液相色谱-串联质谱法同时测定贝类中大田软海绵酸、鳍藻毒素、蛤毒素和虾夷扇贝毒素

建立了同时测定贝类中大田软海绵酸(okadaic acid, OA)及其衍生物鳍藻毒素(dinophysistoxin-1, DTX-1)、蛤毒素(pectenotoxin-2, PTX-2)和虾夷扇贝毒素(yessotoxin, YTX)的液相色谱-串联质谱分析方法。样品经甲醇提取,固相萃取柱净化,C18色谱柱分离,经含甲酸和甲酸铵的乙腈-水溶液为流动相梯度洗脱,选择反应监测(SRM)模式检测,正、负离子切换扫描,基质标准校正,外标法定量。结果表明,OA、DTX-1和YTX的线性范围为2.0～200.0 μg/L,定量限(以信噪比(S/N)≥10计)为1.0 μg/kg; PTX-2的线性范围为1.0～100.0 μg/L,定量限为0.5 μg/kg;几种化合物的添加平均回收率为83.1%～105.7%,相对标准偏差(RSD)为3.16%～9.29%。成功应用本法对黄海灵山湾海域采集的贝类样品进行了分析,发现部分样品中含有大田软海绵酸、鳍藻毒素、蛤毒素和虾夷扇贝毒素。     

Synthesis and cytotoxic activity of novel 2, 6-disubstituted-4-mor- pholinothieno[3, 2-d]pyrimidines as potent anti-tumor agents

正A series of 2,6-disubstituted-4-morpholinothieno[3,2-d]pyrimidine derivatives were synthesized and their cytotoxic activity against H460,HT-29,MDA-MB-231,U87MG and H1975 cancer cell lines were evaluated in vitro.Most of the target compounds exhibited moderate to excellent activity to the tested cell lines.The most promising compound 23(0.84μmol/L,0.23μmol/L, 2.52μmol/L,1.80μmol/L) was 1.0,2.9,29.3 and 4.3 times more active than GDC-0941(0.87μmol/L,0.66μmol/L,73.8μmol/L, 7.77μmol/L) against H460,HT-29,MDA-MB-231 and U87MG cell lines,respectively.     

固体杂多酸在生物质水解转化中的应用

随着化石资源的日益枯竭,寻求可替代清洁能源已成为全球重大课题。生物质是一种可再生的清洁能源,目前人们尝试通过利用生物质转化缓解日益增长的能源需求。杂多酸是应用在清洁工艺中的重要催化剂,结构和酸度的设计调变性及较高的热稳定性,使其广泛用于生物质的水解转化反应平台。目前固体杂多酸在水溶剂、有机溶剂及两相体系中降解生物质有着各自不同的优缺点。本文综述了杂多酸在不同反应体系中水解转化生物质制备精细化学品的研究进展,并对其在生物质水解转化利用中的应用前景进行了展望。     

高效液相色谱外标工作曲线法测定大麻树脂中四氢大麻酚含量的不确定度评定

依据JJF 1059-1999《测量不确定度评定与表示》,以检测大麻树脂中四氢大麻酚含量的实验为例,评定了采用高效液相色谱外标工作曲线法进行含量测定的不确定度.建立了高效色谱外标工作曲线法测定样品含量的数学模型,分析了不确定度的来源并给出了量化结果,合成扩展不确定度为0.15％(k=2).     

Algebro-geometric solutions of the coupled modified Korteweg–de Vries hierarchy

Based on the stationary zero-curvature equation and the Lenard recursion equations, we derive the coupled modified Korteweg–de Vries (cmKdV) hierarchy associated with a 3×3$3\times 3$ matrix spectral problem. Resorting to the Baker–Akhiezer function and the characteristic polynomial of Lax matrix for the cmKdV hierarchy, we introduce a trigonal curve with three infinite points and two algebraic functions carrying the data of the divisor. The asymptotic properties of the Baker–Akhiezer function and the two algebraic functions are studied near three infinite points on the trigonal curve. Algebro-geometric solutions of the cmKdV hierarchy are obtained in terms of the Riemann theta function.     

Hybrid algorithm for the two-dimensional rectangular layer-packing problem

In this paper, a rectangular layer-packing algorithm (RLPA) combined with modified genetic algorithm (GA) or particle swarm optimization (PSO) algorithm is developed to solve the problem with emerging restraints, which is raised from the two-dimensional rectangular packing problem with some small rectangles that need to be packed into a fixed rectangular object. RLPA is designed from the BL algorithm and lowest horizontal line algorithm. GA and PSO are also modified to satisfy the constraint conditions. Best GA or PSO parameters are obtained by conducting experiments on some typical instances. The results are also compared, which validate the quality of the solutions and show the effectiveness of the modified algorithm.     

呋喃[2,3-b]喹啉衍生物的合成及其生物活性研究进展

呋喃[2,3-b]喹啉骨架作为目前发现数目最为庞大的一类天然呋喃喹啉结构,因其丰富的结构与良好的生物活性,吸引了大量研究者的关注。近年来,不仅许多新的天然呋喃[2,3-b]喹啉不断从自然界中被发现,而且基于生物活性研究的衍生物制备也得到蓬勃发展。为了充分利用这一宝贵天然资源,为活性天然产物的结构改造提供一定指导与参考,本文对近二十年来呋喃[2,3-b]喹啉衍生物的合成以及相关生物活性研究进行了总结,并展望其前景。     

Solubilities,densities and refractive indices for the ternary systems ethylene glycol + MCl + H2O (M = Na,K, Rb,Cs) at (15 and 35) °C

The solubilities, densities and refractive indices data for the four ternary systems ethylene glycol + MCl + H₂O (M = Na, K, Rb, Cs) at different temperatures were measured, with mass fractions of ethylene glycol in the range of 0 to 1.0. In all cases, the presence of ethylene glycol significantly reduces the solubility of the salts in aqueous solution. The experimental data of density, refractive index and solubility of saturated solutions for these systems were correlated using polynomial equations as a function of the mass fraction of ethylene glycol. On the other hand, the refractive index and density of unsaturated solutions was also determined for the four ternary systems with varied unsaturated salt concentrations. Values for both the properties were correlated with the salt concentrations and proportions of ethylene glycol in the solutions.     

Pretreatment-free fast ultraviolet detection of melamine in milk products with a disposable microfluidic device

A new method for sensitive and fast screening of melamine (MEL) in milk products was developed with a low-cost disposable microfluidic device coupled with ultraviolet (UV) detection. This method avoided the need of sample pretreatment prior to the separation process, thus was simple and green. Due to the advantages of the device and fracture sampling technique, milk sample could be directly sampled through the fracture to achieve baseline separation from amino acids, and proteins in the sample did not interfere with the detection. Using 20 mM phosphate running buffer (pH 9.0), a sampling time of 3 s at +180 V and a separation voltage of +1800 V (240 V/cm), this method could detect MEL in milk within 75 s. At the detection wavelength of 202 nm, the linear range for MEL was from 1.0 to 100 μg mL⁻¹ with a detection limit of 0.23 μg mL⁻¹ (S/N = 3). The novel protocol had been successfully used to screen MEL in milk samples with recovery more than 82%. The environmentally friendly methodology for pretreatment-free sensitive screening of MEL provided promising applications in monitoring the quality of different foods.     

A novel hydrazine electrochemical sensor based on the high specific surface area graphene

An ultrasensitive platform is presented for the determination of hydrazine by combining the high specific surface area and higher electrical conductivity of poly(sodium styrenesulfonate) (PSS) graphene nanocomposite film with amperometric detection. The PSS-graphene were synthesized by the Hummers method and used to modify a glassy carbon electrode. The material was characterized by scanning electron microscopy and is found to be suitable for sensing hydrazine. The overpotential of hydrazine on the modified electrode is 0.31 V which is lower than in many electrochemical sensors. The calibration curve for hydrazine is linear in the range from 3.0 to 300 µmol L^?1, and the detection limit is as low as 1 µmol L^?1. This is the first report in which such a high sensitivity and low limit of detection has been achieved. It is concluded that PSS graphene represents an efficient electron mediator for sensing hydrazine.