Sérgio Marcos Sanches

Caracterização das frações das substâncias húmicas de diferentes tamanhos moleculares

In this work have been realized the extration of humic substances (SH) proceeding from the peat collected to the edges of the river Mogi-Guacu, according to described methodology for Rosa et al., 2000. The SH had been fractions in an equipment of ultrafiltration in three molecular sizes: between molecular sizes 30 -100 KDa, less than 30 KDa molecular sizes and more than 100 KDa. The fractions had been characterized by different analytical techniques such electron paramagnetic resonance (EPR), infrared spectroscopy, elemental analysis and spectroscopy in the region visible (UV/Vis). It was verified that the fractions of lesser molar mass between 30 - 100 KDa molecular sizes and less than molecular sizes presented a bigger on molecule number with oxygen while that the fraction of bigger molar mass more than100 KDa molecular sizes presented a bigger number aromatical molecules. Through the results of the elementary analyses and eletronic paramagnetic resonance, the fraction evidenced less than 30 KDa showing smaller percentagens of carbon, nitrogen and hydrogen and a smaller amount of free radicals in relation to the othess, indicating that this fraction possess a smaller number of conjugated aromatical rings. Already in the analyses for IV characteristic bands of the SH had been observed.

Estudo da presença da toxina microcistina-LR em águautilizada em clínica de hemodiálise e validação de um método análítico

Some strairs of seaweed, especially of the cyanobacterial type, can produce toxins as such microcystins, which are responsible for the intoxication and death of animals and humans. Literature report on the occurrence of accidents at a haemodialysis clinic in Caruaru, Pernambuco, Brazil, 60 haemodialysis patients died due to the presence of this toxin in the water. This study developed and validated of an analytical method, to quantified micrcocystin-LR using the Hight-Performance Liquid chromatography with detector UV. The following parameters were chosen: linearity, calibration curve, precision, sensibility and assays of recovery. The calibration curve, obtained with seven points, and the correlation coefficients in the were higher than 0.99. The method obtained an linearity in the interval between 0.05 to 5 µg L-1, and the correlation coefficients more than 0.99. Based or these results, the method is considered efficient and can used to monitor microcystins in water. utilized in clinics of haemodialysis.

Influência da taxa de dose na degradação do herbicida ácido diclorofenóxiacético (2,4-d) por meio da radiação gama do cobalto-60

Conventional methods for environmental decontamination sometimes just transfer these residues from one place to another. This study deals to the study of the influence of dose rate in the degradation of 2,4-D herbicide in water and methanol solutions by gamma radiation from cobalt-60. The results showed that pure 2,4-D herbicide in water was totally degraded with a dose of radiation of 30 kGy at a dose rate of 2,7 kGy h-1 and 20 kGy with dose rates of 5- 60 kGy h-1. For a total degradation of pure 2,4-D herbicide in methanol to occur a dose of radiation of 150 kGy at a dose rate of 2,7 kGy h-1 and 100 kGy at a dose rate of 5- 60 kGy h-1 were needed. It is concluded that radiolytic degradation of 2,4-D herbicide depends on of the dose and the dose rate. The radiolytic yield from 2,4-D degradation was calculated.

Conhecimento das orientações sobre redução do teor de sal em pães tipo francês

O padrao alimentar dos brasileiros tem mudado, ocasionando um maior consumo de alimentos prontos industrializados, ricos em gorduras saturadas e sal. Dentre os grandes problemas relacionados a alimentacao destaca-se o consumo excessivo de sodio. Estrategias governamentais vem sendo implementadas visando enfrentar algumas doencas cronicas que afetam a populacao, destacando-se a reducao do teor de sal nos alimentos, entre eles o pao frances. O presente trabalho objetivou verificar se alguns estabelecimentos produtores de pao frances do municipio de Ituiutaba-MG, estao inteirados das novas orientacoes sugeridas pelos orgaos de fiscalizacao vigentes. Durante a visita aos estabelecimentos coletou-se por meio de questionario, informacoes referentes ao mesmo e ao conhecimento sobre o assunto. Concluiu-se que os produtores de pao frances entrevistados tem conhecimento da legislacao e ja estao realizando a reducao gradativa do sal na fabricacao do pao frances, sendo que tal medida foi relatada como sensorialmente perceptivel por alguns produtores, apesar dos consumidores nao terem relatado questionamentos quanto a tal reducao.