高效液相色谱研究丝素亲核基团与一氯均三嗪型活性染料反应动力学

以异丙胺、对甲酚和甲醇分别模拟蚕丝丝素的氨基、酚羟基和醇羟基,应用高效液相色谱分析一氯均三嗪型活性染料与蚕丝丝素的不同亲核基团的反应速率.结果表明:在pH=8～10、70～95 ℃的条件下,染料的酚解总反应速率远大于染料的氨解总反应速率和醇解总反应速率.其中C.I.活性红24 和C.I.活性橙2在pH=9,95 ℃条件下的酚解总速率分别约为其氨解总反应速率的8.5倍和12.5倍,为其醇解总反应速率的23倍和50倍;该两染料的酚解效率分别为47.4和96.3,氨解效率分别为4.6和6.9,醇解效率仅为1左右.通过异丙胺-对甲酚-甲醇混合溶液(1∶ 10∶ 100,V/V)模拟蚕丝与染料的反应,研究一氯均三嗪型活性染料与丝素上亲核基团的反应选择性,推断出一氯均三嗪型活性染料染蚕丝的最适宜条件为pH=8～9,温度85 ℃左右.在此条件下,酚羟基在蚕丝的一氯均三嗪型活性染料染色中起主要作用,氨基起次要作用,而醇羟基的作用甚微.     

色谱柱选择对六味安消胶囊中大黄素和大黄酚含量测定的影响

以中国药典收载的六味安消胶囊中大黄素与大黄酚的含量测定方法为典型案例,揭示了色谱柱是影响HPLC质量控制方法测定结果准确性的关键风险因素。参加能力验证的155家实验室均采用方法规定的C₁₈柱,但由于不同品牌C₁₈柱间的选择性差异,有20家实验室的分析结果中大黄素峰与样品水解产物的色谱峰共流出,导致测定结果明显偏离正常值。统计结果表明,A型（早期开发、硅羟基残留较多）和E型（内嵌极性基团或以极性基团封尾）C₁₈柱更适于六味安消胶囊中大黄素与大黄酚的含量测定,这可能是因为大黄素和大黄酚结构中含有多个酚羟基,能与A型柱的残留硅羟基或E型柱内嵌/封尾的极性基团相互作用,从而增强其保留行为有关。建议相关实验室在制订HPLC质量控制方法时应特别注重色谱柱的耐用性考察,并尝试采用国外色谱柱分类数据库科学地指导色谱柱的选择,尽量采用难分离物质对作为系统适用性指标,完善质量标准,减少由于色谱柱选择不适宜导致测定结果不准确的风险。     

HPLC法快速测定食品添加剂的检测条件研究

建立一种HPLC法快速测定食品中苯甲酸、山梨酸和糖精钠的分析方法.采用C18反向高效液相色谱柱,以甲醇和乙酸铵溶液为流动相洗脱,用紫外检测器于230nm波长处检测.当流动相甲醇与乙酸铵的比例(V/V)为39∶61时,各组分均得到较好的分离,色谱峰分离度达到3.0以上,色谱峰型尖锐,保留时间较短.色谱峰面积和保留时间的RSD均小于1%,表明该方法具有很好的准确度和精密度.在该色谱条件下,分别对饮料、调料等实际样品进行检测,结果表明该色谱条件的HPLC法快速、准确,重现性好,可作为食品中防腐剂和甜味剂的定性定量的参考方法.     

高效液相色谱-共振瑞利散射联用测定大鼠血清中依替米星

应用高效液相色谱-共振瑞利散射联用技术建立了测定依替米星的新方法。采用滂胺天蓝作为分子探针,共振瑞利散射(RRS)检测波长设为λex=λem=361nm,通过优化分子探针浓度、分子探针流速、柱后管长和pH等影响因素,确定了最佳实验条件,在该条件下依替米星的检出限(信噪比为3)为1.0mg/L。以妥布米星为内标物,以内标法定量,依替米星与妥布米星的峰面积比与依替米星的质量浓度之间的线性响应范围为2.5～60mg/L。将该方法应用于大鼠血清中依替米星的药代动力学研究,结果满意。     

2-(11H-苯[a]咔唑)-乙酸在脂肪胺的高效液相色谱分离及质谱鉴定中的应用

采用新型荧光衍生试剂2-(11H-苯[a]咔唑)-乙酸(BCA)进行柱前衍生并经荧光检测对脂肪胺进行高效液相色谱(HPLC)分离和质谱定性.衍生物荧光激发和发射波长为λex=285 nm,λem=384 nm.60 ℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)作催化剂, 衍生反应15 min后获得稳定的荧光产物.在Hypersil BDS C18 (4.0 mm×200 mm, 10 μm) 色谱柱上, 采用梯度洗脱对12种脂肪胺衍生物进行了优化分离.采用大气压化学电离源(APCI Source)正离子模式进行质谱定性, 实现了各种脂肪胺衍生物的快速、准确测定.脂肪胺的线性回归系数不小于0.999 8 , 检出限(S/N=3)为5.73 ～31.3 fmol.     

LC-ESI MS/MS测定蜜胺餐具中三聚氰胺的迁移量

建立了液相色谱串联电喷雾正离子源质谱(LC-ESI MS/MS)检测蜜胺餐具中三聚氰胺迁移量的方法.采用强阳离子交换柱,流动相为乙腈-10 mmol/L乙酸铵/乙酸缓冲溶液(pH 4.0)(40:60,体积比),以多反应离子监测对三聚氰胺做定性定量分析.在水、3%乙酸、10%乙醇模拟物中,三聚氰胺在3.00～130.0...     

胺醇修饰的β-二酮铕配合物对有机小分子胺的高灵敏检测

稀土发光传感器可用于有害的有机小分子胺的检测,然而稀土离子较大的离子半径和不稳定的配位构型,使其在固态下对有机小分子胺实现高灵敏性的发光检测具有一定的挑战。通过在单β-二酮配体上引入胺醇识别基团,使其与稀土铕离子通过配位成功构筑了具有可调控配体内电荷转移(ILCT)性质的单核稀土配合物[Eu(L)₃(H₂O)₂](HL=(2Z)-1-(4-(双(2-羟基乙基)氨基)苯基)-4,4,4-三氟-3-羟基丁-2-烯-1-酮)。配合物的传感研究表明,[Eu(L)₃(H₂O)₂]在弱的亲核作用下对三丙胺等有机小分子胺表现出明显的发光增强响应。     

气相色谱法测定阳离子表面活性剂合成体系中脂肪烷基二甲基叔胺

选用HP-NINOWax毛细管色谱柱及氢火焰离子化检测器（FID），采用程序升温，建立了4种脂肪烷基二甲基叔胺的分析方法。结果表明，4种脂肪烷基二甲基叔胺质量浓度在0.005~1.0 g/L范围内，其峰面积与质量浓度有良好的线性关系，相关系数（R²）在0.9996以上。检出限（LODs，信噪比为3）在0.001~0.002 g/L之间，定量限（LOQs，信噪比为10）在0.003~0.005 g/L之间，回收率在90%~130%之间，相对标准偏差为1.3%~6.9%（n=6）。方法的线性范围宽、回收率高、选择性好，可用于叔胺的产品质量分析及生产过程控制分析。利用该方法对阳离子表面活性剂合成反应中十六烷基二甲基叔胺进行监测，结果很好地符合双分子亲核取代反应。该方法比滴定分析法更快速、精确，与液相色谱法相比，不需要进行柱前衍生或者使用色谱-质谱联用仪器。     

5-羰基咪唑苯并吖啶酮对芳香胺类化合物的荧光标记及质谱鉴定

利用新型双敏感探针5-羰基咪唑苯并吖啶酮(IEBA)作柱前衍生试剂,在Aka-sil-C18反相色谱柱上,采用梯度洗脱,25min内实现6种芳香胺衍生物的快速基线分离,并通过离子阱大气压化学电离源(APCI Source)正离子模式进行在线的柱后质谱鉴定。IEBA与芳香胺的亲核取代产物不仅具有强烈的荧光,也表现出强烈的质谱离子化能力。对染色剂中芳香胺类化合物的测定快速、准确,具有良好的重现性。最大激发和发射波长为λex/λem=272/505nm,荧光定量检测的相关系数大于0.9999,检出限为0.19～0.04ng/mL。     

在线固相萃取-毛细管高效液相色谱联用测定奶酪中的生物胺

采用双二元泵毛细管液相色谱,通过六通阀实现了样品的在线净化与分离定量的自动切换,建立了同时测定奶酪中的15种生物胺的在线固相萃取-毛细管高效液相色谱联用方法。通过优化毛细管高效液相色谱的分离条件,考察在线固相萃取流动相的组成、上样溶液pH值以及六通阀的切换时间对生物胺回收率的影响,确定最佳分析条件为：5%乙腈-水作为固萃柱(Zorbax SB-C18)的流动相,上样溶液pH=11,上样3 min后切换六通阀。采用内标法定量,15种生物胺标准曲线的线性范围为0.25~50.0 mg/L,检出限( LOD)为0.05~0.25 mg/L,定量限(LOQ)为0.15~0.80 mg/L。除了甲胺、乙胺、3-甲基丁胺和5-羟基色胺外,其余生物胺的不同添加水平(1,20和40 mg/kg)下的加标回收率为79.6%~118.7%;除3-甲基丁胺和5-羟基色胺外,其余生物胺的RSD在0.3%~14.9%之间,可用于奶酪中多种生物胺的快速检测。     

HEPT类化合物的QSAR研究

为定量结构／活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法（Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物（1－[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构／活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。     

液滴荧光传感与计算机联用技术在微量分析中的应用

通过在LS55型荧光-磷光-发光分光光度计上加装液滴产生及调节附件,采用计算机采集与分析处理数据,成功地研制了双通道液滴光化学传感装置.利用葡聚糖凝胶对复合维生素B中不同组分的选择性吸附来达到分离与同时检测的目的,并将其用于复合维生素B药片的分析,取得了满意的结果.     

From the Micro- to the Macro-: Managing the Conservation of the Warship,Vasa

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large-scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re-treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.     

Using of the Agglomeration-in-liquid for the Technology of the Fine Materials

The content of the fine and ultrafine particles in the raw material results in difficulty of the separation, the loss of the valuable components and ecological contamination. Secondary using of the fine particles is impossible without their granulation. This problem has been solved by the agglomeration-in-liquid method.An agglomeration-in-liquid method is a process to produce agglomerates in a liquid phase from solid particles suspended in the liquid. The surface of solid particles and the binding liquid must be of identical polarity, but the continuous phase must be of the opposite polarity. The water solutions of the surfactant are the binding liquids or the organic liquids.     

On the scaling of the interface energy of the liquid clusters in the disordered nanoporous medium

Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.     

On the quality of the hardness kernel and the Fukui function to evaluate the global hardness

An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed.     

Copper-containing dendromesogens: the influence of the metal on the mesomorphism

The synthesis and liquid crystalline behaviour of the first and second generations of a dendrimeric structure based on poly(propyleneimine)(DAB-dendr(NH₂)_x) are reported. 4-(4-n-Alkoxybenzoyloxy)salicylaldehydes are used as mesogenic moieties attached at the peripheral amino groups of the dendrimers giving rise to dendromesogens with four and eight mesogenic branches. From these dendromesogens, considered as organic ligands, were prepared six metal-containing dendrimers which incorporate two or four copper atoms in their structures. All the dendrimeric ligands and three of the metal-containing dendrimers exhibit liquid crystalline properties which were studied by optical microscopy, DSC, X-ray diffraction and EPR spectroscopy.     

光亮剂对银电沉积行为的影响

用电势阶跃法和旋转圆盘电极法 (RDE)以及SEM和XRD测试手段 ,初步研究了光亮剂对氰化体系中银电沉积行为的影响 .研究表明 ,光亮剂的加入并未导致银电沉积成核机理的改变 ,但显著增强了镀液的微观平整效应 ,并且所得镀层的表观光滑程度明显改善 .XRD测试亦同时表明光亮剂的加入并未改变镀层的择优取向     

On the dependence of the critical supersaturation on the initial undersaturation in the reverse Wilson chamber

The dependence of the critical supersaturation on the degree of the initial undersaturation has been analyzed in detail.This dependence is explained by means of the Richarch-Powell equation, taking into account the dependence of the -ratio upon the partial pressures of the inert gas and the liquid under investigation.