Abstract

An eco-friendly, simple, and reusable deep eutectic solvents (DESs)–microcrystal cellulose (MCC)–polyvinyl alcohol (PVA) sponge was synthesized using DESs adsorbed on MCC (DESs–MCC), which was subsequently entrapped in a PVA sponge. Under optimal conditions, good linearities were achieved in the concentration range from 0.8 ng mL⁻¹ to 1.6 µg mL⁻¹ for methylparaben (MP) and from 1.6 ng mL⁻¹ to 1.6 µg mL⁻¹ for ethylparaben (EP), propylparaben (PP), and butylparaben (BP). The limits of detection (LODs) were 560.2 ± 2.1, 642.4 ± 4.2, 611.1 ± 3.7, and 746.8 ± 5.6 pg mL⁻¹ for MP, EP, PP, and BP, respectively. Good sorbent-to-sorbent reproducibility (n = 6, %RSD ≤ 4.0) and precision (n = 6, %RSD < 6.0) were also obtained. Interestingly, the DESs–MCC/PVA sponge can be reused up to five times retaining > 80% of its extraction efficiency. The developed DESs–MCC/PVA sponge was able to determine four parabens in milk, beverages, and tea samples; MP and EP were detected in two beverages and tea samples in the range of 29.0 ± 1.1–38.4 ± 1.3 ng mL⁻¹ and 8.01 ± 0.95–10.6 ± 1.2 ng mL⁻¹, respectively. Good recoveries were obtained in the range of 87.6 ± 3.5%–100.8 ± 4.7% for all the tested parabens in the samples. In conclusion, the development of DESs–MCC entrapped in a PVA sponge is simple and environmentally friendly, affording a reusable DESs–MCC/PVA sponge. Additionally, the DESs–MCC/PVA sponge exhibited good efficiency and is promising for the extraction of various trace organic substances.