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941.
液相色谱-串联质谱法同时检测牛奶中20种苯二氮卓类药物残留 总被引:1,自引:0,他引:1
建立了牛奶中20种苯二氮卓类药物的液相色谱-串联质谱(LC-MS/MS)同时检测方法。在pH 5.2乙酸铵缓冲溶液中样品经酶解后,用饱和乙酸铅沉淀蛋白质,用氨水调节pH大于9.5。溶液经乙酸乙酯-异丙醇(5:1,V/V)提取,正己烷脱脂和离子交换柱(MCX)净化,采用多反应监测技术定性和同位素内标法定量。结果表明:20种苯二氮卓类药物在0.5~50μg/L范围内呈良好的线性,线性相关系数均大于0.9990,检测限(S/N≥3)为0.01~0.11μg/kg,定量限(S/N≥10)为0.04~0.37μg/kg。添加浓度水平为1.0,2.0和5.0μg/kg时,平均回收率为67.9%~108.1%,相对标准偏差(RSD)为1.7%~11%。 相似文献
942.
In this work, the extrusion process of a kind of π‐shape automobile rubber seal was considered using computer‐aided simulation technology. The extrusion flow was assumed to be isothermal and steady, and the finite element method was used to analyze the extrusion process. It was found that the velocity profile was quite uneven near the die exit when a straight die, developed strictly according to the desirable product dimension, was used and the local distortion of the extrudate was fairly prominent when compared with the die geometry. We adjusted the structure of the die and predicted the extrudate's swell by the computer simulation in advance. Simulation results confirmed that the distortion of the seal was greatly suppressed if a short enlarged inflow part was added to the upstream of the original straight die. Then, the extrusion experiment, using the newly designed die, was performed under practical conditions and the swell of the rubber seal was reduced to be within the range of acceptable tolerance. The profiles of the acceptable rubber seals were also well predicted by the computer simulation. Finally, the influences of the take‐up imposed on the end of extrudate and flow rate on the final seal shape were also investigated numerically. 相似文献
943.
Xie Jingzhe Li Shulei Yan Hongbin Xie Gongnan 《Journal of Thermal Analysis and Calorimetry》2020,141(1):387-399
Journal of Thermal Analysis and Calorimetry - The deeply precooled air-breathing technique is an effective approach to cool down the extreme hot incoming air for hypersonic engine. This paper... 相似文献
944.
945.
采用封闭酸溶电感耦合等离子体质谱(ICP-MS)法测定岩石样品,分别对47种元素的测量结果不确定度进行评定。通过分析测试方法和测量条件,得到测量结果的不确定度主要由样品称量、样品溶液定容和样品溶液中元素浓度测量引入。在实验室质控条件下,对各不确定度分量进行评定和计算,其中随机因素导致的不确定度采用期间精密度试验综合评价,即采用A类方法评定。共完成了16个岩石国家标准物质(GBW 07103~GBW 07123)47种元素测量结果的不确定度合成,并参照GB/T 6379.2-2004,建立了含量w与扩展不确定度U之间的关系模型,运用这一关系模型可得到测量结果的不确定度估计值,只要测量过程本身或所使用的设备未变化,就不需要再重复进行不确定度评估。 相似文献
946.
以铁基离子液体(Fe-IL) /聚乙二醇二甲醚(NHD)为脱硫体系, 通过静态吸收反应装置研究了共溶体系吸收氧化H2S的动力学过程. 结果表明, 纯Fe-IL脱硫体系的动力学方程可表示为r=54.62exp(-11720/RT)· ·cFe(Ⅲ), Fe-IL/NHD吸收氧化H2S属于快速拟一级反应, 复配NHD后, 对Fe(Ⅲ)的反应级数随NHD复配比的增大而增大, 提高温度和NHD的复配比可强化传质过程, 提高脱硫过程的反应速率. 相似文献
947.
设计合成了基于萘酰亚胺-咪唑鎓的受体分子1和2,通过荧光发射光谱研究了受体分子1和2对阴离子F-、Cl-、Br-、I-、AcO-、HSO-4、H2PO-4、NO-3、ClO-4的识别性能。 研究发现,在受体分子1和2的乙腈溶液(5.0×10-6 mol/L)中加入10倍化学计量的H2PO-4时,受体分子1的荧光猝灭率高达98%,受体分子2的荧光猝灭率仅为24%。 表明具有多重识别位点的受体分子1在构型上与H2PO-4更匹配,可作为H2PO-4的荧光关闭型(turn-off)探针。 受体分子1与H2PO-4的结合比为1∶1,结合常数为(1.25±0.11)×105 L/mol,检出限为6.90×10-6 mol/L。 相似文献
948.
Hongbin Song Guowei Zhou Chunfeng Wang Xiaojie Jiang Cuicui Wu Tianduo Li 《Research on Chemical Intermediates》2013,39(2):747-758
Nitrogen-modified cobalt-doped TiO2 materials were successfully prepared via a modified sol–gel method. The structure and properties of the catalysts were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM, ultraviolet–visible light diffuse reflectance spectra (UV–Vis DRS), N2 adsorption–desorption isotherms, and energy-dispersive X-ray spectroscopy. The XRD patterns of the pure and co-doped TiO2 samples indicate that the predominant phase was anatase. The average grain size obtained from TEM was approximately 10 nm. The Brunauer–Emmett–Teller analysis results indicate that the specific surface area was 77.7 m2 g?1. The UV–Vis DRS results for the co-doped sample reveal an absorption edge that had been red-shifted to 500 nm. The photocatalytic activities of the samples were evaluated through photodegradation of papermaking wastewater under UV and visible light irradiation. Compared with the cobalt-doped TiO2 sample and Degussa P25, the 3 mol% N-doped mesoporous N/Co-TiO2 photocatalyst exhibited the highest photocatalytic activity, which can be ascribed to the synergistic effect of the N and Co co-doping. 相似文献
949.
This note provides the some sum formulas for generalized Fibonacci numbers. The results are proved using clever rearrangements, rather than using induction. 相似文献
950.
IntroductionFluorescent probe labeling 1, 2, microchip and LB (Langmuir-Blodgett) films of DNA and proteins3 are important in molecular electronic and biotechnological applications such as information processing and molecular recognition. As an imitated and simplified model of above complex cases, here we prepare the LB films of dansyl chloride (5-dimethylaminonaphthalene-1-sulfonyl chloride, denoted as DNS) labeled octadecyl amine (AM). A molecule based naphthalene sulfonate is well kno… 相似文献