An environmentally friendly deep eutectic solvent (DES) composed of trifluoroacetamide and benzyltrimethylammonium chloride modified β-cyclodextrin (CD) grafted magnetic beads (MB-NH2@CD@DES) were synthesized for the first time and applied to the solid-phase extraction of trypsin. Among the five trypsin extractants prepared in this work (MB, MB-NH2, MB-NH2@CD, MB-NH2@DES, MB-NH2@CD@DES), the extractant MB-NH2@CD@DES with higher extraction capacity for trypsin was selected as final extractant. The extraction capacity of MB-NH2@CD@DES for trypsin can reach up to 549.87 mg⋅g-1 under the optimized conditions. The Langmuir adsorption equilibrium was found fitted better with equilibrium relation between MB-NH2@CD@DES and trypsin than Freundlich adsorption equilibrium. And a superior extraction for trypsin was verified by comparing the extraction capacity of MB-NH2@CD@DES for trypsin and four other common proteins. Compared with some reported trypsin extractants, the MB-NH2@CD@DES had a shorter extraction process, higher extraction capacity, more convenient operation of separation, a safer and more environmentally friendly synthesis process. With the optimized eluent, a great elution rate (74.32%) of trypsin was achieved. The absolute recovery of trypsin in trypsin standard solution was calculated to be 16.8%. And the extraction capacity of MB-NH2@CD@DES toward trypsin still maintained well after ten times recycling and reuse. The detection limit (LOD) and quantitative limit (LOQ) were 0.072 mg⋅mL-1 and 0.240 mg⋅mL-1 respectively. By sodium dodecyl sulfate polyacrylamide gel electrophoresis experiment, the extraction ability of MB-NH2@CD@DES to trypsin from real sample was fully demonstrated. All above results showed the potential of fabricated MB-NH2@CD@DES as a superior extractant for trypsin from real complex samples.

中文翻译：

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用于胰蛋白酶固相萃取的深共熔溶剂改性磁性β-环糊精颗粒

首次合成了由三氟乙酰胺和苄基三甲基氯化铵改性的β-环糊精（CD）接枝磁珠（MB-NH2@CD@DES）组成的环保型深共熔溶剂（DES），并应用于胰蛋白酶的固相萃取. 本工作制备的五种胰蛋白酶萃取剂（MB、MB-NH2、MB-NH2@CD、MB-NH2@DES、MB-NH2@CD@DES）中，萃取能力较高的萃取剂MB-NH2@CD@DES因为胰蛋白酶被选为最终萃取剂。MB-NH2@CD@DES在优化条件下对胰蛋白酶的提取量可达549.87 mg·g-1。Langmuir吸附平衡与MB-NH2@CD@DES与胰蛋白酶的平衡关系比Freundlich吸附平衡更好。通过比较 MB-NH2@CD@DES 对胰蛋白酶和其他四种常见蛋白质的提取能力，验证了对胰蛋白酶的优越提取能力。MB-NH2@CD@DES与一些已报道的胰蛋白酶萃取剂相比，具有萃取过程更短、萃取容量更高、分离操作更方便、合成过程更安全、更环保等优点。使用优化的洗脱液，胰蛋白酶的洗脱率很高（74.32%）。经计算，胰蛋白酶标准溶液中胰蛋白酶的绝对回收率为16.8%。MB-NH2@CD@DES对胰蛋白酶的提取能力在经过十次回收再利用后仍保持良好。检出限（LOD）和定量限（LOQ）分别为0.072 mg·mL-1和0.240 mg·mL-1。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳实验，充分展示了MB-NH2@CD@DES从真实样品中提取胰蛋白酶的能力。所有上述结果表明，制造的 MB-NH2@CD@DES 具有作为从真实复杂样品中提取胰蛋白酶的优良萃取剂的潜力。