Parallel-disposable pipette extraction (Pa-DPX) using cork as a green high-throughput method for the determination of four pesticides in environmental water samples with quantification by HPLC-DAD.

Abstract

This study utilized cork powder as a green alternative for extractor phase using the parallel-disposable pipette extraction (Pa-DPX) method for the determination of pesticides such as atrazine, carbofuran, diuron, and simazine from aqueous environmental samples. The separation/detection was performed by HPLC-DAD. Optimization experimental conditions was achieved through univariate and multivariate designs, resulting in the following parameters: 15 mg of cork as extractor phase, 7 extraction cycles with 7.5% (m/v) NaCl in the sample, and 10 s were fixed per extraction cycle. For the desorption step, 300 µL of acetonitrile was used as solvent with 1 desorption cycle. The limit of detection and limit of quantification values were 7.5 µg L^-1 and 25 µg L^-1 for atrazine, carbofuran, and diuron, and 15.1 µg L^-1 and 50 µg L^-1 for simazine, respectively. Linear working range varied from 25 to 400 µg L^-1 with coefficients of determination (R²) ≥ 0.983. The values of intraday precision varied from 4.9 to 18.1%, and those of interday precision varied from 21.3 to 32.2%. The accuracy of the method was determined through relative recoveries and the values ranged from 63.4 to 119.9%. The water environmental samples were collected at two different locations in Florianópolis, Santa Catarina, Brazil, and showed no detectable pesticides. The method presented here stands out due to the low consumption of sample and reagents, as well as the use of a renewable and biodegradable extraction phase (cork). The method is also a high-throughput alternative, due to the use of the Pa-DPX apparatus, which allows the preparation of up to five samples simultaneously.