Metabolomics can provide a readout of the biochemical and physiological state of a biological system. Gas chromatography coupled to mass spectrometry (GC-MS) has been widely applied for metabolomic analysis due to its numerous advantages, such as good sensitivity, high resolution, reproducibility, extensive database, lower acquisition cost and greater coverage. In addition, combined with efficient methods of sampling and sample preparation, the metabolomic analysis of damaged skin based on GC-MS can provide an important step toward elucidating several skin diseases. Based on this, this review presents a comprehensive overview of sampling, sample preparation, data processing and GC-MS analysis of metabolomic studies of damaged skin. Also, part of the biological interpretation of metabolites such as cis- and trans-urocanic acid (UCA) altered in photoexposed skin and lauric acid (C12:0) and palmitic acid (C16:0) in melanoma is discussed. Finally, to improve decision-making, a part of the integration of skin metabolomics with other omics sciences for the advancement of diagnosis is presented.

This work presents the application of a simple and sensitive method developed for the simultaneous analysis of the levels of twenty two underivatizated free L-amino acids in plasma samples of preeclampsia patients by high performance liquid chromatography coupled to high-resolution mass spectrometer (LC-HRMS) using hydrophilic interaction liquid chromatography (HILIC) silica column. The linearity was evaluated in the range of 0.009 to 8.018 µmol L-1 showing coefficients of determination (R2) in the range of 0.999 to 0.911 (p < 0.05). The intra- and inter-day precisions were above of 9.84 and 15.31, respectively. The limits of detection (LOD) and quantification (LOQ) were in the range of 0.003 to 0.683 µmol L-1 and 0.009 to 2.276 µmol L-1, respectively. The results of the investigation of free L-amino acids showed that the levels of GABA, Arg, Ser, Leu, Ile, Met, Val, Ala, Gly, Bet, His and Lys in plasma of patients with preeclampsia were significantly different from healthy patients.

Comprehensive two-dimensional gas chromatography has been successfully applied to the analysis of various organic contaminants; however, few studies report its use in the analysis of endocrine disrupting compounds. These compounds are suspected to cause dysfunction of the endocrine system in humans and animals. This work describes the development of a method to analyse dibutylphthalate, benzylbutylphthalate, nonylphenol and octylphenol in water using solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography with a flame ionisation detector. The merit parameters of the comprehensive two-dimensional gas chromatography with flame ionisation detector method were weighed against a gas chromatography/mass spectrometry-single ion monitoring method of endocrine disrupting compounds analysis. The compounds were evaluated over a concentration range of 0.2 to 6.0 µg L-1 . The use of a two-dimensional chromatography method proved to be advantageous in analysing endocrine disrupting compounds, according to the observed increase of the signal relative to the noise and peak resolution.

Compostos carbonílicos, tais como os aldeídos, são amplamente encontrados em produtos alimentares. Estes compostos podem originar-se de matérias-primas, fermentação alcoólica ou como produtos de uma grande variedade de reações químicas. Este Review apresenta estudos realizados para determinar contaminantes de aldeído em produtos alimentares. Entre os métodos utilizados para avaliar a presença de aldeídos em alimentos e bebidas, os mais citados são os métodos cromatográficos. Técnicas cromatográficas empregadas incluem a cromatografia líquida de alta eficiência com detecção ultravioleta, cromatografia gasosa com detecção por ionização em chama e com detecção de espectrometria de massas. Métodos de amostragem e o potencial de uso da microextração em fase sólida para determinação de substâncias químicas nos alimentos também são discutidos neste artigo.

Carbonyl compounds, such as aldehydes, are widely found in food products. These compounds can originate from raw materials, alcoholic fermentation or as products of a wide range of chemical reactions. This Review presents studies performed to determine aldehyde contaminants in food products. Among the methods used to evaluate the presence of aldehydes in food and beverages, chromatographic methods are the most commonly cited. Employed chromatographic techniques include high performance liquid chromatography with ultraviolet (UV) detection, gas chromatography with flame ionization detection and with mass spectrometry detection. Sampling methods and the potential use of solid phase microextraction for determining chemical substances in foods are also discussed.

Este trabalho apresenta o desenvolvimento de um método simples, rápido e preciso para análise dos produtos da hidrogenação eletrocatalítica da ciclohexanona com a técnica de microextração em fase sólida, usando cromatografia a gás com detector de ionização por chama. A otimização preliminar do método foi realizada através de ferramentas quimiométricas. Os resultados de LOD e LOQ foram 0,50% de conversão ou 0,78 mg L-1 e 1,20% de conversão ou 1,86 mg L-1, respectivamente. A curva analítica demonstra boa linearidade (R² = 0,9936).

This work presents a method development for analyzing electrocatalytic hydrogenation products of cyclohexanone with the simple, fast and accurate SPME, coupled with classic gas chromatographic methods using flame ionization detection. Preliminar method optimization was made using chemometric tools. LOD and LOQ obtained were 0.50% conversion or 0.78 mg L-1 and 1.20% conversion or 1.86 mg L-1 respectively. The analytical curve obtained displays good linearity (R² = 0.9936).

Este trabalho descreve um método de Microextração em Fase Sólida (SPME-CG) para a determinação de pesticidas organofosforados em amostras de peixes de água doce, água e outros alimentos por cromatografia em fase gasosa com detector de nitrogênio e fósforo. As amostras foram coletadas entre outubro de 2002 e abril de 2003 nos afluentes e subafluentes do rio Paranaíba que abastecem a cidade de Patos de Minas, Minas Gerais, Brasil. A determinação dos pesticidas co-ral (O,O-dietil-O-(3-cloro-4-metil-2-oxo-2H-1-benzopiran-7-il) fosforotioato)), DDVP (2,2-dicloroetenil dimetilfosfato), di-siston (O,O-dietil S-[2-(etiltio) etil] fosforoditioato), etion (O,O,O',O'-tetraetil S,S'-metilenobisfosforoditioato), forato (O,O-dietil-S-etiltiometilfosforoditioato), fosdrin (O,O-dimetil-1-carbometoxi-1-propen-2-il-fosfato), gution (O,O-dimetil-S-(4-oxo-1,2,3-benzotrizina-3-metil) fosforoditioato)), malationa (O,O-dimetil-S-(etil-1,2-dicarboetoxi) fosforoditioato) e parationa metílica (O-dimetil-O-4-nitrofenilfosforotioato) em amostras de peixes, água e outros alimentos, com o procedimento de SPME-CG utilizando uma microfibra de PDMS de 100 µm, é simples, fácil manuseio, econômica e livre de solvente. As condições otimizadas para a extração dos pesticidas com o método SPME-CG foram: amostras sob agitação, absorção à temperatura ambiente durante 40 min, dessorção a 220°C durante 10 min e volume de amostra no frasco de 16,0 mL. Utilizando-se estas condições foram obtidas curvas analíticas lineares em diferentes faixas de concentração (dependendo de cada pesticida) com coeficientes de correlação entre 0,997 a 0,999. A precisão estava adequada com desvios padrão relativos variando de 4,40 a 15,13%. O limite de detecção variou de 0,05 µg L-1 a 8,37 µg L-1 e o limite de quantificação de 0,09 µg L-1 a 8,70 µg L-1. O método foi empregado para detectar e quantificar pesticidas em 24 amostras de peixes de três espécies diferentes e também em água, batatas, goiaba e café. As amostras analisadas mostraram resíduos de seis pesticidas organofosforados diferentes.

This paper describes a Solid Phase Microextraction method (SPME-CG) to the determination of organophosphorus pesticides in samples of fresh-water fish, water, potatoes, guava and coffee by capillary gas chromatography with nitrogen phosphorus detector. The samples were collected from October 2002 to April 2003 in the tributaries and sub-tributaries of the Paranaiba River, which supplies the city of Patos de Minas, Minas Gerais, Brazil. The determination of the pesticides: co-ral (O,O-diethyl O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) phosphorothioate), DDVP (2,2-dichloroethenyl dimethylphosphate), disyston (O,O-diethyl S-[2-(ethylthio) ethyl] phosphorodithioate), ethion (O,O,O',O'-tetraethyl S,S'-methylene bis(phosphorodithioate)), phorate (O,O-diethyl S-ethylthiomethyl phosphorodithioate), phosdrin (2-methoxycarbonyl-1-methylvinyl dimethyl phosphate), guthion (O,O-dimethyl-S-[(4-oxo-1,2,3-benzotriazin-3(4H)-yl)methyl] phosphorodithioate)), malathion (diethyl (dimethoxy thiophosphorylthio succinate) and methyl-parathion (O,O-dimethyl O-4-nitrophenyl phosphorothioate) in samples of fish, water and others foods with a manual SPME-CG holder using a 100 µm PDMS microfiber, is simple, easy to handle and solvent-free. The optimised conditions for pesticides extraction by SPME-CG method were: sample agitation, absorption at room temperature for 40 min, desorption at 220°C for 10 min, and sample volume in the vial of 16.0 mL. Under these conditions, the analytical curves were linear in different ranges (depend of each pesticide) with correlation coefficients from 0.997 to 0.999 and the precision was good (RSD from 4.40 to 15.13%). The detection limit was 0.05 µg L-1 to 8.37 µg L-1 and the quantitation limit was 0.09 µg L-1 to 8.70 µg L-1. The method was employed to detect and quantify pesticides in 24 fish of three different species and also in water, potatoes, guava and coffee. The samples analyzed showed residues of six different organophosphorus pesticides.