固相萃取–高效液相色谱法测定地表水中4种磺胺类抗生素

建立固相萃取–高效液相色谱法测定地表水中磺胺嘧啶、磺胺二甲嘧啶、磺胺氯哒嗪、醋磺胺甲恶唑4种磺胺类抗生素。样品采用HLB柱进行萃取富集,流动相为甲醇–水(体积比为20∶80),流量为0.5 m L/min,用SPD检测器检测,检测波长为270 nm;采用外标法定量。4种磺胺类抗生素质量浓度在4~160 ng/L范围内与色谱峰面积的线性关系良好,相关系数不低于0.998 2,方法检出限为1.0~1.7 ng/L,样品加标回收率为75.2%~97.4%,测定结果的相对标准偏差为2.8%~6.1%(n=7)。该方法操作简便,灵敏度高,可用于地表水中磺胺类抗生素的检测。     

柱后衍生HPLC法测定功能饮料中的牛磺酸

建立柱后衍生–高效液相色谱法测定功能性饮料中牛磺酸的含量。功能性饮料中的牛磺酸经水溶提取后与邻苯二甲醛柱后衍生,以柠檬酸三钠溶液(p H 3.2)为流动相,用AMINO–NA色谱柱分离,荧光检测器检测,激发波长为338 nm,发射波长为425 nm,柱后衍生反应温度为55℃,流量为0.4 m L/min。牛磺酸质量浓度在5.0~25.0μg/m L范围内与色谱峰面积线性关系良好,r=0.999 8,检出限(S/N=3)为0.11μg/m L,测定结果的相对标准偏差为0.73%(n=6),加标回收率在99.2%~101.6%之间。该方法灵敏度高、选择性好,可用于市售功能性饮料中牛磺酸的测定。     

固相萃取–高效液相色谱法测定豆芽中4-氯苯氧乙酸钠和6-苄基腺嘌呤的残留量

建立了测定豆芽中4-氯苯氧乙酸钠和6-苄基腺嘌呤的固相萃取–高效液相色谱法。样品以0.1 mol/L的盐酸溶液为提取剂,经C18固相萃取柱净化处理,以乙腈–10 mmol/L乙酸铵水溶液(体积比25∶75)为流动相,Tech Mate C_(18)–ST色谱柱分离,4-氯苯氧乙酸钠和6-苄基腺嘌呤的紫外检测波长分别为228 nm和267 nm,色谱峰面积外标法定量。在0.50~100.00 mg/L浓度范围内,4-氯苯氧乙酸钠的相关系数为0.999 8,精密度在1.3%~8.2%之间(n=6),回收率在103.1%~109.0%之间;在0.05~10 mg/L浓度范围内,6-苄基腺嘌呤相关系数为0.999 9,精密度在0.9%~3.8%之间(n=6),回收率在88.0%~95.4%之间。4-氯苯氧乙酸钠和6-苄基腺嘌呤的检出限(S/N=3)分别为0.24,0.02 mg/kg。该法可以同时完成豆芽中4-氯苯氧乙酸钠和6-苄基腺嘌呤的分析检测。     

Synergistic effect of functional carbon nanotubes and graphene oxide on the anti‐corrosion performance of epoxy coating

In this work, we reported the synergistic effect of functional carbon nanotubes (CNTs) and graphene oxide (GO) on the anticorrosion performance of epoxy coating. For this purpose, the GO and CNTs were firstly modified by the 3‐aminophenoxyphthalonitrile to realize the nitrile functionalized graphene oxides (GO‐CN) and carbon nanotubes (CNTs‐CN). As modified GO‐CN and CNTs‐CN were characterized and confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and gravimetric analyzer. It was found that about 19 and 24 wt% of 3‐aminophenoxyphthalonitrile were grafted onto the surface of the GO and CNTs, respectively. The electrochemical impedance spectroscopy results showed that the GO‐CN&CNTs‐CN hybrid materials exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. Significant synergistic effect of the lamellar structural GO‐CN and CNTs‐CN on the anticorrosion performance of epoxy composite coatings was designed. Besides, the epoxy coating with 1 wt% of the GO‐CN&CNTs‐CN hybrid exhibited the best anticorrosion performance, in which the impedance showed the largest one (immersion in 3.5 wt% of NaCl solution for 168 hr). Copyright © 2016 John Wiley & Sons, Ltd.     

四氯化碳液相催化加氢制氯仿多元金属催化剂的制备及其催化性能

以贵金属M(=Pd,Pt)为主要活性成分,掺加过渡金属Fe和Ni作为助剂,采取浸渍和氢气还原法制备了椰壳活性炭(ACcs)负载的单元金属(M/ACcs)、二元金属(M-Ni/ACcs、M-Fe/ACcs)和三元金属(M-Ni-Fe/ACcs)系列催化剂;通过CC_l4液相催化加氢制氯仿反应考察了这些催化剂的催化活性和选择性。结果表明,Pd基催化剂的催化活性明显高于Pt基催化剂,但后者对氯仿的选择性优于前者;在前5 h加氢反应时段,两系列催化剂的活性顺序为:Pd-Ni-Fe/ACcsPd-Fe/ACcsPd/ACcsPd-Ni/ACcs和Pt/ACcs≈Pt-Fe/ACcsPt-Ni/ACcsPt-Ni-Fe/ACcs;总体上,引入Fe对于催化性能的改善效果要优于Ni,Ni的单独引入则会不同程度地降低催化活性。综合考量成本、活性和选择性等因素,优选Pd-Ni-Fe/ACcs作为催化剂,在393 K下反应5 h,可实现CC_l497.6%的转化率以及接近100%氯仿的选择性。     

氯化原位接枝过程与聚合物高性能化

氯化原位接枝过程是一种基于自由基反应的改性聚合物新方法,经该方法改性的聚合物性能显著改变,充分展现了弱影响、强响应的特征。本文简述了氯化原位接枝反应过程、机理,剖析了氯化原位接枝产物的结构特征,并对各类接枝共聚产物结构与性能关系进行了归纳和总结。详细介绍了各类接枝产物的不同用途,例如用于热塑性弹性体、木板粘合剂、增韧改性剂、成膜涂料等。最后对氯化原位接枝过程更广泛的应用及今后的发展趋势进行了展望。     

基于新型螺氧杂蒽主体的高效蓝色磷光有机发光二极管

We synthesized a series of novel spiro[fluorene-9, 9'-xanthene] (SFX)-based host materials via a one-step palladium-catalyzed cross-coupling reaction. These materials have high triple energy levels and high yield, and thus can be used as hosts for blue phosphors. Blue phosphorescent organic light-emitting devices (PHOLEDs) with a bis (3, 5-difluoro-2-(2-pyridyl) phenyl-(2-carboxypyri-dyl) iridium (Ⅲ) (FIrpic) emission were fabricated. Furthermore, we applied cohosts composed of one of the new synthesized materials and the hole transport material di-[4-(N, N-ditolyl-amino)-phenyl]cyclohexane (TAPC) to the blue PHOLEDs to successfully acquire efficient blue emissions. The SFX-based material provided efficient energy transfer while TAPC improved the mobility of the cohost as well as reduced the working voltage. Maximum current efficiencies of 22.56 and 25.93 cd·A^-1 and the maximum brightnesses of 6421 and 6196 cd·m^-2 were obtained for the PHOLEDs with TAPC: 2-(9-phenyl-fluoren-9-yl) spiro[fluorene-9, 9'-xanthene] (PF-SFX) and TAPC: 2-(9-(4-(octyloxy)-phenyl)-9H-fluoren-9-yl) spiro[fluorene-9, 9'-xanthene] (C8OPF-SFX) cohosts, respectively. The experimental results obtained for the four SFX-based host materials were enough to declare that SFX is an effective main unit that can be used to build efficient host materials for blue phosphors containing only C, H, and O basic elements.     

TiO_2纳米管阵列的多重改性及其在超级电容器中应用的最新进展

阳极氧化法制备的TiO_2纳米管阵列因其简单的制备方法、可控的形貌以及环境友好等优点而成为超级电容器领域重点研究的电极材料之一。本文介绍了TiO_2纳米管的多重改性方法,包括引入氧空位、金属或非金属修饰或掺杂、金属化合物(氧化物、氢氧化物、硫化物、氮化物)以及导电聚合物修饰等,以进一步提高TiO_2纳米管的电化学性能。介绍了近年来阳极氧化法制备的TiO_2纳米管阵列在超级电容器中应用的研究进展,为进一步拓展TiO_2纳米管阵列的实际应用提供参考。     

衍生化β-环糊精手性固定相高效液相色谱法拆分米那普仑对映体及其分离机制

建立了新型抗抑郁药米那普仑在环糊精手性固定相上的高效液相色谱拆分方法。在反相色谱条件下采用未衍生化β-环糊精(Cyclobond I 2000)、乙酰基-β-环糊精(AC-β-CD)、2,3-二甲基-β-环糊精(DM-β-CD)、3,5-二甲基苯基氨基甲酸酯-β-环糊精(DMP-β-CD)4种手性柱分离米那普仑对映体。考察了固定相、流动相比例、pH、流速和柱温对拆分的影响。利用分子对接和结合能计算方法,研究米那普仑分子与AC-β-CD的对接过程,探讨其可能的分离机制。优化后的拆分条件如下:固定相为乙酰基-β-环糊精手性柱Astec CYCLOBONDTMI 2000 AC(25 cm×4.6 mm,5μm),流动相为乙腈-0.1%(体积分数)pH 5.0醋酸三乙胺溶液(TEAA)(5∶95,v/v),流速为0.4mL/min,柱温为25℃,检测波长为220 nm。在此条件下,米那普仑对映体获得快速拆分,分离度(Rs)为1.74,理论塔板数为10 125。分子模拟结果表明引起手性识别的作用力主要是环糊精衍生化的乙酰基导致的氢键作用差异。该方法快速、高效、重现性好。     

丹磺酰肼衍生-高效液相色谱-荧光检测法测定包装纸中的甲醛和乙醛

建立了丹磺酰肼(DNSH)衍生-高效液相色谱-荧光检测测定包装纸中甲醛和乙醛的分析方法,并与2,4-二硝基苯肼(DNPH)衍生法进行了比较。纸张样品经衍生化试剂振荡萃取30 min,衍生化反应24 h,萃取液经PSA/C18净化管净化处理后,以Diamonsil~ C18(2)色谱柱(150 mm×4.6 mm,5μm)为固定相,用醋酸水溶液(pH2.55)-乙腈为流动相进行梯度洗脱。采用荧光检测器检测,激发波长为330 nm,发射波长为484 nm。结果表明,衍生剂、甲醛-DNSH和乙醛-DNSH在20 min内可完全分离,方法的加标回收率为81.64%~106.78%,相对标准偏差(RSD)为2.02%~5.53%(n=5),甲醛和乙醛的检出限分别为19.2μg/kg和20.7μg/kg,定量限分别为63.9μg/kg和69.1μg/kg。该法操作简单,灵敏度高,比常规方法具有更低的检出限,能很好地应用到实际样品检测中,为低含量醛类化合物的检测提供了一种新思路。