Sustainable single drop microextraction approach using magnetic deep eutectic solvents for the analysis of fipronil and two degradation products in honey samples from southern Brazil

The increased use of pesticides in modern agriculture has led to environmental contamination, affecting biomes and causing significant problems in various ecosystems. In this regard, the massive death of bees, commonly known as colony collapse disorder (CCD), has resulted in severe socioeconomic impacts. The determination of these contaminants in honey represents an important tool for evaluating its overall quality. Given the emerging need to develop efficient analytical methodologies with reduced environmental impact capable of assessing pesticide contamination, this study involved an innovative analytical approach for the analysis of fipronil and two of its degradation products (fipronil desulfinyl and fipronil sulfide) in honey samples. Single drop microextraction (SDME) using a magnetic deep eutectic solvent (MDES) extraction phase was employed followed by high-performance liquid chromatography with diode array detection (HPLC-DAD). The optimized extraction parameters, determined through both univariate and multivariate strategy based on central composite design, consisted of sample volume of 4.5 mL (honey:water at 1:6 v/v), 10 mg of MDES, and an extraction time of 55 min. Importantly, the methodology was semi-automated allowing for the analysis of six simultaneous extractions resulting in enhanced sample throughput compared with traditional SDME-based approaches. The method was validated, providing coefficients of determination higher than 0.9939 and limits of detection and quantification of 4.5 μg L −1 (3.2 μg kg −1 ) and 15 μg L −1 (10.6 μg kg −1 ), respectively, for all analytes. Intraday precision ranged from 6.7% to 15.6%, interday precision varied from 8.8% to 18.6%, and accuracy varied from 90.8% to 102.7%. The methodology was applied to analyze fifteen honey samples produced by small-scale producers in the state of Rio Grande do Sul, Brazil. • A green, low-cost, and high throughput sample preparation workflow was developed. • A sustainable sample preparation strategy based on SDME using magnetic-DES was proposed to analyze honey samples. • Experimental conditions were optimized through a central composite design. • The greenness and practicality of the proposed experimental workflow were assessed. • The analytical method allowed for the determination of fipronil, fipronil desulfinyl, and fipronil sulfide in honey.