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超高效液相色谱-串联质谱法测定壮阳类保健品中非法添加的5种5型磷酸二酯酶抑制剂杨坤,张建炀,石庆楠摘 要:称取经研磨后的样品0.500 0g,用甲醇超声溶解,并定容至50mL,以10 000r·min-1转速离心10 min,上清液经0.25μm滤膜过滤后,采用Waters Symmetry Shield RP色谱柱(100mm×2.1mm,5μm)分离5种5型磷酸二酯酶(PDE-5)抑制剂(西地那非,他达拉非,红地那非,伐地那非,伪伐地那非),以含0.1%(体积分数,下同)甲酸的甲醇和含0.1%甲酸的10mmol·L-1乙酸铵溶液为流动相,进行梯度洗脱.在电喷雾正离子模式下以多反应监测模式检测,采用外标法定量.结果表明,5种PDE-5药物的质量浓度在一定范围内与其峰面积呈线性关系,检出限(3S/N......
be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures......
in the target located at 0.16 mm from target–solder layer interface and at a distance of 0.78 mm from symmetry axis. The optimal design in target assembly has the combination of indium solder material......
was determined by ICP-AES.The experimental results indicate that heavy metal doping contributes to a higher symmetry of C3S except for Pb.Addition of up to 3.0wt%,Cr will lead to a decomposition of C3S into C2S......
of considerable size with the screw axis symmetry of 2π/4along the c-axis.Furthermore,it is found that during the process of diffusion the interstitially dissolved Cu(Ag) atoms would combine......
Young’s modulus in c direction. The maximum to minimum Young’s modulus ratio is 2.41 and 2.45 for YB2C2 with P42/mmc and P4/mbm symmetry, respectively. The most likely systems for shear sliding......
tunable topological properties. Due its symmetry topological protection essence,the structure investigation provides a solid basement for tuning its topological transport properties.On Sr TiO3(111......
Luminescent properties of YVO4·xTa2O5:Eu3+王忠志1,2,沈雷军1,2,李波1,2,高乐乐1,2,周永勃1,2,张国斌31. National Engineering Research Center of Rare Earth Metallurgy and Performance Meterials2. Baotou Research Institute of Rare Earths3. National Synchrotron Radiation Laboratory,University of Science and Technology of Ch......
compositions crystallized in rhombohedral symmetry of space group R3 c.The undoped sample consisted needle shape particles while rare earth substitution preferred platelet like particles as clarified from......
-orange emission in CIE. The 5D0→7F1 occupied a dominate position in hexagonal specimens, which indicated that more Eu3+ in the hexagonal structure were occupied inversion center of symmetry sites.