Validation of a multi-residue method and estimation of measurement uncertainty of pesticides in drinking water using gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry.

A rapid and efficient sample extraction using solid-phase extraction coupled with gas- and liquid-chromatography-mass spectrometry was studied for the analyses of 124 different types and chemical groups pesticides from drinking water. The extraction was performed using a Bond Elut Florisil cartridge. The GC analysis was divided into two (analysis 1 and 2), while a single method was used for LC analysis. A full validation of the method was performed. Linearity (1-250 ng/L range), intra-day precision (2.31-19.54% RSD) and inter-day precision (4.35-27.15% RSD), matrix effects (low matrix effects were observed for most compounds ≤20%) and limits of quantification (3.19 and 146.24 ng/L) were calculated. The recovery rates were between 55.54 and 121.21% (with RSD mean of 11.34% for all of the compounds). The method was suitable for 95.2% of the compounds. The information obtained from the full method validation has been used to estimate the expanded uncertainty and the uncertainty contributions of the different individual steps of the method for the determination of pesticides at trace levels in water. Expanded relative uncertainties ranged from 10% to 49%.

Levels of polychlorinated biphenyls (PCBs) in whole milk powderand estimated daily intake for a population of children / Níveis de bifenilos policlorados (PCBs) em leite em pó integral e ingestão diária estimada para uma população infantil

ABSTRACT: Polychlorinated biphenyls (PCBs) are chemical contaminants classified as persistent organic pollutants. Although, their use has been banned for several decades, PCBs are still scattered in the environment and; therefore, all living organisms may be exposed to these compounds. Diet, especially fatty foods such as milk, has been recognized as one of the main sources of human exposure to PCBs. Hence, the aim of this study was to evaluate the residual levels of indicator PCBs in whole milk powder consumed by preschool children in the Municipality of Imbé, State of Rio Grande do Sul, Brazil and to determine the estimated daily intake of these PCBs through this food. Analyses were performed by GC-μECD and the results were confirmed by GC/MS. The PCBs 28, 52 and 153 displayed values ​​below the limit of quantification. The PCBs 138 and 180 showed mean values of 0.073 and 0.157ng.g-1 lipid, respectively. These values were below the reference limits established by the European Community. The estimated total daily intake of PCBs was 0.110ng.g-1 lipid of body weight per day, a value lower than that established by the legislations of Belgium and Norway.

RESUMO: Os bifenilos policlorados (PCBs) são contaminantes químicos classificados como poluentes orgânicos persistentes. Embora seu uso tenha sido banido há mais de décadas, os PCBs ainda encontram-se presentes no meio ambiente e portanto, todos os organismos vivos podem estar expostos a esses compostos. A alimentação, especialmente alimentos gordurosos, como leite, tem sido reconhecida como uma das principais fontes de exposição humana aos PCBs. Assim, o objetivo deste estudo foi avaliar os níveis residuais de PCBs indicadores em leite em pó integral consumido por pré-escolares no Município de Imbé, Rio Grande do Sul, e determinar a ingestão estimada desses PCBs por meio deste alimento. As análises foram realizadas em GC-µECD e os resultados foram confirmados em GC/MS. Os PCBs 28, 52 e 153 apresentaram valores abaixo do limite de quantificação. Os PCBs 138 e 180 apresentaram valores médios de 0,073 e 0,157ng.g-1 lipídio, respectivamente. Estes valores estavam abaixo dos limites de referência estabelecidos pela Comunidade Europeia. A ingestão diária total estimada de PCBs foi de 0,110ng.g-1 de peso corporal por dia, valor inferior ao estabelecido pelas legislações da Bélgica e da Noruega.

In vitro and ex vivo activity of Melaleuca alternifolia against protoscoleces of Echinococcus ortleppi.

Cystic echinococcosis is a zoonotic disease of difficult diagnosis and treatment. The use of protoscolicidal agents in procedures is of utmost importance for treatment success. This study was aimed at analysing the in vitro and ex vivo activity of Melaleuca alternifolia oil (tea tree oil - TTO), its nanoemulsion formulation (NE-TTO) and its major component (terpinen-4-ol) against Echinococcus ortleppi protoscoleces obtained from cattle. Concentrations of 2·5, 5 and 10 mg mL-1 of TTO, 10 mg mL-1 of NE-TTO and 1, 1·5 and 2 mg mL-1 of terpinen-4-ol were evaluated in vitro against protoscoleces at 5, 10, 15 and 30 min. TTO was also injected directly into hydatid cysts (ex vivo analysis, n = 20) and the viability of protoscoleces was evaluated at 5, 15 and 30 min. The results indicated protoscolicidal effect at all tested formulations and concentrations. Terpinen-4-ol (2 mg mL-1) activity was superior when compared with the highest concentration of TTO. NE-TTO reached a gradual protoscolicidal effect. TTO at 20 mg mL-1 showed 90% protoscolicidal action in hydatid cysts at 5 min. The results showed that TTO affects the viability of E. ortleppi protoscoleces, suggesting a new protoscolicidal option to the treatment of cystic equinococcosis.

Polychlorinated biphenyls in umbilical cord serum of newborns from Rio Grande do Sul state, Brazil.

BACKGROUND: Polychlorinated biphenyls (PCBs) are food-chain contaminants that have been shown to contaminate foods worldwide. The newborn are exposed to these organochlorine compounds across the placenta and through breastfeeding. They are proven to be carcinogenic and may contribute to congenital malformation etiology. METHODS: This study examined levels of five PCB congeners (28, 52, 138, 153 and 180) in umbilical cord serum samples from 148 newborns from Rio Grande do Sul state, Brazil. Serum concentrations of PCBs were analyzed by gas chromatography with electron capture detection and mass spectrometry. RESULTS: Levels of ∑PCBs ranged from 0.35 to 55.17 ng/ml in umbilical cord serum positive samples, and PCB 138 was the most prevalent congener. Only 7.4% of samples presented no PCB congener. CONCLUSIONS: Some PCB congener cord serum levels were related to the locale of the mothers' residence, smoking and drinking habits, fruit consumption, and congenital malformation.

Bifenilos policlorados em arroz e feijão do estado do Rio Grande do Sul / Polychlorinated biphenyls in rice and beans from Rio Grande do Sul state, Brazil

Os bifenilos policlorados (PCBs) estão entre os poluentes mais tóxicos presentes no meio ambiente, apresentando os alimentos como principal fonte de exposição humana. Com base nisso, este trabalho teve como objetivo determinar os sete PCBs indicadores de contaminação ambiental em 22 amostras de arroz e 18 de feijão do estado do Rio Grande do Sul, Brasil. Além disso, objetivou-se calcular a ingestão diária estimada de resíduos, a partir da contaminação existente no arroz e feijão, assim como determinar o teor de gordura das amostras para correlacioná-lo com os níveis de PCBs. A extração e purificação dos compostos foram realizadas pelo método QuEChERS, seguido de identificação e quantificação por CG-EM. Os PCBs 153 e 101 apresentaram as maiores concentrações médias nas amostras de arroz e feijão, respectivamente. Considerando o somatório dos PCBs, este foi de 4,39ng g-1 para o arroz e de 4,17ng g-1 para o feijão. Quanto à ingestão diária estimada, esta foi de 7,82ng kg-1 e de 3,14ng kg-1 de peso corporal por dia, para o arroz e o feijão, respectivamente. Em relação ao percentual de gordura, o arroz e o feijão apresentaram teores de gordura de 0,32% e de 1,1%, respectivamente. No entanto, a correlação com os níveis de PCBs não foi significativa. Os resultados demonstram que o estado do RS apresenta fontes importantes de contaminação desses resíduos químicos persistentes.

Polychlorinated biphenyls (PCBs) are among the most toxic pollutants in the environment showing foods as the main source of human exposure. Based on this, this study aimed to determine 7 PCBs indicators of environmental contamination in 22 samples of rice and 18 samples of beans in Rio Grande do Sul state, Brazil. Furthermore, this study aimed to calculate the waste estimated daily intake, starting from the existing contamination in rice and beans, as well as wanted to determine the samples fat content to correlate with levels of PCBs. The extraction and purification of the compounds were performed via QuEChERS method followed by identification and quantification by GC-MS. PCBs 153 and 101 showed the highest mean concentration in the samples of rice and bean, respectively. Considering the sum of PCBs in the samples, this was 4.39ng g-1 for the rice and 4.17ng g-1 for the beans. In estimated daily intake, this was 7.82ng kg-1 and 3.14ng kg-1 of body weight per day, for the rice and beans, respectively. Regarding the percentage of fat the rice and beans samples had fat contents of 0.32% and 1.1%, respectively. However, the correlation with the PCBs levels was not significant. The results demonstrate that the State of RS has important sources of these persistent chemical waste contaminations.

Composition and antioxidant capacity of the essential oil of leaves of Vitex megapotamica (Sprengel) Moldenke.

This study is designed to examine the chemical composition and antioxidant activity of the essential oil of Vitex megapotamica. Gas chromatography-mass spectrometry analysis resulted in the detection of 27 components, representing 92.36% of the total oil composition. The main components in the oil were butylated hydroxytoluene (BHT) (34.17%), phytol (12.66%), α-caryophyllene (11.84%), δ-elemene (10.65%), ß-caryophyllene (7.82%), γ-elemene (4.24%) and germacrene D (2.82%). The antioxidant activity of the oil was evaluated in terms of their free-radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl. The oil showed percentage inhibition of 35.62% and 75.25% at concentrations of 76 and 101.6 mg mL(-1), respectively. BHT (36.30%) was also determined by HPLC-DAD in the hexane fraction from the leaves. To the best of our knowledge, this is the first study of the composition and antioxidant activity of the essential oil of the species V. megapotamica.

Chemical composition and antioxidant activity of the essential oil of Tabernaemontana catharinensis A. DC. leaves.

The essential oils obtained by hydrodistillation from the leaves of Tabernaemontana catharinensis had their composition analysed by GC-MS. A total of 18 substances were identified, consisting of a complex mixture of sesquiterpenes (83.52%), monoterpenes (5.46%) and triterpenes (4.56%). The main components in the oil were ß-caryophyllene (56.87%), α-cadinol (12.52%), 8S,13-cedran-diol (5.41%), α-terpineol (3.99%), ß-eudesmol (2.54%), caryophyllene oxide (2.51%) and ethyl iso-allocholate (2.03%) along with ß-cubebene, γ-cadinene, cubenol, 1,8-cineol, o-cymene, curcumenol, spathulenol, friedeline and ß-sitosterol as minor constituents. An antioxidant property was tested with the oil obtained by means of 1,1-diphenyl-2-picrylhydrazyl assay; the oil presented interesting radical scavenging activity. To the best of our knowledge, this is the first study of the composition and antioxidant activity of essential oil from the T. catharinensis collected from Brazil.

Isolation and chromatographic analysis of bioactive triterpenoids from the bark extract of Cariniana domestica (Mart) Miers.

The Lecythidaceae family is composed of 25 genera and 400 species that occur in the form of trees with a pantropical distribution. The genera Cariniana belongs to the family Lecythidaceae, and there are few reports considering these species. In this work, fractionation of the dichloromethane fraction obtained from the aqueous extract of the stem bark of Cariniana domestica (Mart) Miers, popularly known as Jequitibá-roxo, led to the isolation of two mixtures of triterpenoids: lupeol and ß-amyrin and ß-sitosterol and stigmasterol. The structures of the isolated compounds were elucidated by spectroscopic (NMR) and chromatographic (GC-MS) techniques as well as literature data comparisons. ß-Sitosterol, stigmasterol, lupeol and ß-amyrin were quantified in dichloromethane fraction by high-performance liquid chromatography (HPLC/DAD). The dichloromethane fraction was also investigated for antioxidant and antifungal activities. The isolated compounds and their biological activities are reported for the first time for the species C. domestica.