Uma metodologia baseada em espectrometria UV-VIS e quimiometria para a determinação de n,n-dietil-3-metilbenzamida em repelentes

Abstract

In recent years outbreaks of vector-borne diseases have caused great concern to the population. The repellents appear as an affordable prevention alternative and it becomes increasingly important the quality control of these cosmetics, since the content of the active ingredient is directly related to the efficiency and the protection time provided by the repellent. This work proposes the development of a methodology to the determination of N, N- Diethyl-3-methylbenzamide (DEET) in insect repellents in lotion using UV-VIS spectrometry and multivariate calibration. For this propose, chemometric models based on Partial Least Squares (PLS) regression, Interval Partial Least Squares (iPLS) regression and Multiple Linear Regression (MLR) with previous variable selection by Successive Projections Algorithm (SPAMLR), Genetic Algorithm (GA-MLR) and Stepwise formulation (SW-MLR) were developed and compared. Satisfactory results were found with all the models, with RMSEP values varying from 0.88 to 0.92% m/m. An F- test performed at a confidence level of 95% indicated that there was not statistically significant difference between the different models developed. Additionally, a paired t-test (95% of confidence) did not identify differences between the proposed methods and the reference method. The results demonstrated the potential of UV-VIS spectrometry associated with multivariate calibration to determine DEET content in repellent like a fast, simple strategy and with a good correlation between the values estimated by the model and the reference values.