一个新的流泄风参数化公式及验证

本文推导了一个新的由热力强迫的流泄风参数化公式。该公式用数值模拟计算结果和场地实验观测结果作了验证。这些验证结果表明,该参数化公式能再现流泄风的结构。     

顺十八碳四烯酸荧光探针法研究PPARγ与配体的结合亲和性

蛋白质与小分子结合的研究中,处理单位点结合模型的经典方法在计算解离平衡常数(Kd,Ki)时有缺点;文中推导的两个公式拟解决这个问题.公式直接使用受体总浓度([R]t)、配体总浓度([L]t)和探针分子总浓度([P]t),其适用性不受受体浓度、受体被探针饱和的程度,以及配体活性高低等因素的影响.基于这两个公式使用非线性拟合方法,可以从结合实验求得探针分子的Kd,从竞争实验求得配体的Ki.以CPA为荧光探针,运用推导的公式,则测定了PPARγ和一些配体结合的Ki,并首次报道了PPARγ-LY171883的Ki.     

固体比表面积与孔径分布的测定——孔径分布测定中实验条件变化的计算机模拟

用流动色谱法测定固体样品的孔径分布繁复费时.计算时要经过作图、内插、查表等步骤,不是由一个或几个数学方程式所能表示,因而无法用一般误差传递公式来考察各个实验参数的变化对结果的影响.用重复试验的方法或用一般计算器进行模拟计算工作量都太大,只有应用电子计算机,才有可能模拟大量的实验条件变化,考察所得到的结果.     

5-甲基水杨醛缩对氨基水杨酸席夫碱的合成、表征及性质

用5-甲基水杨醛和对氨基水杨酸为原料,合成了一种新型席夫碱,用元素分析、IR、1 H NMR、MS验证其结构.采用荧光光谱法研究该化合物与牛血清白蛋白(BSA)的相互作用机制,采用位点结合模型公式、热力学公式求解出不同温度下的结合常数、结合位点数、热力学参数,得出其淬灭机制为静态淬灭,结合位点数为1,作用力类型为氢键和范德华力.     

含内环化A_a－B_b，C_c缩聚反应的溶胶－凝胶分配

结合Ａａ－Ｂｂ，Ｃｃ型缩聚反应，给出了溶胶中含内环化的溶胶－凝胶分配公式及凝胶化条件。     

牛血清白蛋白与甲基橙结合反应的研究

用分光光度法研究了牛血清白蛋白与甲基登在酸性溶液中的结合反应，认为两者通过非共价键结合，研究了溶液吸光 度与组分浓度的关系，对Ｓｃａｔｃｈａｒｄ模型用于自理蛋白质染色反应时存在的总是作了讨论，提出了表观结合常数的概念，推导了求算表观结合常数和最大结合数的线性回归公式。     

顺十八碳四烯酸荧光探针法研究PPARg与配体的结合亲和性

蛋白质与小分子结合的研究中, 处理单位点结合模型的经典方法在计算解离平衡常数(K_d, K_i)时有缺点; 文中推导的两个公式拟解决这个问题. 公式直接使用受体总浓度([R]_t)、配体总浓度([L]_t)和探针分子总浓度([P]_t), 其适用性不受受体浓度、受体被探针饱和的程度, 以及配体活性高低等因素的影响. 基于这两个公式使用非线性拟合方法, 可以从结合实验求得探针分子的Kd, 从竞争实验求得配体的Ki. 以CPA为荧光探针, 运用推导的公式, 则测定了PPARg和一些配体结合的K_i, 并首次报道了PPARg-LY171883的K_i.     

含内环化A—Bb,Cc缩聚反应的溶胶—凝胶分配

结合Ａａ－Ｂｂ，Ｃｃ型缩聚反应，给出了溶胶中含内环化的溶胶－凝胶分配公式及凝胶化条件。     

不可逆电活性药物米托蒽醌与脱氧核糖核酸的相互作用

研究了抗癌新药米托蒽醌(MXT)的电化学行为及与脱氧核糖核酸(DNA)的相互作用，推导了适用于研究不可逆电活性分子与DNA相互作用的电化学公式，运用该公式可以简便、快速地测定靶向分子与DNA的结合常数和结合位点数。实验发现，MXT与小牛胸腺DNA的结合以蒽醌母核的嵌插作用为主，同时，烃氨基侧链与骨架磷酸基团之间的静电吸引对母核起稳定作用，使化合物易于嵌入DNA的平面结构。MXT与DNA相互作用引起的峰电流的变化可以用于分析测定DNA。     

荧光淬灭和加强理论公式合理性的热力学分析

通过荧光法在不同温度下研究了3种第三代头孢新药: 盐酸头孢吡肟、头孢匹胺和头孢唑肟钠与人血清白蛋白(HSA)和牛血清白蛋白(BSA)的作用, 分别应用荧光淬灭和荧光加强理论公式计算了它们的结合常数等, 进而分别计算了它们的热力学函数. 因对应于不同的理论公式得出的K_A值并不完全相同, 由此得到它们相应的热力学参数也有所不同. 本文对这些热力学数据的差异进行了分析比较, 结果表明: 基于荧光加强理论公式(4)获得的热力学数据显示更为合理. 因而我们建议, 即使在研究受体-底物的荧光淬灭反应时, 采用荧光加强理论公式(4)可以获得更符合实际的结果.     

Quantitative determination of beta-ionone in red wines and grapes of Bordeaux using a stable isotope dilution assay.

Quantitative analysis of beta-ionone has been developed, using a stable isotope dilution assay. This was applied to red wines from different cultivars and regions. The Burgundy Pinot noir wines exhibited the highest levels of beta-ionone. The variation in the levels of beta-ionone in grape samples and in their corresponding wines, of Merlot, Cabernet Sauvignon and Cabernet franc from Bordeaux regions was monitored at four different stages towards the end of maturation: the levels of beta-ionone were almost similar, exhibiting only a slight decrease during maturation. beta-Ionone occurred in all the grapes and wines samples analysed at levels higher than, or close to its odour threshold which was determined in a model wine solution and was found to be of 90 ng l-1. In a previously supplemented model wine solution with beta-ionone (250 ng l-1), the odour threshold was found to be of 980 ng l-1 (total levels).     

Rapid dioxin assessment in fish products by fatty acid pattern recognition

A novel, cost- and time-effective dioxin screening method relying on fatty acid profile was developed for fish products. The method is based on multivariate covariance between fatty acid composition and dioxin. A dioxin range varying from 1.1 to 47.1 ng TEQ-WHO kg fat(-1) was investigated using 64 fish meal samples. An optimal multivariate dioxin prediction model was developed based on reduction from the original 32 to 13 fatty acids, thus increasing the parsimony and the robustness of the model. The model obtained with three partial least squares regression (PLS) components included the following 13 fatty acids: C14:1 n-5, C16:4 n-1, C18:1 n-9, C18:2 n-6, C18:3 n-6, C18:3 n-3, C20:0, C20:1 n-9, C20:4 n-6, C20:3 n-3, C22:1 n-7, C22:6 n-3, C24:1 n-9. Considering the whole investigated dioxin range, the performance of the PLS model based upon full cross-validation yielded a correlation of 0.90 (r(2)) and a prediction error of 3.31 ng PCDD/F TEQ-WHO kg fat(-1). A submodel of samples in the lower dioxin range 1 to 15 ng PCDD/F TEQ-WHO kg fat(-1) returned a r(2) of 0.88 and an error of 1.85 ng PCDD/F TEQ-WHO kg fat(-1).     

Determination of soluble and insoluble nickel compounds in airborne particulate matter by graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry

An extraction procedure for the determination of soluble and insoluble nickel and its compounds in ambient air dust was investigated employing a special device for the generation of test aerosols and using water-soluble NiCl2, partly water-soluble NiCO3 and water-insoluble NiO as model compounds. Additionally, results of the separation and determination of different nickel species down to some ng/m3 in ambient aerosols are discussed. The extraction was carried out with a solution containing 0.01 mol/L EDTA in order to determine partly water-soluble compounds such as NiCO3 and water-soluble, non-toxic nickel compounds in one step. Airborne dust was sampled on filters at locations close to two metallurgical plants in Northrhine-Westphalia (Germany), and first results on the nickel concentration (mean (median) values over a period of 4 months: 8.6+/-6.5 ng/m3 (6.7 ng/m3) and 27.7+/-36 ng/m3 (10.8 ng/m3), respectively) in the collected dust are presented. For EDTA-soluble nickel compounds the maximum and mean fractions of total nickel were found to be 77.1% and 18.6+/-12%, respectively.     

Preparation of PDMS-coated microspheres by sol-gel method for sorptive extraction of PAHs

In this paper, a novel SPME mode, PDMS-coated solid glass microspheres （SGMs）, were prepared by sol-gel method. Using homemade thermal desorption unit coupled with CGC-FID, six PAHs as model analytes, the performance of the new mode was characterized. The new extractive phase exhibited high thermal stability and satisfactory extraction capability. The detection limits were 0.01-0.045 ng/mL, and the linearity was from 0.5 ng/mL to 96 ng/mL. The R.S.D.s of repeatability for retention time and peak area were all within 0.074% and 6.7%, respectively. The recoveries of the PAHs were 78-127% from the samples taken from river water.     

固相萃取液相色谱-质谱/质谱联用测定河水中大环内酯类抗生素

应用固相萃取（SPE）及LC—MS／MS技术，建立了水中痕量大环内酯类抗生素即红霉素、脱水红霉素、罗红霉素的分析方法，优化了固相萃取、液相色谱-质谱／质谱等相关条件。水样经HLB固相萃取柱富集净化，以多反应检测方式（MRM）对待测物进行定性和定量分析。3种抗生素在10-2000ng／L范围内具有良好的线性。其定量下限为5ng／L（S／N〉10）。加标纯水和实际水样的回收率在71％-111％之间，相对标准偏差（RSD）在3．7％-8．6％之间。该方法灵敏度高、选择性好、准确度高，适合实际水样中痕量大环内酯类药物的检测。使用该方法测得珠江广州河段某水样中红霉素、脱水红霉素和罗红霉素质量浓度分别为164、291和134ng／L。     

A Highly-Sensitive Colorimetric Assay Method for Antibody Array Based on an Tyramide Signal Amplification System

In this work, a highly-sensitive and cost-effective detection approach based on the integration of tyramide signal amplification with a silver enhancement method (SEM-TSA) has been developed successfully. To demonstrate the feasibility of this approach, human IgG as a model target protein was employed and its concentration was assayed based on colorimetric detection. The analytical parameters including the concentrations of detection antibody, streptavidin-horseradish peroxidase, biotinyl tyramide, and streptavidin-nanogold were systematically optimized. The quantitative analysis was performed and a dynamic range was obtained from 0.18 ng/mL to 39.1 ng/mL, while no detectable images could be observed when the silver enhancement method (SEM) without TSA was used. The detection limits were 0.18 ng/mL and 21 ng/mL for SEM-TSA and SEM, respectively. The results showed that sensitivity of the presented colorimetric assay significantly increased by two-orders of magnitude. In addition, this method has been successfully applied in analyzing normal human serum samples. The results suggested the colorimetric detection method based on TSA-SEM has promising potential applications in biomedical analysis and clinical diagnosis.     

Development of multi‐response optimization and quadratic calibration curve for determination of ten pesticides in complex sample matrices using QuEChERS dispersive liquid–liquid microextraction followed by gas chromatography

In this study, QuEChERS combined with dispersive liquid‐liquid microextraction is developed for extraction of ten pesticides in complex sample matrices of water and milk. In this regard, effective factors of proposed extraction technique combined with gas chromatography with flame ionization detector were designed, modeled, and optimized using central composite design, multiple linear regression, and Nelder–Mead simplex optimization. Later, univariate calibration model for ten pesticides was developed in concentration range of 0.5–100 ng/mL. Surprisingly, quadratic calibration behavior was observed for some of the pesticides. In this regard, Mandel's test was used for evaluating linearity and types of calibration equation. Finally, four pesticides followed linear calibration curve with sensitivity (0.23–0.66 mL/ng), analytical sensitivity (0.20–0.32), regression coefficient (0.988–0.995), limit of detection (0.39–1.83 ng/mL), and limit of quantitation (1.30–6.10 ng/mL) and six of them followed quadratic calibration curve with sensitivity (0.18–0.93 mL/ng), analytical sensitivity (0.25–0.86), regression coefficient (0.944–0.999), limit of detection (0.59–1.92 ng/mL), and limit of quantitation (1.96–6.40 ng/mL). The calculated limits of detection were below the maximum residue limits according to European Union pesticides database of European Commission. Finally, the proposed analytical method was used for determination of ten pesticides in water and milk samples.     

Determination of gallium in biological fluids using inductively coupled plasma mass spectrometry

A procedure for the determination of gallium in biological fluids by inductively coupled plasma mass spectrometry was developed. The detection limits of gallium calculated from the 3s value were 60 ng/L for urine, 32 ng/L for a model solution of intestinal juice, and 50 ng/L for serum. The accuracy of the procedure was tested using a standard addition method. The nature of a background signal on the masses of gallium isotopes was studied with the use of a high-resolution mass spectrometer, and the background concentration of gallium in biological fluids was evaluated (5–7 ng/L). It was found that a background level in measurements performed on a quadrupole mass spectrometer depends on the interfering influence of polyatomic ions with close m/z ratios rather than on the background concentration of gallium. The procedure makes it possible to study the stability of pharmaceutical preparations based on gallium in biological media, their metabolism, and the excretion of preparations from the body.     

Comparison between charged aerosol detection and light scattering detection for the analysis of Leishmania membrane phospholipids

The performance of charged aerosol detection (CAD) was compared to evaporative light scattering detection (ELSD) for the analysis of Leishmania membrane phospholipid (PL) classes by NP-HPLC. In both methods, a PVA-Sil column was used for the determination of the major Leishmania membrane PLs, phosphatidic acid, phosphatidylglycerol, cardiolipin, phosphatidylinositol, phosphatidylethathanolamine, phosphatidylserine, lysophosphatidylethathanolamine, phosphatidylcholine, sphingomyelin and lysophosphatidylcholine in the same analysis. Although the response of both detection methods can be fitted to a power function, CAD response can also be described by a linear model with determination coefficients (R(2)) ranging from 0.993 to 0.998 for an injected mass of 30 ng to 20.00 microg. CAD appeared to be directly proportional when a restricted range was used and it was found to be more sensitive at lowest mass range than ELSD. With HPLC-ELSD the limits of detection (LODs) were between 71 and 1195 ng and the limits of quantification (LOQs) were between 215 and 3622 ng. With HPLC-CAD, the LODs were between 15 and 249 ng whereas the limits of quantification (LOQs) were between 45 and 707 ng. The accuracy of the methods ranged from 62.8 to 115.8% and from 58.4 to 110.5% for ELSD and CAD, respectively. The HPLC-CAD method is suitable to assess the influence of miltefosine on the composition of Leishmania membrane phospholipids.     

Determination of paeonol in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies following oral administration of Moutan cortex decoction

Quantification of paeonol, the principal bioactive component of Moutan cortex, in rat plasma following oral administration of Moutan cortex decoction was achieved by using a simple and sensitive high-performance liquid chromatographic method. The calibration curves for paeonol were linear in both the low (25-200 ng/mL) and the high concentration range (200-4000 ng/mL) with r(2) values of 0.9928 and 0.9993, respectively. The coefficients of variation of intra- and inter-day assays were 14.36, 6.52, 1.76, 1.25, 5.36, 3.30 and 1.42% and 12.70, 1.19, 2.98, 1.91, 1.75, 1.78 and 0.96% at concentrations of 25, 50, 100, 200, 500, 1000 and 2000 ng/mL, respectively. The recoveries of paeonol from rat plasma were found to be 101.9, 104.5, 105.4 and 101.2% for concentrations of 50, 500, 1000 and 2000 ng/mL, respectively. The paeonol plasma concentrations were fitted to two-compartment model with fi rst order absorption. The mean terminal half-lives (t(1/2)) of paeonol was 80.9 min.