Determination of moisture content in lyophilized solids is fundamental to predict quality and stability of freeze-dried products, but conventional methods are time-consuming, invasive and destructive. The aim of this study was to develop and optimize a fast, inexpensive, noninvasive and nondestructive method for determination of moisture content in lyophilized mannitol, based on an NIR micro-spectrometer instead of a conventional NIR spectrometer. Measurements of lyophilized mannitol were performed through the bottom of rotating glass vials by means of a reflectance probe. The root mean standard error of prediction (RMSEP) and the correlation coefficient (R 2 pred ), yielded by the pre-treatments and calibration method proposed, was 0.233% (w/w) and 0.994, respectively.Uniterms: Near-infrared spectroscopy. Lyophilization. Multivariate analysis. Moisture content. Mannitol. Micro-spectrometer.A determinação do conteúdo de umidade em sólidos liofilizados é fundamental para se prever a qualidade e a estabilidade de produtos liofilizados, mas os métodos convencionais consomem muito tempo, são invasivos e destrutivos. O objetivo desse estudo foi desenvolver e otimizar um método rápido, econômico, não invasivo e não destrutivo para a determinação do conteúdo de umidade em manitol liofilizado, com base em microespectrômetro de infravermelho próximo ao invés de um espectrômetro de infravermelho próximo convencional. As medidas de manitol liofilizado foram realizadas através do fundo de recipiente de vidro em rotação por meio de sonda de reflectância. A raíz do erro médio padrão de predição (RMSEP) e o coeficiente de correlação (R 2 pred ) obtidos pelo prétratamento e pelo método de calibração proposto foram, respectivamente, 0,233% (p/p) e 0,994. Uniterms: Espectroscopia de infravermelho próximo. Liofilização. Análise multivariada. Análise de unidade. Manitol. Microespectrômetro.
-Simulation of saline extractive distillation columns is a difficult task owing to the high nonlinearity of the rigorous models that represent these systems. The use of simple models to obtain initial estimates of equilibrium compositions may improve the stability and rate of convergence. One of the simplest models to study the vapor-liquid equilibrium of binary liquid mixtures + salt systems is the Furter equation. This model was analyzed in the present work by means of the incorporation of activity coefficient models in the ratio of relative volatility. This approach allowed systematic extensions of the Furter equation and a brief review of the theoretical basis of the original equation. As a result of these extensions, two simple equations were proposed and tested with experimental data from 20 systems, including binary liquid mixtures + salt systems and binary liquid mixtures + ionic liquid systems. Finally, one of these proposed equations was incorporated into the GKTM software in order to assess the utility of these simple models in the simulation of saline extractive distillation columns. The obtained results showed a significant improvement over the previous algorithm.
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