Maurício Xavier Coutrim

Determination of endocrine‐disrupting compounds in waters from Rio das Velhas, Brazil, by liquid chromatography/high resolution mass spectrometry (ESI‐LC‐IT‐TOF/MS)

Some organic microcontaminants, known as endocrine‐disrupting compounds (EDC), are frequently found in surface waters and are of concern because of their ability to alter the normal functioning of the endocrine system. In this study five of these EDCs (estradiol, ethynylestradiol, bisphenol A, nonylphenol and diethylphthalate) in surface water samples, collected at the upper part of Rio das Velhas river (located between Ouro Preto and Nova Lima, Minas Gerais state, Brazil) were analysed. The analytical methodology, which employed solid‐phase extraction and high‐performance liquid chromatography coupled to high resolution mass spectrometry (HPLC‐MS/MS), was properly validated and resulted in limits of quantification (LOQ, S/N = 10) of 4.3 ng/L for diethylphtalate, 3.9 ng/L for nonylphenol, 3.6 ng/L for estradiol, 4.7 ng/L for ethynylestradiol and 2.5 ng/L for bisphenol. The five compounds were monitored for eight months, from sites where the hormones were occasionally found. Ethynylestradiol and estradiol concentrations varied from 5.6 to 63.8 ng/L. Bisphenol was present in all samples in a concentration that ranged from 8.6 to 168.3 ng/L. The other two compounds were at quantifiable levels in all collected samples, with nonylphenol varying from 25.9 to 1435.3 ng/L and diethylphthalate from 5.0 to 410.9 ng/L. The study showed that nonylphenol pollution seemed to originate from agricultural run‐off, while diethylphthalate pollution originated from the discharge of domestic sewage. Risk analysis studies showed that the environmental concentrations of nonylphenol and diethylphthalate do not present risks to human health; however, the concentrations found for bisphenol and ethinylestradiol could be toxic to humans, especially infants, if such compounds are not effectively removed at water treatment plants.

Strategies to select yeast starters cultures for production of flavor compounds in cachaça fermentations

In this work, we have used classical genetics techniques to find improved starter strains to produce cachaça with superior sensorial quality. Our strategy included the selection of yeast strains resistant to 5,5′,5″-trifluor-d,l-leucine (TLF) and cerulenin, since these strains produce higher levels of higher alcohols and esters than parental strains. However, no clear relationship was observed when levels of flavoring compounds were compared with the levels expression of the genes (BAT1, BAT2, ATF2, EEB1 genes) involved with the biosynthesis of flavoring compounds. Furthermore, we determined the stability of phenotypes considered as the best indicators of the quality of the cachaça for a parental strain and its segregants. By applying the principal component analysis, a cluster of segregants, showing a high number of characteristics similar to the parental strain, was recognized. One segregant, that was resistant to TLF and cerulenin, also showed growth stability after six consecutive replications on plates containing high concentrations of sugar and ethanol. “Cachaça” produced at laboratory scale using a parental strain and this segregant showed a higher level of flavoring compounds. Both strains predominated in an open fermentative process through seven cycles, as was shown by mitochondrial restriction fragment length polymorphisms analysis. Based on the physical chemical composition of the obtained products, the results demonstrate the usefulness of the developed strategies for the selection of yeast strains to be used as starters in “cachaça” production.

Avaliação dos métodos analíticos para a determinação de metabólitos do benzeno como potenciais biomarcadores de exposição humana ao benzeno no ar

Increasing attention is being paid to the use of biomarkers for determining the exposure of humans to air toxics. Biomarkers include the nonreacted toxic substance, their metabolites, or the reaction products of these toxics with naturally substances in the body. Significant progress has been made in the measurement of biomarkers during the past several years. Much of this progress has been because of the development of advanced analytical techniques for identification and quantification of the chemical species in complex matrix, such as biological fluids. The assessment of the potential cancer risk associated with exposure to benzene at occupational and non-occupational ambient is necessary because of the toxicological implications of this air pollutant. Thus, in this review, the analytical methodologies used to determine the benzene metabolites, in special, urinary muconic acid and S-phenylmercapturic acid, are described and several problems affecting the precision of these procedures are discussed. Finally, in view of the difficulty pointed out for selecting the more adequate biomarker, further studies to evaluate the human exposure levels to benzene should be done.

Biotechnological potential of yeast isolates from cachaça: the Brazilian spirit

This study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichiaanomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to inter-cycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications.

OTIMIZAÇÃO E VALIDAÇÃO DE MÉTODOS ANALÍTICOS PARA DETERMINAÇÃO DE BTEX EM ÁGUA UTILIZANDO EXTRAÇÃO POR HEADSPACE E MICROEXTRAÇÃO EM FASE SÓLIDA

Three analytical methods for the determination of BTEX in water were optimized and validated. With the best method the analytes were extracted of 10 mL of sample with 2.50 g of NaCl in headspace vial of 20 mL by HS and SPME to 40 oC for 30 min for adsorption and to 250 oC for 4 min for desorption and were analyzed by GC-MS. The recovery was between 97.9% and 104.3%, and the limit of detection was 2.4 ng L-1 for o-xylene. This method was using to analyze BTEX in water supply and surface water in Ouro Preto city. No sample had concentrations of BTEX above the legislation.

Determination of endocrine disrupters and pharmaceuticals in sewage samples by tandem solid phase clean up/extraction and high performance liquid chromatography-negative and positive electrospray high-resolution mass spectrometry

A new method for the determination of three endocrine disrupters (estradiol, ethinyl estradiol, and bisphenol A) and five pharmaceuticals (sulfamethoxazole, trimethoprim, diclofenac, bezafibrate and miconazole) in raw sewage samples using tandem solid phase extraction (SPE) sorbents and high-performance liquid chromatography-negative and positive electrospray high-resolution mass spectrometry (HPLC-HRMS) was developed and validated. The SPE procedure used both a strong ion exchange sorbent (SAX) and a modified divinylbenzene-pyrrolidone SPE sorbent to reduce the levels of linear alkylbenzene sulfonate (LAS) and to concentrate the analytes of interest from the sewage samples. The influence of matrix composition on the ionisation efficiency, the SPE recoveries, and the sensitivity of the method was identified and quantified. The method was successfully applied to the determination of analytes in raw sewage samples collected from the entrance of the Arrudas Sewage Treatment Plant, Belo Horizonte, Brazil.