Determination of DEET, Icaridin, and IR3535 in insect repellents using excitation-emission matrix (EEM) fluorescence spectroscopy and multiway calibration

Due to rising temperatures in recent years, there has been an increase in outbreaks of arboviral diseases like Dengue, chikungunya, Zika, and yellow fever, which are primarily transmitted by two mosquitos. The outbreak has sparked significant concern among the population and prompted countries to heighten their precautions, specially by increasing the use of insects repellents. Regarding the regulatory demands of these products, this study develops a novel analytical method for the determination of DEET, Icaridin, and IR3535 in insect repellents combining excitation-emission matrix (EEM) fluorescence spectroscopy with higher-order multivariate calibration techniques. For this purpose, a dataset comprising 21 samples containing the studied active ingredients was used to construct Parallel Factor Analysis (PARAFAC) and Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) models. As a result, DEET, Icaridin, and IR3535 were quantified with a RMSEP lower than 1.84% for PARAFAC and below 11.30% for MCR-ALS. The EJCR test confirmed the accuracy of the proposed methods, which agreed with the high-performance liquid chromatography reference method at a 95% confidence level. These findings suggest that developing multiway calibration models using EEM proves to be accurate and cost-effective for quality control in repellent-based products.