Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only...Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only molecular ions are measured by virtue of nearthreshold photoionization. While increasing photon energy to 11.7 eV or more, four distinct fragment ions are obtained for tyramine and dopamine, respectively. Besides, the ionization energies of tyramine and dopamine are determined to be 7.984-0.05 and 7.674-0.05 eV by measuring the photoionization efficiency curves of corresponding molecular ions. With help of density function theory calculations, the detailed fragmentation pathways are established as well. These two molecular cations have similar aminoethyl group elimination pathways, CTHsO2＋ （m/z=124） and C7H8O＋ （m/z=108） are supposed to be generated by the McLafferty rearrangement via γ-hydrogen （7-H） shift inducing β-fission. And CH2NH2＋ is proposed to derive from the direct fission of C7-C8 bond. Besides, the McLafferty rearrangement and the C7-C8 bond fission are validated to be dominant dissociation pathways for tyramine and dopamine cations.展开更多
The objective of this review is the determination of tyramine in 13 nonalcoholic beers (Maoshaieer) of Tehran market and survey of it’s probably interaction with monoamine oxidase inhibitor drugs (MAOIs) has been inv...The objective of this review is the determination of tyramine in 13 nonalcoholic beers (Maoshaieer) of Tehran market and survey of it’s probably interaction with monoamine oxidase inhibitor drugs (MAOIs) has been investigated. Tyramine was at the highest levels in Baltika (111.34 ± 8.19 μg/ml) and at the lowest level in Bitmalt (8.01 ± 2.09 μg/ml). Comparing different flavors of malt drinks, the highest tyramine content was shown for classic or normal flavor (average 72.99 ± 30.87 μg/ml), while the lowest value belonged to cantaloupe flavored drinks (average 10.55 ± 1.29 μg/ml). In our study, it is seen that there is a significant difference between import and Iranian non-alcoholic beers, the import ones has more tyramine than Iranians. A number of 10 kinds of 13 samples interact whit MAOIs in one serving (250 ml) usage 18.50 mg. The highest tyramine content of Iranian ones is 17.74 mg/250ml and for import ones is 27.83 mg/250ml.展开更多
目的建立测定鱼露中章鱼胺含量的高效液相色谱学方法。方法采用phenomenex luna C18柱,以0.02mol.L-1柠檬酸-0.02mol.L-1磷酸二氢钠(7:3)为流动相,检测波长λ=274nm。结果章鱼胺在0.0057～50μg.mL-1范围内,浓度与峰面积线性关系良好(r=...目的建立测定鱼露中章鱼胺含量的高效液相色谱学方法。方法采用phenomenex luna C18柱,以0.02mol.L-1柠檬酸-0.02mol.L-1磷酸二氢钠(7:3)为流动相,检测波长λ=274nm。结果章鱼胺在0.0057～50μg.mL-1范围内,浓度与峰面积线性关系良好(r=0.9991),平均加样回收率为104.4%,RSD为1.53%。最低检出浓度为5.7ng.mL-1。结论本法操作简便,结果可靠,可用于鱼露中章鱼胺及相关物质含量的测定,鳀鱼鱼露含章鱼胺1055μg.mL-1。展开更多
基金Authors thank Dr. Yang Pan for useful discussions This work was supported by the National Natural Science Foundation of China （No.10805047）.
文摘Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only molecular ions are measured by virtue of nearthreshold photoionization. While increasing photon energy to 11.7 eV or more, four distinct fragment ions are obtained for tyramine and dopamine, respectively. Besides, the ionization energies of tyramine and dopamine are determined to be 7.984-0.05 and 7.674-0.05 eV by measuring the photoionization efficiency curves of corresponding molecular ions. With help of density function theory calculations, the detailed fragmentation pathways are established as well. These two molecular cations have similar aminoethyl group elimination pathways, CTHsO2＋ （m/z=124） and C7H8O＋ （m/z=108） are supposed to be generated by the McLafferty rearrangement via γ-hydrogen （7-H） shift inducing β-fission. And CH2NH2＋ is proposed to derive from the direct fission of C7-C8 bond. Besides, the McLafferty rearrangement and the C7-C8 bond fission are validated to be dominant dissociation pathways for tyramine and dopamine cations.
文摘The objective of this review is the determination of tyramine in 13 nonalcoholic beers (Maoshaieer) of Tehran market and survey of it’s probably interaction with monoamine oxidase inhibitor drugs (MAOIs) has been investigated. Tyramine was at the highest levels in Baltika (111.34 ± 8.19 μg/ml) and at the lowest level in Bitmalt (8.01 ± 2.09 μg/ml). Comparing different flavors of malt drinks, the highest tyramine content was shown for classic or normal flavor (average 72.99 ± 30.87 μg/ml), while the lowest value belonged to cantaloupe flavored drinks (average 10.55 ± 1.29 μg/ml). In our study, it is seen that there is a significant difference between import and Iranian non-alcoholic beers, the import ones has more tyramine than Iranians. A number of 10 kinds of 13 samples interact whit MAOIs in one serving (250 ml) usage 18.50 mg. The highest tyramine content of Iranian ones is 17.74 mg/250ml and for import ones is 27.83 mg/250ml.
文摘目的建立测定鱼露中章鱼胺含量的高效液相色谱学方法。方法采用phenomenex luna C18柱,以0.02mol.L-1柠檬酸-0.02mol.L-1磷酸二氢钠(7:3)为流动相,检测波长λ=274nm。结果章鱼胺在0.0057～50μg.mL-1范围内,浓度与峰面积线性关系良好(r=0.9991),平均加样回收率为104.4%,RSD为1.53%。最低检出浓度为5.7ng.mL-1。结论本法操作简便,结果可靠,可用于鱼露中章鱼胺及相关物质含量的测定,鳀鱼鱼露含章鱼胺1055μg.mL-1。
