A lignocellulosic natural sorbent in bar adsorptive microextraction for the determination of emerging contaminants in river water

Abstract

Conventional analytical methodologies for the determination of organic contaminants in water matrices are often laborious and time-consuming, and require a large amount of chemicals. In this study, we have developed a green sample preparation approach using Araucaria angustifolia bracts as a natural sorbent in the bar adsorptive microextraction technique. The determination of eight emerging contaminants (methyl, propyl, and butylparaben, bisphenols A and F, estradiol, ethinylestradiol, and benzophenone) in river-water samples were carried out, employing high-performance liquid chromatography with diode-array detection (HPLC-DAD). Central composite design revealed that the best conditions for the extraction step involved adding 30 % (w/v) NaCl to the sample at pH 6 and leaving it for 180 min. Simplex-centroid design indicated 80 μL of a mixture of acetonitrile and water (3:1) as the best desorption solvent. Desorption time was univariately evaluated as 40 min. Calibration curves obtained correlation coefficients higher than 0.995. The limits of quantification were in the range of 1 to 10 µg L−1 with inter-day precision from 13 to 22 %. Relative recoveries in two river-water samples varied from 62 to 116 %, exhibiting relative standard deviations from 5 to 28 %, which confirmed the method's accuracy and precision. This method contributes to the development of more environmentally friendly sample preparation strategies.

Keywords

• Araucaria angustifolia
• Bar adsorptive microextraction
• Emerging contaminants
• Green analytical chemistry
• Natural sorbents
• Sample preparation