The tenfold lowering in binding energy for TU-Tyrosine in immobilized urease (Kb: 4.7 × 103) with respect to the native enzyme (Kb: 6.5 × 104) begets easy desorption of thiourea (TU) by glucose (GL) with an eventual formation of a more strong TU- GL adduct; that rejuvenates the kit-material ready for the subsequent cycle(s). The sorption-desorption heeds fluorescence turn-off and turn-on in DCM for selective sensing of TU- GL pair at their respective linear range of concentration 2.5-26.1 ppm and 2.36-11.57 ppm. The process was found to be static (KSV ≥ 2.25 × 103 L mol-1), exothermic (ΔH: -0.08 kJ mol-1), spontaneous (ΔG: -21.1 kJ mol-1) and marginally entropy gaining (ΔS: 0.07 kJ mol-1 K-1). The 'bulk material' (200 ± 20 μm) brilliantly preconcentrates TU with an enrichment factor of 106.2 after its selective extraction at near-neutral pH from a large volume sample (800 mL) of low concentration (30 ppm). A very dilute solution (0.05 mmol L-1) of GL at minimum volume (6 mL) acts as a stripping agent and provides a longer life (200 cycles with good extraction efficiency) to the material. The method was found to be efficient in the analysis of fruit juice as a real sample.

中文翻译：

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“脲酶固定单试剂盒”用于检测硫脲-葡萄糖对，使用荧光“关闭-开启”，并作为硫脲选择性样品净化的有效吸附剂

相对于天然酶 (Kb: 6.5 × 104)，固定化脲酶 (Kb: 4.7 × 103) 中 TU-酪氨酸的结合能降低了 10 倍，导致硫脲 (TU) 容易被葡萄糖 (GL) 解吸并最终形成更强的 TU-GL 加合物；使套件材料恢复活力，为后续循环做好准备。吸附-解吸在 DCM 中关注荧光的关闭和开启，以选择性地检测 TU-GL 对在它们各自的线性浓度范围 2.5-26.1 ppm 和 2.36-11.57 ppm 下。该过程被发现是静态的 (KSV ≥ 2.25 × 103 L mol-1)、放热的 (ΔH: -0.08 kJ mol-1)、自发的 (ΔG: -21.1 kJ mol-1) 和微量的熵增 (ΔS: 0.07 kJ mol-1 K-1)。“块状材料”（200 ± 20 μm）以 106 的富集因子出色地预浓缩 TU。2 在接近中性 pH 值下从低浓度 (30 ppm) 的大体积样品 (800 mL) 中选择性提取后。最小体积 (6 mL) 的非常稀的 GL 溶液 (0.05 mmol L-1) 作为剥离剂，为材料提供更长的使用寿命（200 次循环，具有良好的萃取效率）。发现该方法可有效分析作为实际样品的果汁。