Resumo Neste estudo, foi proposto um método para determinar a somatória das concentrações de inosina 5'-monofosfato (IMP) e guanosina 5'-monofosfato (GMP) em produtos finais e intermediários, através de uma combinação de espectroscopia UV e calibração multivariada. Na proposição do método, empregou-se Partial Least Squares (PLS), para a análise de dados, e os métodos propostos apresentaram erros em torno de 4 mg/L. Além disso, apresenta custo de análise 10 vezes menor quando comparado com o método cromatográfico de referência, sendo que a frequência analítica é de 20 amostras/hora.

Abstract This study proposed a method to determine the sum of the concentrations of inosine 5’-monophosphate (IMP) and guanosine 5’-monophosphate (GMP) in final and intermediate products through a combination of UV spectroscopy and multivariate calibration. Partial Least Squares regression (PLS regression) was used for the data analysis and the proposed methods presented errors of around 4 mg/L. In addition, the analysis cost is 10 times lower than the reference chromatographic method and the analytical frequency is 20 samples/hour.

The seasonal behavior of NO2 concentration shows a maximum occurring during sugarcane crop and this suggests that the biomass burning is significant source of emission at this time of the year. Along the day, the variation of the NO2 showed a decrease during the increased sunlight and an increase thereafter, caused by occurrence of photochemical reactions. Measurements of NO2 were done inside of residential and industrial kitchens and also inside of a parking garage located in the underground of a supermarket building. The indoor concentrations of NO2 were significantly higher than the concentrations of the external atmosphere and it shows the importance of the sources of internal emissions.

An alternative analytical method for nitrogen dioxide (NO2) in atmosphere was developed. The collection of NO2 is performed by a Sep-Pack C-18 cartridge impregnated with 11% (v/v) of triethanolamine plus 3,6 % (v/v) of ethylene glycol plus 25 % (v/v) of acetone combined solution. When the impregnating is used, NO2 is collected with good repeatibility (CV = 3,3 %). The NO2 absorbed in the sampler was stripped from the sorbent with a methanol 5% (v/v) aqueous solution and was determined by colorimetry as nitrite by using the Griess-Saltzman reagent. The detection limit of 1,4 ppb for 60 min sampling at 0,5 L min-1 flow rate was obtained. Preparation and conditioning procedures for TEA-C-18 cartridge, sampling flow rate, absorption capacity and interference of other species are discussed.

Os óxidos de nitrogênio e a amônia são os mais importantes compostos gasosos nitrogenados emitidos para a atmosfera e possuem grande interesse ambiental. Na atmosfera, esses compostos podem sofrer diversas reações resultando em mudanças nas propriedades químicas e físicas da atmosfera. Atividades humanas, principalmente relacionadas com produção de alimentos, energia e uso de fertilizantes têm aumentado as emissões dessas espécies nitrogenadas para o ambiente, causando distúrbios no seu ciclo natural. Com o objetivo de avaliar as variações dos níveis de concentração e inferir sobre os processos de remoção de compostos de nitrogênio da atmosfera na região de Araraquara, foram feitas determinações em paralelo de amônia (NH3) e dióxido de nitrogênio (NO2). Os resultados de concentração mostraram a estreita correlação entre esses compostos na atmosfera, que sugerem diferentes processos de remoção em diferentes épocas do ano.

Nitrogen oxides and ammonia are important nitrogen compounds which are emitted to the atmosphere. They are very important substances in the environment. In the atmosphere, these substances may undergo diverse reactions that result in changes of chemical and physical atmosphere's property. Atmospheric removal mechanisms of nitrogen substances may ocurr either dry deposition or wet deposition. Human activity such as food production, energy and fertilizer have increased the nitrogen emissons to environment, causing disturbances in the natural nitrogen cicle. Parallel determinations of ammonia (NH3) and nitrogen dioxide (NO2) were made to assess variations of concentration and to infer about removal processes theses nitrogen compounds of Araraquara's atmosphere. Results showed the narrow relationship between these substances in the studied atmosphere. This relationship between ammonia and nitrogen dioxide suggested different removal processes at different periods during the year.