in the scientific community realm.

The goal of this article is to discuss the application of comprehensive two-dimensional gas chromatography (GCxGC) to petrochemical samples. The use of GCxGC for petroleum and petroleum derivatives characterization, through group type analysis, or BTEX (benzene, toluene, ethylbenzene, xylenes), total aromatic hydrocarbons, polyaromatic hydrocarbons, sulfur-containing, oxygen-containing, and nitrogen-containing compounds is presented. The capability of GCxGC to provide additional specific chemical information regarding petroleum processing steps, such as dehydrogenation of linear alkanes, the Fischer-Tropsch process, hydrogenation and oligomerization is also described. In addition, GCxGC analyses of petrochemical biomarkers and environmental pollutants derived from petrochemicals are reported.