Optimization of a sampling method to determine polycyclic aromatic hydrocarbons in smoke from incomplete biomass combustion

Application of curcumin as a green and new sorbent in deep eutectic solvent-based dispersive micro-solid phase extraction of several polycyclic aromatic hydrocarbons from honey samples prior to gas chromatography-mass spectrometry determination

A green, simple, and efficient dispersive micro-solid phase extraction method was developed for the extraction of polycyclic aromatic hydrocarbons from honey samples. In this method, for the first time, curcumin was used as an efficient and green sorbent to extract the analytes from the sample. After that the adsorbed analytes were eluted using a deep eutectic solvent prepared by mixing tetrabutylammonium chloride: ethylene glycol and analyzed by gas chromatography-mass spectrometry. Important experimental factors affecting adsorption and desorption steps of the method were optimized and under optimal experimental conditions, low limits of detection (0.14-0.37 ng/g) and quantification (0.49-1.3 ng/g), wide linear range (1.3-500 ng/g) with a coefficient of determination ≥0.994 were obtained. Relative standard deviation values for intra- and interday precisions were ≤7.5% for all of the analytes at a concentration of 2 ng/g for each analyte (n = 6). Extraction recovery of the method was in the range of 72-81%. Finally, 20 honey samples were analyzed and the analytes were successfully detected. The method is environment friendly because of the use of curcumin as a sorbent. Also, biodegradability of the used deep eutectic solvent components is another advantage of the method.

Polycyclic aromatic hydrocarbons in soybean grains

During the burning of the organic material (firewood) in the drying, combustion may occur incompletely, thus generating smoke contaminants such as polycyclic aromatic hydrocarbons (PAHs) in the furnaces. This study aimed to identify possible contamination by PAHs in soybean grains from storage units in municipalities in the Midwest region that have undergone drying in a direct-fired furnace with firewood as fuel. The soybean grains were collected in different municipalities of the Midwest region of Brazil, totaling 22 samples. A survey of possible contamination of soybean grains by PAHs was carried out using High-Performance Liquid Chromatography. The experiment was carried out in a completely randomized design with three replicates, and the data were subjected to analysis of variance, with means compared by Tukey test. The sum of the groups was: PAH4 - 1.45 μg kg-1 for Edéia (2), PAH8 - 2.97 μg kg-1 for Catalão (19) and PAHT - 5.06 μg kg-1 for Edéia (2); for benzo(a)pyrene, the sum was below 2.0 μg kg-1, not exceeded by the value of 0.64 μg kg-1 for Edéia (1). The values found of PAHs did not exceed the maximum limits established by the European Union, except for infant food.

Presença de hidrocarbonetos policíclicos aromáticos em produtos alimentícios e a sua relação com o método de cocção e a natureza do alimento

Resumo Hidrocarbonetos Policíclicos Aromáticos (HPA) podem estar associados à carcinogênese em humanos. Tais compostos penetram no organismo pelo trato gastrointestinal, o que faz da dieta uma importante via de contaminação. O objetivo desta revisão é analisar a relação entre a formação/ingestão desses compostos e a alimentação. Foi encontrada associação direta do método de cocção empregado com o aumento dos níveis de HPA nos alimentos e a formação de novos compostos. A fonte térmica aplicada, a composição do alimento, o tipo de óleo utilizado, especialmente nos processos de fritura, bem como o tipo de tratamento empregado ao alimento antes da cocção, são fatores que influenciam o teor de HPA no produto final. A legislação brasileira é pouco abrangente em relação a esses compostos e a necessidade de ampliação das normas nacionais se torna ainda mais evidente quando este tema é visto como uma questão de Segurança de Alimentos.

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown. The growing awareness of the impact of particulate aerosols on climate, and the incompletely recognised but serious effects of anthropogenic constituents on air quality and human health, have conducted to several scientific studies. These investigations have provided information about the behaviour of atmospheric particulate matter and the description of the character of its carbonaceous content. The compilation of such results is important as they append to the emergent global-wide dataset of the organic composition of atmospheric aerosols. The contribution of the major emission sources to regional particulate pollution can be diagnosed by using specific molecular markers. This overview is mainly focused on results obtained with gas chromatography coupled with mass spectrometry, since it is the analytical method of choice in elucidating the solvent-extractable organic compounds in atmospheric particulate matter. A synopsis of the selection of organic tracers and the application of geochemical parameters to the analysis of organic constituents as a tool for source apportionment is shown here. Besides the assessment of current knowledge, this paper also presents the identification of further areas of concern.

Box-Behnken design: An alternative for the optimization of analytical methods

The present paper describes fundamentals, advantages and limitations of the Box-Behnken design (BBD) for the optimization of analytical methods. It establishes also a comparison between this design and composite central, three-level full factorial and Doehlert designs. A detailed study on factors and responses involved during the optimization of analytical systems is also presented. Functions developed for calculation of multiple responses are discussed, including the desirability function, which was proposed by Derringer and Suich in 1980. Concept and evaluation of robustness of analytical methods are also discussed. Finally, descriptions of applications of this technique for optimization of analytical methods are presented.

Characterisation of polycyclic aromatic hydrocarbons in atmospheric aerosols by gas chromatography–mass spectrometry

An accurate and reliable method for determining polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosols is described. This optimised gas chromatography-mass spectrometry (GC-MS) method permits a wide range of concentrations to be analysed without the influence of interferences. Pre-treatment comparison of four kinds of aerosol collector filters determined that quartz and glass fibre filters were the most suitable. Solvents like cyclohexane, toluene, acetonitrile and dichloromethane were evaluated for their PAH-extraction capacity. Ultrasonic extraction using CH2Cl2 was selected because it is rapid and easy; moreover, this solvent increases the sample-throughput capacity. PAH compounds were quantitatively collected and ultrasonically extracted twice using 15 mL of CH2Cl2 for 15 min for each replicate. Rotavapor concentration, fractionation and dissolution were also optimised. A certified standard mixture (16 EPA PAHs), a deuterated compound and precision recovery assays were used for validating the proposed methodology. Adequate analytical parameters were obtained. Detection limits were (1.6-26.3) x 10(-5) ng and quantification limits were (5.2-87.6) x 10(-5) ng. Analysis of the environmental samples detected 4-10 EPA list PAH compounds. In addition, 2-11 tentative compounds were found, and their molecular structures were described for the first time. Our study of both Youden method and the standard addition method has shown that the proposed determination of PAHs in environmental samples is free of systematic errors. In conclusion, this unbiased methodology improves the identification and quantification of PAH compounds. High sensitivity as well as acceptable detection and quantification limits were obtained for the environmental applications.