排序方式: 共有49条查询结果,搜索用时 484 毫秒
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Fast quantitative detection of cocaine in beverages using nanoextractive electrospray ionization tandem mass spectrometry 总被引:1,自引:0,他引:1
Bin Hu Xuejiao Peng Shuiping Yang Haiwei Gu Huanwen Chen Yanfu Huan Tingting Zhang Xiaolin Qiao 《Journal of the American Society for Mass Spectrometry》2010,21(2):290-293
Without any sample pretreatment, effervescent beverage fluids were manually sprayed into the primary ion plume created by
using a nanoelectrospray ionization source for direct ionization, and the analyte ions of interest were guided into an ion
trap mass spectrometer for tandem mass analysis. Functional ingredients (e.g., vitamins, taurine, and caffeine, etc.) and
spiked impurity (e.g., cocaine) in various beverages, such as Red Bull energy drink, Coco-cola, and Pepsi samples were rapidly
identified within 1.5 s. The limit of detection was found to be 7 ∼ 15 fg (S/N = 3) for cocaine in different samples using the characteristic fragment (m/z 150) observed in the MS3 experiments. Typical relative standard deviation and recovery of this method were 6.9% ∼ 8.6% and 104% ∼ 108% for direct
analysis of three actual samples, showing that nanoextractive electrospray ionization tandem mass spectrometry is a useful
technique for fast screening cocaine presence in beverages. 相似文献
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表面解吸常压化学电离质谱法直接分析牙齿微区表面 总被引:1,自引:0,他引:1
采用纳升取样表面解吸常压化学电离质谱法(nano-SDAPCI-MS)结合主成分分析(PCA),建立了一种采用具有微米级针尖的金属取样针直接对龋齿不同部位取样并进行快速质谱分析的方法.数据分析结果表明,同一颗龋齿不同部位的质谱指纹谱图之间存在差异;在不需要样品预处理的前提下通过串联质谱快速测定了龋齿中的乳酸、丙酮酸、苯乙酸和丙酸等成分.采用PCA方法可较好地将龋齿病灶位置与邻近正常组织进行区分,也可对不同牙病及健康牙齿进行区分.本方法可方便地对牙齿进行直接微区分析,为鉴别牙齿疾病及观测治疗效果提供了一种快速、简单的方法,为生物体中微细部位的快速取样及直接质谱分析提供了一种可能的解决方案. 相似文献
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Zhou Shuiping Zhou Xiaoyang Tang Gen Guo Xiang Pang Aimin 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2529-2540
Journal of Thermal Analysis and Calorimetry - Differences of thermal decomposition characteristics and combustion properties between CL-20-based propellants and HMX-based propellants were... 相似文献
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The electronic properties of fluorine-doped SnO2 films were calculated using the plane-wave-based pseudopotential method based on the density functional theory within the local density approximation. The calculated band structure and density of states show that the band gap of SnO2 narrows due to the presence of the F impurity energy levels in the bottom of the conduction band. The energy of the valence electrons is reduced as the optical absorption edge shifts towards a higher frequency. The charge density and effective masses of carriers of fluorine-doped SnO2 were also calculated. 相似文献
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A multichannel double-polarization bandpass optical filter, which has the performance of variable channel interval, is theoretically proposed. The filter consists of a stack of two one-dimensional photonic crystals (1D PCs). Based on the resonant couple of evanescent waves localized at the interfaces between neighboring layers, the linear transmission properties of the filter are numerically simulated by the transfer matrix method. The simulation results show that channel number of the filter can be changed by varying the thickness of the middle layer in the centrosymmetric 1D PC structure, while the bandwidth and wavelength of the channel can be adjusted by the incident angle of light. This work may be helpful in designing multichannel double-polarization bandpass optical filter in optical communication systems. 相似文献
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