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41.
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Two accurate, reliable, and highly sensitive spectrofluorimetric methods were developed for simultaneous determination of binary mixture gemfibrozil and rosiglitazone in human plasma without prior separation steps. The first method is based on synchronous fluorescence spectrometry using double scans. At Δλ = 27 nm, gemfibrozil yields detectable signal that is independent of the presence of rosiglitazone. Similarly, at Δλ = 120 nm the signal of rosiglitazone is not influenced by the presence of gemfibrozil. Signals at two wavelengths, 301 (Δλ = 27 nm) and 368 nm (Δλ = 120 nm) vary linearly with gemfibrozil and rosiglitazone concentrations over the range 100-700 ng mL−1 (for gemfibrozil) and 20-140 ng mL−1 (for rosiglitazone), respectively. The limits of detection (LOD) were 2.3 and 2.72 ng mL−1 for gemfibrozil and rosiglitazone, respectively. The second method is based on the technique of simultaneous equations (Vierodt's method), in which 258 nm was selected as the excitation wavelength. Two equations are constructed based on the fact that at (λEm2=302 nm of gemfibrozil) and (λEm2=369 nm of rosiglitazone) the fluorescence of the mixture is the sum of the individual fluorescence of gemfibrozil and rosiglitazone. The limits of detection (LOD) were 28.1 and 23.63 ng mL−1 for gemfibrozil and rosiglitazone, respectively. The proposed methods were successfully applied for the determination of the two compounds in synthetic mixtures and in human plasma with a good recovery. 相似文献
43.
A simple, rapid and sensitive synchronous fluorescence method is put forward for the determination of enrofloxacin (ENRO) in the pharmaceutical formulation and its residue in milk based on the yttrium (III)-perturbed luminescence. When Y3+ is added into the ENRO solution, the fluorescence of ENRO is significantly enhanced. The synchronous fluorescence technology is employed in the method to determine trace amount of ENRO residue in milks. The synchronous fluorescence intensity of the system is measured in a 1-cm quartz cell with excitation wavelength of 328 nm, Δλ = 80 nm. A good linear relationship between the fluorescence intensity and the ENRO concentration is obtained in the range of 1.0 × 10−9 to 2.0 × 10−6 mol L−1 (r2 = 0.9992). The limit of detection (LOD) of this method attains as low as 3.0 × 10−10 mol L−1 (S/N = 3). The selectivity of this method is also very good. Common metal ions, rare-earth ions and some pharmaceuticals, which are usually used together with ENRO, do not interfere with the determination of ENRO under the actual conditions. The proposed method can be applied to determine ENRO residue in milks, and limit of quantification (LOQ) determined in the spiked milk is estimated to be 2.8 × 10−8 mol L−1 (10 μg L−1). Moreover, this method can be used as a rapid screening for judging whether the ENRO residues in milks exceed Minimal Risk Levels (MRLs) or not. In addition, the mechanism of the fluorescence enhancement is also discussed in detail. 相似文献
44.
平行因子-同步荧光法测定食品中维生素B1,B2和B6 总被引:11,自引:5,他引:6
文章应用同步荧光法对维生素B1、B2和B6的混合物进行了分析。由于维生素B的荧光波谱存在重叠本工作采用三维同步荧光技术结合平行因子分析法(PARAFAC),对维生素B1,B2和B6混合物的三维荧光数据进行了测定和解析,并以高效液相色谱法(HPLC)作对照,获得了较好的结果。实验中取Ex=200~500nm和△λ=20~120nm。 相似文献
45.
46.
Michael Ph. Pyshnyi Svetlana V. Pyshnaya Galina S. Nechitailo Anatoly A. Kuznetsov 《Journal of magnetism and magnetic materials》2009,321(10):1552-1556
We considered applicability of acoustic imaging technology for the detection of magnetic microparticles and nanoparticles inside soft biological tissues. Such particles are widely used for magnetically targeted drug delivery and magnetic hyperthermia. We developed a new method of ultrasonic synchronous tissue Doppler imaging with magnetic modulation for in vitro and in vivo detection and visualization of magnetic ultradisperse objects in soft tissues. Prototype hardware with appropriate software was produced and the method was successfully tested on magnetic microparticles injected into an excised pig liver. 相似文献
47.
利用同步荧光光谱快速鉴别潲水油 总被引:2,自引:0,他引:2
为快速鉴别潲水油,采用三维同步荧光光谱结合平行因子法解析潲水油的特征波长差(Δλ),并利用支持向量机建立潲水油鉴别模型。结果表明,潲水油的特征Δλ为60 nm;特征Δλ下的样品原始同步荧光光谱经过主成分分析提取5个主成分,以径向基函数(RBF)为核函数,利用网格搜索和6-fold交叉验证优化建模参数,得到惩罚因子C=512、核参数g=0.5,该条件下建立的模型对训练集和预测集的判别率均达到100%。采用同步荧光光谱可以快速、准确地鉴别潲水油。 相似文献
48.
Paolo Pennacchi 《Nonlinear dynamics》2009,57(4):607-622
Electromechanical interaction in rotating machinery is an interesting nonlinear phenomenon. The methods used to analyze this
phenomenon depend on the type of the electrical machine, synchronous or asynchronous, and on its size, but they are often
related to the study of the unbalanced magnetic pull (UMP). In this paper the nonlinear behavior of generators with smooth
poles of high-speed turbogenerators is presented during and after the excitation of the magnetic field in the air-gap in order
to fully exploit the effect of the UMP. In the first part of the paper a method, which allows the simulation of the dynamical
behavior of a flexible rotor caused by the UMP, is presented. In the second part, the simulation of a magnetic field excitation
transient in a turbogenerator is presented and the nonlinear aspects in the system response and forcing are highlighted. 相似文献
49.
基于不同光谱技术的原油样品的荧光分析 总被引:9,自引:2,他引:7
应用同步扫描、三维发射以及目前石油荧光仪所采用的二维发射荧光分析技术对胜利油田15个井区25种原油样品在10-4 g·L-1~10 g·L-1浓度范围内进行了光谱采集,对比分析了不同光谱技术所获取的光谱信息与浓度之间的相应关系。结果表明,对于原油这种多组分样品,二维发射光谱难以满足分析要求;三维光谱信息丰富但数据采集与提取困难。同步扫描光谱具有简单快捷、光谱特征丰富明显、干扰小等特点,选择Δλ为40 nm获得的原油同步扫描光谱可反映三维光谱的主要信息。与二维发射光谱和三维光谱相比,同步荧光法在原油样品分析中显现出较大优势和发展空间,可望发展成为石油录井中对岩屑岩芯样品含油量的定量分析的新方法。 相似文献
50.
基于蛋白质对双嵌吲哚染料具有良好的荧光增强作用,以新型水溶性吲哚基同型二聚体探针I,建立了一种灵敏的蛋白质同步荧光分析体系。实验考察了吲哚探针的荧光特征、吲哚探针浓度、缓冲体系pH、盐浓度等参数对体系荧光的影响。在酸性条件下,蛋白质分子与探针I发生结合作用,同步荧光明显增强并向长波方向发生红移,且同步荧光强度与蛋白质浓度成良好的线性关系。在最优条件下,牛血清白蛋白BSA的线性响应范围5.00×10-7~2.50×10-5 g·mL-1,检测限(3σ/K)为3 ×10-8 g·mL-1;测定了血清蛋白BSA的合成样品,不同浓度BSA样品回收率为98.6%~103.0%,相对标准偏差1.1%~1.9%;与蛋白质紫外标准测定法比较,测定偏差为0.4%~3.9%。 相似文献