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Um método para a determinação de bifenilas policloradas (PCB) no leite materno foi desenvolvido e aplicado para avaliar a contaminação de amostras procedentes de quatro cidades brasileiras. Os PCB foram extraídos através da Microextração de Fase Sólida e analisados por Cromatografia Gasosa com Detector por Captura de Elétrons. As figuras de mérito estudadas foram linearidade (1 a 16 µg L -1 , r > 0,9884), precisão (RSD < 12%, n = 5), recuperação (71 a 127%) e limite de quantificação (entre 0,45 e 2,42 µg L -1 ). A análise das vinte amostras revelou níveis de PCB acima de 11,8 µg L -1 na região metropolitana de São Paulo, sendo o PCB 153 encontrado em todas essas amostras. Em Vitória/ES e Florianópolis/SC foram encontrados PCB em 100 e 60% das amostras, respectivamente. Nenhuma contaminação foi detectada nas amostras do Rio Branco/Acre. Sendo assim, uma alta correlação entre a contaminação dessas amostras e o nível de industrialização da região foi encontrada.A method for the determination of polychlorinated biphenyls (PCB) in breast milk was developed and applied to evaluate the contamination of samples that proceed from four Brazilian cities. PCB were extracted by Solid-Phase Microextraction and analyzed by Gas Chromatography with Electron Capture Detector. The figures of merit studied were linearity (to 16 µg L -1 , r > 0.9884), precision (RSD < 12%, n = 5), recovery (71 to 127%) and limit of quantification (between 0.45 and 2.42 µg L -1 ). The analysis of the twenty samples revealed PCB levels above 11.8 µg L -1 in São Paulo metropolitan area being the PCB 153 found in all these samples. In Vitória/ES and Florianopolis/ SC were found PCB in 100 and 60% of the samples, respectively. No contamination was detected in the samples from Rio Branco/AC. Thus, a high correlation between the contamination of these samples and the level of industrialization of the region was found. Keywords: PCB, HS-SPME, validation, breast milk, contamination IntroductionPolychlorinated biphenyls (PCB) have been used commercially since 1929 as dielectric and heat exchange fluids as well as in a variety of other applications. However, the distribution of PCB in the environment was not recognized until 1966, when Jensen identified PCB in human and wildlife samples. 1 Owing to their physicochemical properties, these compounds are extremely resistant to chemical and biological degradation and are easily bioaccumulated through the trophic pyramid, 2,3 especially due to their lipophilic character (which causes their accumulation on fat tissues). 4,5 Therefore, the PCB contamination is a serious issue, and despite the fact that their production and use has been banned during the 1970's and 1980's, they are still detected in the ecosystem. [6][7][8] In Brazil, a law implemented in 1981 prohibits the importation, the manufacture, the use and the marketing of PCB and demands the substitution of the electric system equipments in operation only for others that do not contain PCB. Besides, the law prohibits to discard these equipments in sanitary l...

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Due to the tendency of polychlorinated biphenyls (PCB) to accumulate in matrixes with high lipid content, the contamination of the breast milk with these compounds is a serious issue, mainly to the newborn. In this study, milk samples were collected from breastfeeding mothers belonging to 4 Brazilian regions (south, southeast, northeast and north). Twelve PCB were analyzed by HS-SPME-GC-ECD and the corresponding peak areas were correlated to the answers to a questionnaire of general habits, breastfeeding and characteristics of the living places. To realize this exploratory analyze, self-organizing maps generated applying Kohonen neural network were applied. It was possible to verify the occurrence of different PCB congeners in the breast milk relating to the region of the Brazil that the breastfeeding lives, the proximity to an industry, the proximity to a contaminated river or sea, the type of milk (colostrum, foremilk and hindmilk) and the number of past pregnancies.

The objective of this research was to determine the levels of enrichment of vitamins B1, B2, B6 and B3 in different types and brands of enriched cookies. The chromatographic separation was performed in a C18 column with gradient elution and UV detection at 254 and 287 nm. The results show that only 5 of the 24 brands evaluated are in accordance with the Brazilian legislation with respect to the vitamin content declared on the labels. However, consumption of approximately 100-150 g of most of the brands supplies the recommended dietary intake for children and adults of the vitamins evaluated