高效液相色谱与飞行时间质谱联用技术研究

用青岛曹家汶河口沉积物中分离出的细菌L-10(希瓦氏菌属)进行了水体中甲基对硫磷的细菌降解研究.研究表明,该菌对甲基对硫磷具有显著的降解性.采用高效液相色谱/飞行时间质谱(HPLC-TOF-MS)联用技术对甲基对硫磷及其细菌降解产物进行了分析.样品经SPE-C18小柱富集分离后,进行液相色谱和在线电喷雾飞行时间质谱分析.采用C18反相色谱柱(15 cm×4.6 mm i.d. 5 μm), 线性梯度为0 min 乙腈/水(30/70),5 min 乙腈/水(30/70),20 min 乙腈/水(80/20),25 min 乙腈/水(80/20);流速0.8 ml/min,甲酸铵缓冲溶液浓度为0.1% (V/V);电喷雾正离子(ESI)模式,m/z扫描范围50～1000进行TOF-MS扫描、测定,测定结果用Analyst QS软件进行分析.结果表明,与甲基对硫磷光降解产生甲基对氧磷和对硝基酚不同,在降解菌L-10的存在下,甲基对硫磷发生了取代、氧化、还原等一系列反应,产生了相应的降解产物.降解过程的机理很复杂,从甲基对硫磷及其降解产物的分子结构式来分析,推断可能与细菌本身的代谢有关.     

基于多齿功能单体的三聚氰胺印迹材料的制备及应用

以三聚氰胺(MEL)为模板分子,采用沉淀聚合方法研究了以衣康酸(IA)为多齿功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂时,组分之间摩尔比对三聚氰胺印迹聚合物(MIP)选择性的影响.研究发现,当MEL与IA摩尔比为1∶1.5时,所合成的MIP对三聚氰胺具有最佳选择性,选择性系数k=10.41(以三聚氰酸为对照物).此时IA的识别位点(羧基)与三聚氰胺的可识别位点(胺基)摩尔比为1∶1,因此,不会出现由过量功能单体引起的非特异性吸附.Scatchard分析结果表明,这种MIP能够在更宽的三聚氰胺浓度范围(1～100 mg/L)内只表现出特异性吸附.以灭蝇胺为对照物时,kNIP<1但kMIP>1,该结果证明MIP对分子的形状有良好的识别能力.最后,以制备的MIP为固相萃取吸附剂,结合高效液相色谱/紫外检测器(HPLC/UV)建立了三聚氰胺测定方法.当牛奶(奶粉)中MEL的加标浓度分别为15,600和4500μg/L(μg/kg)时检测的加标回收率为92.34%～109.4%.     

Synthesis of Triazole-Linked Glycoconjugates by Copper(I)-Catalyzed Regiospecific Cycloaddition of Alkynes and Azides

Several 1,2,3-triazole-linked glycoconjugates were efficiently synthesized via a Cu(I)-mediated 1,3-dipolar cycloaddition with high regiospecificity and yield (≥ 85%), providing a simple and efficient route to synthesize protected and unprotected neoglycoconjugates. Introduction of a spacer between glycosyl moieties and other compounds reduces steric hindrance, promotes yield, and expands the varieties of glycoconjugates to satisfy various needs of biological events. The structures of all the synthesized glycoconjugates were clearly confirmed by infrared(IR), ¹H NMR, ¹³C NMR, elemental analysis (EA), or MS.     

“Signal-on” Electrogenerated Chemiluminescence Biosensing Method for the Determination of Matrix Metalloproteinase 2

A simple, selective and sensitive “signal-on” electrogenerated chemiluminescence (ECL) biosensing method was developed for matrix metalloproteinase 2 (MMP-2). Ru(bpy)₃²⁺, gold nanoparticles (AuNPs) and Nafion were modified onto glassy carbon electrode (GCE) to form Ru(bpy)₃²⁺/AuNPs/Nafion/GCE as sensitive ECL platform and then ferrocene (Fc) labeled peptide was assembled onto the modified electrode to form ECL biosensing platform. The ECL intensity increased when the ECL biosensing electrode reacted with MMP-2 because of MMP-2-induced cleavage of Fc labeled peptide. The ECL method was applied to determine MMP-2 with detection limit of 0.3 ng/mL and one-step recognition, which is promising for point-of-care test of protease.     

Fingerprint chromatogram analysis of Pseudostellaria heterophylla (Miq.) Pax root by high performance liquid chromatography

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the fingerprinting of extracts from the root of Pseudostellaria heterophylla (Miq.) Pax. HPLC with gradient elution was performed on an authentic reference standard of powdered P. heterophylla (Miq.) Pax root and 11 plant samples of the root were collected from different geographic locations. The HPLC chromatograms have been standardized through the selection and identification of reference peaks and the normalization of retention times and peak intensities of all the common peaks. The standardized HPLC fingerprints show high stability and reproducibility, and thus can be used effectively for the screening analysis or quality assessment of the root or its derived products. Similarity index calculations based on cosine angle values or correlation methods have been performed on the HPLC fingerprints. As a group, the fingerprints of the P. heterophylla (Miq.) Pax samples studied are highly correlated with closely similar fingerprints. Within the group, the samples can be further divided into subgroups based on hierarchical clustering analysis (HCA). Sample grouping based on HCA coincides nicely with those based on the geographical origins of the samples. The HPLC fingerprinting techniques thus have high potential in authentication or source-tracing types of applications.     

Divergent Total Syntheses of (−)‐Daphnilongeranin B and (−)‐Daphenylline

(?)‐Daphnilongeranin B and (?)‐daphenylline are two hexacyclic Daphniphyllum alkaloids, each containing a complex cagelike backbone. Described herein are the first asymmetric total synthesis of (?)‐daphnilongeranin B and a bioinspired synthesis of (?)‐daphenylline with an unusual E ring embedded in a cagelike framework. The key features include an intermolecular [3+2] cycloaddition, a late‐stage aldol cyclization to install the F ring of daphnilongeranin B, and a bioinspired cationic rearrangement leading to the tetrasubstituted benzene ring of daphenylline.     

流动注射一超声雾化器一电感耦合等离子体-原子发射光谱(FI-UN-ICP-AES)同时测定头发中多种元素条件的优化

建立了FI－UN－ICP－AES联用技术，用所发展技术进行了头发中多种微量元素的同时测定，对载流流速、积分时间、进样体积等进行了优化。多次注射测定的再现性（RSD）在0.6％一5．0％范围内，标准加入回收率为90％一101％。