液相色谱-氢化物发生-原子荧光联用同时测定洛克沙胂及其代谢物

利用液相色谱-氢化物发生-原子荧光联用技术同时检测5种砷形态化合物(亚砷酸、砷酸、一甲基胂酸、二甲基胂酸和洛克沙胂).结果表明,在梯度洗脱条件下,以C18反相柱作分离柱,含0.5 mmol/L四丁基溴化铵的NaH2PO4-CH3OH溶液为流动相,5种砷化合物得以完全分离;以20 g/L K2S2O8为氧化剂进行紫外消解,7% HCl为载流,20 g/L KBH4为还原剂,砷化合物形成最佳的原子荧光信号.5种砷化合物在一定的浓度范围内与荧光峰面积呈良好的线性关系; 检出限＜10 μg/L; 加标回收率为81.4%～105.6%; 相对标准偏差RSD<4.0%.本方法适用于饲料、鸡粪、土壤和植物样品中洛克沙胂及其代谢物(亚砷酸、砷酸、一甲基胂酸和二甲基胂酸)的含量分析.     

聚丙烯酰胺凝胶电泳前活性染料与蛋白质共价染色的条件探索

采用聚丙烯酰胺凝胶电泳前染色法,考察了多种类型活性染料与牛血清白蛋白共价染色的条件.实验发现,活性蓝KN-R型标记效果最佳,其优化标记条件为: pH 10.0, 60 ℃, 50 min,蛋白检出限达200 ng,重复性和测试范围内的定量性较好,可在电泳时直接实时观测,作为蛋白标示剂有一定的应用前景.     

气相色谱-正化学源-质谱联用技术测定葡萄和葡萄酒中多种唑类杀菌剂的残留量

建立了可用于葡萄和葡萄酒中20种唑类杀菌剂残留量的分散型固相萃取-气相色谱-正化学离子源质谱分析方法.葡萄和葡萄酒样品分别用乙腈(含1%冰醋酸)和乙酸乙酯提取,分散型固相萃取法净化,由气相色谱-正化学离子源质谱分时段选择离子监测技术进行测定与确证,外标法定量.20种农药在50～1000 μg/L范围内线性均良好; 所有农药的方法定量限(LOQ)均低于10 μg/kg;在3个添加水平(10, 20和40 μg/kg)下,所有农药的回收率均处于71.2%～102.2%之间, RSD≤10.6%.     

Reaction mechanism of methanol decomposition on Pt‐based model catalysts: A theoretical study

The decomposition mechanisms of methanol on five different Pt surfaces, the flat surface of Pt(111), Pt‐defect, Pt‐step, Pt(110)(1 × 1), and Pt(110)(2 × 1), have been studied with the DFT‐GGA method using the repeated slab model. The adsorption energies under the most stable configuration of the possible species and the activation energy barriers of the possible elementary reactions involved are obtained in this work. Through systematic calculations for the reaction mechanism of methanol decomposition on these surfaces, we found that such a reaction shows the same reaction mechanism on these Pt‐based model catalysts, that is, the final products are all H (H_ads) and CO (CO_ads) via O? H bond breaking in methanol and C? H bond scission in methoxy. These results are in general agreement with the previous experimental observations. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010.     

Construction of two fluorescence‐labeled non‐combined DNA index system miniSTR multiplex systems to analyze degraded DNA samples in the Chinese Han Population

MiniSTR loci have been demonstrated to be an effective approach in recovering genetic information from degraded specimens, because of the reduced PCR amplicon sizes which improved the PCR efficiency. Eight non‐combined DNA index system miniSTR loci suitable for the Chinese Han Population were analyzed in 300 unrelated Chinese Han individuals using two novel five fluorescence‐labeled miniSTR multiplex systems(multiplex I: D10S1248, D2S441, D1S1677 and D9S2157; multiplex II: D9S1122, D10S1435, D12ATA63, D2S1776 and Amelogenin). The allele frequency distribution and forensic parameters in the Chinese Han Population were reported in this article. The Exact Test demonstrated that all loci surveyed here were found to be no deviation from Hardy–Weinberg equilibrium. The accumulated power of discrimination and power of exclusion for the eight loci were 0.999999992 and 0.98, respectively. The highly degraded DNA from artificially degraded samples and the degraded forensic case work samples was assessed with the two miniSTR multiplex systems, and the results showed that the systems were quite effective.     

Selective oxidation of styrene on an oxygen‐adsorbed Cu(111): A comparison with Au(111)

The reaction mechanism for the styrene selective oxidation on the oxygen preadsorbed Cu(111) surface has been studied by the density functional theory calculation with the periodic slab model. The calculated result indicated that the process includes two steps: forming the oxametallacycle intermediate (OMMS) and then producing the products. In addition, it was found that the second step, from OMMS to the product, is the rate‐controlling step, which is similar to the previous work of ethylene selective oxidation. The present result indicated that the selectivity towards the formation of styrene epoxide on Cu(111) is much higher than that on Au(111). More importantly, we found that the mechanism via the OMMS (2) (i.e., the preadsorbed atomic oxygen bound to the CH₂ group involved in C₆H₅? CH?CH₂) to produce styrene epoxide is kinetically favored than that of OMMS (1). We also found that the selectivity toward the styrene epoxide formation on Cu₂O is similar to that of Cu(111). © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010     

具有抗凝性能的肝素化ε-己内酯/L-丙交酯共聚酯的合成及电纺丝加工

以辛酸亚锡为催化剂,1,4-丁二醇为引发剂,制备出ε-己内酯/L-丙交酯共聚酯(PLCL).以1-(3-二甲氨基丙基)-3-乙基碳二亚胺/N-羟基琥珀酰亚胺为缩合剂将肝素连接在PLCL两侧端基上.采用1HNMR技术测定了共聚酯端基的肝素化率;用XPS分析了肝素化后聚酯中N和S含量,利用甲苯胺蓝紫外分光光度计法测定了表面肝素含量,并根据静态接触角测定结果讨论了材料表面的亲水性变化.凝血酶原时间、凝血酶时间和部分凝血活酶时间测试数据表明,肝素化后PLCL的抗凝血性能得到明显改善.探索了该共聚酯进行电纺丝加工的可行性.     

A novel cyclopentene derivative and a polyhydroxylated steroid from a South China Sea gorgonian Menella sp

A chemical investigation on a South China Sea gorgonian, Menella sp. resulted in the isolation and elucidation of menellin A (1), a highly oxygenated racemate with C(8) skeleton, and a polyhydroxylated steroid, menellsteroid C (2), along with eight known compounds (3-10). The structures of the new compounds were elucidated by means of MS, 1D and 2D NMR spectra, and the relative stereochemistry of 1 was determined by X-ray single-crystal diffraction analysis. In addition, compound 7 was isolated as a new natural product. Compounds 1-3 and 7 were selected to test the anti-inflammatory inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. 1 and 3 exhibited modest inhibitory effects with IC(50) of 71.3, 33.9 μM, respectively, compared to the positive control aminoguanidine (IC(50) 25.0 μM).