The environmental impact of sample preparation should be minimized through simplification of the procedures and the use of natural, renewable and/or reusable materials. In such scenario, thin-film microextraction fulfils the former criteria, as it enables few steps and miniaturization, thus small amount of extraction phase. At the same time, the use of sorbents such as biochars obtained from biomass waste is even more promoted due to their availability at low cost and increased life-cycle in a circular economy vision. However, it is not always easy to combine these criteria in sample preparation. A thin film microextraction was developed for the determination of steroids in aqueous samples, entailing a membrane made of cellulose triacetate and a wood-derived biochar (Nuchar®) as carbon precursor. Different characterization techniques showed the successful preparation, whereas the sorption kinetics experiments demonstrated that biochar is responsible for the extraction with the polymer acting as a smart support. After a study about membranes’ composition in terms of biochar amounts (4 %, 10 %, 16 % wt) and type of synthesis set up, the ceramic 3D-mold was selected, achieving reproducible and ready-to-use membranes with composition fixed as 10 %. Different elution conditions, type and time of agitation, type, composition and volume of eluent, were evaluated. The final microextraction followed by HPLC-MS/MS quantification was successfully validated in river and wastewater treatment plant effluent samples in terms of accuracy (R% 64–123 %, RSD<19 % in river; R% 61–118 %, RSD <18 % in effluent, = 4), sensitivity (MQLs 0.2–8.5 ng L) and robustness. This novel biochar-based polymeric film proved to be a valid and sustainable sorbent, in terms of extraction capability, ease of preparation and greenness. By comparison with literature and the greenness evaluation with the most recent metric tools, this method expands the potential applicability of the thin-film microextraction and opens up innovative scenarios for sustainable procedures entailing the use of biochars entrapped in bio-polymers.

中文翻译：

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基于生物炭的聚合物薄膜作为可持续且高效的吸附相，用于预浓缩环境水和废水中的类固醇激素


应通过简化程序和使用天然、可再生和/或可重复使用的材料，最大限度地减少样品制备对环境的影响。在这种情况下，薄膜微萃取满足前面的标准，因为它可以实现步骤少和小型化，因此萃取相量小。与此同时，从生物质废物中获得的生物炭等吸附剂的使用更加得到推广，因为它们成本低廉，并且在循环经济愿景中延长了生命周期。然而，在样品制备中结合这些标准并不总是那么容易。开发了一种薄膜微萃取技术，用于测定水样中的类固醇，需要使用由三醋酸纤维素制成的膜和作为碳前体的木材生物炭 (Nuchar®)。不同的表征技术显示了成功的制备，而吸附动力学实验表明生物炭负责提取，聚合物作为智能载体。在对膜的生物炭含量（4%、10%、16% wt）和合成类型进行研究后，选择了陶瓷 3D 模具，实现了成分固定的可重复且即用型膜为 10%。评估了不同的洗脱条件、搅拌类型和时间、洗脱液的类型、组成和体积。最终微萃取随后进行 HPLC-MS/MS 定量，在河流和废水处理厂废水样品中成功验证了准确性（河流中 R% 64–123 %，RSD<19 %；R% 61–118 %，RSD <流出物中 18%，= 4)、灵敏度（MQL 0.2–8.5 ng L）和稳健性。 这种新型生物炭基聚合物薄膜在提取能力、易于制备和绿色环保方面被证明是一种有效且可持续的吸附剂。通过与文献和最新度量工具的绿色度评估进行比较，该方法扩展了薄膜微萃取的潜在适用性，并为需要使用生物聚合物中捕获的生物炭的可持续程序开辟了创新方案。