苯基修饰二氧化硅纳米片纤维的制备及其对多环芳烃的固相微萃取

采用水热处理和溶胶-凝胶法在镍钛合金（NiTi）纤维表面组装了二氧化硅纳米片（SiO₂NFs）,成功制备了新型SiO₂纤维涂层,并用苯基三氯硅烷进行了自组装表面修饰,得到了可用于固相微萃取（SPME）的NiO/TiO₂@SiO₂NFs-Ph纤维。将制备的SPME纤维与高效液相色谱联用,通过对典型芳香化合物的分析评价了所制备纤维的萃取性能。该纤维对多环芳烃（PAHs）具有较高的萃取率和良好的萃取选择性。实验优化了pH值、搅拌速率、萃取温度、萃取时间和离子强度对PAHs萃取率的影响。在优化条件下,5种PAHs在各自的范围内呈良好的线性关系,相关系数（r）大于0.999,检出限为0.013~0.108 μg/L。使用单根纤维对含有50 μg/L PAHs的加标水样进行萃取,其含量的日内及日间RSD分别为4.1%~5.9%和4.8%~6.8%。实际环境水样中5种PAHs在10 μg/L和30 μg/L加标水平下的加标回收率分别为90.8%~105.7%和93.6%~103.1%。该法制备的NiO/TiO₂@SiO₂NFs-Ph纤维稳定性高、制备重现性好,适用于环境水样中目标PAHs的富集和测定。     

铱催化叠氮化物和亚酰胺环加成反应的密度泛函研究

用密度泛函理论（DFT）B3LYP方法对铱催化的环加成合成5-氨基1,2,3-三唑化合物机理进行了计算研究. 计算结果表明：（1）通过叠氮化合物的端基氮分别进攻不同炔烃碳原子形成两种竞争机制;（2）释放催化剂得到目标产物的还原消除过程是反应的关键步骤;（3）对于进攻苯基一侧炔烃碳原子的反应通道,具有相对较低的活化自由能;（4）两个竞争通道存在一定的能量差,表明反应具有较好的选择性,计算研究对实验报道进行了很好的补充和解释.     

Self-assembly of silica nanosheets on titanium fibers for solids-phase microex⁃traction of UV absorbers in environmental water samplesEI北大核心CSCD

Silica nanosheets （SiO2NSs）were successfully assembled on titanium （Ti）wires by sol-gel method. TiO2 nanosheets （TiO2NSs）were grown in situ on Ti wires using anodic oxidation in a fluoride-containing electrolyte to obtain Ti@TiO2NSs. The Ti@TiO2NSs@SiO2NSs fibers were obtained by coating Ti@TiO2NSs with SiO2NSs. It was characterized by scanning electron microscopy （SEM） and X-ray energy dispersive spectroscopy （EDS）. The fibers were used for solid-phase microextraction of ultraviolet absorbers （UVFs）. Under the optimized conditions, six UVFs presented good linearity with the correlation coefficients （R2） greater than 0.999, and the limits of detection （LODs）ranged from 9 to 59 ng/L. The intra-day and inter-day relative standard deviations （RSDs） were from 4.3% to 5.1% and 4.6% to 5.8% for a single fiber at the spiked level of 25 μg/L, respectively. The developed method was successfully applied to the selective enrichment and determination of target UVFs in environmental water samples with recoveries from 93.2% to 108.1% and RSDs from 4.5% to 7.1%. Moreover, the fiber can be fabricated in a precisely controllable manner and is stable for at least 200 extraction and desorption cycles. © 2023, Youke Publishing Co.,Ltd. All rights reserved.