连续流动分析法(CFA)快速测量废水中微量铀

应用FS-Ⅳ流动分析仪,以TBP-二甲苯作萃取剂,偶氮胂Ⅲ为反萃剂,NaNO3为盐析剂,EDTA为掩蔽剂,建立了废水中微量铀连续流动分析法.该方法的检出限(MDL)15.7 μg/L,加标回收率97%～104.5%.方法已应用于实际废水样的分析.     

罗丹宁纤维富集-极谱法测定矿石和冶金样品中的钯

本文报道了罗丹宁纤维富集-极谱法测定矿石及冶金样品中Pd4 的方法。对影响Pd4 分离富集及极谱法测定的诸因素进行了研究,实验确定了最佳条件。方法测定Pd4 的线性范围为2.5~600μg.L-1,检出限为0.5μg.L-1;将该法用于矿石及冶金样品中Pd4 的分析测定,其结果与火试金法的测定结果吻合良好。本方法具有选择性好,灵敏度高,操作简便等特点,可用于Pd含量为0.02 g.t-1以上矿石和冶金样品中钯的测定。     

Specific Proteins in the Indirect Somatic Embryogenesis of Freesia Refracta

IntroductionHaberlandt[1]proposed the conception of plantso-matic embryo in 1902, which states that plant cellsexhibit totipotency; each cell could divide ceaselesslyand eventually develops into a mature plantlet. Allthese provide a theoretical evidence for somatic embryo-genesis. The related researches reveal thatplantembry-ogenesis occurs as a result of the selective expression ofsets of genes that allowthe synthesis of special proteinsin a temporal and spatial sequential manner under themut…     

固相萃取/超高效液相色谱-串联质谱法同时测定水产养殖“非药品”投入品中37种禁限兽药

建立了固相萃取/超高效液相色谱-串联质谱(SPE/UPLC-MS/MS)同时测定水产养殖“非药品”投入品中37种禁限兽药(磺胺类、酰胺醇类、硝基咪唑类、苯并咪唑类、抗病毒类)残留量的分析方法。样品经含0.2%甲酸的80%乙腈水溶液提取,Mcllvaine-乙二胺四乙酸二钠(Mcllvaine-Na₂EDTA)缓冲液螯合,超声波萃取,Waters PRiME-HLB固相萃取柱净化,通过C₁₈色谱柱分离,采用UPLC-MS/MS选择电喷雾ESI离子源在正、负离子多反应监测模式下分析测定,基质添加标准曲线外标法定量。37种禁限兽药标准曲线的相关系数均不低于0.991,检出限为0.156～1.94μg/kg,定量下限为0.520～6.47μg/kg,加标回收率为71.6%～119%,相对标准偏差为1.2%～15%。该方法快速、准确、灵敏度高,可应用于水产养殖“非药品”投入品中37种禁限兽药残留的快速准确筛查和检测。     

Qualitative and Quantitative Analysis of Ejiao-Related Animal Gelatins through Peptide Markers Using LC-QTOF-MS/MS and Scheduled Multiple Reaction Monitoring (MRM) by LC-QQQ-MS/MS

Donkey-hide gelatin, also called Ejiao (colla corii asini), is commonly used as a food health supplement and valuable Chinese medicine. Its growing popular demand and short supply make it a target for fraud, and many other animal gelatins can be found as adulterants. Authentication remains a quality concern. Peptide markers were developed by searching the protein database. However, donkeys and horses share the same database, and there is no specific marker for donkeys. Here, solutions are sought following a database-independent strategy. The peptide profiles of authentic samples of different animal gelatins were compared using LC-QTOF-MS/MS. Fourteen specific markers, including four donkey-specific, one horse-specific, three cattle-specific, and six pig-specific peptides, were successfully found. As these donkey-specific peptides are not included in the current proteomics database, their sequences were determined by de novo sequencing. A quantitative LC-QQQ multiple reaction monitoring (MRM) method was further developed to achieve highly sensitive and selective analysis. The specificity and applicability of these markers were confirmed by testing multiple authentic samples and 110 batches of commercial Ejiao products, 57 of which were found to be unqualified. These results suggest that these markers are specific and accurate for authentication purposes.     

The LAM of the Rings: Large Amplitude Motions in Aromatic Molecules Studied by Microwave Spectroscopy

Large amplitude motions (LAMs) form a fundamental phenomenon that demands the development of specific theoretical and Hamiltonian models. In recent years, along with the strong progress in instrumental techniques on high-resolution microwave spectroscopy and computational capacity in quantum chemistry, studies on LAMs have become very diverse. Larger and more complex molecular systems have been taken under investigation, ranging from series of heteroaromatic molecules from five- and six-membered rings to polycyclic-aromatic-hydrocarbon derivatives. Such systems are ideally suited to create families of molecules in which the positions and the number of LAMs can be varied, while the heteroatoms often provide a sufficient dipole moment to the systems to warrant the observation of their rotational spectra. This review will summarize three types of LAMs: internal rotation, inversion tunneling, and ring puckering, which are frequently observed in aromatic five-membered rings such as furan, thiophene, pyrrole, thiazole, and oxazole derivatives, in aromatic six-membered rings such as benzene, pyridine, and pyrimidine derivatives, and larger combined rings such as naphthalene, indole, and indan derivatives. For each molecular class, we will present the representatives and summarize the recent insights on the molecular structure and internal dynamics and how they help to advance the field of quantum mechanics.     

给定主曲率函数的一类特殊曲面的位置向量场

本文给出了 Ｒ３,Ｒ２．１内给定主曲率函数的一类特殊曲面在定义域范围内的位置向量场,从而完满地解决了［１］中所讨论的问题．     

Laser polarization facility

An overview of the laser polarizer facility at ISAC is provided. The charge-exchange cell is described in some detail.